Thesis for doctoral degree (Ph.D.)
2017
Hatha yogic exercises for physical function in
healthy individuals and patients with obstructive
respiratory disorders
Hatha yogic exercises for physical function in healthy individuals and patients
with obstructive respiratory disorders
Marian E Papp
Marian E Papp
Department of Neurobiology, Care Sciences and Society
Division of Family medicine
Karolinska Institutet, Stockholm, Sweden
Department of Neurobiology, Care Sciences and Society
Division of Family medicine
Karolinska Institutet, Stockholm, Sweden
Hatha yogic exercises for physical
function in healthy individuals and
patients with obstructive respiratory
disorders
Hatha yogic exercises for physical
function in healthy individuals and
patients with obstructive respiratory
disorders
Marian E Papp, MSc
Marian E Papp, MSc
Stockholm 2017
Stockholm 2017
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All previously published papers have been reproduced with permission from the publisher
All previously published papers have been reproduced with permission from the publisher
Published by Karolinska Institutet
Published by Karolinska Institutet
Printed by E-print AB 2017
Printed by E-print AB 2017
Illustrations by Pollyanna Von Knorring, photos by Marian Papp
Illustrations by Pollyanna Von Knorring, photos by Marian Papp
© Copyright Marian Papp, 2017
© Copyright Marian Papp, 2017
ISBN nr: 978-91-7676-517-3
ISBN nr: 978-91-7676-517-3
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Department of Neurobiology, Care Sciences and Society, Division of Family medicine
Department of Neurobiology, Care Sciences and Society, Division of Family medicine
Karolinska Institutet, Stockholm, Sweden
Karolinska Institutet, Stockholm, Sweden
Hatha yogic exercises for physical function in healthy
individuals and patients with obstructive respiratory
disorders
Hatha yogic exercises for physical function in healthy
individuals and patients with obstructive respiratory
disorders
Marian E Papp, MSc
Principal supervisor:
Professor Per Wändell
Karolinska Institutet
Department of Neurobiology, Care
Sciences and Society
Division of Family Medicine
Opponent:
MD PhD Lars Jerdén
Uppsala University and Dalarna
University
Center for Clinical Research Dalarna
Examination board:
Associate Professor Liselotte SchäferElinder
Karolinska Institutet
Department of Public Health Sciences
Social Medicine
Co-supervisors:
Professor Petra Lindfors
Stockholm University
Department of Psychology
PhD Malin Nygren-Bonnier
Karolinska Institutet
Department of Neurobiology, Care
Sciences and Society,
Division of Physiotherapy
Associate Professor Karin Wadell
Umeå University
Department of Community Medicine and
Rehabilitation
Unit of Physiotherapy
PhD Lennart Gullstrand
Gothenburg University
Department of Food and Nutrition and
Sport Medicine
Associate Professor Malin André
Uppsala University
Department of Public Health and Caring
Sciences
Family Medicine and Preventive
Medicine
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Marian E Papp, MSc
Principal supervisor:
Professor Per Wändell
Karolinska Institutet
Department of Neurobiology, Care
Sciences and Society
Division of Family Medicine
Opponent:
MD PhD Lars Jerdén
Uppsala University and Dalarna
University
Center for Clinical Research Dalarna
Examination board:
Associate Professor Liselotte SchäferElinder
Karolinska Institutet
Department of Public Health Sciences
Social Medicine
Co-supervisors:
Professor Petra Lindfors
Stockholm University
Department of Psychology
PhD Malin Nygren-Bonnier
Karolinska Institutet
Department of Neurobiology, Care
Sciences and Society,
Division of Physiotherapy
Associate Professor Karin Wadell
Umeå University
Department of Community Medicine and
Rehabilitation
Unit of Physiotherapy
PhD Lennart Gullstrand
Gothenburg University
Department of Food and Nutrition and
Sport Medicine
Associate Professor Malin André
Uppsala University
Department of Public Health and Caring
Sciences
Family Medicine and Preventive
Medicine
3
ABSTRACT
ABSTRACT
Background and aim: The use of hatha yogic exercises (YE) is increasing, with both healthy
individuals and patients asking for alternative treatments and other means of prevention and exercise.
To investigate the physical effects and experiences of practicing YE among different groups thus seem
important. Specifically, this thesis aimed to investigate heart rate variability, blood pressure,
cardiovascular fitness and blood parameters using different YE programs for healthy populations.
Another aim was to investigate walking distance, breathlessness, lung function and health related
quality of life in participants with obstructive pulmonary disease.
Background and aim: The use of hatha yogic exercises (YE) is increasing, with both healthy
individuals and patients asking for alternative treatments and other means of prevention and exercise.
To investigate the physical effects and experiences of practicing YE among different groups thus seem
important. Specifically, this thesis aimed to investigate heart rate variability, blood pressure,
cardiovascular fitness and blood parameters using different YE programs for healthy populations.
Another aim was to investigate walking distance, breathlessness, lung function and health related
quality of life in participants with obstructive pulmonary disease.
Participants and methods: Study I was a pilot study without a control group investigating the effects
of practicing yogic inversions among 12 naïve, untrained and healthy persons (median age 51, 4
women and 8 men) while measuring cardiovascular health as heart rate variability, hand-grip strength
and blood pressure. Study II used an RCT design and investigated the effects of practicing high
intensity sun salutations among 44 healthy students (median age 25, 38 women and 6 men) while
measuring cardiovascular fitness and blood parameters as apolipoproteins, adiponectin, leptin and
glycosylated haemoglobin. Study III used an RCT design and investigated the effects of practicing an
adapted YE program compared to a treatment as usual group (CTP) among 36 individuals with
obstructive pulmonary disease (median age 64, 23 women and 13 men) while measuring six minute
walk distance, dyspnea, lung function and disease specific quality of life. Study IV used a qualitative
approach to investigate the experiences after YE (used in Study III) among 15 persons with
obstructive pulmonary disease (median age 61, 10 women and 5 men).
Participants and methods: Study I was a pilot study without a control group investigating the effects
of practicing yogic inversions among 12 naïve, untrained and healthy persons (median age 51, 4
women and 8 men) while measuring cardiovascular health as heart rate variability, hand-grip strength
and blood pressure. Study II used an RCT design and investigated the effects of practicing high
intensity sun salutations among 44 healthy students (median age 25, 38 women and 6 men) while
measuring cardiovascular fitness and blood parameters as apolipoproteins, adiponectin, leptin and
glycosylated haemoglobin. Study III used an RCT design and investigated the effects of practicing an
adapted YE program compared to a treatment as usual group (CTP) among 36 individuals with
obstructive pulmonary disease (median age 64, 23 women and 13 men) while measuring six minute
walk distance, dyspnea, lung function and disease specific quality of life. Study IV used a qualitative
approach to investigate the experiences after YE (used in Study III) among 15 persons with
obstructive pulmonary disease (median age 61, 10 women and 5 men).
Results: Study I showed increased heart rate variability with a significant increase in pNN50% (ES
0.45) and hand-grip strength but no effect on blood pressure. Study II showed no between-group effect
and no effect on cardiovascular fitness. However, within the YE-group 35-40 minutes of high intensity
sun salutation had an effect on the blood parameters as adiponectin and apoplipoproteinA1. Study III
found no significant between-group effect using t-tests in any parameter after the intervention.
Analysis of variance differences emerged in CRQ fatigue and emotional domains favouring the
treatment as usual group (CTP). Improved six-minute walk distance in the YE-group and CTP-group
emerged after 12 weeks with no between-group effects. Disease specific quality of life measuring
(CRQ) showed improvement in the mastery domain in YE and in all domains in the CTP-group. The
YE-group showed lower respiratory rates, the CTP-group did not. Lung function and respiratory
muscle strength did not improve in YE but did in the CTP-group. Dyspnea related distress did not
improve in any group. Study IV found that the power of practicing (learning by doing) seemed central
to the facilitation of self-awareness, controlling symptoms, dyspnea and permitted discovery of new
ways of breathing.
Results: Study I showed increased heart rate variability with a significant increase in pNN50% (ES
0.45) and hand-grip strength but no effect on blood pressure. Study II showed no between-group effect
and no effect on cardiovascular fitness. However, within the YE-group 35-40 minutes of high intensity
sun salutation had an effect on the blood parameters as adiponectin and apoplipoproteinA1. Study III
found no significant between-group effect using t-tests in any parameter after the intervention.
Analysis of variance differences emerged in CRQ fatigue and emotional domains favouring the
treatment as usual group (CTP). Improved six-minute walk distance in the YE-group and CTP-group
emerged after 12 weeks with no between-group effects. Disease specific quality of life measuring
(CRQ) showed improvement in the mastery domain in YE and in all domains in the CTP-group. The
YE-group showed lower respiratory rates, the CTP-group did not. Lung function and respiratory
muscle strength did not improve in YE but did in the CTP-group. Dyspnea related distress did not
improve in any group. Study IV found that the power of practicing (learning by doing) seemed central
to the facilitation of self-awareness, controlling symptoms, dyspnea and permitted discovery of new
ways of breathing.
Conclusions: The main findings following the evaluation of different yogic programs in Studies I-III
showed that the programs were feasible and safe with no documented adverse effects. Study I was a
pilot study calling for caution when interpreting the results. However, there still emerged significantly
increased heart rate variability and hand-grip strength. In Study II no significant effect emerged
between the groups. However, the yogic exercise group (YE) showed increased levels of
apolipoproteinA1 and adiponectin following YE intervention. Study III demonstrated improvement in
all CRQ-domains in the CTP-group and in the mastery domain in the YE-group following a 12 week
intervention. Taken together, the study resulted in significant improvements in walking distance in
both groups following the 12 weeks. In the YE-group, lowered respiratory rate, improved mastery of
the disease and increased oxygen saturation also emerged after the intervention. Study IV found that
practicing YE can be a method used to empower individuals with obstructive pulmonary disorders and
to help control symptoms and dyspnea. Yogic practice can serve as an efficient tool for learning new
ways of breathing as well as strengthening one’s self-efficacy and mastery of the disease.
Conclusions: The main findings following the evaluation of different yogic programs in Studies I-III
showed that the programs were feasible and safe with no documented adverse effects. Study I was a
pilot study calling for caution when interpreting the results. However, there still emerged significantly
increased heart rate variability and hand-grip strength. In Study II no significant effect emerged
between the groups. However, the yogic exercise group (YE) showed increased levels of
apolipoproteinA1 and adiponectin following YE intervention. Study III demonstrated improvement in
all CRQ-domains in the CTP-group and in the mastery domain in the YE-group following a 12 week
intervention. Taken together, the study resulted in significant improvements in walking distance in
both groups following the 12 weeks. In the YE-group, lowered respiratory rate, improved mastery of
the disease and increased oxygen saturation also emerged after the intervention. Study IV found that
practicing YE can be a method used to empower individuals with obstructive pulmonary disorders and
to help control symptoms and dyspnea. Yogic practice can serve as an efficient tool for learning new
ways of breathing as well as strengthening one’s self-efficacy and mastery of the disease.
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To all those who want to immerse themselves in the yogic experience
To all those who want to immerse themselves in the yogic experience
“In the end.. it’s not going to matter how many breaths you took
But how many moments took your breath away” - Shing Xiong
“In the end.. it’s not going to matter how many breaths you took
But how many moments took your breath away” - Shing Xiong
“Do your practise and all is coming” – Patthabi Jois
“Do your practise and all is coming” – Patthabi Jois
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LIST OF SCIENTIFIC PAPERS
LIST OF SCIENTIFIC PAPERS
The thesis is based on the following original papers. Each paper will be referred to by its Roman
numeral (Study I-IV)
The thesis is based on the following original papers. Each paper will be referred to by its Roman
numeral (Study I-IV)
I
Marian Papp, Petra Lindfors, Niklas Storck, Per Wändell, Increased heart rate
variability but no effect on blood pressure from 8 weeks of hatha yoga – a pilot study,
BMC Research Notes 2013 6:59
I
Marian Papp, Petra Lindfors, Niklas Storck, Per Wändell, Increased heart rate
variability but no effect on blood pressure from 8 weeks of hatha yoga – a pilot study,
BMC Research Notes 2013 6:59
II
Marian Papp, Petra Lindfors, Malin Nygren-Bonnier, Lennart Gullstrand, Per Wändell,
Effects of High-Intensity Hatha Yoga on Cardiovascular Fitness, Adipocytokines, and
Apolipoproteins in Healthy Students: A Randomized Controlled Study, The Journal of
Alternative and Complementary Medicine, 2016, 22(1): 81-87
II
Marian Papp, Petra Lindfors, Malin Nygren-Bonnier, Lennart Gullstrand, Per Wändell,
Effects of High-Intensity Hatha Yoga on Cardiovascular Fitness, Adipocytokines, and
Apolipoproteins in Healthy Students: A Randomized Controlled Study, The Journal of
Alternative and Complementary Medicine, 2016, 22(1): 81-87
III
Marian Papp, Petra Lindfors, Per E Wändell, Malin Nygren-Bonnier, Effects of yogic
exercises on functional capacity, lung function and quality of life in subjects with
obstructive pulmonary disease – A Randomized Controlled Study, Eur J Phys Rehabil
Med. 2016 Nov 10. [Epub ahead of print], PMID: 27830924
III
Marian Papp, Petra Lindfors, Per E Wändell, Malin Nygren-Bonnier, Effects of yogic
exercises on functional capacity, lung function and quality of life in subjects with
obstructive pulmonary disease – A Randomized Controlled Study, Eur J Phys Rehabil
Med. 2016 Nov 10. [Epub ahead of print], PMID: 27830924
IV
Marian Papp; Maria Henriques; Gabriele Biguet; Per E Wändell; Malin NygrenBonnier, Experiences of hatha yogic exercises among patients with obstructive
pulmonary disease-a qualitative study, Submitted
IV
Marian Papp; Maria Henriques; Gabriele Biguet; Per E Wändell; Malin NygrenBonnier, Experiences of hatha yogic exercises among patients with obstructive
pulmonary disease-a qualitative study, Submitted
All reprints have been made by permission of BMC Research Notes, The Journal of Alternative and
Complementary Medicine and European Journal of Physical and Rehabilitation Medicine (open
access).
All reprints have been made by permission of BMC Research Notes, The Journal of Alternative and
Complementary Medicine and European Journal of Physical and Rehabilitation Medicine (open
access).
Study IV. May change prior to final publication
Study IV. May change prior to final publication
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CONTENTS
CONTENTS
1 Introduction ........................................................................................................................................ 13
1 Introduction ........................................................................................................................................ 13
1.1 Health .......................................................................................................................................... 13
1.1 Health .......................................................................................................................................... 13
1.2 Definitions of physical function and physical activity ................................................................. 13
1.2 Definitions of physical function and physical activity ................................................................. 13
1.3 Health benefits of physical activity for adults ............................................................................. 14
1.3 Health benefits of physical activity for adults ............................................................................. 14
1.4 Using hatha yogic exercises as physical activity .......................................................................... 14
1.4 Using hatha yogic exercises as physical activity .......................................................................... 14
1.5 Current recommendations for multifaceted physical activity that includes YE .......................... 15
1.5 Current recommendations for multifaceted physical activity that includes YE .......................... 15
1.6 Hatha yoga - traditional view and philosophy............................................................................. 16
1.6 Hatha yoga - traditional view and philosophy............................................................................. 16
1.7 General research on yogic exercises for disease prevention and comparison with usual care .. 17
1.7 General research on yogic exercises for disease prevention and comparison with usual care .. 17
1.8 Physical activity for disease prevention ...................................................................................... 18
1.8 Physical activity for disease prevention ...................................................................................... 18
1.8.1 Physical activity and rehabilitation for obstructive pulmonary disease patients ................ 18
1.8.1 Physical activity and rehabilitation for obstructive pulmonary disease patients ................ 18
1.9 Yogic exercises for cardiovascular health.................................................................................... 20
1.9 Yogic exercises for cardiovascular health.................................................................................... 20
1.10 Yogic exercises for physical/cardiorespiratory fitness .............................................................. 20
1.10 Yogic exercises for physical/cardiorespiratory fitness .............................................................. 20
1.11 Yogic exercises for obstructive pulmonary diseases ................................................................. 21
1.11 Yogic exercises for obstructive pulmonary diseases ................................................................. 21
1.12 Yoga for dysfunctional breathing .............................................................................................. 21
1.12 Yoga for dysfunctional breathing .............................................................................................. 21
1.13 Yogic exercises for blood parameters ....................................................................................... 23
1.13 Yogic exercises for blood parameters ....................................................................................... 23
1.14 Other benefits of yogic exercises .............................................................................................. 23
1.14 Other benefits of yogic exercises .............................................................................................. 23
1.15 Adverse effects and injuries related to yogic exercises ............................................................ 24
1.15 Adverse effects and injuries related to yogic exercises ............................................................ 24
1.16 The mechanisms of hatha yoga ................................................................................................. 24
1.16 The mechanisms of hatha yoga ................................................................................................. 24
2 Rationale for the thesis ...................................................................................................................... 26
2 Rationale for the thesis ...................................................................................................................... 26
3 Aim...................................................................................................................................................... 27
3 Aim...................................................................................................................................................... 27
4 Material and methods ........................................................................................................................ 28
4 Material and methods ........................................................................................................................ 28
4.1 Study design and analysis ............................................................................................................ 28
4.1 Study design and analysis ............................................................................................................ 28
4.2 Study population ......................................................................................................................... 28
4.2 Study population ......................................................................................................................... 28
4.2.1 Inclusion and exclusion criteria ............................................................................................ 28
4.2.1 Inclusion and exclusion criteria ............................................................................................ 28
4.2.2 Participant flow .................................................................................................................... 29
4.2.2 Participant flow .................................................................................................................... 29
4.3 Intervention, measurements and procedure .............................................................................. 29
4.3 Intervention, measurements and procedure .............................................................................. 29
4.3.1 Data collection and intervention location ............................................................................ 29
4.3.1 Data collection and intervention location ............................................................................ 29
4.3.2 Instructions to participants .................................................................................................. 29
4.3.2 Instructions to participants .................................................................................................. 29
4.3.3 Interventions Study I-IV ........................................................................................................ 29
4.3.3 Interventions Study I-IV ........................................................................................................ 29
4.3.4 Measurements and test leaders........................................................................................... 31
4.3.4 Measurements and test leaders........................................................................................... 31
4.3.5 Heart rate variability and heart rate .................................................................................... 31
4.3.5 Heart rate variability and heart rate .................................................................................... 31
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4.3.6 Respiratory rate .................................................................................................................... 32
4.3.6 Respiratory rate .................................................................................................................... 32
4.3.7 Oxygen saturation ................................................................................................................ 32
4.3.7 Oxygen saturation ................................................................................................................ 32
4.3.8 Respiratory muscle strength ................................................................................................ 32
4.3.8 Respiratory muscle strength ................................................................................................ 32
4.3.9 Lung function ........................................................................................................................ 32
4.3.9 Lung function ........................................................................................................................ 32
4.3.10 Cardiovascular performance monitoring/oxygen uptake (VO2max ) .................................... 32
4.3.10 Cardiovascular performance monitoring/oxygen uptake (VO2max ) .................................... 32
4.3.11 Rating of perceived exertion, RPE ...................................................................................... 33
4.3.11 Rating of perceived exertion, RPE ...................................................................................... 33
4.3.12 Blood pressure.................................................................................................................... 33
4.3.12 Blood pressure.................................................................................................................... 33
4.3.13 Hand-grip strength ............................................................................................................. 33
4.3.13 Hand-grip strength ............................................................................................................. 33
4.3.14 Apolipoproteins .................................................................................................................. 33
4.3.14 Apolipoproteins .................................................................................................................. 33
4.3.15 Adiponectin/Leptin............................................................................................................. 33
4.3.15 Adiponectin/Leptin............................................................................................................. 33
4.3.16 Glycosylated haemoglobin (HbA1c) ................................................................................... 33
4.3.16 Glycosylated haemoglobin (HbA1c) ................................................................................... 33
4.3.17 Waist circumference .......................................................................................................... 33
4.3.17 Waist circumference .......................................................................................................... 33
4.3.18 Physical capacity, six-minute walk distance test (6MWD) ................................................. 34
4.3.18 Physical capacity, six-minute walk distance test (6MWD) ................................................. 34
4.3.19 Dyspnea related distress .................................................................................................... 34
4.3.19 Dyspnea related distress .................................................................................................... 34
4.3.20 Chronic respiratory disease questionnaire (CRQ), health related quality of life ............... 34
4.3.20 Chronic respiratory disease questionnaire (CRQ), health related quality of life ............... 34
4.3.21 Self-reported health ........................................................................................................... 34
4.3.21 Self-reported health ........................................................................................................... 34
4.3.22 Qualitative content approach ............................................................................................ 34
4.3.22 Qualitative content approach ............................................................................................ 34
4.3.22.1 Qualitative content data collection procedures.............................................................. 34
4.3.22.1 Qualitative content data collection procedures.............................................................. 34
4.3.22.2 Qualitative content analysis ............................................................................................ 34
4.3.22.2 Qualitative content analysis ............................................................................................ 34
4.4 Statistical analyses....................................................................................................................... 36
4.4 Statistical analyses....................................................................................................................... 36
4.5 Ethical considerations ................................................................................................................. 36
4.5 Ethical considerations ................................................................................................................. 36
5 RESULTS .............................................................................................................................................. 37
5 RESULTS .............................................................................................................................................. 37
5.1 Heart rate variability.................................................................................................................... 38
5.1 Heart rate variability.................................................................................................................... 38
5.2 Respiratory rate and oxygen saturation ...................................................................................... 38
5.2 Respiratory rate and oxygen saturation ...................................................................................... 38
5.3 Respiratory muscle strength ....................................................................................................... 39
5.3 Respiratory muscle strength ....................................................................................................... 39
5.4 Lung function ............................................................................................................................... 39
5.4 Lung function ............................................................................................................................... 39
5.5 FEV1/FVC ratio ............................................................................................................................. 40
5.5 FEV1/FVC ratio ............................................................................................................................. 40
5.6 Cardiovascular performance, VO2max .......................................................................................... 40
5.6 Cardiovascular performance, VO2max .......................................................................................... 40
5.7 Rating of perceived exertion, RPE (Borg) .................................................................................... 41
5.7 Rating of perceived exertion, RPE (Borg) .................................................................................... 41
5.8 Blood pressure (BP) ..................................................................................................................... 42
5.8 Blood pressure (BP) ..................................................................................................................... 42
5.9 Hand-grip strength ...................................................................................................................... 43
5.9 Hand-grip strength ...................................................................................................................... 43
5.10 Blood parameters – adiponectin, leptin and apolipoproteins .................................................. 43
5.10 Blood parameters – adiponectin, leptin and apolipoproteins .................................................. 43
5.11 Glycosylated haemoglobin (HbA1c) .......................................................................................... 44
5.11 Glycosylated haemoglobin (HbA1c) .......................................................................................... 44
5.12 Physical capacity, six minute walk distance (6MWD)................................................................ 45
5.12 Physical capacity, six minute walk distance (6MWD)................................................................ 45
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5.13 Dyspnea related distress (DD-index) ......................................................................................... 46
5.13 Dyspnea related distress (DD-index) ......................................................................................... 46
5.14 Self-reported health .................................................................................................................. 46
5.14 Self-reported health .................................................................................................................. 46
5.15 Disease specific chronic respiratory disease questionnaire (CRQ) -quality of life .................... 47
5.15 Disease specific chronic respiratory disease questionnaire (CRQ) -quality of life .................... 47
5.16 Correlation between six-minute walk test and self-reported health........................................ 48
5.16 Correlation between six-minute walk test and self-reported health........................................ 48
5.17 Qualitative content analysis ...................................................................................................... 49
5.17 Qualitative content analysis ...................................................................................................... 49
6 Discussion ........................................................................................................................................... 51
6 Discussion ........................................................................................................................................... 51
6.1 Heart rate variability (HRV) in relation to body position and respiration ................................... 51
6.1 Heart rate variability (HRV) in relation to body position and respiration ................................... 51
6.2 Respiratory parameters............................................................................................................... 53
6.2 Respiratory parameters............................................................................................................... 53
6.3 Heart rate (HR) ............................................................................................................................ 54
6.3 Heart rate (HR) ............................................................................................................................ 54
6.4 Cardiorespiratory fitness, maximal oxygen consumption (VO2max) ............................................. 54
6.4 Cardiorespiratory fitness, maximal oxygen consumption (VO2max) ............................................. 54
6.5 Duration, dose and intensity ....................................................................................................... 56
6.5 Duration, dose and intensity ....................................................................................................... 56
6.6 Blood pressure (BP) ..................................................................................................................... 59
6.6 Blood pressure (BP) ..................................................................................................................... 59
6.7 Hand-grip strength ...................................................................................................................... 60
6.7 Hand-grip strength ...................................................................................................................... 60
6.8 Apolipoproteins ........................................................................................................................... 60
6.8 Apolipoproteins ........................................................................................................................... 60
6.9 Adiponectin, leptin and cytokines ............................................................................................... 60
6.9 Adiponectin, leptin and cytokines ............................................................................................... 60
6.10 Physical function: walk distance................................................................................................ 60
6.10 Physical function: walk distance................................................................................................ 60
6.11 Dyspnea-related distress (DD-index)......................................................................................... 61
6.11 Dyspnea-related distress (DD-index)......................................................................................... 61
6.12 Disease specific quality of life – chronic respiratory disease questionnaire (CRQ) .................. 61
6.12 Disease specific quality of life – chronic respiratory disease questionnaire (CRQ) .................. 61
6.13 Self-reported health .................................................................................................................. 62
6.13 Self-reported health .................................................................................................................. 62
6.14 General effects after 6 months in Study III ............................................................................... 62
6.14 General effects after 6 months in Study III ............................................................................... 62
6.15 Experiences: qualitative content analysis ................................................................................. 62
6.15 Experiences: qualitative content analysis ................................................................................. 62
7 Methodological considerations .......................................................................................................... 64
7 Methodological considerations .......................................................................................................... 64
7.1 Design .......................................................................................................................................... 64
7.1 Design .......................................................................................................................................... 64
7.2 Recruitment ................................................................................................................................. 65
7.2 Recruitment ................................................................................................................................. 65
7.3 Hawthorne/Placebo effect .......................................................................................................... 66
7.3 Hawthorne/Placebo effect .......................................................................................................... 66
7.4 Intervention program .................................................................................................................. 66
7.4 Intervention program .................................................................................................................. 66
7.5 Measurements ............................................................................................................................ 67
7.5 Measurements ............................................................................................................................ 67
7.6 Statistical considerations ............................................................................................................. 70
7.6 Statistical considerations ............................................................................................................. 70
7.6.1 Power calculation ................................................................................................................. 70
7.6.1 Power calculation ................................................................................................................. 70
8 Future perspectives ............................................................................................................................ 70
8 Future perspectives ............................................................................................................................ 70
9 Practical implications.......................................................................................................................... 72
9 Practical implications.......................................................................................................................... 72
10 Clinical implications .......................................................................................................................... 72
10 Clinical implications .......................................................................................................................... 72
11 Conclusions ....................................................................................................................................... 73
11 Conclusions ....................................................................................................................................... 73
12 Acknowledgements .......................................................................................................................... 74
12 Acknowledgements .......................................................................................................................... 74
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9
13 References ........................................................................................................................................ 76
13 References ........................................................................................................................................ 76
14 Appendix........................................................................................................................................... 89
14 Appendix........................................................................................................................................... 89
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List of abbreviations
List of abbreviations
6MWD
Six-minute walk distance
HRQL
Health-related quality of life
6MWD
Six-minute walk distance
HRQL
Health-related quality of life
Apo B
Apolipoprotein B
HRV
Heart rate variability
Apo B
Apolipoprotein B
HRV
Heart rate variability
ApoA1
Apolipoprotein A1
HY
Hatha Yoga
ApoA1
Apolipoprotein A1
HY
Hatha Yoga
BP
Blood pressure
ITT
Intention-to-treat
BP
Blood pressure
ITT
Intention-to-treat
COPD
Chronic obstructive pulmonary disease
MCID
Minimal clinical important difference
COPD
Chronic obstructive pulmonary disease
MCID
Minimal clinical important difference
CRP
C-reactive protein
MET
Metabolic equivalent
CRP
C-reactive protein
MET
Metabolic equivalent
CRQ
Chronic Respiratory disease
Questionnaire
NIH
National Centre for Complementary
and Integrative health
CRQ
Chronic Respiratory disease
Questionnaire
NIH
National Centre for Complementary
and Integrative health
CTP
Conventional training program
PEmax
Maximal expiratory pressure
CTP
Conventional training program
PEmax
Maximal expiratory pressure
DD-index
Dyspnea related distress
PEP
Positive expiratory pressure
DD-index
Dyspnea related distress
PEP
Positive expiratory pressure
ECG
Electro cardiogram
PImax
Maximal inspiratory pressure
ECG
Electro cardiogram
PImax
Maximal inspiratory pressure
EQ-5D
EuroQoL-5D
pNN50%
NN50 count divided by the total
number of all NN intervals
EQ-5D
EuroQoL-5D
pNN50%
NN50 count divided by the total
number of all NN intervals
f
Respiratory rate
f
Respiratory rate
RMSSD
The square root of the mean of the sum
of the squares of differences between
adjacent NN intervals
FaR
Physical activity on prescription (fysisk
aktivitet på recept)
RMSSD
The square root of the mean of the sum
of the squares of differences between
adjacent NN intervals
RPE
Ratings of perceived exertion (Borg)
FEV1
Forced expiratory volume in one
second
RPE
Ratings of perceived exertion (Borg)
RSA
Respiratory sinus arrhythmia
FVC
Forced vital capacity
RSA
Respiratory sinus arrhythmia
SpO2
Oxygen saturation (peripheral)
GINA
Global Initiative of Asthma
SpO2
Oxygen saturation (peripheral)
SS
Sun salutations
GOLD
SS
Sun salutations
VAS
Visual analogue scale
Global Initiative for Chronic
Obstructive Lung Disease
VAS
Visual analogue scale
FaR
Physical activity on prescription (fysisk
aktivitet på recept)
FEV1
Forced expiratory volume in one
second
FVC
Forced vital capacity
GINA
Global Initiative of Asthma
GOLD
Global Initiative for Chronic
Obstructive Lung Disease
HbA1c
Glycated haemoglobin
VO2max
Maximal oxygen uptake
HbA1c
Glycated haemoglobin
VO2max
Maximal oxygen uptake
HR
Heart rate
YE
Hatha yogic exercises
HR
Heart rate
YE
Hatha yogic exercises
11
11
12
12
1 Introduction
1 Introduction
From a yogic perspective health and well-being is about self-regulation, using the yogic
exercises (YE) to control and strengthen the individual. There are three main components of
YE, based as it is on modern hatha yoga; namely body, breath and mind. Access to yogic
tools may enable individual resources to be fully utilized in order to develop and maintain
health and well-being. Optimal physical and emotional functioning suited to each person’s
capacity can in turn provide freedom for the individual. In yoga, it is considered a skill and a
freedom to be in tune with the body and bodily changes as well as having the capacity to
adapt one’s needs to it, while simultaneously being able to, to some extent, forget about the
body. Being in the present moment using body postures and breathing techniques to control
the body is assumed to lead to strengthening self-efficacy and the ability to handle different
challenges in daily life more efficiently. The yogic way of using body, breath and mind
simultaneously often results in a calm and strong body as well as a stable mind empty of
rumination. Together, these factors are considered to improve individuals’ health in the form
of physical functioning, well-being and quality of life.
From a yogic perspective health and well-being is about self-regulation, using the yogic
exercises (YE) to control and strengthen the individual. There are three main components of
YE, based as it is on modern hatha yoga; namely body, breath and mind. Access to yogic
tools may enable individual resources to be fully utilized in order to develop and maintain
health and well-being. Optimal physical and emotional functioning suited to each person’s
capacity can in turn provide freedom for the individual. In yoga, it is considered a skill and a
freedom to be in tune with the body and bodily changes as well as having the capacity to
adapt one’s needs to it, while simultaneously being able to, to some extent, forget about the
body. Being in the present moment using body postures and breathing techniques to control
the body is assumed to lead to strengthening self-efficacy and the ability to handle different
challenges in daily life more efficiently. The yogic way of using body, breath and mind
simultaneously often results in a calm and strong body as well as a stable mind empty of
rumination. Together, these factors are considered to improve individuals’ health in the form
of physical functioning, well-being and quality of life.
1.1 Health
1.1 Health
1
Health refers to function and well-being in the physical, mental and social domains .
This thesis’ focus rests primarily on health, not disease, as well as how improving one’s
health empowers individuals to live an active and productive life 2. Moreover, health remains
a resource in everyday life, not the objective of living 3. Health promotion is the process
whereby you enable people to increase their control over the factors contributing to their
health 4.
Health refers to function and well-being in the physical, mental and social domains 1.
This thesis’ focus rests primarily on health, not disease, as well as how improving one’s
health empowers individuals to live an active and productive life 2. Moreover, health remains
a resource in everyday life, not the objective of living 3. Health promotion is the process
whereby you enable people to increase their control over the factors contributing to their
health 4.
1.2 Definitions of physical function and physical activity
1.2 Definitions of physical function and physical activity
Physical function can be defined as “The capacity of an individual to carry out the physical
activities of daily living” 5. Physical function mirrors motor function and control, physical
fitness, and routine physical activity 6 7 and is an independent predictor of functional
freedom8, incapacity 9, illness, and mortality 10. The decline of physical function could
arguably differ somewhat depending on physical activity level 11. Baseline physical
functioning usually influences the rate of decline that accelerates with age 11 12, with poor
health often being associated with lower levels of the objective measures of physical function.
A few such often used and valid objective physical function measures include walking speed,
respiratory capacity, muscular strength, hand-grip strength, cardiovascular performance,
standing balance performance and chair rise time. However, physical function can also be
measured with subjective measures. Such measures include self-reports, for example the short
form health survey (SF-36) 13. Though the survey mainly assesses health, it also looks at
physical function. Other commonly used self-report measures covering additional aspects of
health and function include, among others, disability (incapacity), sleep, energy and mental
functioning.
To maintain and prevent the decline of physical function, physical activity may be used 14.
Physical activity can be defined as, ‘‘any bodily movement produced by skeletal muscles that
results in energy expenditure’’ 15 above resting (basal) levels 16. Interestingly enough,
physical activity and physical fitness are often used interchangeably, with fitness representing
Physical function can be defined as “The capacity of an individual to carry out the physical
activities of daily living” 5. Physical function mirrors motor function and control, physical
fitness, and routine physical activity 6 7 and is an independent predictor of functional
freedom8, incapacity 9, illness, and mortality 10. The decline of physical function could
arguably differ somewhat depending on physical activity level 11. Baseline physical
functioning usually influences the rate of decline that accelerates with age 11 12, with poor
health often being associated with lower levels of the objective measures of physical function.
A few such often used and valid objective physical function measures include walking speed,
respiratory capacity, muscular strength, hand-grip strength, cardiovascular performance,
standing balance performance and chair rise time. However, physical function can also be
measured with subjective measures. Such measures include self-reports, for example the short
form health survey (SF-36) 13. Though the survey mainly assesses health, it also looks at
physical function. Other commonly used self-report measures covering additional aspects of
health and function include, among others, disability (incapacity), sleep, energy and mental
functioning.
To maintain and prevent the decline of physical function, physical activity may be used 14.
Physical activity can be defined as, ‘‘any bodily movement produced by skeletal muscles that
results in energy expenditure’’ 15 above resting (basal) levels 16. Interestingly enough,
physical activity and physical fitness are often used interchangeably, with fitness representing
13
13
a more precise measure of physical activity than self-report 17. As such, physical fitness is a,
“physiologic state of well-being that allows one to meet the demands of daily living that
provides the basis for sport performance, or both” 12. To further understand the different
definitions related to physical function, others have described fitness as a form of physical
function 14. Additionally, physical fitness may be characterized by performing daily chores
with vitality and without fatigue as well as with sufficient energy to enjoy recreations. “The
health-related components of physical fitness is cardiorespiratory endurance, muscular
endurance, muscular strength, body composition, flexibility” 15, metabolism, agility and
balance 5 12. As noted above, physical fitness may mirror the definition of physical function.
Lastly, physical exercise is defined as, ‘‘Physical activity that is planned, structured, and
repetitive bodily movement with an objective to improve or maintain physical fitness
components’’15.
a more precise measure of physical activity than self-report 17. As such, physical fitness is a,
“physiologic state of well-being that allows one to meet the demands of daily living that
provides the basis for sport performance, or both” 12. To further understand the different
definitions related to physical function, others have described fitness as a form of physical
function 14. Additionally, physical fitness may be characterized by performing daily chores
with vitality and without fatigue as well as with sufficient energy to enjoy recreations. “The
health-related components of physical fitness is cardiorespiratory endurance, muscular
endurance, muscular strength, body composition, flexibility” 15, metabolism, agility and
balance 5 12. As noted above, physical fitness may mirror the definition of physical function.
Lastly, physical exercise is defined as, ‘‘Physical activity that is planned, structured, and
repetitive bodily movement with an objective to improve or maintain physical fitness
components’’15.
1.3 Health benefits of physical activity for adults
1.3 Health benefits of physical activity for adults
Some of the proven benefits of physical activity show reduced rates of all-cause mortality,
high blood pressure (BP), coronary heart disease and stroke, metabolic syndrome, type 2
diabetes, breast and colon cancer, depression and rates of falling. Moreover, additional
reported health effects of physical activity include increased cardiorespiratory and muscular
fitness, increased bone health, increased functional health with healthier body composition
and improved cognitive function 18-21. To provide alternative forms of exercise is important
considering disease due to inactivity is the fourth leading cause of death worldwide 22.
Physical inactivity has been estimated to cause 6% of all coronary heart diseases in the world,
and inactivity is considered a risk factor at the same level as smoking 21. In 2015, the leading
global causes of death from non-communicable diseases were cardiovascular disease and
chronic respiratory diseases. Between 1990 and 2005, deaths due to ischemic heart disease
increased by 25.8% globally while COPD decreased by 4.6%. Between 2005 and 2015, the
prevalence of cardiovascular disease decreased by 10.2% and COPD by 3%, but no doubt
have to decrease even further 23.
Some of the proven benefits of physical activity show reduced rates of all-cause mortality,
high blood pressure (BP), coronary heart disease and stroke, metabolic syndrome, type 2
diabetes, breast and colon cancer, depression and rates of falling. Moreover, additional
reported health effects of physical activity include increased cardiorespiratory and muscular
fitness, increased bone health, increased functional health with healthier body composition
and improved cognitive function 18-21. To provide alternative forms of exercise is important
considering disease due to inactivity is the fourth leading cause of death worldwide 22.
Physical inactivity has been estimated to cause 6% of all coronary heart diseases in the world,
and inactivity is considered a risk factor at the same level as smoking 21. In 2015, the leading
global causes of death from non-communicable diseases were cardiovascular disease and
chronic respiratory diseases. Between 1990 and 2005, deaths due to ischemic heart disease
increased by 25.8% globally while COPD decreased by 4.6%. Between 2005 and 2015, the
prevalence of cardiovascular disease decreased by 10.2% and COPD by 3%, but no doubt
have to decrease even further 23.
1.4 Using hatha yogic exercises as physical activity
1.4 Using hatha yogic exercises as physical activity
24
Yoga derives from the Sanskrit word root Yuj, “to yoke”; to join, harness and gain control
over the mind’s senses 25. One of its principal aims is to increase self-realization 26 27, selfefficacy 28 and self-empowerment 29, with improved health and well-being as one of its
assumed positive effects. During the practice of yogic postures, there is a great emphasis on
body awareness, breath regulation and mindfulness 24 30 31 29 . Furthermore, the practice of
yogic exercises during a form of physical yoga such as hatha yoga may be described as quite
forceful. This style of yoga often emphasizes the body, breathing exercises and concentration
in order to achieve liberation by means of perfecting a strong yogic-body 24 32 that is immune
to disease 25. Many people in the West are practicing modern hatha yoga, it being the most
common style of physical yoga in the West today 33.
Yoga derives from the Sanskrit word root Yuj, “to yoke”; to join, 24 harness and gain control
over the mind’s senses 25. One of its principal aims is to increase self-realization 26 27, selfefficacy 28 and self-empowerment 29, with improved health and well-being as one of its
assumed positive effects. During the practice of yogic postures, there is a great emphasis on
body awareness, breath regulation and mindfulness 24 30 31 29 . Furthermore, the practice of
yogic exercises during a form of physical yoga such as hatha yoga may be described as quite
forceful. This style of yoga often emphasizes the body, breathing exercises and concentration
in order to achieve liberation by means of perfecting a strong yogic-body 24 32 that is immune
to disease 25. Many people in the West are practicing modern hatha yoga, it being the most
common style of physical yoga in the West today 33.
The number of participants worldwide exceeds 300 million, of which approximately 19%
resides in Germany 31 and 36.7 million in the US (Yoga in America Study 2016) 34.
Considering its popularity, there’s clearly a need to evaluate its effects on physical function.
The number of participants worldwide exceeds 300 million, of which approximately 19%
resides in Germany 31 and 36.7 million in the US (Yoga in America Study 2016) 34.
Considering its popularity, there’s clearly a need to evaluate its effects on physical function.
14
14
Yogic exercises is defined by the American College of Sports Medicine as a form of
multimodal (neuromotor) exercise training and can be used with the aim to increase and
maintain physical function and reduce falls among the elderly 5 . The National Centre for
Complementary and Integrative health (NIH) meanwhile refers to yoga as a style of mindbody practice as well as a form of meditative movement used for health purposes. Both
institutions define yogic practice as a style of exercise training, though NIH adds the
dimension of yogic exercises also being a meditative movement. While performing yogic
exercises it’s especially important to include the “paying attention” part, otherwise it becomes
“gymnastics”. Furthermore, hatha yoga is described as a means of balancing psychophysical
energies in the body and may also be called “psychophysical yoga”, emphasising the need for
reflection and attention while practicing 35. The access to modern hatha yogic exercises (YE)
have become more common both in health centers, gyms but also in primary care and
hospitals. In Sweden, many physiotherapists participate in shorter courses and thereafter bring
YE into their physiotherapy programs. This means that hatha yoga is already today used as a
complement to conventional treatments, often described as a form of physical activity and
exercise. There are many similarities between physical exercise and YE, both in healthy and
diseased populations 30 36, when it comes to the achieved physical and mental effects, though
YE displays greater mental effects than physical exercise directly after practice. YE is
considered a safe intervention; indeed as safe as usual care and exercise 37. One could posit
that some participants with low physical status are more attracted to yogic exercises
considering the form is different from conventional exercise, while others use it for restorative
purposes.The components of physical fitness span both health and skill 15. The health-related
components include cardiorespiratory and muscular endurance, body composition and
flexibility. Yogic exercises include most of the health-related components, except possibly
cardiorespiratory endurance unless one is carrying out the sun salutation sequence. Skillrelated fitness components involve agility, balance, coordination, speed, power and reactiontime. These components are also often included in YE, with the possible exception of speed
and power. This, however, depends greatly on style. Including yogic jumpings and rapid
vinyasa (one breath per movement) in the program may improve also speed and power 15.
Yogic exercises is defined by the American College of Sports Medicine as a form of
multimodal (neuromotor) exercise training and can be used with the aim to increase and
maintain physical function and reduce falls among the elderly 5 . The National Centre for
Complementary and Integrative health (NIH) meanwhile refers to yoga as a style of mindbody practice as well as a form of meditative movement used for health purposes. Both
institutions define yogic practice as a style of exercise training, though NIH adds the
dimension of yogic exercises also being a meditative movement. While performing yogic
exercises it’s especially important to include the “paying attention” part, otherwise it becomes
“gymnastics”. Furthermore, hatha yoga is described as a means of balancing psychophysical
energies in the body and may also be called “psychophysical yoga”, emphasising the need for
reflection and attention while practicing 35. The access to modern hatha yogic exercises (YE)
have become more common both in health centers, gyms but also in primary care and
hospitals. In Sweden, many physiotherapists participate in shorter courses and thereafter bring
YE into their physiotherapy programs. This means that hatha yoga is already today used as a
complement to conventional treatments, often described as a form of physical activity and
exercise. There are many similarities between physical exercise and YE, both in healthy and
diseased populations 30 36, when it comes to the achieved physical and mental effects, though
YE displays greater mental effects than physical exercise directly after practice. YE is
considered a safe intervention; indeed as safe as usual care and exercise 37. One could posit
that some participants with low physical status are more attracted to yogic exercises
considering the form is different from conventional exercise, while others use it for restorative
purposes.The components of physical fitness span both health and skill 15. The health-related
components include cardiorespiratory and muscular endurance, body composition and
flexibility. Yogic exercises include most of the health-related components, except possibly
cardiorespiratory endurance unless one is carrying out the sun salutation sequence. Skillrelated fitness components involve agility, balance, coordination, speed, power and reactiontime. These components are also often included in YE, with the possible exception of speed
and power. This, however, depends greatly on style. Including yogic jumpings and rapid
vinyasa (one breath per movement) in the program may improve also speed and power 15.
1.5 Current recommendations for multifaceted physical activity that
includes YE (also called neuromotor exercise training and functional fitness training)5.
1.5 Current recommendations for multifaceted physical activity that
includes YE (also called neuromotor exercise training and functional fitness training)5.
The available recommendations for multifaceted physical activity are ≥2-3 days a week for
≥20-30 minutes per session. Though the intensity, volume, progression and pattern remain
unspecified, current strength training guidelines are:
Major muscle group strength training (2-4 sets of 10-20 repetitions each) 5
Novice to intermediate
60-70% of 1RM (repetition max)
Experienced
80% of 1RM
Seniors
40-50% of 1RM
Improvements of muscular endurance requires
20-50% 1 RM
Current stretching guidelines for yogic exercises (which include stretching) are:
Use stretching for the major muscle groups (best effect if warmed up)
60 seconds per exercise (seniors recommended to hold 30-60 seconds)
Repeat each exercise 2-4 times. Methods for optimal progression remain unspecified.
The available recommendations for multifaceted physical activity are ≥2-3 days a week for
≥20-30 minutes per session. Though the intensity, volume, progression and pattern remain
unspecified, current strength training guidelines are:
Major muscle group strength training (2-4 sets of 10-20 repetitions each) 5
Novice to intermediate
60-70% of 1RM (repetition max)
Experienced
80% of 1RM
Seniors
40-50% of 1RM
Improvements of muscular endurance requires
20-50% 1 RM
Current stretching guidelines for yogic exercises (which include stretching) are:
Use stretching for the major muscle groups (best effect if warmed up)
60 seconds per exercise (seniors recommended to hold 30-60 seconds)
Repeat each exercise 2-4 times. Methods for optimal progression remain unspecified.
15
15
1.6 Hatha yoga - traditional view and philosophy
1.6 Hatha yoga - traditional view and philosophy
The below meta-analysis uses many different styles of yoga, though hatha yoga is the most
common 33 38. However, the specific effect of hatha yoga in particular requires further
elucidation. Hatha yoga is a spiritual discipline to increase self-realization, self-empowerment
and liberation by means of achieving a strong body and is partly based on yogic texts29 26 27 25.
One definition of the yogic technique is, “yogah-cittavritti-nirodhah”39, translated as, “Yoga is
the cessation of movements in the consciousness”. Yoga is therefore the control of the
conscious mind and mental operations (Yoga sutras 1.2, yoga cittavrtti nirodhah= vrtti
meaning “waves” that disturb the mind). The yogi turns his mind inward, detaching from the
material world in order to realize the true nature of the self 34. The word hatha is divided into
two life force energy (prana) channels, Ha = sun/surya/right/yin and tha =
moon/chandra/left/yang. Hatha yoga is the union between these two psycho-energetic
principles. Hatha yoga places great emphasis on asana and breathing, the purpose being to
regulate the upper (prana) and lower (apana) breaths, also called winds/vayus. One aim is to
use mechanical means such as body postures (asana), breathing exercises, body seals and
locks (mudras/bandhas) to cleanse the body, control and regulate the life force
(prana/winds/vayus) and preserving and raising bindu (a form of liquid considered to be the
essence of life (amrita) inside the brain 40). Three different body seals/locks located in the
beginning, middle and end of the spine are used to control the prana. The body utilizes these
mechanical techniques to cleanse itself (shat-karmas). Common areas to cleanse include the
nose, tongue, ears, eyes, mouth, stomach, heart, bladder, skull, anus and intestines 40 41. Theos
Bernard, who wrote the first dissertation on hatha yoga in the USA (in the 1950s), emphasized
the importance of breath-holding 27.
The below meta-analysis uses many different styles of yoga, though hatha yoga is the most
common 33 38. However, the specific effect of hatha yoga in particular requires further
elucidation. Hatha yoga is a spiritual discipline to increase self-realization, self-empowerment
and liberation by means of achieving a strong body and is partly based on yogic texts29 26 27 25.
One definition of the yogic technique is, “yogah-cittavritti-nirodhah”39, translated as, “Yoga is
the cessation of movements in the consciousness”. Yoga is therefore the control of the
conscious mind and mental operations (Yoga sutras 1.2, yoga cittavrtti nirodhah= vrtti
meaning “waves” that disturb the mind). The yogi turns his mind inward, detaching from the
material world in order to realize the true nature of the self 34. The word hatha is divided into
two life force energy (prana) channels, Ha = sun/surya/right/yin and tha =
moon/chandra/left/yang. Hatha yoga is the union between these two psycho-energetic
principles. Hatha yoga places great emphasis on asana and breathing, the purpose being to
regulate the upper (prana) and lower (apana) breaths, also called winds/vayus. One aim is to
use mechanical means such as body postures (asana), breathing exercises, body seals and
locks (mudras/bandhas) to cleanse the body, control and regulate the life force
(prana/winds/vayus) and preserving and raising bindu (a form of liquid considered to be the
essence of life (amrita) inside the brain 40). Three different body seals/locks located in the
beginning, middle and end of the spine are used to control the prana. The body utilizes these
mechanical techniques to cleanse itself (shat-karmas). Common areas to cleanse include the
nose, tongue, ears, eyes, mouth, stomach, heart, bladder, skull, anus and intestines 40 41. Theos
Bernard, who wrote the first dissertation on hatha yoga in the USA (in the 1950s), emphasized
the importance of breath-holding 27.
Hatha yoga can be described as that of using the body, breath and mind simultaneously 30 35 40
41
.
Hatha yoga can be described as that of using the body, breath and mind simultaneously 30 35 40
41
.






Physical poses (asanas, mudra, bandhas) **
Breathing exercises (pranayama, extending, controlling and maintaining one’s
breathing, (kumbhaka)
Purification techniques (shat-karmas)
Sense-withdrawal (pratyahara)
Contemplation/mindfulness/observation/meditation (dharana, dhyana, bindu (inner
essence, atman = soul)
Samadhi, absolute light (jyotis)






Physical poses (asanas, mudra, bandhas) **
Breathing exercises (pranayama, extending, controlling and maintaining one’s
breathing, (kumbhaka)
Purification techniques (shat-karmas)
Sense-withdrawal (pratyahara)
Contemplation/mindfulness/observation/meditation (dharana, dhyana, bindu (inner
essence, atman = soul)
Samadhi, absolute light (jyotis)
**Some important yogic postures include: dhanurasana, matsyendrasana, paschimottanasana,
kukkutasana, kurmasana, mayurasana, uttanakurmasana. There are also seated and lying
poses.
**Some important yogic postures include: dhanurasana, matsyendrasana, paschimottanasana,
kukkutasana, kurmasana, mayurasana, uttanakurmasana. There are also seated and lying
poses.
Hatha yoga is based on a number of old texts: “Hatha yoga pradipika”, authored by
Svatmarama yogi in the 15th century A.D., is the first text to include asana (physical
postures); Patanjali – “yoga sutras” (Raja yoga), written around 300-500 A.D., Gheranda
samhita (18th century) and Shiva samhita 25-27.Yoga is often thought of as a system of
awareness/consciousness of physical and psychological controls 41 42. Merging the true self
Hatha yoga is based on a number of old texts: “Hatha yoga pradipika”, authored by
Svatmarama yogi in the 15th century A.D., is the first text to include asana (physical
postures); Patanjali – “yoga sutras” (Raja yoga), written around 300-500 A.D., Gheranda
samhita (18th century) and Shiva samhita 25-27.Yoga is often thought of as a system of
awareness/consciousness of physical and psychological controls 41 42. Merging the true self
16
16
(atman=individual soul/pure consciousness) with the ultimate principle of the universal soul
(Brahman)27 is one of the philosophical goals of yoga 26. According to Patanjali there are
eight paths to freedom (liberation) 26, of which number 3, 4, 6 and 7 are the most common
Western entry points to yoga practice43. These paths are: 1. Yama=Moral principles; 2.
Niyama=Self-awareness, discipline; 3. Asana=Body postures; 4. Pranayama=Breath control;
5. Pratyahara=Sense control; 6. Dharana=Concentration; 7. Dhyana=Meditation; and 8.
Samadhi= Insight.
(atman=individual soul/pure consciousness) with the ultimate principle of the universal soul
(Brahman)27 is one of the philosophical goals of yoga 26. According to Patanjali there are
eight paths to freedom (liberation) 26, of which number 3, 4, 6 and 7 are the most common
Western entry points to yoga practice43. These paths are: 1. Yama=Moral principles; 2.
Niyama=Self-awareness, discipline; 3. Asana=Body postures; 4. Pranayama=Breath control;
5. Pratyahara=Sense control; 6. Dharana=Concentration; 7. Dhyana=Meditation; and 8.
Samadhi= Insight.
The class of yoga styles where union is central include ; Jnana yoga, union by knowledge;
Bhakti yoga, union by love and devotion; Karma yoga, union by action and service; Mantra
yoga, union by voice and sound; Yantra yoga, union by vision and form; Laya and kundalini
yoga, union by arousal of latent psychic nerve-force; Tantric yoga, general term for the
physiological disciplines but also union by harnessing sexual energy; Hatha yoga, union by
bodily mastery; and Raja yoga, union by mental mastery 41 44.
The class of yoga styles where union is central include ; Jnana yoga, union by knowledge;
Bhakti yoga, union by love and devotion; Karma yoga, union by action and service; Mantra
yoga, union by voice and sound; Yantra yoga, union by vision and form; Laya and kundalini
yoga, union by arousal of latent psychic nerve-force; Tantric yoga, general term for the
physiological disciplines but also union by harnessing sexual energy; Hatha yoga, union by
bodily mastery; and Raja yoga, union by mental mastery 41 44.
For more details on all aspects and description of HY, please read 29 25 30 40 41 44 45.
For more details on all aspects and description of HY, please read 29 25 30 40 41 44 45.
1.7 General research on yogic exercises for disease prevention and
comparison with usual care
1.7 General research on yogic exercises for disease prevention and
comparison with usual care
By analysing and searching through the meta-analyses of YE in pubmed (approx. 120) one
may conclude that, overall, YE can be used with promising results in small to moderate effect
size groups in different populations. However, larger randomized studies with active control
groups of higher quality are still needed, and interpretations of the meta-analysis results have
to be approached with caution. Moreover, the methodology is limited and the heterogeneity of
YE studies requires further studies to be able to describe the long-term effects of yoga.
A review of the systematic reviews of the management of chronic diseases demonstrates that
yoga seems most effective for reducing symptoms such as anxiety, depression, and pain 46. A
larger cross-sectional study showed that the main aims of attending yogic practise is to
achieve general wellness, disease prevention, improved energy and immune function, reduced
stress levels and improved overall health 47 .
Compared to usual care, yoga resulted in significant improvements in exercise capacity and
health related quality of life (HRQL). Yogic exercises may be a useful addition to formal
rehabilitation exercises 48. YE programs also have similar design and component structure
across chronic disease populations. Yoga is generally considered a safe therapeutic
intervention that is effective when trying to diminish other health-related symptoms 49 . Yogic
exercises in the West is used primarily to treat musculoskeletal and psychological symptoms
50
, and seem to increase parasympathetic activity by modulating the vagal nerve 35 36 51-55 both
during and after practice.
The effects of yoga intervention on fatigue, anxiety, depression and sleep disturbances were
small to moderate, particularly in cancer patients (where exercise is more effective), which
suggests that yoga may be used as an ancillary intervention to improve health-related quality
of life when compared to psychosocial interventions 56. Hatha yoga represents a promising
method for treating anxiety 57 and could be considered an additional treatment option for
patients with depressive disorders 58. Additionally, yoga is a form of meditative movement
with a moderate positive effect on the quality of sleep among older healthy people with sleep
By analysing and searching through the meta-analyses of YE in pubmed (approx. 120) one
may conclude that, overall, YE can be used with promising results in small to moderate effect
size groups in different populations. However, larger randomized studies with active control
groups of higher quality are still needed, and interpretations of the meta-analysis results have
to be approached with caution. Moreover, the methodology is limited and the heterogeneity of
YE studies requires further studies to be able to describe the long-term effects of yoga.
A review of the systematic reviews of the management of chronic diseases demonstrates that
yoga seems most effective for reducing symptoms such as anxiety, depression, and pain 46. A
larger cross-sectional study showed that the main aims of attending yogic practise is to
achieve general wellness, disease prevention, improved energy and immune function, reduced
stress levels and improved overall health 47 .
Compared to usual care, yoga resulted in significant improvements in exercise capacity and
health related quality of life (HRQL). Yogic exercises may be a useful addition to formal
rehabilitation exercises 48. YE programs also have similar design and component structure
across chronic disease populations. Yoga is generally considered a safe therapeutic
intervention that is effective when trying to diminish other health-related symptoms 49 . Yogic
exercises in the West is used primarily to treat musculoskeletal and psychological symptoms
50
, and seem to increase parasympathetic activity by modulating the vagal nerve 35 36 51-55 both
during and after practice.
The effects of yoga intervention on fatigue, anxiety, depression and sleep disturbances were
small to moderate, particularly in cancer patients (where exercise is more effective), which
suggests that yoga may be used as an ancillary intervention to improve health-related quality
of life when compared to psychosocial interventions 56. Hatha yoga represents a promising
method for treating anxiety 57 and could be considered an additional treatment option for
patients with depressive disorders 58. Additionally, yoga is a form of meditative movement
with a moderate positive effect on the quality of sleep among older healthy people with sleep
17
17
complaints 59. Interestingly enough, the odds of a YE study reporting positive conclusions is
25 times higher among Indian studies than elsewhere 31.
complaints 59. Interestingly enough, the odds of a YE study reporting positive conclusions is
25 times higher among Indian studies than elsewhere 31.
1.8 Physical activity for disease prevention
1.8 Physical activity for disease prevention
Regular physical activity may act both as a primary and secondary prevention method for the
prevention of chronic diseases, associated as it is with a reduced risk of premature death
where there is a graded linear relation between volume and health status 12, often along with
the motto “more is better”. Not to forget that participants with the lowest physical status will
show the greatest improvement in health status 12 and is often the group that needs to improve
their physical function the most.
Regular physical activity may act both as a primary and secondary prevention method for the
prevention of chronic diseases, associated as it is with a reduced risk of premature death
where there is a graded linear relation between volume and health status 12, often along with
the motto “more is better”. Not to forget that participants with the lowest physical status will
show the greatest improvement in health status 12 and is often the group that needs to improve
their physical function the most.
1.8.1 Physical activity and rehabilitation for obstructive pulmonary disease patients
1.8.1 Physical activity and rehabilitation for obstructive pulmonary disease patients
Prevalence: Chronic Obstructive Pulmonary Disease (COPD) and asthma have an estimated
worldwide prevalence of 5-10% 60-63, with both involving chronic inflammation and airflow
limitations in the lung tissue. In disease projections for the year 2020, COPD is ranked fifth
worldwide in terms of burden of disease.
Symptoms and diagnosis: COPD causes breathlessness (dyspnea), excessive sputum
production, coughing and exacerbations with a persistent airflow limitation. It is a chronic
inflammation in the lung tissue with structural changes 63. However, as COPD involves
permanent structural changes 63 due to a variety of different causes 64 65, it remains largely
under-diagnosed 64. The disease progression usually covers tissue destruction with narrowing
of the small airways as well as small airway fibrosis with a decreased lung elastic recoil
resulting in airways that cannot remain open during expiration. These changes often lead to
hyperinflation and air/gas trapping and sometimes in hypersecretion 63. The clinical diagnosis
of COPD is dyspnea, chronic cough and/or sputum production where a post-bronchodilator
test below 0.70 confirms the persistent airflow limitation. In line with this, the Global
Initiative for Chronic Obstructive Lung disease (GOLD)63 has divided COPD into 4 grades
(formerly called stages), of which grade 4 is the most severe. The previously used indicator
forced expiratory volume in one second (FEV1) is today considered an inadequate and
unreliable method of measuring the disease progression, severity of breathlessness, exercise
limitation and health status impairment of COPD patients. Instead a ratio of FEV1/FVC
(FVC=forced vital capacity) below 0.70 is currently used for all grades.
Prevalence: Chronic Obstructive Pulmonary Disease (COPD) and asthma have an estimated
worldwide prevalence of 5-10% 60-63, with both involving chronic inflammation and airflow
limitations in the lung tissue. In disease projections for the year 2020, COPD is ranked fifth
worldwide in terms of burden of disease.
Symptoms and diagnosis: COPD causes breathlessness (dyspnea), excessive sputum
production, coughing and exacerbations with a persistent airflow limitation. It is a chronic
inflammation in the lung tissue with structural changes 63. However, as COPD involves
permanent structural changes 63 due to a variety of different causes 64 65, it remains largely
under-diagnosed 64. The disease progression usually covers tissue destruction with narrowing
of the small airways as well as small airway fibrosis with a decreased lung elastic recoil
resulting in airways that cannot remain open during expiration. These changes often lead to
hyperinflation and air/gas trapping and sometimes in hypersecretion 63. The clinical diagnosis
of COPD is dyspnea, chronic cough and/or sputum production where a post-bronchodilator
test below 0.70 confirms the persistent airflow limitation. In line with this, the Global
Initiative for Chronic Obstructive Lung disease (GOLD)63 has divided COPD into 4 grades
(formerly called stages), of which grade 4 is the most severe. The previously used indicator
forced expiratory volume in one second (FEV1) is today considered an inadequate and
unreliable method of measuring the disease progression, severity of breathlessness, exercise
limitation and health status impairment of COPD patients. Instead a ratio of FEV1/FVC
(FVC=forced vital capacity) below 0.70 is currently used for all grades.
Asthma is characterized by chronic inflammation and involves episodic smooth muscle
contractions due to genetic or environmental causes. Factors that trigger asthma include
allergens such as pollution and strong odours, but also physical exertion 66. Poor symptom
control seem to be associated with low physical function in persons with asthma 67. Postbronchodilator spirometry and symptom control using an asthma control test60 is often used
for diagnosis. According to the Global Initiative of Asthma (GINA) 66, asthma can be divided
into 3 grades depending on its severity. This is determined by to the number of exacerbations
and includes controlled, with no exacerbations (normal lung function), partly controlled, with
one or more exacerbations a year (<80% predicted FEV1 (or PEF)), and uncontrolled, with
one exacerbation in any given week.
Asthma is characterized by chronic inflammation and involves episodic smooth muscle
contractions due to genetic or environmental causes. Factors that trigger asthma include
allergens such as pollution and strong odours, but also physical exertion 66. Poor symptom
control seem to be associated with low physical function in persons with asthma 67. Postbronchodilator spirometry and symptom control using an asthma control test60 is often used
for diagnosis. According to the Global Initiative of Asthma (GINA) 66, asthma can be divided
into 3 grades depending on its severity. This is determined by to the number of exacerbations
and includes controlled, with no exacerbations (normal lung function), partly controlled, with
one or more exacerbations a year (<80% predicted FEV1 (or PEF)), and uncontrolled, with
one exacerbation in any given week.
18
18
Treatment: COPD and asthma treatments span both pharmacological and nonpharmacological methods, including smoking cessation. 63 Regular physical activity is
recommended as part of a non-pharmacological treatment modality for both COPD and
asthma63 68, with the aim being to improve physical function as exercise tolerance and
decreased dyspnea and tiredness. Individuals with decreased lung function often have low
physical function and may avoid physical activity and rehabilitation due to fear of dyspnea 69.
Patients with obstructive pulmonary diseases tend to reduce their physical activity levels
(already at GOLD II), even though rehabilitation and health maintenance through physical
activity is an important factor in preventing deconditioning and slowing the disease
progression 70 71. Using physical activity can increase physical function, decrease dyspnea and
prevent fear of performing physical activity in persons with asthma 72. However, pulmonary
rehabilitation and education remain important components of the non-pharmacological
treatment 69 73 .
Treatment: COPD and asthma treatments span both pharmacological and nonpharmacological methods, including smoking cessation. 63 Regular physical activity is
recommended as part of a non-pharmacological treatment modality for both COPD and
asthma63 68, with the aim being to improve physical function as exercise tolerance and
decreased dyspnea and tiredness. Individuals with decreased lung function often have low
physical function and may avoid physical activity and rehabilitation due to fear of dyspnea 69.
Patients with obstructive pulmonary diseases tend to reduce their physical activity levels
(already at GOLD II), even though rehabilitation and health maintenance through physical
activity is an important factor in preventing deconditioning and slowing the disease
progression 70 71. Using physical activity can increase physical function, decrease dyspnea and
prevent fear of performing physical activity in persons with asthma 72. However, pulmonary
rehabilitation and education remain important components of the non-pharmacological
treatment 69 73 .
Non-pharmacological rehabilitation exercise training programmes with the goal of
maintaining and improving one’s health often benefit chronic obstructive pulmonary disease
(COPD) patients (provided they are able to walk without difficulties). Such improvements for
example include increased exercise tolerance, fewer perceived symptoms of dyspnea and
reduced fatigue 74.
Non-pharmacological rehabilitation exercise training programmes with the goal of
maintaining and improving one’s health often benefit chronic obstructive pulmonary disease
(COPD) patients (provided they are able to walk without difficulties). Such improvements for
example include increased exercise tolerance, fewer perceived symptoms of dyspnea and
reduced fatigue 74.
Current recommendations for pulmonary rehabilitation75 state a frequency of 2-3 days/week
for a duration of at least 8 weeks at Borg-RPE 12-13 with 40-50% of VO2 reserve HR, as well
as resistance training loads of 50-85% of maximum voluntary contraction. Others suggest that
light to moderate physical activity 30 minutes per day most days of the week can improve the
quality of life in individuals with COPD 76.
Physical activity may indeed improve physical endurance and strength, as well as breathing
efficiency and tolerance - especially in severely impaired persons – but nevertheless cannot
reverse the physiological and structural deficits in COPD patients. However, an individualized
progressive exercise program might be able to increase the functional capacity (physical
function) of COPD patients with 70-80% after six weeks 76. Moreover, previous findings
concur with the substantial evidence that concludes that exercise training increases exercise
performance and fitness in asthmatics 77. Physically active individuals with asthma showed
less of a decline in lung function than inactive participants with asthma 78.
The pharmacological treatments often reverse obstructive symptoms more efficiently in
individuals with asthma compared to patients with COPD. Thus, any pharmacological
treatment is often supplemented by pulmonary rehabilitation in the form of physical activity
and is equally important for both asthma and COPD to be able to optimize physical function,
prevent muscle dysfunction, reduce symptoms and improve quality of life 75. The gas
trapping may and often is prevented by extended exhalations 79 80. Yet, relatively few patients
attend pulmonary hospital-based rehabilitation programs in Sweden81 . One reason for this
may involve practical barriers and worries of not being able to manage the exercises 82.
However, additional randomized controlled trials, RCT studies of breathing control and
pulmonary rehabilitation exercises 79 are still needed to help patients with breathing disorders
improve their physical function, symptoms and health related quality of life. Such
Current recommendations for pulmonary rehabilitation75 state a frequency of 2-3 days/week
for a duration of at least 8 weeks at Borg-RPE 12-13 with 40-50% of VO2 reserve HR, as well
as resistance training loads of 50-85% of maximum voluntary contraction. Others suggest that
light to moderate physical activity 30 minutes per day most days of the week can improve the
quality of life in individuals with COPD 76.
Physical activity may indeed improve physical endurance and strength, as well as breathing
efficiency and tolerance - especially in severely impaired persons – but nevertheless cannot
reverse the physiological and structural deficits in COPD patients. However, an individualized
progressive exercise program might be able to increase the functional capacity (physical
function) of COPD patients with 70-80% after six weeks 76. Moreover, previous findings
concur with the substantial evidence that concludes that exercise training increases exercise
performance and fitness in asthmatics 77. Physically active individuals with asthma showed
less of a decline in lung function than inactive participants with asthma 78.
The pharmacological treatments often reverse obstructive symptoms more efficiently in
individuals with asthma compared to patients with COPD. Thus, any pharmacological
treatment is often supplemented by pulmonary rehabilitation in the form of physical activity
and is equally important for both asthma and COPD to be able to optimize physical function,
prevent muscle dysfunction, reduce symptoms and improve quality of life 75. The gas
trapping may and often is prevented by extended exhalations 79 80. Yet, relatively few patients
attend pulmonary hospital-based rehabilitation programs in Sweden81 . One reason for this
may involve practical barriers and worries of not being able to manage the exercises 82.
However, additional randomized controlled trials, RCT studies of breathing control and
pulmonary rehabilitation exercises 79 are still needed to help patients with breathing disorders
improve their physical function, symptoms and health related quality of life. Such
19
19
rehabilitation may include yogic exercises and as well as both long-term and short-term
physiotherapeutic interventions 83 84. Yogic exercises have been tested in conjunction with
various diseases and report improved symptoms and physiological effects.
rehabilitation may include yogic exercises and as well as both long-term and short-term
physiotherapeutic interventions 83 84. Yogic exercises have been tested in conjunction with
various diseases and report improved symptoms and physiological effects.
1.9 Yogic exercises for cardiovascular health
1.9 Yogic exercises for cardiovascular health
85
Yogic exercises show promising evidence of improving cardio-metabolic health , while
secondary prevention methods in cardiovascular health diseases remains unproven 86. Studies
have reported significant but small effects on BP after 3-8 weeks of YE training among
hypertensive individuals 87, however it would be much more efficient if all three components
- body, breath and mind – were to be used. Using 8-12 week YE interventions, some studies
managed to decrease BP to similar levels as those associated with usual care in participants
with mild to moderate hypertension 88-91, while others only reported low-quality evidence in
hypertensive patients 92. Others still have reported that primary prevention with YE has
favorable effects on diastolic blood pressure, high density lipoprotein (HDL) cholesterol and
triglycerides, but uncertain effects on low density (LDL) cholesterol 93. Moreover, systolic BP
has shown to be improved after YE in persons with metabolic syndrome not adhering to
conventional forms of exercise 94 . Furthermore, yogic exercises may enhance peak VO2max
and health related quality of life in patients with chronic heart failure and could be considered
for inclusion in cardiac rehabilitation programs 95. Cardiovascular endurance training and YE
seem to have an equal effect on pulse-wave velocity and stiffness in carotid arteries, with YE
practitioners having a slower speed compared to sedentary individuals. This implies that YE
and aerobic participants have similar elasticity in arteries 96. Increased heart rate variability
(HRV) indicates greater parasympathetic control with increased cardiac vagal modulation 97
98
, and the physiological adaptation to YE are often similar 52 99 or better than conventional
exercise 36 53, with a lowered resting HR indicating vagal dominance after YE 52 98 100. Studies
have reported that YE may enhance the plasticity of the autonomic nervous system and
improve the ability to recover after stress 98 101. Performing slow breathing and/or a head
below the heart position (inversion) activates the baroreceptors from an altered negative
pressure in the upper body 54 55 88 102.
The mechanism of inverted posture and slow breathing may involve vagal stimulation and
alternating carotid sinus pressure (baroreceptors) that can restore or reactivate the
baroreceptor reflex function 54 102-105. Other smaller case studies report that the upside-down
position have the potential to treat tachycardia 102 104 105 when no other methods, such as
medication and manual stimulation of the vagal nerve, work. Tai 102 reported a case study
where a woman with arrhythmia was able to restore normal sinus rhythm with a 20-second
hand-stand after all conventional methods had failed. Yogic exercises is a safe and effective
way of reducing waist circumference and systolic BP in individuals with metabolic syndrome
not adhering to conventional forms of exercise 94.
Yogic exercises show promising evidence of improving cardio-metabolic health 85, while
secondary prevention methods in cardiovascular health diseases remains unproven 86. Studies
have reported significant but small effects on BP after 3-8 weeks of YE training among
hypertensive individuals 87, however it would be much more efficient if all three components
- body, breath and mind – were to be used. Using 8-12 week YE interventions, some studies
managed to decrease BP to similar levels as those associated with usual care in participants
with mild to moderate hypertension 88-91, while others only reported low-quality evidence in
hypertensive patients 92. Others still have reported that primary prevention with YE has
favorable effects on diastolic blood pressure, high density lipoprotein (HDL) cholesterol and
triglycerides, but uncertain effects on low density (LDL) cholesterol 93. Moreover, systolic BP
has shown to be improved after YE in persons with metabolic syndrome not adhering to
conventional forms of exercise 94 . Furthermore, yogic exercises may enhance peak VO2max
and health related quality of life in patients with chronic heart failure and could be considered
for inclusion in cardiac rehabilitation programs 95. Cardiovascular endurance training and YE
seem to have an equal effect on pulse-wave velocity and stiffness in carotid arteries, with YE
practitioners having a slower speed compared to sedentary individuals. This implies that YE
and aerobic participants have similar elasticity in arteries 96. Increased heart rate variability
(HRV) indicates greater parasympathetic control with increased cardiac vagal modulation 97
98
, and the physiological adaptation to YE are often similar 52 99 or better than conventional
exercise 36 53, with a lowered resting HR indicating vagal dominance after YE 52 98 100. Studies
have reported that YE may enhance the plasticity of the autonomic nervous system and
improve the ability to recover after stress 98 101. Performing slow breathing and/or a head
below the heart position (inversion) activates the baroreceptors from an altered negative
pressure in the upper body 54 55 88 102.
The mechanism of inverted posture and slow breathing may involve vagal stimulation and
alternating carotid sinus pressure (baroreceptors) that can restore or reactivate the
baroreceptor reflex function 54 102-105. Other smaller case studies report that the upside-down
position have the potential to treat tachycardia 102 104 105 when no other methods, such as
medication and manual stimulation of the vagal nerve, work. Tai 102 reported a case study
where a woman with arrhythmia was able to restore normal sinus rhythm with a 20-second
hand-stand after all conventional methods had failed. Yogic exercises is a safe and effective
way of reducing waist circumference and systolic BP in individuals with metabolic syndrome
not adhering to conventional forms of exercise 94.
1.10 Yogic exercises for physical/cardiorespiratory fitness
1.10 Yogic exercises for physical/cardiorespiratory fitness
Cardiorespiratory fitness is defined as the ability to perform dynamic, moderate- to highintensity exercise for prolonged periods of time 106. Many movements in YE, for example the
sun salutation (SS), is performed with synchronized breathing (vinyasa) involving opening
and uprising exercises on inhalation and closing and downward moving exercises on
Cardiorespiratory fitness is defined as the ability to perform dynamic, moderate- to highintensity exercise for prolonged periods of time 106. Many movements in YE, for example the
sun salutation (SS), is performed with synchronized breathing (vinyasa) involving opening
and uprising exercises on inhalation and closing and downward moving exercises on
20
20
exhalation. Sun salutations is the most common sequence used in yoga classes 107, but as of
yet no long term improvement in cardiovascular fitness in healthy individuals have been
reported. Some studies have reported immediate responses such as increased oxygen
consumption and heart rate (HR) at a satisfactory cardiovascular training level during
dynamic high intensity SS, inversions and certain back bending postures 32 108 109, while others
have reported no effect 110. Interestingly, a recent larger trial showed improvements in VO2max
after YE 111 carried out by 173 healthy
participants (mean age 52). The study found significant effects on VO2max (1.3-2.61
mL/kg/min) during most of the demanding hatha yogic standing postures, seated postures,
inversions, back-bends and plank poses following 3 months (60 minutes per week plus 165
min. home training) without SS. Tran et. al. studied the long-term effects of hatha yoga and
found a significant increase in oxygen uptake32, 6%, when using a minimum of two hatha
yoga classes per week for 8 weeks. They used a “frog” pose - a dynamic and rapid knee
bending posture32, dynamic lunges, 2-3 rounds of SS and other static postures. A “outlier”
cross-sectional study from the US measured the acute effects of performing SS and reported a
graded increase in oxygen consumption 108 from 7mL/kg/min at the beginning of the program
to 28 ml/kg/min (80% of max HR) at the end, indicating that high intensity SS training could
possibly improve and maintain cardiorespiratory fitness. Yet, one-time measures may present
higher values compared to the measurement of long-term effects. Others have shown levels of
41% 112 and 40% 113 of VO2max with YE.
exhalation. Sun salutations is the most common sequence used in yoga classes 107, but as of
yet no long term improvement in cardiovascular fitness in healthy individuals have been
reported. Some studies have reported immediate responses such as increased oxygen
consumption and heart rate (HR) at a satisfactory cardiovascular training level during
dynamic high intensity SS, inversions and certain back bending postures 32 108 109, while others
have reported no effect 110. Interestingly, a recent larger trial showed improvements in VO2max
after YE 111 carried out by 173 healthy
participants (mean age 52). The study found significant effects on VO2max (1.3-2.61
mL/kg/min) during most of the demanding hatha yogic standing postures, seated postures,
inversions, back-bends and plank poses following 3 months (60 minutes per week plus 165
min. home training) without SS. Tran et. al. studied the long-term effects of hatha yoga and
found a significant increase in oxygen uptake32, 6%, when using a minimum of two hatha
yoga classes per week for 8 weeks. They used a “frog” pose - a dynamic and rapid knee
bending posture32, dynamic lunges, 2-3 rounds of SS and other static postures. A “outlier”
cross-sectional study from the US measured the acute effects of performing SS and reported a
graded increase in oxygen consumption 108 from 7mL/kg/min at the beginning of the program
to 28 ml/kg/min (80% of max HR) at the end, indicating that high intensity SS training could
possibly improve and maintain cardiorespiratory fitness. Yet, one-time measures may present
higher values compared to the measurement of long-term effects. Others have shown levels of
41% 112 and 40% 113 of VO2max with YE.
1.11 Yogic exercises for obstructive pulmonary diseases
1.11 Yogic exercises for obstructive pulmonary diseases
Moderate-quality evidence show that YE leads to small improvements in quality of life,
asthmatic symptoms 114, lung function and exercise capacity, and that it could be used as an
complementary pulmonary rehabilitation program in COPD patients 115. Yoga may be
considered an ancillary intervention method or as an alternative to breathing exercises for
asthma patients interested in complementary interventions 116. Using breathing exercises for
4-15 weeks have not only shown to improve functional exercise capacity in COPD patients
but also dyspnea and health-related quality of life (HRQL), however no consistent effects
have so far been demonstrated. Furthermore, breathing exercises can be used to improve
exercise tolerance, respiratory muscle recruitment and respiratory muscle performance as well
as reduce dyspnea in those persons with COPD who are unable to undertake exercise training.
A review written by Holland et. al. suggests that only using breathing exercises in the
comprehensive management of people with COPD is not to be recommended117 .
Moderate-quality evidence show that YE leads to small improvements in quality of life,
asthmatic symptoms 114, lung function and exercise capacity, and that it could be used as an
complementary pulmonary rehabilitation program in COPD patients 115. Yoga may be
considered an ancillary intervention method or as an alternative to breathing exercises for
asthma patients interested in complementary interventions 116. Using breathing exercises for
4-15 weeks have not only shown to improve functional exercise capacity in COPD patients
but also dyspnea and health-related quality of life (HRQL), however no consistent effects
have so far been demonstrated. Furthermore, breathing exercises can be used to improve
exercise tolerance, respiratory muscle recruitment and respiratory muscle performance as well
as reduce dyspnea in those persons with COPD who are unable to undertake exercise training.
A review written by Holland et. al. suggests that only using breathing exercises in the
comprehensive management of people with COPD is not to be recommended117 .
1.12 Yoga for dysfunctional breathing
1.12 Yoga for dysfunctional breathing
Considering we do it approximately 720 times per hour or 21 000 times per day, the way we
breathe can influence our health status. Consequently, small improvements in breathing
technique may have significant effects on our health. Dysfunctional breathing is commonly
found in patients with breathing disorders, chronic back and neck pain sufferers and in
persons with cardiovascular disease, anxiety and depression80. It’s been suggested that
dysfunctional breathing can be found in as many as 30% of asthma patients and 83% of
people with anxiety, while in the general population it remains around 5-11%80.
Considering we do it approximately 720 times per hour or 21 000 times per day, the way we
breathe can influence our health status. Consequently, small improvements in breathing
technique may have significant effects on our health. Dysfunctional breathing is commonly
found in patients with breathing disorders, chronic back and neck pain sufferers and in
persons with cardiovascular disease, anxiety and depression80. It’s been suggested that
dysfunctional breathing can be found in as many as 30% of asthma patients and 83% of
people with anxiety, while in the general population it remains around 5-11%80.
21
21
Hyperinflated lungs, common in COPD, is suggested to increase air trapping with elevated
functional residual capacity in the lungs and as a result the diaphragm can lose its doming80.
Hyperinflation involves inflammation, spasms, hypersecretion with a reduced lung elastic
recoil pressure and destruction of lung parenchyma that may decrease the diameter of the
airway lumen, in turn increasing expiratory resistance and prompting airway collapse
(atelectasis = airways cannot remain open) at normal functional residual capacity levels 118 .
Applying resistance during breathing can be used to improve breathing. Resistance during
exhalation is called positive expiratory pressure (PEP) and can be used for different purposes
in order to improve lung volumes (functional residual capacity and tidal volume) and gas
exchange, reduce the work of breathing and hyperinflation as well as improve airway
clearance and manage dyspnea in obstructed patients. To create breathing resistance,
physiotherapy often uses PEP devices, “blow bottle techniques” and pursed lip breathing118. A
pressure of 10-25 cm H20 is considered normal.
Hyperinflated lungs, common in COPD, is suggested to increase air trapping with elevated
functional residual capacity in the lungs and as a result the diaphragm can lose its doming80.
Hyperinflation involves inflammation, spasms, hypersecretion with a reduced lung elastic
recoil pressure and destruction of lung parenchyma that may decrease the diameter of the
airway lumen, in turn increasing expiratory resistance and prompting airway collapse
(atelectasis = airways cannot remain open) at normal functional residual capacity levels 118 .
Applying resistance during breathing can be used to improve breathing. Resistance during
exhalation is called positive expiratory pressure (PEP) and can be used for different purposes
in order to improve lung volumes (functional residual capacity and tidal volume) and gas
exchange, reduce the work of breathing and hyperinflation as well as improve airway
clearance and manage dyspnea in obstructed patients. To create breathing resistance,
physiotherapy often uses PEP devices, “blow bottle techniques” and pursed lip breathing118. A
pressure of 10-25 cm H20 is considered normal.
The pursed lip breathing technique and PEP devises can be used to decrease functional
residual capacity in participants with hyperinflated lungs for the purposes of preventing air
trapping80 118. Participants with breathing disorders often display inefficient expiration and
partial contraction of the diaphragm80. Shallow and rapid breathing, that is breathing mainly
using the chest and assisting breathing muscles, is usually prevented by using the diaphragm.
Lateral expansion of the waist is in turn a common method used to promote diaphragm
breathing119. Furthermore, diaphragmatic breathing creates a deeper breathing pattern,
improves the breathing technique 120, prevents partial contraction of the diaphragm 80 and
encourages the use of the abdominal wall 69 and greater mobility of the diaphragm, increasing
functional and inspiratory capacity 121. Breathing difficulties can also be caused by incorrect
head posture80. Using the abdominals during exhalations assists the diaphragm doming and
long, non-forceful exhalations lengthens the diaphragm and may strengthen the expiratory
phase80. The extended exhalations result in a more efficient contraction of the diaphragm
(eccentric work) and a more effective contraction during inhalation.
The pursed lip breathing technique and PEP devises can be used to decrease functional
residual capacity in participants with hyperinflated lungs for the purposes of preventing air
trapping80 118. Participants with breathing disorders often display inefficient expiration and
partial contraction of the diaphragm80. Shallow and rapid breathing, that is breathing mainly
using the chest and assisting breathing muscles, is usually prevented by using the diaphragm.
Lateral expansion of the waist is in turn a common method used to promote diaphragm
breathing119. Furthermore, diaphragmatic breathing creates a deeper breathing pattern,
improves the breathing technique 120, prevents partial contraction of the diaphragm 80 and
encourages the use of the abdominal wall 69 and greater mobility of the diaphragm, increasing
functional and inspiratory capacity 121. Breathing difficulties can also be caused by incorrect
head posture80. Using the abdominals during exhalations assists the diaphragm doming and
long, non-forceful exhalations lengthens the diaphragm and may strengthen the expiratory
phase80. The extended exhalations result in a more efficient contraction of the diaphragm
(eccentric work) and a more effective contraction during inhalation.
Some of the yogic breathing techniques (pranayama) use “internal” body resistance such as
the nose and the throat. Extended exhalations are usually a common goal in pranayama,
especially when a restorative effect is preferred. Ujjayi breathing (ocean sounding or
victorious breath) places an internal resistance on the breathing muscles during both
inspiration and expiration. The resistance is formed by constricting the throat at the same time
as issuing a soft hissing sound. Yogic breathing primarily uses the nose during both inhalation
and exhalation, the result being prolonged breathing phases and slower respiratory rates.
Every so often a hand is used to partially block the nostrils to increase resistance further
during unilateral or bilateral nostril breathing. Yogic exercises use body weight and different
body positions such as strong twists to strengthen the breathing muscles. Yogic exercises also
use gravity assisted body positions, for example inversions, for the purpose of assisting in
airway clearance and diaphragm functioning. Moreover, a controlled and slower respiratory
rate prevents hyperventilation and may improve the autonomic nervous system balance, for
example through increased vagal tone. Untreated hyperventilation can lead to inspiratory
muscle exhaustion 80 .
Some of the yogic breathing techniques (pranayama) use “internal” body resistance such as
the nose and the throat. Extended exhalations are usually a common goal in pranayama,
especially when a restorative effect is preferred. Ujjayi breathing (ocean sounding or
victorious breath) places an internal resistance on the breathing muscles during both
inspiration and expiration. The resistance is formed by constricting the throat at the same time
as issuing a soft hissing sound. Yogic breathing primarily uses the nose during both inhalation
and exhalation, the result being prolonged breathing phases and slower respiratory rates.
Every so often a hand is used to partially block the nostrils to increase resistance further
during unilateral or bilateral nostril breathing. Yogic exercises use body weight and different
body positions such as strong twists to strengthen the breathing muscles. Yogic exercises also
use gravity assisted body positions, for example inversions, for the purpose of assisting in
airway clearance and diaphragm functioning. Moreover, a controlled and slower respiratory
rate prevents hyperventilation and may improve the autonomic nervous system balance, for
example through increased vagal tone. Untreated hyperventilation can lead to inspiratory
muscle exhaustion 80 .
22
22
1.13 Yogic exercises for blood parameters
1.13 Yogic exercises for blood parameters
Hatha yoga has been shown to have an anti-inflammatory effect122. Previous findings have
also reported increased adiponectin and lowered leptin levels following physical exercise123
124
. Studies done on experienced yogic practitioners have when compared to novices shown
higher adiponectin levels and lower leptin levels123 125-127. One study 127 showed higher
degrees of inflammation with higher interleukin-6 (IL-6), C-reactive protein and leptin levels
in novice yogic practitioners when compared to yogic experts (2 or more years’ experience),
while 3 months YE have been shown to decrease IL-6, but not tumor necrosis factor (TNFalpha)126, in breast cancer survivors. This could be related to differences in stress response
between the two groups, with different resting vagal tone varying from individual to
individual. The level of the anti-inflammatory protein adiponectin was higher in yoga experts
while the adiponectin to leptin ratio (ALR) was twice as high in the yoga group125. Study II
showed an ALR increase, though not a significant one in either group. ALR is usually higher
in yoga practitioners and the ratio is a sensitive and reliable marker of insulin resistance.
Intense yoga participation seems to alter the leptin and adiponectin production 125 and have
also been shown to increase adiponectin levels in obese postmenopausal women following
yogic intervention128. Moreover, adiponectin levels can change relatively fast; a ten day pilot
yoga intervention done on obese men resulted in increased adiponectin levels and decreased
IL-6, as well as decreased BMI, BP and HR129. Yet, since the design involved only men this
brings up the question of the difference in adiponectin between the sexes. Moreover, even
though the participants in the aforementioned study were normotensive, their BP decreased. It
could be posited that since stress hormone levels fluctuate with the menstrual cycle this may
be one of the reasons for why men and women respond differently to stress. Other studies 130
131
have reported decreased cortisol, IL-6 and TNF-alpha levels as well as increased betaendorphin levels following a 10 day yogic lifestyle intervention. A subgroup gender based
analysis showed similar responses to cortisol and TNF-alpha levels while beta-endorphin
levels increased in females only and IL-6 increased in males only130 It's been suggested that
YE may benefit adult patients with Type 2 diabetes (fasting blood glucose, HbA1c, blood
lipids) 132 and may be considered as an add-on intervention for the management of Type 2
diabetes 133. Yogic practice could be considered a complementary therapy of Type 2 diabetes
due to its positive effects on short-term glycaemic control and possible effect on the lipid
profile 134. Some evidence indicates that mind-body therapies (YE included) may increase
immune responses to vaccination and reduce markers of inflammation as well as influence
virus-specific immune responses to vaccination 135.
Hatha yoga has been shown to have an anti-inflammatory effect122. Previous findings have
also reported increased adiponectin and lowered leptin levels following physical exercise123
124
. Studies done on experienced yogic practitioners have when compared to novices shown
higher adiponectin levels and lower leptin levels123 125-127. One study 127 showed higher
degrees of inflammation with higher interleukin-6 (IL-6), C-reactive protein and leptin levels
in novice yogic practitioners when compared to yogic experts (2 or more years’ experience),
while 3 months YE have been shown to decrease IL-6, but not tumor necrosis factor (TNFalpha)126, in breast cancer survivors. This could be related to differences in stress response
between the two groups, with different resting vagal tone varying from individual to
individual. The level of the anti-inflammatory protein adiponectin was higher in yoga experts
while the adiponectin to leptin ratio (ALR) was twice as high in the yoga group125. Study II
showed an ALR increase, though not a significant one in either group. ALR is usually higher
in yoga practitioners and the ratio is a sensitive and reliable marker of insulin resistance.
Intense yoga participation seems to alter the leptin and adiponectin production 125 and have
also been shown to increase adiponectin levels in obese postmenopausal women following
yogic intervention128. Moreover, adiponectin levels can change relatively fast; a ten day pilot
yoga intervention done on obese men resulted in increased adiponectin levels and decreased
IL-6, as well as decreased BMI, BP and HR129. Yet, since the design involved only men this
brings up the question of the difference in adiponectin between the sexes. Moreover, even
though the participants in the aforementioned study were normotensive, their BP decreased. It
could be posited that since stress hormone levels fluctuate with the menstrual cycle this may
be one of the reasons for why men and women respond differently to stress. Other studies 130
131
have reported decreased cortisol, IL-6 and TNF-alpha levels as well as increased betaendorphin levels following a 10 day yogic lifestyle intervention. A subgroup gender based
analysis showed similar responses to cortisol and TNF-alpha levels while beta-endorphin
levels increased in females only and IL-6 increased in males only130 It's been suggested that
YE may benefit adult patients with Type 2 diabetes (fasting blood glucose, HbA1c, blood
lipids) 132 and may be considered as an add-on intervention for the management of Type 2
diabetes 133. Yogic practice could be considered a complementary therapy of Type 2 diabetes
due to its positive effects on short-term glycaemic control and possible effect on the lipid
profile 134. Some evidence indicates that mind-body therapies (YE included) may increase
immune responses to vaccination and reduce markers of inflammation as well as influence
virus-specific immune responses to vaccination 135.
1.14 Other benefits of yogic exercises
1.14 Other benefits of yogic exercises
Yogic interventions have been reported to result in small improvements in balance and
medium improvements in physical mobility in people aged 60+ years 136. Moreover, yoga
appears to offer a promising modality for arthritis 137 and may be beneficial for symptoms
such as chronic neck pain and functional disability 138. There is also strong evidence to
suggest YE's short-term effectiveness, and moderate evidence for its long-term effectiveness,
on chronic lower back pain, making it suitable as an additional therapy for patients with
chronic lower back pain 139 140. There have been no reported adverse effects. The strongest
and most consistent evidence pertains to the short-term benefits of yoga on functional
Yogic interventions have been reported to result in small improvements in balance and
medium improvements in physical mobility in people aged 60+ years 136. Moreover, yoga
appears to offer a promising modality for arthritis 137 and may be beneficial for symptoms
such as chronic neck pain and functional disability 138. There is also strong evidence to
suggest YE's short-term effectiveness, and moderate evidence for its long-term effectiveness,
on chronic lower back pain, making it suitable as an additional therapy for patients with
chronic lower back pain 139 140. There have been no reported adverse effects. The strongest
and most consistent evidence pertains to the short-term benefits of yoga on functional
23
23
disability for lower back pain 140. On the issue of fibromyalgia, studies on YE have reported a
medium-to-high effect on pain reduction without known side effects 141. Yoga practice has
also been shown to offer moderate improvements to chronic function 142 and the induction of
functional and structural brain modifications in expert meditation practitioners, especially in
areas involved in self-referential processes such as self-awareness and self-regulation. It's
been suggested that meditation techniques should be embraced in clinical populations for the
purpose of disease prevention 143.
disability for lower back pain 140. On the issue of fibromyalgia, studies on YE have reported a
medium-to-high effect on pain reduction without known side effects 141. Yoga practice has
also been shown to offer moderate improvements to chronic function 142 and the induction of
functional and structural brain modifications in expert meditation practitioners, especially in
areas involved in self-referential processes such as self-awareness and self-regulation. It's
been suggested that meditation techniques should be embraced in clinical populations for the
purpose of disease prevention 143.
1.15 Adverse effects and injuries related to yogic exercises
1.15 Adverse effects and injuries related to yogic exercises
No adverse effects/events connected to YE have been reported in any of the previous metaanalyses, nor has there been any proven additional adverse effects when compared to other
forms of physical activity.
However, some cases have suggested that performing unusually intense sessions and/or
having a medical precondition may lead to stroke, neuropathy and worsening glaucoma in
conjunction with injury31. The risk of yoga-related injuries is estimated at 1.45 injuries per
1,000 hours of yoga practice. Moreover, a recent report points to the trunk being the area most
commonly injured through sprains/strains (46.6% and 45.0% respectively). Since the largest
increase in injuries (8-fold) was demonstrated among those 65 years or older, senior citizens
are recommended to practise with qualified teachers for safety purposes 144.
No adverse effects/events connected to YE have been reported in any of the previous metaanalyses, nor has there been any proven additional adverse effects when compared to other
forms of physical activity.
However, some cases have suggested that performing unusually intense sessions and/or
having a medical precondition may lead to stroke, neuropathy and worsening glaucoma in
conjunction with injury31. The risk of yoga-related injuries is estimated at 1.45 injuries per
1,000 hours of yoga practice. Moreover, a recent report points to the trunk being the area most
commonly injured through sprains/strains (46.6% and 45.0% respectively). Since the largest
increase in injuries (8-fold) was demonstrated among those 65 years or older, senior citizens
are recommended to practise with qualified teachers for safety purposes 144.
1.16 The mechanisms of hatha yoga
1.16 The mechanisms of hatha yoga
Self-disciplines, moral
and ethical principles
yama, niyama Closing
off senses pratyahara
Self-disciplines, moral
and ethical principles
yama, niyama Closing
off senses pratyahara
Concentration,
meditation
dhyana
dharana
Concentration,
meditation
dhyana
dharana
Bliss
samadhi
Bliss
samadhi
Figure 1. The principle of yogic practice is to work from the outside and in. Western entry points to modern
hatha yoga involve body exercises, breathing exercises and concentration - represented by the outer layer in
figure 1. Starting with the body is the least subtle and a common starting point for the novice yoga practitioner.
The interventions in Study I-IV all focused on the component postures, breathing exercises and concentration.
Based on model from Gard et al 43. Sanskrit names in italics.
24
Figure 1. The principle of yogic practice is to work from the outside and in. Western entry points to modern
hatha yoga involve body exercises, breathing exercises and concentration - represented by the outer layer in
figure 1. Starting with the body is the least subtle and a common starting point for the novice yoga practitioner.
The interventions in Study I-IV all focused on the component postures, breathing exercises and concentration.
Based on model from Gard et al 43. Sanskrit names in italics.
24
The systems network model of yoga are using 43 a top-down and bottom-up perspectives
(Figure 2) and shows how practicing YE can influence self-regulation. By doing the exercises
(“learning by doing”) and observing with the mind the participant then feels the effects.
Experiencing positive effects in body/mind in turn increases motivation and empowers the
participant to continue practising. Yogic exercises are considered to increase parasympathetic
activity both during (depending on style) and after practice. Parasympathetic activity
decreases inflammation and may also be related to the inflammatory reflex model 51. The
nervous system can suppress an ongoing inflammation via the hypothalamic pituitary adrenal
axis (HPA-axis) or via a pathway called the inflammatory reflex. The inflammatory reflex is
comprised of an afferent arm of the vagus nerve that senses inflammation (via cytokines) and
an efferent arm called the cholinergic anti-inflammatory pathway. The efferent arm in the
inflammatory reflex modifies immune function and modulates innate immune responses while
maintaining homeostasis (the alpha 7 subunit of the nicotinic acetylcholine receptor expressed
on cytokine-producing cells (macrophages, mainly in tissues) that is activated via the efferent
arm of the vagus nerve) 145 146.
The systems network model of yoga are using 43 a top-down and bottom-up perspectives
(Figure 2) and shows how practicing YE can influence self-regulation. By doing the exercises
(“learning by doing”) and observing with the mind the participant then feels the effects.
Experiencing positive effects in body/mind in turn increases motivation and empowers the
participant to continue practising. Yogic exercises are considered to increase parasympathetic
activity both during (depending on style) and after practice. Parasympathetic activity
decreases inflammation and may also be related to the inflammatory reflex model 51. The
nervous system can suppress an ongoing inflammation via the hypothalamic pituitary adrenal
axis (HPA-axis) or via a pathway called the inflammatory reflex. The inflammatory reflex is
comprised of an afferent arm of the vagus nerve that senses inflammation (via cytokines) and
an efferent arm called the cholinergic anti-inflammatory pathway. The efferent arm in the
inflammatory reflex modifies immune function and modulates innate immune responses while
maintaining homeostasis (the alpha 7 subunit of the nicotinic acetylcholine receptor expressed
on cytokine-producing cells (macrophages, mainly in tissues) that is activated via the efferent
arm of the vagus nerve) 145 146.
Figure 2. Systems network model explaining self-regulation from the bottom-up and top-down perspective used
while practicing yogic exercises. Major yogic components have been included in the blue box and dotted lines
signify new, adaptive pathways for reacting to stress. The regulatory processes of yoga are in yellow boxes.
Used by permission of Gard et. al. 43.
Figure 2. Systems network model explaining self-regulation from the bottom-up and top-down perspective used
while practicing yogic exercises. Major yogic components have been included in the blue box and dotted lines
signify new, adaptive pathways for reacting to stress. The regulatory processes of yoga are in yellow boxes.
Used by permission of Gard et. al. 43.
25
25
2 Rationale for the thesis
2 Rationale for the thesis
The work included in this thesis aims to investigate the effects of newly developed hatha
yogic programs (YE) among both healthy participants and in patients with obstructive
pulmonary diseases. The rationale for choosing hatha yoga relates to it being the most
common style of yoga practiced in the West today. Also it is easily adopted and represents the
primary yoga style used in previous research 33 38, which makes it the ideal candidate for
further research.
The work included in this thesis aims to investigate the effects of newly developed hatha
yogic programs (YE) among both healthy participants and in patients with obstructive
pulmonary diseases. The rationale for choosing hatha yoga relates to it being the most
common style of yoga practiced in the West today. Also it is easily adopted and represents the
primary yoga style used in previous research 33 38, which makes it the ideal candidate for
further research.
Among both healthy and diseased populations, there is a growing need and demand for
alternative forms of complementary body-mind medicine and physical activity modalities that
have the power to get more people involved in physical activity. Since more alternatives are
likely to involve more people and allowing them to maintain activity levels, this in turn
should lead to improved physical function, well-being and health in a greater percentage of
the population. The following points provide the specific rationale for this thesis:
Among both healthy and diseased populations, there is a growing need and demand for
alternative forms of complementary body-mind medicine and physical activity modalities that
have the power to get more people involved in physical activity. Since more alternatives are
likely to involve more people and allowing them to maintain activity levels, this in turn
should lead to improved physical function, well-being and health in a greater percentage of
the population. The following points provide the specific rationale for this thesis:









There is a need for further evaluation of YE due to many heterogenetic studies with
poor quality.
The number of participants using YE are increasing both in the exercise arena but also
in primary health care.
Yogic exercise programs are inexpensive and can be taught in a few hour long
sessions, and then continued independently and used as a form of biofeedback.
Certain yogic programs and YE (i.e., inversions, high intensity sun salutations; certain
type of YE with a certain breathing exercise sequences) remain to be investigated
There is a lack of knowledge regarding the efficiency of YE and regarding some of the
most common yogic sequences on cardiovascular fitness and health.
Previous studies have not evaluated heart rate variability and the effects of inversions,
nor the relaxation effects of using inversions during a longer time frame.
Knowledge of yogic exercises, when using a certain sequence of breathing and
postural exercises, for obstructive pulmonary diseases is limited.
Lack of knowledge of obstructive pulmonary disease patients’ experiences of YE after
participation in a YE-program.
The feasibility of the newly developed and adapted YE programs has yet to be
investigated.
26









There is a need for further evaluation of YE due to many heterogenetic studies with
poor quality.
The number of participants using YE are increasing both in the exercise arena but also
in primary health care.
Yogic exercise programs are inexpensive and can be taught in a few hour long
sessions, and then continued independently and used as a form of biofeedback.
Certain yogic programs and YE (i.e., inversions, high intensity sun salutations; certain
type of YE with a certain breathing exercise sequences) remain to be investigated
There is a lack of knowledge regarding the efficiency of YE and regarding some of the
most common yogic sequences on cardiovascular fitness and health.
Previous studies have not evaluated heart rate variability and the effects of inversions,
nor the relaxation effects of using inversions during a longer time frame.
Knowledge of yogic exercises, when using a certain sequence of breathing and
postural exercises, for obstructive pulmonary diseases is limited.
Lack of knowledge of obstructive pulmonary disease patients’ experiences of YE after
participation in a YE-program.
The feasibility of the newly developed and adapted YE programs has yet to be
investigated.
26
3 Aim
3 Aim
The overall aim of this thesis has been to investigate the objective and subjective effects of
different hatha yogic exercise (YE) programs on physical function, health and health related
quality of life using interventions spanning 6-12 weeks. Three different intervention programs
were developed and adapted, Study I and II for healthy populations and Study III and IV for
diseased.
Specific aims:
The overall aim of this thesis has been to investigate the objective and subjective effects of
different hatha yogic exercise (YE) programs on physical function, health and health related
quality of life using interventions spanning 6-12 weeks. Three different intervention programs
were developed and adapted, Study I and II for healthy populations and Study III and IV for
diseased.
Specific aims:




To investigate the effects of YE focusing on inversions on heart rate variability, blood
pressure and hand-grip-strength (Study I) in healthy sedentary middle aged adults.
To investigate the effects of high intensity YE on cardiovascular fitness and metabolic
biological parameters as apolipoproteins and adipocytokines (Study II) in healthy
students.
To investigate the effects of YE on physical function, mastery of the disease, quality
of life, dyspnea-related distress and pulmonary function (Study III) in participants
with obstructive pulmonary disease.
To explore the experiences of participants with obstructive pulmonary disease
following YE (Study IV).
27




To investigate the effects of YE focusing on inversions on heart rate variability, blood
pressure and hand-grip-strength (Study I) in healthy sedentary middle aged adults.
To investigate the effects of high intensity YE on cardiovascular fitness and metabolic
biological parameters as apolipoproteins and adipocytokines (Study II) in healthy
students.
To investigate the effects of YE on physical function, mastery of the disease, quality
of life, dyspnea-related distress and pulmonary function (Study III) in participants
with obstructive pulmonary disease.
To explore the experiences of participants with obstructive pulmonary disease
following YE (Study IV).
27
4 Material and methods
4 Material and methods
4.1 Study design and analysis
4.1 Study design and analysis
Study I was an uncontrolled experimental pilot study while Studies II and III were
randomized controlled experimental clinical trials (RCT). Study IV was a cross-sectional
interview study with a qualitative approach. The analyses in Study I and II were performed as
per protocol, Study III used an intention-to-treat model. Study IV employed an inductive
qualitative content analysis.
Study I was an uncontrolled experimental pilot study while Studies II and III were
randomized controlled experimental clinical trials (RCT). Study IV was a cross-sectional
interview study with a qualitative approach. The analyses in Study I and II were performed as
per protocol, Study III used an intention-to-treat model. Study IV employed an inductive
qualitative content analysis.
4.2 Study population
4.2 Study population
Study I involved sedentary middle-aged working adults Study II focused on younger healthy
students while Study III and IV studied middle aged COPD and asthma patients. Study I and
II involved healthy populations while Study III and IV looked at participants with obstructive
pulmonary diseases. All participants were residents of Stockholm, Sweden (Table C).
Study I involved sedentary middle-aged working adults Study II focused on younger healthy
students while Study III and IV studied middle aged COPD and asthma patients. Study I and
II involved healthy populations while Study III and IV looked at participants with obstructive
pulmonary diseases. All participants were residents of Stockholm, Sweden (Table C).
4.2.1 Inclusion and exclusion criteria
4.2.1 Inclusion and exclusion criteria
The inclusion criteria for Study I were: people between 25–60 years of age, of good general
health with slightly elevated blood pressure (no higher than 145/95), new to YE, showcasing
no regular exercise routines nor physical activity at medium to high intensity (Borg >13). The
exclusion criteria were: people > 60 years of age, people diagnosed with high blood pressure
and/or taking blood pressure medication or other medication which may affect the
performance of inversions, as well as people having had surgery during the previous
6 months.
Study I and II also included the following exclusion criteria: people suffering from or
diagnosed with a chronic disease that could potentially impede the performance of YE, such
as eye disease, depression, burnout, indigestion (reflux) and heartburn, musculoskeletal
injuries in the back and/or neck, or people suffering from headaches in the morning or while
coughing or sneezing.
The inclusion criteria for Study I were: people between 25–60 years of age, of good general
health with slightly elevated blood pressure (no higher than 145/95), new to YE, showcasing
no regular exercise routines nor physical activity at medium to high intensity (Borg >13). The
exclusion criteria were: people > 60 years of age, people diagnosed with high blood pressure
and/or taking blood pressure medication or other medication which may affect the
performance of inversions, as well as people having had surgery during the previous
6 months.
Study I and II also included the following exclusion criteria: people suffering from or
diagnosed with a chronic disease that could potentially impede the performance of YE, such
as eye disease, depression, burnout, indigestion (reflux) and heartburn, musculoskeletal
injuries in the back and/or neck, or people suffering from headaches in the morning or while
coughing or sneezing.
Physical activity limits for exclusion:
Study I: More than twice a month and/or at medium or high intensity (out of breath and
sweating, Borg >13) were excluded
Study II: More than 2 hours a week at medium or high intensity (out of breath and sweating,
Borg >13) were excluded.
The inclusion criteria for Study II were healthy students between 20–40 years of age,
sedentary or performing physical exercise at medium intensity <2 hours per week or at a high
intensity <1 hour per week. The exclusion criteria were: people <20 or >40 years of age,
people diagnosed with chronic cardiovascular disease, depression and/or taking medication
for heart disease, depression, anxiety or any medication that affects reactivity.
Physical activity limits for exclusion:
Study I: More than twice a month and/or at medium or high intensity (out of breath and
sweating, Borg >13) were excluded
Study II: More than 2 hours a week at medium or high intensity (out of breath and sweating,
Borg >13) were excluded.
The inclusion criteria for Study II were healthy students between 20–40 years of age,
sedentary or performing physical exercise at medium intensity <2 hours per week or at a high
intensity <1 hour per week. The exclusion criteria were: people <20 or >40 years of age,
people diagnosed with chronic cardiovascular disease, depression and/or taking medication
for heart disease, depression, anxiety or any medication that affects reactivity.
The inclusion criteria for studies III and IV were: people between 35-85 years of age
diagnosed (according to electronic patient records) with obstructive pulmonary disease, e.g.
COPD, with mild to severe obstructions with GOLD 1-3, FEV1/FVC < 0.70 or people
diagnosed with asthma with FEV1 and a FEV% of predicted respiratory function of 30% ≤
FEV1 ≤ 90%. The exclusion criteria included people with severe neurological, orthopedic or
The inclusion criteria for studies III and IV were: people between 35-85 years of age
diagnosed (according to electronic patient records) with obstructive pulmonary disease, e.g.
COPD, with mild to severe obstructions with GOLD 1-3, FEV1/FVC < 0.70 or people
diagnosed with asthma with FEV1 and a FEV% of predicted respiratory function of 30% ≤
FEV1 ≤ 90%. The exclusion criteria included people with severe neurological, orthopedic or
28
28
rheumatologic injuries or diseases (each patient were examined and each case evaluated to
determine if eligible to perform the exercises), people unable to walk less than 200 meters,
people with decreased mobility or a chronic disease that could have had an effect on
performance, people with an upcoming surgery in the next 6 months, people with a severe
mental disease diagnosis (incl. those taking medication affecting attention), people who had
had a heart infarction in the last 12 months or a change in medication during the last 6 weeks.
The causes for exclusion covered (total n=33) high blood pressure, upcoming surgery (n=2),
mental disorder (n=5), chronic illness (n=13), lack of time (n=6), language problems (n=5),
scheduling problems (n=7) and no specific reason (n=3).
rheumatologic injuries or diseases (each patient were examined and each case evaluated to
determine if eligible to perform the exercises), people unable to walk less than 200 meters,
people with decreased mobility or a chronic disease that could have had an effect on
performance, people with an upcoming surgery in the next 6 months, people with a severe
mental disease diagnosis (incl. those taking medication affecting attention), people who had
had a heart infarction in the last 12 months or a change in medication during the last 6 weeks.
The causes for exclusion covered (total n=33) high blood pressure, upcoming surgery (n=2),
mental disorder (n=5), chronic illness (n=13), lack of time (n=6), language problems (n=5),
scheduling problems (n=7) and no specific reason (n=3).
4.2.2 Participant flow
4.2.2 Participant flow



Study I: Of the 794 invited, 32 responded and 12 fulfilled the inclusion criteria (no
drop-outs).
Study II: 260 responders of which 54 were enrolled; 44 participants completed the
study (21 yoga, 23 control). 4 drop-outs in control and 6 drop-outs in YE group.

Study III: 127 responders of which 53 were accepted for baseline measurements, 74
failed to meet the inclusion criteria. This resulted in 40 eligible patients who were
randomized for participation with 20 in each group. 3 drop-outs in YE and 1 in CTP.


Study I: Of the 794 invited, 32 responded and 12 fulfilled the inclusion criteria (no
drop-outs).
Study II: 260 responders of which 54 were enrolled; 44 participants completed the
study (21 yoga, 23 control). 4 drop-outs in control and 6 drop-outs in YE group.
Study III: 127 responders of which 53 were accepted for baseline measurements, 74
failed to meet the inclusion criteria. This resulted in 40 eligible patients who were
randomized for participation with 20 in each group. 3 drop-outs in YE and 1 in CTP.
For an overview of study design, participants, intervention and outcome measures using
different hatha yoga programs (YE), see TABLE C (page 31)
For an overview of study design, participants, intervention and outcome measures using
different hatha yoga programs (YE), see TABLE C (page 31)
4.3 Intervention, measurements and procedure
4.3 Intervention, measurements and procedure
4.3.1 Data collection and intervention location
4.3.1 Data collection and intervention location
In Study I, measurement took place at the participants workplace in a conference room and
intervention took place at the workplace gym in Stockholm. In Study II, measurements took
place in changing rooms at the sports arena and intervention took place in the exercise hall at
Karolinska Institutet (Huddinge). In Study III+IV, measurements, interviews and intervention
took place at the Karolinska University Hospital Huddinge.
In Study I, measurement took place at the participants workplace in a conference room and
intervention took place at the workplace gym in Stockholm. In Study II, measurements took
place in changing rooms at the sports arena and intervention took place in the exercise hall at
Karolinska Institutet (Huddinge). In Study III+IV, measurements, interviews and intervention
took place at the Karolinska University Hospital Huddinge.
4.3.2 Instructions to participants
4.3.2 Instructions to participants
In each intervention the participants were instructed as a group by the instructor. The
instruction covered how to achieve the best technique, biomechanics and breathing in each
yogic pose and breathing exercise. The instructor also demonstrated modifications and
progression of each posture. The participants were encouraged to do as much home exercising
as possible during all three interventions (Study I-IV). In Study I they received a leaflet with
the essential poses and in Study II-IV they received both a DVD and a leaflet containing the
important poses. Study III offered encouragement to continue the training during the 6-month
break.
In each intervention the participants were instructed as a group by the instructor. The
instruction covered how to achieve the best technique, biomechanics and breathing in each
yogic pose and breathing exercise. The instructor also demonstrated modifications and
progression of each posture. The participants were encouraged to do as much home exercising
as possible during all three interventions (Study I-IV). In Study I they received a leaflet with
the essential poses and in Study II-IV they received both a DVD and a leaflet containing the
important poses. Study III offered encouragement to continue the training during the 6-month
break.
4.3.3 Interventions Study I-IV
4.3.3 Interventions Study I-IV
The three different interventions used in this thesis (see Appendix) were partly based on
research and individually adapted to the three different study populations. The programs were
run by experienced yoga teachers individually trained by the author in the three different
The three different interventions used in this thesis (see Appendix) were partly based on
research and individually adapted to the three different study populations. The programs were
run by experienced yoga teachers individually trained by the author in the three different
29
29
hatha YE programs. The programs did not include the philosophical parts of yoga and the
majority of the participants were new to YE. For dose, intensity and adherence, see Table A.
The YE program in Study I (Figure 3) was performed for 8 weeks in 1 hour sessions. The
program focused on inverted postures and the time performing the inversions progressed from
10 min to approximately 15-20 min during the last 4-5 weeks.
hatha YE programs. The programs did not include the philosophical parts of yoga and the
majority of the participants were new to YE. For dose, intensity and adherence, see Table A.
The YE program in Study I (Figure 3) was performed for 8 weeks in 1 hour sessions. The
program focused on inverted postures and the time performing the inversions progressed from
10 min to approximately 15-20 min during the last 4-5 weeks.
Figure 3. Major inversion poses used in the intervention in Study I
Figure 3. Major inversion poses used in the intervention in Study I
Study II used high intensity dynamic YE postures (60 min./6 weeks) consisting of the
classical sun salutation (SS) for approx. 30-40 minutes (Figure 4) and the remaining inversion
poses for approx. 15 min. The SS includes 12 poses forming a dynamic sequence that is
synchronized with one's breathing (vinyasa).
Study II used high intensity dynamic YE postures (60 min./6 weeks) consisting of the
classical sun salutation (SS) for approx. 30-40 minutes (Figure 4) and the remaining inversion
poses for approx. 15 min. The SS includes 12 poses forming a dynamic sequence that is
synchronized with one's breathing (vinyasa).
Figure 4. Vigorous sun-salutation used in Study II (note that the 3rd exercise in the top row was
performed with bent knees and the 7th exercise in the top row was performed with knees on the
ground, arms straight and hips high; a synthesis between the cobra pose and dog up pose.
Figure 4. Vigorous sun-salutation used in Study II (note that the 3rd exercise in the top row was
performed with bent knees and the 7th exercise in the top row was performed with knees on the
ground, arms straight and hips high; a synthesis between the cobra pose and dog up pose.
Study III and IV yogic exercises (YE) using deep and regulated breathing performed twice a
week for 60-70 min. at a time for 12 weeks. General postural and breathing instructions
focused on deep breathing opened the class and each individual was then instructed to work at
their own capacity. The general recommendation was to focus on extended exhalations. The
program included standing, seated and back-bending poses and breathing exercises (Figure 5).
Each class ended with relaxation and body scanning.
Study III and IV yogic exercises (YE) using deep and regulated breathing performed twice a
week for 60-70 min. at a time for 12 weeks. General postural and breathing instructions
focused on deep breathing opened the class and each individual was then instructed to work at
their own capacity. The general recommendation was to focus on extended exhalations. The
program included standing, seated and back-bending poses and breathing exercises (Figure 5).
Each class ended with relaxation and body scanning.
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30
Figure 5. Some of the yogic exercises included in Study III. Note that many exercises were
individually modified with props to suit the participants.
Figure 5. Some of the yogic exercises included in Study III. Note that many exercises were
individually modified with props to suit the participants.
A conventional training program (CTP) (physiotherapeutic intervention) with the same
number of sessions a week and duration as the YE group (x2/week for 60 min for 12 weeks)
was used as an active control group during Study III. The program included strength and
endurance training as well as stationary exercise biking (10-15 min).
A conventional training program (CTP) (physiotherapeutic intervention) with the same
number of sessions a week and duration as the YE group (x2/week for 60 min for 12 weeks)
was used as an active control group during Study III. The program included strength and
endurance training as well as stationary exercise biking (10-15 min).
4.3.4 Measurements and test leaders
4.3.4 Measurements and test leaders
Measurements were performed by different test leaders in each study. Study I involved only
one test leader, Study II involved five different test leaders, Study III involved 8-9 different
test leaders and Study IV involved one test leader (performing the interviews). No complete
blinding could be achieved during any of the clinical studies. The participants were blinded to
the test results during the actual intervention, though afterwards some requested and received
their results. All measurements taken during Study I-III were performed within one week
prior to commencing the interventions and within one week following the intervention.
Measurements were performed by different test leaders in each study. Study I involved only
one test leader, Study II involved five different test leaders, Study III involved 8-9 different
test leaders and Study IV involved one test leader (performing the interviews). No complete
blinding could be achieved during any of the clinical studies. The participants were blinded to
the test results during the actual intervention, though afterwards some requested and received
their results. All measurements taken during Study I-III were performed within one week
prior to commencing the interventions and within one week following the intervention.
4.3.5 Heart rate variability and heart rate
4.3.5 Heart rate variability and heart rate
Heart rate variability (HRV) was measured usingan Aria-Delmar Holter Analyzer
electrocardiogram (ECG) in Study I. Study III saw the use of a heart rate monitor device.
Study I recorded heart rate variability for 24 hours, but only 2 hours (2-4 pm) were analysed
using the Aria-Delmar Holter Analyzer (Spacelabs Healthcare,WA, USA). The sampling rate
was 2048 Hz. The Kubios HRV analysis program, University of Kuopio, Finland, was used
for the ECG analysis and performed in a lab.
Study III measured HRV with a Polar heart rate monitor (RCX5, Polar Electro Oy, Kempele,
Finland) using the default settings for the Polar Pro Trainer software. Study II used the Polar
HR monitor to record HR. Normal beats (RR-intervals, also called NN) in the time domain of
HRV, equivalent to the difference between each R wave in milliseconds, was computed. The
intervals between contiguous QRS complexes in the ECG resulting from true sinus node
depolarisations were defined as NN-intervals 147. The NN50 count equals the number of pairs
of successive NN intervals differing by more than 50 ms during the 2 hour sampling period.
The time domain proportion (p) pNN50% is defined as the number of all NN intervals in
which the change in successive normal sinus intervals exceeds 50 milliseconds divided by the
Heart rate variability (HRV) was measured usingan Aria-Delmar Holter Analyzer
electrocardiogram (ECG) in Study I. Study III saw the use of a heart rate monitor device.
Study I recorded heart rate variability for 24 hours, but only 2 hours (2-4 pm) were analysed
using the Aria-Delmar Holter Analyzer (Spacelabs Healthcare,WA, USA). The sampling rate
was 2048 Hz. The Kubios HRV analysis program, University of Kuopio, Finland, was used
for the ECG analysis and performed in a lab.
Study III measured HRV with a Polar heart rate monitor (RCX5, Polar Electro Oy, Kempele,
Finland) using the default settings for the Polar Pro Trainer software. Study II used the Polar
HR monitor to record HR. Normal beats (RR-intervals, also called NN) in the time domain of
HRV, equivalent to the difference between each R wave in milliseconds, was computed. The
intervals between contiguous QRS complexes in the ECG resulting from true sinus node
depolarisations were defined as NN-intervals 147. The NN50 count equals the number of pairs
of successive NN intervals differing by more than 50 ms during the 2 hour sampling period.
The time domain proportion (p) pNN50% is defined as the number of all NN intervals in
which the change in successive normal sinus intervals exceeds 50 milliseconds divided by the
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31
total number of NN intervals measured (pNN50 = (NN50/n-1)*100%)147 148. SDNN is the
standard deviation of all NN intervals and RMSSD is the square root of the mean of the sum
of the squares of the differences between end-to-end NN intervals. The frequency domain of
the low/high frequency (LF/HF) ratio was calculated (using fast fourier transformation) to
measure the balanced activity of the sympathetic and parasympathetic nervous system. High
frequency refers to the power in the HF range of HRV and reflects efferent vagal activity,
whereas LF reflects sympathetic activity. LF and HF were measured in normalized units (n.u)
representing the relative value of each power frequency range component in relation to the
total power minus the VLF (very low frequency) component 147. Study I deleted all technical
artefacts from the ECG. A text file was constructed using subsequent RR-intervals from Aria
Holter and imported to Kubios software (filter setting on medium). A time series was then
calculated from the RR-intervals using spline interpolation with an interpolation rate of 4 Hz.
The linear trend was deleted and a Welch filter applied.
total number of NN intervals measured (pNN50 = (NN50/n-1)*100%)147 148. SDNN is the
standard deviation of all NN intervals and RMSSD is the square root of the mean of the sum
of the squares of the differences between end-to-end NN intervals. The frequency domain of
the low/high frequency (LF/HF) ratio was calculated (using fast fourier transformation) to
measure the balanced activity of the sympathetic and parasympathetic nervous system. High
frequency refers to the power in the HF range of HRV and reflects efferent vagal activity,
whereas LF reflects sympathetic activity. LF and HF were measured in normalized units (n.u)
representing the relative value of each power frequency range component in relation to the
total power minus the VLF (very low frequency) component 147. Study I deleted all technical
artefacts from the ECG. A text file was constructed using subsequent RR-intervals from Aria
Holter and imported to Kubios software (filter setting on medium). A time series was then
calculated from the RR-intervals using spline interpolation with an interpolation rate of 4 Hz.
The linear trend was deleted and a Welch filter applied.
4.3.6 Respiratory rate
4.3.6 Respiratory rate
The respiratory rate (f) in Study III was measured using a RESPeRATE ultra Omron 149 on a
supine participant with a strap wound across the lower chest. Occasional manual
measurements were performed to validate the results of the apparatus. Respiratory rates in
Study I and II was measured approximately and visually during the YE sessions.
The respiratory rate (f) in Study III was measured using a RESPeRATE ultra Omron 149 on a
supine participant with a strap wound across the lower chest. Occasional manual
measurements were performed to validate the results of the apparatus. Respiratory rates in
Study I and II was measured approximately and visually during the YE sessions.
4.3.7 Oxygen saturation
4.3.7 Oxygen saturation
Oxygen saturation (%) (SpO2) in Study III was measure using a saturation- and pulse
oximeter; (Ohmeda tuffsat) before and after the 6MWT, placed on the ring or middle finger.
Oxygen saturation (%) (SpO2) in Study III was measure using a saturation- and pulse
oximeter; (Ohmeda tuffsat) before and after the 6MWT, placed on the ring or middle finger.
4.3.8 Respiratory muscle strength
4.3.8 Respiratory muscle strength
Maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax) in Study III
was taken with a MicroRPM™ (Respiratory Pressure Meter) 150 to measure respiratory
muscle strength (values in cm H2O).
Maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax) in Study III
was taken with a MicroRPM™ (Respiratory Pressure Meter) 150 to measure respiratory
muscle strength (values in cm H2O).
4.3.9 Lung function
4.3.9 Lung function
Lung function in Study III was measured with Spirometry, Micro Loop, CareFusion and
Micro spirometry 150 151, expressed as FEV1, FVC and FEV1/FVC (values in litres). Flow and
strength measurements were performed with the participant seated and equipped with a nose
clip and a disposable mouthpiece and included three trials.
Lung function in Study III was measured with Spirometry, Micro Loop, CareFusion and
Micro spirometry 150 151, expressed as FEV1, FVC and FEV1/FVC (values in litres). Flow and
strength measurements were performed with the participant seated and equipped with a nose
clip and a disposable mouthpiece and included three trials.
4.3.10 Cardiorespiratory fitness monitoring/oxygen uptake (VO2max )
4.3.10 Cardiorespiratory fitness monitoring/oxygen uptake (VO2max )
Study II involved providing instructions on proper technique, how to use the RPE-Borg scale
and how to achieve true performance values during the Coopers test. Test leaders offered
encouragement and recorded the time, perceived exertion and heart rate recovery (difference
between maximal heart rate at the end of the Coopers test and after 1 minute). Systematic
errors were counteracted by offering a “pre-Coopers test” before the actual test and by having
the test leaders offer equal verbal encouragement to all participants.
The Coopers walk run test was used to measure cardiorespiratory performance/fitness
(estimated maximal oxygen uptake, VO2max) with a correlation of 0.92 versus 0.897 compared
to the treadmill test with true VO2max measurements 152 153. An additional tool
Study II involved providing instructions on proper technique, how to use the RPE-Borg scale
and how to achieve true performance values during the Coopers test. Test leaders offered
encouragement and recorded the time, perceived exertion and heart rate recovery (difference
between maximal heart rate at the end of the Coopers test and after 1 minute). Systematic
errors were counteracted by offering a “pre-Coopers test” before the actual test and by having
the test leaders offer equal verbal encouragement to all participants.
The Coopers walk run test was used to measure cardiorespiratory performance/fitness
(estimated maximal oxygen uptake, VO2max) with a correlation of 0.92 versus 0.897 compared
to the treadmill test with true VO2max measurements 152 153. An additional tool
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(“konditionssnurran”) was used to measure the time it took to run a distance of 2.000 meters
at full speed 153 .
(“konditionssnurran”) was used to measure the time it took to run a distance of 2.000 meters
at full speed 153 .
4.3.11 Rating of perceived exertion, RPE
4.3.11 Rating of perceived exertion, RPE
Study II and III used both the Borg CR-10 and Borg 20-RPE scales for perceived exertion
while Study I only saw the use of Borg 20. The scales were also used when practicing the
programs during all interventions (Study I-IV). In Study III the rating of perceived exertion
was registered before and directly after the 6MWT using a Borg CR-10 for measuring fatigue
in breathing and legs. The Borg 20-RPE was used to measure general tiredness in Study II
before and after a completed Coopers test 154 155.
Study II and III used both the Borg CR-10 and Borg 20-RPE scales for perceived exertion
while Study I only saw the use of Borg 20. The scales were also used when practicing the
programs during all interventions (Study I-IV). In Study III the rating of perceived exertion
was registered before and directly after the 6MWT using a Borg CR-10 for measuring fatigue
in breathing and legs. The Borg 20-RPE was used to measure general tiredness in Study II
before and after a completed Coopers test 154 155.
4.3.12 Blood pressure
4.3.12 Blood pressure
Blood pressure (BP) in Study I and III was measured 156 after approximately 5 minutes of rest
in a seated position using an automatic oscillometric BP monitoring device (Omron mx3). A
pillow was used to support the arm and the monitor attached to the upper arm. The
measurement was standardized for all participants; in the upper arm, at the same time of the
day, in the same seated position with legs on the floor, back supported and no crossed arms or
legs and no talking. In Study II, BP was measured using a Welch Allyn Durashock 2-hose
non-automated aneroid sphygmomanometer (AJM-8001-00l, 12 · 35 cm) with an inflatable
cuff and a screw valve and the help of a stethoscope (Panascope Combination Stethoscope for
auscultation).
Blood pressure (BP) in Study I and III was measured 156 after approximately 5 minutes of rest
in a seated position using an automatic oscillometric BP monitoring device (Omron mx3). A
pillow was used to support the arm and the monitor attached to the upper arm. The
measurement was standardized for all participants; in the upper arm, at the same time of the
day, in the same seated position with legs on the floor, back supported and no crossed arms or
legs and no talking. In Study II, BP was measured using a Welch Allyn Durashock 2-hose
non-automated aneroid sphygmomanometer (AJM-8001-00l, 12 · 35 cm) with an inflatable
cuff and a screw valve and the help of a stethoscope (Panascope Combination Stethoscope for
auscultation).
4.3.13 Hand-grip strength
4.3.13 Hand-grip strength
An electronic hand dynamometer (Camry model EH101) was used to analyse hand-grip
strength in Study I, with the participant standing upright with the monitor held in the
dominant hand, arm straight in line with the chest. The grip-test was first performed at
maximum strength. Then the grip was maintained for two minutes at a third of the person’s
maximum strength 157.
An electronic hand dynamometer (Camry model EH101) was used to analyse hand-grip
strength in Study I, with the participant standing upright with the monitor held in the
dominant hand, arm straight in line with the chest. The grip-test was first performed at
maximum strength. Then the grip was maintained for two minutes at a third of the person’s
maximum strength 157.
4.3.14 Apolipoproteins
4.3.14 Apolipoproteins
ApoA1/ApoB samples were analysed with DXC/LX (Beckman-Coulter).
ApoA1/ApoB samples were analysed with DXC/LX (Beckman-Coulter).
4.3.15 Adiponectin/Leptin
4.3.15 Adiponectin/Leptin
The blood samples were taken in laboratories and collected via a catheter. Adiponectin and
leptin samples were frozen and analysed after approximately 6 months. Adiponectin levels
were determined using radioimmunoassay (EMD Millipore). Leptin levels were determined
using radioimmunoassay (Millipore/Linco).
The blood samples were taken in laboratories and collected via a catheter. Adiponectin and
leptin samples were frozen and analysed after approximately 6 months. Adiponectin levels
were determined using radioimmunoassay (EMD Millipore). Leptin levels were determined
using radioimmunoassay (Millipore/Linco).
4.3.16 Glycosylated haemoglobin (HbA1c)
4.3.16 Glycosylated haemoglobin (HbA1c)
HbA1c was measured using a Variant II Turbo (Bio-Rad, Hercules,CA).
HbA1c was measured using a Variant II Turbo (Bio-Rad, Hercules,CA).
4.3.17 Waist circumference
4.3.17 Waist circumference
Study I-IV participants' waist circumferences were measured by placing a measuring tape
horizontally midway between the lower rib margin and the hip bone. Hip measurements were
taken at the widest point between the two bony prominences at the front of the hips. Waist-hip
ratio was used to measure the degree of obesity 158.
Study I-IV participants' waist circumferences were measured by placing a measuring tape
horizontally midway between the lower rib margin and the hip bone. Hip measurements were
taken at the widest point between the two bony prominences at the front of the hips. Waist-hip
ratio was used to measure the degree of obesity 158.
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33
4.3.18 Physical capacity, six-minute walk distance test (6MWD)
4.3.18 Physical capacity, six-minute walk distance test (6MWD)
150
A six-minute walk test done in Study III was performed to measure functional capacity .
The test was performed in a 50 meter long hallway with cones placed on the inside at the ends
of the 50 meters in accordance with the American Thoracic Society. Cues were given every
minute. The participants were told to walk as fast and as long as possible for six minutes.
A six-minute walk test done in Study III was performed to measure functional capacity 150.
The test was performed in a 50 meter long hallway with cones placed on the inside at the ends
of the 50 meters in accordance with the American Thoracic Society. Cues were given every
minute. The participants were told to walk as fast and as long as possible for six minutes.
4.3.19 Dyspnea related distress
4.3.19 Dyspnea related distress
Study III's dyspnea related distress (DD-index) 159 160 was calculated by dividing the CR-10
Borg scores at the end of 6MWT by the total distance walked in feet during 6MWT x 1000
(meters were first converted to feet). One point was required in order to achieve minimal
clinical important difference (MCID) 160.
Study III's dyspnea related distress (DD-index) 159 160 was calculated by dividing the CR-10
Borg scores at the end of 6MWT by the total distance walked in feet during 6MWT x 1000
(meters were first converted to feet). One point was required in order to achieve minimal
clinical important difference (MCID) 160.
4.3.20 Chronic respiratory disease questionnaire (CRQ), health related quality of life
4.3.20 Chronic respiratory disease questionnaire (CRQ), health related quality of life
The Chronic Respiratory Disease Questionnaire - Self-Administrative Standardized Activities
(CRQ-SAS) 161 contains 20 questions separated into 4 domains (dyspnea, fatigue, emotional
and mastery). The questionnaire was completed by the participants in Study III. Each question
is scored from 1-7 (with the exception of the dyspnea domain, which is scored from 1-5), with
higher scores representing less severe cases. MCID required 0.5 points per domain.
The Chronic Respiratory Disease Questionnaire - Self-Administrative Standardized Activities
(CRQ-SAS) 161 contains 20 questions separated into 4 domains (dyspnea, fatigue, emotional
and mastery). The questionnaire was completed by the participants in Study III. Each question
is scored from 1-7 (with the exception of the dyspnea domain, which is scored from 1-5), with
higher scores representing less severe cases. MCID required 0.5 points per domain.
4.3.21 Self-reported health
4.3.21 Self-reported health
Self-reported health in Study III was assessed using EuroQoL-5D (EQ-5D)162 and included
the question “how is your health today” along with a 10 cm visual analogue scale (VAS)
ranging from 0-100 (100=excellent health). The participant was asked to both tick the scale
and write down the number.
Self-reported health in Study III was assessed using EuroQoL-5D (EQ-5D)162 and included
the question “how is your health today” along with a 10 cm visual analogue scale (VAS)
ranging from 0-100 (100=excellent health). The participant was asked to both tick the scale
and write down the number.
4.3.22 Qualitative content approach
4.3.22 Qualitative content approach
Study IV used a qualitative content analysis. It included semi-structured interviews based on
inductive content analysis in accordance with Graneheim and Lundman 163.
Study IV used a qualitative content analysis. It included semi-structured interviews based on
inductive content analysis in accordance with Graneheim and Lundman 163.
4.3.22.1 Qualitative content data collection procedures
4.3.22.1 Qualitative content data collection procedures
Semi-structured interviews were conducted face to face (in Swedish) at the hospital, lasting
approx. 20-45 minutes. The topics included in the interviews were: expectations, previous
experience with YE and advice. The interview consisted of open-ended and broad questions
concerning the participants’ experiences during and after the YE. The interviews were audio
recorded with a digital Dictaphone (Olympus Digital Voice recorder VN-8500PC) and then
transcribed verbatim. The interviews were numbered and the interview transcripts were
anonymized.
Semi-structured interviews were conducted face to face (in Swedish) at the hospital, lasting
approx. 20-45 minutes. The topics included in the interviews were: expectations, previous
experience with YE and advice. The interview consisted of open-ended and broad questions
concerning the participants’ experiences during and after the YE. The interviews were audio
recorded with a digital Dictaphone (Olympus Digital Voice recorder VN-8500PC) and then
transcribed verbatim. The interviews were numbered and the interview transcripts were
anonymized.
4.3.22.2 Qualitative content analysis
4.3.22.2 Qualitative content analysis
The first analytical step involved reading the interview transcripts to get a general idea of the
content. Then came the formation of meaning units, i.e. the extraction and condensation of
parts of the original text that is closely associated with the research question. The content was
then read by the investigators and compared and discussed until such a time the group had
reached a consensus regarding the meaning units. The analysis proceeded with the summation
of the condensed meaning units and the labeling of these with a code representing a
description close to the text. The text was then reread and checked against the codes several
The first analytical step involved reading the interview transcripts to get a general idea of the
content. Then came the formation of meaning units, i.e. the extraction and condensation of
parts of the original text that is closely associated with the research question. The content was
then read by the investigators and compared and discussed until such a time the group had
reached a consensus regarding the meaning units. The analysis proceeded with the summation
of the condensed meaning units and the labeling of these with a code representing a
description close to the text. The text was then reread and checked against the codes several
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34
times to ensure that no information was lost. The codes were sorted into groups representing a
higher level of abstraction, and then further divided into subcategories and categories by
comparing similarities and differences in codes and code groups. Both categories and subcategories were considered expressions of the manifest content of the text and examined to be
mutually exclusive. Finally, an overall theme was developed to link the underlying meaning
with the emerging categories. This theme describes the latent content of the text which has to
be interpreted 163. During the analytical steps, the credibility of the preliminary findings and
the process of reflexivity were addressed among the research group by carefully following up
on the whole analytical process and categorization work. Divergent views concerning the
categorization were discussed until such a time a consensus was reached 164 165.
times to ensure that no information was lost. The codes were sorted into groups representing a
higher level of abstraction, and then further divided into subcategories and categories by
comparing similarities and differences in codes and code groups. Both categories and subcategories were considered expressions of the manifest content of the text and examined to be
mutually exclusive. Finally, an overall theme was developed to link the underlying meaning
with the emerging categories. This theme describes the latent content of the text which has to
be interpreted 163. During the analytical steps, the credibility of the preliminary findings and
the process of reflexivity were addressed among the research group by carefully following up
on the whole analytical process and categorization work. Divergent views concerning the
categorization were discussed until such a time a consensus was reached 164 165.
Meaning unit
Condensed
meaning unit
Code
Meaning unit
Condensed
meaning unit
Code
after a couple of times I was able to get into
that mood very quickly, when you filter out
all unnecessary things, you don’t bring along
any thoughts about different things, instead I
could easily focus on being there, in that
moment and I thought that was a positive
effect
after a couple of
times I was able
to filter out all
unnecessary
things, and easily
focus on being
there, which I
thought of as
something
positive
Focus on
the
moment
after a couple of times I was able to get into
that mood very quickly, when you filter out
all unnecessary things, you don’t bring along
any thoughts about different things, instead I
could easily focus on being there, in that
moment and I thought that was a positive
effect
after a couple of
times I was able
to filter out all
unnecessary
things, and easily
focus on being
there, which I
thought of as
something
positive
Focus on
the
moment
in the beginning, when we started this
breathing training, then I often started
coughing and sometimes I felt that I was
hyperventilating and yes, but then when you
have found the pace, that is your own pace
and work on it, well I felt that this makes a
difference, that is when the Yoga gave me
something more than it did in the beginning
It was only when To focus
I found my own
on oneself
pace in the
breathing training
that I felt the
difference that the
yoga made and it
gave something
back
in the beginning, when we started this
breathing training, then I often started
coughing and sometimes I felt that I was
hyperventilating and yes, but then when you
have found the pace, that is your own pace
and work on it, well I felt that this makes a
difference, that is when the Yoga gave me
something more than it did in the beginning
It was only when To focus
I found my own
on oneself
pace in the
breathing training
that I felt the
difference that the
yoga made and it
gave something
back
Table A. Example of data analysis using content analysis
35
Subcategory
Category
A new focus
To focus on
and
oneself
awareness
Table A. Example of data analysis using content analysis
35
Subcategory
Category
A new focus
To focus on
and
oneself
awareness
4.4 Statistical analyses
4.4 Statistical analyses
Study
I
II
III
Study
I
II
III
Statistics
Student t-test
Mann-Whitney/
Wilcoxon
Mann-Whitney
Mann-Whitney
/Wilcoxon
Statistics
Student t-test
Mann-Whitney/
Wilcoxon
Mann-Whitney
Mann-Whitney
/Wilcoxon
/Wilcoxon
Student t-test
Student t-test
Analysis of differences
/variances
Spearman/Pearson
ANOVA
Spearman/Pearson
Chi-square test
/Wilcoxon
Student t-test
Student t-test
Analysis of differences
/variances
Spearman/Pearson
ANOVA
Spearman/Pearson
Chi-square test
Table B. Statistical methods. Statistical significance was set to p<0.05 in Study I, II and III. Results
were presented as mean and/or median with one standard deviation (SD) and/or range and a 95 %
confidence interval. Statistical analysis was performed by using Stata software (Stata Corp., College
Station, TX)/Version 11 and 14 and MATLAB (partly in Study I). In Study II, no significance was
found between the two groups' baseline.
Table B. Statistical methods. Statistical significance was set to p<0.05 in Study I, II and III. Results
were presented as mean and/or median with one standard deviation (SD) and/or range and a 95 %
confidence interval. Statistical analysis was performed by using Stata software (Stata Corp., College
Station, TX)/Version 11 and 14 and MATLAB (partly in Study I). In Study II, no significance was
found between the two groups' baseline.
4.5 Ethical considerations
4.5 Ethical considerations
Current ethical guidelines for medical research on human participants were followed and
considered before, during and after the clinical trials in order to protect the participants 166.
The programs were individually adapted for safety purposes and to prevent injury. Written
and oral information was given out to all participants before the commencement of the study
and all participants signed informed consent forms. The research was approved by the
regional research ethics committee in Stockholm.
Current ethical guidelines for medical research on human participants were followed and
considered before, during and after the clinical trials in order to protect the participants 166.
The programs were individually adapted for safety purposes and to prevent injury. Written
and oral information was given out to all participants before the commencement of the study
and all participants signed informed consent forms. The research was approved by the
regional research ethics committee in Stockholm.
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5 RESULTS
5 RESULTS
TABLE C. Summary of three different yoga interventions (III+IV=same intervention), ITT=
intention- to-treat, PP=per-protocol. Study design, intervention, outcome measures and results
after practicing different hatha yoga programs (YE).
I. Inversions
II. Sun salutation
III. Yoga & breathing IV. Yoga &
YOGA (YE)
(n=12/9*)
(SS) (n=44)
(n=36)
breathing (n=15)
Intervention
TABLE C. Summary of three different yoga interventions (III+IV=same intervention), ITT=
intention- to-treat, PP=per-protocol. Study design, intervention, outcome measures and results
after practicing different hatha yoga programs (YE).
I. Inversions
II. Sun salutation
III. Yoga & breathing IV. Yoga &
YOGA (YE)
(n=12/9*)
(SS) (n=44)
(n=36)
breathing (n=15)
Intervention
Design
Length of
intervention
Analysis
Pilot
8 weeks
1h./week
PP
RCT
6 weeks
1 h./week
PP
RCT
12 weeks
2 h./week
ITT
Participants
Healthy inactive
working adults
4/8
51 (38-59)
6 (1-8) max 8
Healthy students
Asthma and/or COPD
38/6
25 (20-39)
4 (1-6) max 6
Women/men
Age
Adherence to
number of yoga
classes
Borg 20- RPE
(general) during
YE
Primary
outcomes
Secondary
outcomes
Results of
significance
13
(Somewhat hard)
13-15
(Somewhat hardHard)
Heart rate
Cardiovascular
variability (HRV) fitness/endurance
(VO2max )
Blood pressure
Adiponectin
Hand-grip
Blood lipids strength
(apolipoproteins)
Blood pressure
↑pNN50
↑Adiponectin
(HRV measure) ↑ApolipoproteinA1
(n=9)
↑Hand-grip
strength (n=9)
Cross-sectional interview
12 weeks
2 h./week
Inductive qualitative
content analysis
Asthma and/or COPD
Design
Length of
intervention
Analysis
Pilot
8 weeks
1h./week
PP
RCT
6 weeks
1 h./week
PP
RCT
12 weeks
2 h./week
ITT
Participants
Healthy students
Asthma and/or COPD
23/13
64 (40-84)
20 (3-24) max 24
CTP-training group;
19.5 (12-22) max 24
10
(Very light/Fairly light)
10/5
61 (44-76)
20 (6-24) max 24
38/6
25 (20-39)
4 (1-6) max 6
23/13
64 (40-84)
20 (3-24) max 24
CTP-training group;
19.5 (12-22) max 24
10
(Very light/Fairly light)
10/5
61 (44-76)
20 (6-24) max 24
Walking distance
(6MWD)
Dyspnea (breathlessness)
Lung function, Healthrelated quality of life,
Respiratory rate
Experiences after yoga
intervention
Women/men
Age
Adherence to
number of yoga
classes
Borg 20- RPE
(general) during
YE
Primary
outcomes
Healthy inactive
working adults
4/8
51 (38-59)
6 (1-8) max 8
Walking distance
(6MWD)
Dyspnea (breathlessness)
Lung function, Healthrelated quality of life,
Respiratory rate
Experiences after yoga
intervention
↑Walking distance
(6MWD)
↑Disease specific
quality of life (CRQ)
↓Respiratory rate
↑Oxygen saturation
Improved well-being and
dyspnea control
↑Walking distance
(6MWD)
↑Disease specific
quality of life (CRQ)
↓Respiratory rate
↑Oxygen saturation
Improved well-being and
dyspnea control
10
Secondary
outcomes
Results of
significance
13
(Somewhat hard)
13-15
(Somewhat hardHard)
Heart rate
Cardiovascular
variability (HRV) fitness/endurance
(VO2max )
Blood pressure
Adiponectin
Hand-grip
Blood lipids strength
(apolipoproteins)
Blood pressure
↑pNN50
↑Adiponectin
(HRV measure) ↑ApolipoproteinA1
(n=9)
↑Hand-grip
strength (n=9)
Cross-sectional interview
12 weeks
2 h./week
Inductive qualitative
content analysis
Asthma and/or COPD
10
*12/9=12 total, 9 in ECG group. Note: not all participants were present during the Borg-RPE
measurements. Age, adherence and Borg-RPE are presented as median and range.
*12/9=12 total, 9 in ECG group. Note: not all participants were present during the Borg-RPE
measurements. Age, adherence and Borg-RPE are presented as median and range.
All graphs below: Dashed lines show yogic exercise (YE) group. All graphs presenting
means and medians with profile-plots and box-plots if not otherwise stated.
All graphs below: Dashed lines show yogic exercise (YE) group. All graphs presenting
means and medians with profile-plots and box-plots if not otherwise stated.
37
37
5.1 Heart rate variability
5.1 Heart rate variability
Study I, using an 8 week YE program, showed a medium effect (ES 0.45) on heart rate
variability (HRV), with a significant increase in proportion (p) pNN50% (p=0.035)
(12.7±12.5 to 18.2±13.3) at night (2h recording) after the intervention. Study III did not show
any effects on HRV (5 min recording), graph not shown.
Study I, using an 8 week YE program, showed a medium effect (ES 0.45) on heart rate
variability (HRV), with a significant increase in proportion (p) pNN50% (p=0.035)
(12.7±12.5 to 18.2±13.3) at night (2h recording) after the intervention. Study III did not show
any effects on HRV (5 min recording), graph not shown.
Figure 6. Study I HRV measures: NN-intervals and pNN50% each differing by more than 50
ms.
Figure 6. Study I HRV measures: NN-intervals and pNN50% each differing by more than 50
ms.
5.2 Respiratory rate and oxygen saturation
5.2 Respiratory rate and oxygen saturation
In Study III the respiratory rate (f) decreased (p=0.05) and oxygen saturation at rest increased
(p=0.02) within the YE group. No significant effect emerged in the CTP group.
In Study III the respiratory rate (f) decreased (p=0.05) and oxygen saturation at rest increased
(p=0.02) within the YE group. No significant effect emerged in the CTP group.
Figure 7. Changes in respiratory rate and oxygen saturation in Study III
Figure 7. Changes in respiratory rate and oxygen saturation in Study III
38
38
5.3 Respiratory muscle strength
5.3 Respiratory muscle strength
In Study III the inspiratory muscle strength (p=0.03) and expiratory muscle strength
(p=0.004) increased within the CTP group. No significant effect in YE group.
In Study III the inspiratory muscle strength (p=0.03) and expiratory muscle strength
(p=0.004) increased within the CTP group. No significant effect in YE group.
Figure 8. Changes in respiratory muscle strength measured across three points in the
conventional and YE groups in Study III.
Figure 8. Changes in respiratory muscle strength measured across three points in the
conventional and YE groups in Study III.
5.4 Lung function
5.4 Lung function
Forced Expiratory Volume in one second (FEV1) increased significantly within CTP group
(p=0.01) in Study III following the intervention. No effect in YE group.
Forced Expiratory Volume in one second (FEV1) increased significantly within CTP group
(p=0.01) in Study III following the intervention. No effect in YE group.
Figure 9a. Changes in FEV1 and Forced Vital Capacity (FVC) measured across three points
in Study III. See Table F for MCID.
Figure 9a. Changes in FEV1 and Forced Vital Capacity (FVC) measured across three points
in Study III. See Table F for MCID.
39
39
5.5 FEV1/FVC ratio
5.5 FEV1/FVC ratio
In Study III the FEV1/FVC ratio decreased significantly in YE group (p=0.04) after 12-weeks
and a trend in CTP group emerged. However no significant effects between groups.
In Study III the FEV1/FVC ratio decreased significantly in YE group (p=0.04) after 12-weeks
and a trend in CTP group emerged. However no significant effects between groups.
Figure 9b. Changes in FEV1 and Forced Vital Capacity (FVC) ratio across three points in
time in Study III.
Figure 9b. Changes in FEV1 and Forced Vital Capacity (FVC) ratio across three points in
time in Study III.
5.6 Cardiorespiratory fitness, VO2max
5.6 Cardiorespiratory fitness, VO2max
Study II showed no significant effects on cardiovascular fitness following high intensity YE
(estimated using Coopers test). Mean dose: 390 minutes, ranging from 210–800 min.
Study II showed no significant effects on cardiovascular fitness following high intensity YE
(estimated using Coopers test). Mean dose: 390 minutes, ranging from 210–800 min.
Figure 10. Maximal oxygen uptake measured with Coopers test before and after 6 weeks of
high intensity YE during Study II, see also Table D.
Figure 10. Maximal oxygen uptake measured with Coopers test before and after 6 weeks of
high intensity YE during Study II, see also Table D.
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40
Cardiorespiratory fitness and adiponectin
Cardiorespiratory fitness and adiponectin
Table D: Study II; oxygen uptake, VO2max (estimated using Coopers test), time, non-responders and
improvements > 2 ml O2/kg/min and improvements in adiponectin using 6 weeks of high intensity
hatha yogic exercises (YE) (range in parenthesis)
N=44
YE (n=21)
Control (n=23)
Table D: Study II; oxygen uptake, VO2max (estimated using Coopers test), time, non-responders and
improvements > 2 ml O2/kg/min and improvements in adiponectin using 6 weeks of high intensity
hatha yogic exercises (YE) (range in parenthesis)
N=44
YE (n=21)
Control (n=23)
Minutes/seconds Coopers test
(2 km) and range
11.40 (8.18-18.31)
11.18 (8.07-18.01)
Minutes/seconds Coopers test
(2 km) and range
11.40 (8.18-18.31)
11.18 (8.07-18.01)
Non responders to Coopers test
5 (24%)
4 (17%)
Non responders to Coopers test
5 (24%)
4 (17%)
Improvement > 2 ml O2/kg/min
5 (24%)
3 (13%)
Improvement > 2 ml O2/kg/min
5 (24%)
3 (13%)
Adiponectin mg/L improvement
>2 units, (5-30 mg/L normal)
7 (2-6.1)
4 (2.4-7)
Adiponectin mg/L improvement
>2 units, (5-30 mg/L normal)
7 (2-6.1)
4 (2.4-7)
5.7 Rating of perceived exertion, RPE (Borg)
5.7 Rating of perceived exertion, RPE (Borg)
No significance was detected between or within the groups on the RPE-Borg scales in any of
the interventions.
No significance was detected between or within the groups on the RPE-Borg scales in any of
the interventions.
Table E. RPE Borg-20 during YE in Study I-III
Table E. RPE Borg-20 during YE in Study I-III
Study I
RPE-Borg 20
13
Study I
RPE-Borg 20
13
Study II
14 (9-17), 15 (10-18) (after 25 min. and 45 min. respectively)
Study II
14 (9-17), 15 (10-18) (after 25 min. and 45 min. respectively)
Study III
10 (3.5-14)
Note: Median and ranges. Not all participants were measured, see also Table C.
41
Study III
10 (3.5-14)
Note: Median and ranges. Not all participants were measured, see also Table C.
41
5.8 Blood pressure (BP)
5.8 Blood pressure (BP)
No changes in BP were detected in Study I and II. Improved effects in diastolic blood
pressure (p=0.05) emerged in CTP group in Study III after follow-up (Fig.13).
No changes in BP were detected in Study I and II. Improved effects in diastolic blood
pressure (p=0.05) emerged in CTP group in Study III after follow-up (Fig.13).
Figure 11. Changes in diastolic and systolic blood pressure in Study I (pilot study) after 8
weeks.
Figure 11. Changes in diastolic and systolic blood pressure in Study I (pilot study) after 8
weeks.
Figure 12. Changes in diastolic and systolic blood pressure in Study II after 6 weeks.
Figure 12. Changes in diastolic and systolic blood pressure in Study II after 6 weeks.
Figure 13. Changes in diastolic and systolic blood pressure across 3 time points in Study III
Figure 13. Changes in diastolic and systolic blood pressure across 3 time points in Study III
42
42
5.9 Hand-grip strength
5.9 Hand-grip strength
Hand-grip strength improved (p=0.02) in the YE group in Study I.
Hand-grip strength improved (p=0.02) in the YE group in Study I.
Figure 14. Changes in max. hand-grip strength in YE group in Study I
Figure 14. Changes in max. hand-grip strength in YE group in Study I
5.10 Blood parameters – adiponectin, leptin and apolipoproteins
5.10 Blood parameters – adiponectin, leptin and apolipoproteins
Study II showed no significant effects on adiponectin and leptin levels between the YE and
CTP group. However, adiponectin levels showed significant increases within the YE group
after six weeks (8.32±3.32 to 9.68±3.83; (p=0.003)).
Study II showed no significant effects on adiponectin and leptin levels between the YE and
CTP group. However, adiponectin levels showed significant increases within the YE group
after six weeks (8.32±3.32 to 9.68±3.83; (p=0.003)).
Figure 15. Changes after 6 weeks in adiponectin and leptin levels in Study II. Data shown
applies to women as women have higher levels of adiponectin and leptin than men.
Figure 15. Changes after 6 weeks in adiponectin and leptin levels in Study II. Data shown
applies to women as women have higher levels of adiponectin and leptin than men.
43
43
Blood parameters
Blood parameters
In Study II there were no significant effects on apolipoproteins levels at baseline or after the
intervention between the two groups. However, ApoA1 increased within the YE group from
1.47±0.17 to 1.55±0.16; (p=0.03).
In Study II there were no significant effects on apolipoproteins levels at baseline or after the
intervention between the two groups. However, ApoA1 increased within the YE group from
1.47±0.17 to 1.55±0.16; (p=0.03).
Figure 16. Changes after 6 weeks in ApolipoproteinA1 and Apolipoprotein B in Study II in
YE and control groups
Figure 16. Changes after 6 weeks in ApolipoproteinA1 and Apolipoprotein B in Study II in
YE and control groups
5.11 Glycosylated haemoglobin (HbA1c)
5.11 Glycosylated haemoglobin (HbA1c)
Study II demonstrated no significant changes to HbA1c in the control group, but in the YE
group HbA1c was lowered in near significant amounts (p=0.07).
Study II demonstrated no significant changes to HbA1c in the control group, but in the YE
group HbA1c was lowered in near significant amounts (p=0.07).
Figure 17. Changes after 6 weeks in glycosylated HbA1c in Study II
Figure 17. Changes after 6 weeks in glycosylated HbA1c in Study II
44
44
5.12 Physical capacity, six minute walk distance (6MWD)
5.12 Physical capacity, six minute walk distance (6MWD)
Study III showed significant improvements in six minute walk distance results (6MWD) after
12 weeks of intervention (YE: mean difference 32.6 m; CI 10.1-55.1, (p=0.014); CTP: mean
difference 42.4 m; CI 17.9-67.0, (p=0.006) for both groups. Improvements after follow-up (6
months) emerged only in the CTP group for 6MWD (p=0.04).
Study III showed significant improvements in six minute walk distance results (6MWD) after
12 weeks of intervention (YE: mean difference 32.6 m; CI 10.1-55.1, (p=0.014); CTP: mean
difference 42.4 m; CI 17.9-67.0, (p=0.006) for both groups. Improvements after follow-up (6
months) emerged only in the CTP group for 6MWD (p=0.04).
Figure 18. Six minute walk distance measured across three time points in Study III, see also
Table F
Figure 18. Six minute walk distance measured across three time points in Study III, see also
Table F
Table F: Number of patients in Study III with obstructive pulmonary disease (range in parenthesis) across
different points in time, with minimal clinically important difference (MCID) for six minute walk distance
(6MWD) (>30, >50 meters), dyspnea related distress (DD-index) (<1 point). Forced expiratory volume in one
second in litres (FEV1) ≥100 ml 167.
Table F: Number of patients in Study III with obstructive pulmonary disease (range in parenthesis) across
different points in time, with minimal clinically important difference (MCID) for six minute walk distance
(6MWD) (>30, >50 meters), dyspnea related distress (DD-index) (<1 point). Forced expiratory volume in one
second in litres (FEV1) ≥100 ml 167.
YE=yoga
YE (n=19)
YE (n=15 )
YE (n=15)
CT (n=17)
CT (n=15)
CT (n=15)
YE=yoga
YE (n=19)
YE (n=15 )
YE (n=15)
CT (n=17)
CT (n=15)
CT (n=15)
CTP=conventional
1→2
2→3
1 →3
1→2
2→3
1→3
CTP=conventional
1→2
2→3
1 →3
1→2
2→3
1→3
6MWD
7
1
5
10
5
11
6MWD
7
1
5
10
5
11
(>30 meters)
(37-113)
(34)
(41-107)
(31-135)
(30-53)
(49.5-123)
(>30 meters)
(37-113)
(34)
(41-107)
(31-135)
(30-53)
(49.5-123)
6MWD
5
0
3
9
1
10 **
6MWD
5
0
3
9
1
10 **
(>50 meters)
(82-113)
(53-107)
(57-135)
(53)
(54-123)
(>50 meters)
(82-113)
(53-107)
(57-135)
(53)
(54-123)
DD-index
respiration
3 (16%)
0
1
7 (41%)
4
5
DD-index
respiration
3 (16%)
0
1
7 (41%)
4
5
DD-index legs
2
1
0
5
0
4
DD-index legs
2
1
0
5
0
4
FEV1/L ≥100 ml,
mean/sd
8 (110-330) (42%)
4 (110-360)
198±111
5 (110-490)
9 (100-540) (53%)
3 (230-470)
337±122
5 (140-440)
8 (110-330) (42%)
4 (110-360)
198±111
5 (110-490)
9 (100-540) (53%)
3 (230-470)
337±122
5 (140-440)
240±152
244± 155
FEV1/L ≥100 ml,
mean/sd
240±152
244± 155
**
**
220±92.6
**
**
**
302±123
** p = <0.05; Points in time, 1=baseline; 2=after intervention; 3=six months follow up; 6MWT= Six minute walk test; DDindex=dyspnea related distress; FEV1=forced expiratory volume in one second; T-test and Wilcoxon calculations used.
45
**
**
220±92.6
**
**
**
302±123
** p = <0.05; Points in time, 1=baseline; 2=after intervention; 3=six months follow up; 6MWT= Six minute walk test; DDindex=dyspnea related distress; FEV1=forced expiratory volume in one second; T-test and Wilcoxon calculations used.
45
5.13 Dyspnea related distress (DD-index)
5.13 Dyspnea related distress (DD-index)
No significant effect on dyspnea-related distress appeared in any group in Study III; however
MCID appeared for some participants in both groups (Table F).
No significant effect on dyspnea-related distress appeared in any group in Study III; however
MCID appeared for some participants in both groups (Table F).
Figure 19. Dyspnea related distress in breathing (fatigue for legs not presented) across 3
points in time Study III.
Figure 19. Dyspnea related distress in breathing (fatigue for legs not presented) across 3
points in time Study III.
5.14 Self-reported health
5.14 Self-reported health
No between group effects emerged in self-reported health using (EQ-5D/VAS) in Study III.
Eight patients in each group reported improved self-reported health after the intervention
using (EQ-5D/VAS) of MCID (10 units) data not shown.
No between group effects emerged in self-reported health using (EQ-5D/VAS) in Study III.
Eight patients in each group reported improved self-reported health after the intervention
using (EQ-5D/VAS) of MCID (10 units) data not shown.
Figure 21. The EQ-5D decreased significantly within the CTP group (p=0.03) after 6 months.
Figure 21. The EQ-5D decreased significantly within the CTP group (p=0.03) after 6 months.
46
46
5.15 Disease specific chronic respiratory disease questionnaire (CRQ) quality of life
5.15 Disease specific chronic respiratory disease questionnaire (CRQ) quality of life
In Study III, while testing for interactions (group x time) with ANOVAs, there emerged
significant effects on the fatigue (p=0.04) and emotional (p=0.02) domains of the CRQ, with
improvements shown in the CTP group but not in the YE group after the 12 week long
intervention (p=0.02 and 0.01, respectively). Improved effects after follow-up (6 months)
emerged for the CTP group in the CRQ emotional domain (p=0.01). Significant effects also
emerged in the YE group with regards to the CRQ mastery domain following 12 weeks.
In Study III, while testing for interactions (group x time) with ANOVAs, there emerged
significant effects on the fatigue (p=0.04) and emotional (p=0.02) domains of the CRQ, with
improvements shown in the CTP group but not in the YE group after the 12 week long
intervention (p=0.02 and 0.01, respectively). Improved effects after follow-up (6 months)
emerged for the CTP group in the CRQ emotional domain (p=0.01). Significant effects also
emerged in the YE group with regards to the CRQ mastery domain following 12 weeks.
Figure 20. Above (four graphs): changes in all four CRQ domains across three points in time
in Study III. Higher scores indicate less severity.
Figure 20. Above (four graphs): changes in all four CRQ domains across three points in time
in Study III. Higher scores indicate less severity.
47
47
5.16 Correlation between six-minute walk test and self-reported health
5.16 Correlation between six-minute walk test and self-reported health
Study III showed differences between 6MWD and EQ/5D VAS health at baseline and directly
following intervention (12 weeks) favoring the YE group (p=0.01) (CTP group p=0.9).
Study III showed differences between 6MWD and EQ/5D VAS health at baseline and directly
following intervention (12 weeks) favoring the YE group (p=0.01) (CTP group p=0.9).
Figure 22. Correlation line for CTP and YE groups (R=0.59)
Figure 22. Correlation line for CTP and YE groups (R=0.59)
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48
5.17 Qualitative content analysis
5.17 Qualitative content analysis
In Study IV three main categories emerged of the qualitative content analysis: “A new focus
and awareness”, “To gain new knowledge by practice” and “To experience how one can
influence the own situation”. The overall theme “From limitation to opportunity – to develop
awareness and control over one’s breathing” illustrates a learning process on different levels.
Specifically, it illustrates that the participants perceived improved physical symptoms and
breathing technique, greater energy/stamina and body awareness along with a new sense of
control over their breathing in different situations.
In Study IV three main categories emerged of the qualitative content analysis: “A new focus
and awareness”, “To gain new knowledge by practice” and “To experience how one can
influence the own situation”. The overall theme “From limitation to opportunity – to develop
awareness and control over one’s breathing” illustrates a learning process on different levels.
Specifically, it illustrates that the participants perceived improved physical symptoms and
breathing technique, greater energy/stamina and body awareness along with a new sense of
control over their breathing in different situations.
In Study IV the analysis resulted in an overall theme, 3 categories and 7 sub categories
(Table G).
In Study IV the analysis resulted in an overall theme, 3 categories and 7 sub categories
(Table G).
Table G: Overview of the findings in Study IV using qualitative content analysis
Table G: Overview of the findings in Study IV using qualitative content analysis
Overall theme
Overall theme
From limitation to opportunity – to develop awareness and control over
one’s breathing
From limitation to opportunity – to develop awareness and control over
one’s breathing
Categories
Categories
A new focus and
awareness
To gain new
To experience how
knowledge by practice one can influence the
A new focus and
awareness
To gain new
To experience how
knowledge by practice one can influence the
own situation
own situation
Subcategories
Subcategories
To focus on oneself
To feel safe and be
guided
To be able to control
the breathing
To focus on oneself
To feel safe and be
guided
To be able to control
the breathing
To be aware of
breathing and to
discover
Learning by doing
To be able to manage
To be aware of
breathing and to
discover
Learning by doing
To be able to manage
stress and achieve
stress and achieve
balance
balance
To have more stamina
To have more stamina
and to master
and to master
challenges
challenges
In Study IV the three categories were (Table G):
In Study IV the three categories were (Table G):
A new focus and awareness: where the participants described YE as an opportunity to focus
and to be aware of their breathing in a new way. Both the focus and awareness of the
participants breathing was experienced in a new way and as an important part of practicing
YE. Awareness and focus during practise of YE seemed necessary for developing new
insights about different ways of breathing.
A new focus and awareness: where the participants described YE as an opportunity to focus
and to be aware of their breathing in a new way. Both the focus and awareness of the
participants breathing was experienced in a new way and as an important part of practicing
YE. Awareness and focus during practise of YE seemed necessary for developing new
insights about different ways of breathing.
49
49
To gain new knowledge by practice: revealed that actively participating in YE involved
conquering new knowledge about the body and breath by doing the exercises, that is “learning
by doing”. Even individuals with little previous experience of YE, mentioned that
participating in YE deepened their knowledge about breathing techniques and how to use the
techniques in daily life. Explicitly, the YE was experienced as an opportunity to anchor the
new knowledge through the hands-on trying and practising.
To gain new knowledge by practice: revealed that actively participating in YE involved
conquering new knowledge about the body and breath by doing the exercises, that is “learning
by doing”. Even individuals with little previous experience of YE, mentioned that
participating in YE deepened their knowledge about breathing techniques and how to use the
techniques in daily life. Explicitly, the YE was experienced as an opportunity to anchor the
new knowledge through the hands-on trying and practising.
To experience how one can influence the own situation: revealed that participating in YE
created opportunities for participants themselves to control symptoms related to the lung
disease but also in daily life situations. The participants reported that they were able to control
the breathing and stress voluntarily, thus achieving feelings of harmony and balance. They
also experienced increased energy, improved stamina, coping and feelings of safety and
security while doing the YE and other physical activities.
To experience how one can influence the own situation: revealed that participating in YE
created opportunities for participants themselves to control symptoms related to the lung
disease but also in daily life situations. The participants reported that they were able to control
the breathing and stress voluntarily, thus achieving feelings of harmony and balance. They
also experienced increased energy, improved stamina, coping and feelings of safety and
security while doing the YE and other physical activities.
Some selected citations of the participants’ experiences in Study IV:
I think some exercises have been really good, that is you immediately feel that they open up
the airways and that you get a lot of oxygen during these exercises and so that was a great
surprise, that you get that feeling in just one exercise” Interview No. 3
Some selected citations of the participants’ experiences in Study IV:
I think some exercises have been really good, that is you immediately feel that they open up
the airways and that you get a lot of oxygen during these exercises and so that was a great
surprise, that you get that feeling in just one exercise” Interview No. 3
I actually think that if I feel the asthma, so instead of taking a quick Ventolin (medication), it
is possible to do a breathing exercise and it works. It is not that I have stopped taking my
meds but instead feel that perhaps I should but instead I do these breathing exercises and it
becomes better.” Interview No. 6
I actually think that if I feel the asthma, so instead of taking a quick Ventolin (medication), it
is possible to do a breathing exercise and it works. It is not that I have stopped taking my
meds but instead feel that perhaps I should but instead I do these breathing exercises and it
becomes better.” Interview No. 6
I have realized that I can cope with situations in a different way. I can do more now, can and
have the strength to do more, I realize that I can walk longer without having to rest”
Interview No. 13
I have realized that I can cope with situations in a different way. I can do more now, can and
have the strength to do more, I realize that I can walk longer without having to rest”
Interview No. 13
I feel I learned these exercises, I will continue with these…I got this control and harmony and
balance thing, and now I have it. I understand how to master it…I did, I didn’t do that when I
started. I will take this to my heart …” Interview No. 14
I feel I learned these exercises, I will continue with these…I got this control and harmony and
balance thing, and now I have it. I understand how to master it…I did, I didn’t do that when I
started. I will take this to my heart …” Interview No. 14
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50
6 Discussion
6 Discussion
The main findings of this thesis involve results of evaluating different yogic exercise
programs as those in Studies I-III. All programs were feasible and safe with no documented
adverse effects. Study I was a pilot study calling for caution when interpreting the results.
However, significant increases in heart rate variability and hand-grip strength still emerged.
Study II showed no significant effect between the two groups. However, the yogic exercise
group (YE) demonstrated increased levels of apolipoproteinA1 and adiponectin following the
YE intervention. As a result of Study II, one might suggest that low doses of YE can improve
cardiovascular and metabolic health in healthy individuals, even though cardiovascular fitness
remains unaffected.
Study III found no significant between-group effect in any parameter after the intervention
using t-tests. Analysis of variance differences emerged in CRQ fatigue and CRQ emotional
domains favouring treatment as usual group (CTP).
After 12 weeks of intervention, all CRQ domains showed improvement in the CTP group
whereas in the YE group only the mastery domain showed improvement. Both groups
displayed significant improvements in walking distance after 12 weeks. Within the YE group
showed lowered respiratory rate, improved CRQ mastery of the disease and increased oxygen
saturation and a significant correlation when comparing differences in walking distance and
self-reported health following the intervention. However significant effects in lung function
and respiratory muscle strength emerged within CTP group but not in YE group. Study IV
found that practicing YE may act to empower individuals with obstructive pulmonary
disorders and help them control their symptoms and dyspnea. Yogic practice may serve as an
efficient tool for learning new ways of breathing as well as strengthening one's self-efficacy
and mastery of the disease.
The main findings of this thesis involve results of evaluating different yogic exercise
programs as those in Studies I-III. All programs were feasible and safe with no documented
adverse effects. Study I was a pilot study calling for caution when interpreting the results.
However, significant increases in heart rate variability and hand-grip strength still emerged.
Study II showed no significant effect between the two groups. However, the yogic exercise
group (YE) demonstrated increased levels of apolipoproteinA1 and adiponectin following the
YE intervention. As a result of Study II, one might suggest that low doses of YE can improve
cardiovascular and metabolic health in healthy individuals, even though cardiovascular fitness
remains unaffected.
Study III found no significant between-group effect in any parameter after the intervention
using t-tests. Analysis of variance differences emerged in CRQ fatigue and CRQ emotional
domains favouring treatment as usual group (CTP).
After 12 weeks of intervention, all CRQ domains showed improvement in the CTP group
whereas in the YE group only the mastery domain showed improvement. Both groups
displayed significant improvements in walking distance after 12 weeks. Within the YE group
showed lowered respiratory rate, improved CRQ mastery of the disease and increased oxygen
saturation and a significant correlation when comparing differences in walking distance and
self-reported health following the intervention. However significant effects in lung function
and respiratory muscle strength emerged within CTP group but not in YE group. Study IV
found that practicing YE may act to empower individuals with obstructive pulmonary
disorders and help them control their symptoms and dyspnea. Yogic practice may serve as an
efficient tool for learning new ways of breathing as well as strengthening one's self-efficacy
and mastery of the disease.
6.1 Heart rate variability (HRV) in relation to body position and respiration
6.1 Heart rate variability (HRV) in relation to body position and respiration
Study I, which measured HRV, included only sedentary individuals with no previous
experience of YE. The rationale behind this thinking was to be able to more clearly see the
effects on HRV. Study I showed improved HRV (pNN50%) after eight weeks of YE
intervention with a focus on inversions, while Study III displayed no effect on HRV. Previous
findings from smaller sample populations are consistent with the findings in Study I, however
these do not always including inversions 98 99 101 168, while others report that YE is no better
than usual care 169 or cycling 53 when it comes to HRV. Factors alternating HRV include
supine 170 and inverted postures 54 170, but also slow respiratory rates (6/min) and respiratory
sinus arrhythmia (RSA) has its maximal amplitude with enhanced baroreflex sensitivity 55 171.
However, while the YE group in Study III showed significantly slower respiratory rates, there
Study I, which measured HRV, included only sedentary individuals with no previous
experience of YE. The rationale behind this thinking was to be able to more clearly see the
effects on HRV. Study I showed improved HRV (pNN50%) after eight weeks of YE
intervention with a focus on inversions, while Study III displayed no effect on HRV. Previous
findings from smaller sample populations are consistent with the findings in Study I, however
these do not always including inversions 98 99 101 168, while others report that YE is no better
than usual care 169 or cycling 53 when it comes to HRV. Factors alternating HRV include
supine 170 and inverted postures 54 170, but also slow respiratory rates (6/min) and respiratory
sinus arrhythmia (RSA) has its maximal amplitude with enhanced baroreflex sensitivity 55 171.
However, while the YE group in Study III showed significantly slower respiratory rates, there
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51
was no reported effect on HRV. This could be due to the short HRV recording time (5 min.),
the time of recording (daytime) and the use of a heart monitor watch. Longer monitoring time
would in all likelihood have been needed in order to record any significant effect.
Furthermore, previous findings have reported slower breathing frequency and resting HR
following a yogic intervention 100 168. While the recommended breathing frequency was a rate
of 0.1 Hz (6 breaths/minute), Study I-III saw the majority of the participants breathing at a
rate of 0.2 Hz (12 breaths/minute). However, this was not measured directly and so only
represents a rough estimate of the instructor's visual inspection of breathing frequency in
Study I and II. Yet, all interventions encouraged slow and deep breathing. Study I showed
similar findings to those reported previously in another 12 week long yogic intervention for
participants with chronic back pain. The patients participated in easy yoga with twists and
light back-bending exercises and slow breathing 168 and showed significant effects on
pNN50% in the YE group but no effect on HF.
was no reported effect on HRV. This could be due to the short HRV recording time (5 min.),
the time of recording (daytime) and the use of a heart monitor watch. Longer monitoring time
would in all likelihood have been needed in order to record any significant effect.
Furthermore, previous findings have reported slower breathing frequency and resting HR
following a yogic intervention 100 168. While the recommended breathing frequency was a rate
of 0.1 Hz (6 breaths/minute), Study I-III saw the majority of the participants breathing at a
rate of 0.2 Hz (12 breaths/minute). However, this was not measured directly and so only
represents a rough estimate of the instructor's visual inspection of breathing frequency in
Study I and II. Yet, all interventions encouraged slow and deep breathing. Study I showed
similar findings to those reported previously in another 12 week long yogic intervention for
participants with chronic back pain. The patients participated in easy yoga with twists and
light back-bending exercises and slow breathing 168 and showed significant effects on
pNN50% in the YE group but no effect on HF.
Inversions were used more or less in both programs in Study I and II, though with longer
duration in Study I where performance of the inversions progressed from approx. 7 min. to 20
min. during the 8 weeks of intervention. Previous research suggests that supine and inverted
body postures stimulate the baroreceptor reflex (from an altered negative pressure in the upper
body) and may enable parasympathetic (vagal) activity 88 102 104 172, while upright postures
inhibit it 172. The baroreceptor reflex that regulates heart rate is most likely linked to the
parasympathetic nervous system 170. However, increased vagal activity as a result of increased
HRV seemed in Study I . Existing findings suggest that atrial arrhythmia can be restored
through an inversion program 173 . A 40-minute program (divided into 10-minute intervals
that alternates between stimulating the vagal and the sinus nerve) has been suggested as an
effective form om medication for 50% of patients with atrial arrhythmia. Other smaller
studies and case reports suggest that the upside-down position may have the power to treat
paroxysmal supraventricular tachycardia 102 104 105 when no other methods, such as medication
and manual stimulation of the vagal nerve, work. Moreover, inversions have also been known
to reactivate the malfunctioning baroreflex mechanism by alternating the pressure on the
baroreceptors. The mechanism may involve vagal stimulation due to increased carotid sinus
pressure that in turn may restore the baroreceptor reflex function 54 102-105. The baroreflex arc
is thought to function improperly in hypertensive, ageing, stressed, inactive and depressed
individuals, which in turn results in a low HRV 88 174-177. Such was the rationale for choosing
to include only inactive and healthy individuals without previous experience of practicing YE
in Study I.
Inversions were used more or less in both programs in Study I and II, though with longer
duration in Study I where performance of the inversions progressed from approx. 7 min. to 20
min. during the 8 weeks of intervention. Previous research suggests that supine and inverted
body postures stimulate the baroreceptor reflex (from an altered negative pressure in the upper
body) and may enable parasympathetic (vagal) activity 88 102 104 172, while upright postures
inhibit it 172. The baroreceptor reflex that regulates heart rate is most likely linked to the
parasympathetic nervous system 170. However, increased vagal activity as a result of increased
HRV seemed in Study I . Existing findings suggest that atrial arrhythmia can be restored
through an inversion program 173 . A 40-minute program (divided into 10-minute intervals
that alternates between stimulating the vagal and the sinus nerve) has been suggested as an
effective form om medication for 50% of patients with atrial arrhythmia. Other smaller
studies and case reports suggest that the upside-down position may have the power to treat
paroxysmal supraventricular tachycardia 102 104 105 when no other methods, such as medication
and manual stimulation of the vagal nerve, work. Moreover, inversions have also been known
to reactivate the malfunctioning baroreflex mechanism by alternating the pressure on the
baroreceptors. The mechanism may involve vagal stimulation due to increased carotid sinus
pressure that in turn may restore the baroreceptor reflex function 54 102-105. The baroreflex arc
is thought to function improperly in hypertensive, ageing, stressed, inactive and depressed
individuals, which in turn results in a low HRV 88 174-177. Such was the rationale for choosing
to include only inactive and healthy individuals without previous experience of practicing YE
in Study I.
Measures taken after stretching typically show a rapid increase in parasympathetic activity as
well as lowered HR, meaning improved HRV, and YE does indeed include a stretching
component178. This may be one explanation for the feelings of relaxation and increased
parasympathetic activity that often follows YE. The increased HRV reported after stretching
may be related to the release of vasodilative agents (EDRF=endothelium-derived relaxing
factor) which reduces muscle tone, but could also result from a general systemic psychicphysical relaxation 101. Note that HRV may temporarily decrease during stretching.
Measures taken after stretching typically show a rapid increase in parasympathetic activity as
well as lowered HR, meaning improved HRV, and YE does indeed include a stretching
component178. This may be one explanation for the feelings of relaxation and increased
parasympathetic activity that often follows YE. The increased HRV reported after stretching
may be related to the release of vasodilative agents (EDRF=endothelium-derived relaxing
factor) which reduces muscle tone, but could also result from a general systemic psychicphysical relaxation 101. Note that HRV may temporarily decrease during stretching.
52
52
Yoga has been recommended as a life-style modifier for pre-hypertensives and patients
suffering from other diseases, including sympatho-vagal imbalances as alteration in the HRV
measure of low-frequency high-frequency (LF-HF) ratio. One research group has suggested
that body mass index (BMI) contributes independently to changes in LF-HF ratio and that
there's a correlation between BMI and diastolic blood pressure 179. The body mass index was
somewhat high (26) in Study I, but within normal range in Study II (22) and III (25).
Yoga has been recommended as a life-style modifier for pre-hypertensives and patients
suffering from other diseases, including sympatho-vagal imbalances as alteration in the HRV
measure of low-frequency high-frequency (LF-HF) ratio. One research group has suggested
that body mass index (BMI) contributes independently to changes in LF-HF ratio and that
there's a correlation between BMI and diastolic blood pressure 179. The body mass index was
somewhat high (26) in Study I, but within normal range in Study II (22) and III (25).
6.2 Respiratory parameters
6.2 Respiratory parameters
Study III showed a significant increase in oxygen saturation (SpO2 ) and lowered respiratory
rate in the YE group after 12 weeks of intervention, though no such effects were observed in
the CTP group. Oxygen saturation has been reported to improve after YE 180 and the
mechanism seems to primarily involve the lowered respiratory rate. Furthermore, slower and
deeper breathing patterns can offer an advantage to obstructive patients 180 181 and also raise
SpO2 levels. Studies I-III encouraged nasal and extended exhalations with deep breathing,
which may have lowered the breathing frequency. The complete yogic three-part breath as
practiced in Study III makes full use of the diaphragm and has been reported to lower the
respiratory rate and improve SpO2 180 in patients with COPD during and after yoga 115 182, as
well as in elderly women 182.
Study III showed a significant increase in oxygen saturation (SpO2 ) and lowered respiratory
rate in the YE group after 12 weeks of intervention, though no such effects were observed in
the CTP group. Oxygen saturation has been reported to improve after YE 180 and the
mechanism seems to primarily involve the lowered respiratory rate. Furthermore, slower and
deeper breathing patterns can offer an advantage to obstructive patients 180 181 and also raise
SpO2 levels. Studies I-III encouraged nasal and extended exhalations with deep breathing,
which may have lowered the breathing frequency. The complete yogic three-part breath as
practiced in Study III makes full use of the diaphragm and has been reported to lower the
respiratory rate and improve SpO2 180 in patients with COPD during and after yoga 115 182, as
well as in elderly women 182.
Patients with COPD and asthma usually display a dysfunctional breathing pattern 183 184.
Diaphragmatic breathing as practiced in all YE interventions and particularly in Study III
could have had an influence on dysfunctions already present in the participant. However, not
all screening measures 184, e.g. breath holding time, CO2 and mechanical function, was
measured, and the detected CRQ dyspnea was not significant in the YE group in Study III.
Study IV did however confirm that dyspnea improved. Moreover, others have reported that
YE can strengthen the torso (e.g. through inversions, back-bends and prone poses along with
strong breathing exercises) and initiate diaphragmatic breathing that in turn improves
performance 183, lowers breathing frequency and increases chest expansion. To achieve
optimal chest expansion, more intense yogic and breathing exercises than those included in
Study III may be required. With most of the participants across all studies being new to YE,
we refrained from including such high intensity exercises.
Patients with COPD and asthma usually display a dysfunctional breathing pattern 183 184.
Diaphragmatic breathing as practiced in all YE interventions and particularly in Study III
could have had an influence on dysfunctions already present in the participant. However, not
all screening measures 184, e.g. breath holding time, CO2 and mechanical function, was
measured, and the detected CRQ dyspnea was not significant in the YE group in Study III.
Study IV did however confirm that dyspnea improved. Moreover, others have reported that
YE can strengthen the torso (e.g. through inversions, back-bends and prone poses along with
strong breathing exercises) and initiate diaphragmatic breathing that in turn improves
performance 183, lowers breathing frequency and increases chest expansion. To achieve
optimal chest expansion, more intense yogic and breathing exercises than those included in
Study III may be required. With most of the participants across all studies being new to YE,
we refrained from including such high intensity exercises.
Regarding the expiratory pressure that is an advantage for patients with COPD and asthma,
the yogic technique of ujjayi involving constriction of the throat to control and soften the
breath was not added to a greater extent in the YE program in Study III.
Study III found no effect on either inspiratory or expiratory respiratory muscle strength in the
YE group, though this did show up the CTP group after 12 weeks of intervention. Some pilot
studies have reported increased strength and mobility of respiratory muscles after YE in both
healthy persons and patients with COPD 62 180 185 186, while others have reported no
improvements 187. The yogic breathing techniques used in Study III used coordinated
breathing movements of the upper and lower rib cage and the waist to extend the exhalation
and prevent hyperinflation and “air trapping”, both common in obstructive patients 80. As
reported in Study IV, where greater breathing control and less dyspnea was achieved, other
factors may explain the walk-test improvement.
Regarding the expiratory pressure that is an advantage for patients with COPD and asthma,
the yogic technique of ujjayi involving constriction of the throat to control and soften the
breath was not added to a greater extent in the YE program in Study III.
Study III found no effect on either inspiratory or expiratory respiratory muscle strength in the
YE group, though this did show up the CTP group after 12 weeks of intervention. Some pilot
studies have reported increased strength and mobility of respiratory muscles after YE in both
healthy persons and patients with COPD 62 180 185 186, while others have reported no
improvements 187. The yogic breathing techniques used in Study III used coordinated
breathing movements of the upper and lower rib cage and the waist to extend the exhalation
and prevent hyperinflation and “air trapping”, both common in obstructive patients 80. As
reported in Study IV, where greater breathing control and less dyspnea was achieved, other
factors may explain the walk-test improvement.
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53
The forced vital capacity increased significantly in the CTP group, however, no significant
between-group effect appeared. The cause for redundant effects in the YE group on lung
function may relate to how lung function seldom improves in COPD, but may also be related
to the YE being of an unsatisfactory dose or intensity or other unidentified factors. Deep
breathing exercises was used during the YE, however, this did not improve the lung function
of the participants in Study III. On the other hand, the interviews in Study IV showed
improved dyspnea, control and coordination of breathing. Another reason may be that the
randomization resulted in more participants with COPD ending up in the YE group and more
obstructive participants with asthma ending up in the CTP group. Obviously one limitation
related to the groups being imbalanced with respect to diagnoses.
The forced vital capacity increased significantly in the CTP group, however, no significant
between-group effect appeared. The cause for redundant effects in the YE group on lung
function may relate to how lung function seldom improves in COPD, but may also be related
to the YE being of an unsatisfactory dose or intensity or other unidentified factors. Deep
breathing exercises was used during the YE, however, this did not improve the lung function
of the participants in Study III. On the other hand, the interviews in Study IV showed
improved dyspnea, control and coordination of breathing. Another reason may be that the
randomization resulted in more participants with COPD ending up in the YE group and more
obstructive participants with asthma ending up in the CTP group. Obviously one limitation
related to the groups being imbalanced with respect to diagnoses.
As suggested in the meta-analysis 117 yogic breathing techniques constitute a safe and
complementary alternative to other breathing exercises, and often seem to be more effective
than usual care methods for asthma control, asthma symptoms, FEV1, peak expiratory flow
rate and health-related quality of life 62. Previous data show little evidence of YE improving
the FEV1/FVC ratio in either healthy persons 185 or people with COPD188, and indeed this
parameter did not improve in any of the groups in Study III. Conversely, small improvements
in FEV1 115 188 and the FEV1/FVC-ratio after YE have been reported in both healthy and
obstructive participants 160. Improvements in FEV1 with a recommended MCID of 100 ml 167
were seen in more participants in the CTP group (however non-significant) compared to the
YE group, with 42% in the YE and 53% in the CTP group (Table D). The FEV1/FVC ratio is
however a more advantageous measure than FEV1 69 63. However no large changes regarding
the FEV1/FVC ratio in any of the groups emerged in Study III. Study IV also showed
improvements in dyspnea (during exertion) and quality of life even though the quantitative
Study III found no such effects. One could posit that qualitative studies show more clearly the
effects after YE when it comes to breathing function.
As suggested in the meta-analysis 117 yogic breathing techniques constitute a safe and
complementary alternative to other breathing exercises, and often seem to be more effective
than usual care methods for asthma control, asthma symptoms, FEV1, peak expiratory flow
rate and health-related quality of life 62. Previous data show little evidence of YE improving
the FEV1/FVC ratio in either healthy persons 185 or people with COPD188, and indeed this
parameter did not improve in any of the groups in Study III. Conversely, small improvements
in FEV1 115 188 and the FEV1/FVC-ratio after YE have been reported in both healthy and
obstructive participants 160. Improvements in FEV1 with a recommended MCID of 100 ml 167
were seen in more participants in the CTP group (however non-significant) compared to the
YE group, with 42% in the YE and 53% in the CTP group (Table D). The FEV1/FVC ratio is
however a more advantageous measure than FEV1 69 63. However no large changes regarding
the FEV1/FVC ratio in any of the groups emerged in Study III. Study IV also showed
improvements in dyspnea (during exertion) and quality of life even though the quantitative
Study III found no such effects. One could posit that qualitative studies show more clearly the
effects after YE when it comes to breathing function.
6.3 Heart rate (HR)
6.3 Heart rate (HR)
A lowered resting HR was observed with 2 beats/min. in Study II (not significant), an increase
by approx. one beat in Study II and one beat in Study III following intervention. However, the
changes were non-significant across all studies. Other studies have shown lowered resting HR
52 98
following YE, something which often signifies a vagal dominance 88 102 168 178. With the
measurement including another person in the room, which may create a “white coat effect”,
HR can differ greatly and is not an optimal measure of health or vagal dominance. While
heart rate measurement wasn't performed during YE in any of the studies, RPE were. HR is
not an appropriate marker for detecting the intensity of YE. When it comes to vagal
dominance, measurement of HRV and breathing rate probably represents a better method for
measuring YE than HR, however the time of day and recording time for measurements is
important and can differ greatly between different studies.
A lowered resting HR was observed with 2 beats/min. in Study II (not significant), an increase
by approx. one beat in Study II and one beat in Study III following intervention. However, the
changes were non-significant across all studies. Other studies have shown lowered resting HR
52 98
following YE, something which often signifies a vagal dominance 88 102 168 178. With the
measurement including another person in the room, which may create a “white coat effect”,
HR can differ greatly and is not an optimal measure of health or vagal dominance. While
heart rate measurement wasn't performed during YE in any of the studies, RPE were. HR is
not an appropriate marker for detecting the intensity of YE. When it comes to vagal
dominance, measurement of HRV and breathing rate probably represents a better method for
measuring YE than HR, however the time of day and recording time for measurements is
important and can differ greatly between different studies.
6.4 Cardiorespiratory fitness, maximal oxygen consumption (VO2max)
6.4 Cardiorespiratory fitness, maximal oxygen consumption (VO2max)
In Study II there were no differences in VO2max found either between or in groups. This may
be related to low intensity YE and total performance time, but also to the fact that the
participants had a good baseline for cardiovascular fitness. A recent meta-analysis 189
In Study II there were no differences in VO2max found either between or in groups. This may
be related to low intensity YE and total performance time, but also to the fact that the
participants had a good baseline for cardiovascular fitness. A recent meta-analysis 189
54
54
classified yoga as a low-intensity physical activity, but only certain exercises, such as the sun
salutations (SS), met the appropriate intensity level (above three metabolic equivalents
(MET)) for improvements in cardiovascular endurance in accordance with the American
College of Sports Medicine and the American Heart Association guidelines5. This means that
asana practice with MET intensities above three can be counted toward daily
recommendations for moderate or vigorous physical activity 189.
classified yoga as a low-intensity physical activity, but only certain exercises, such as the sun
salutations (SS), met the appropriate intensity level (above three metabolic equivalents
(MET)) for improvements in cardiovascular endurance in accordance with the American
College of Sports Medicine and the American Heart Association guidelines5. This means that
asana practice with MET intensities above three can be counted toward daily
recommendations for moderate or vigorous physical activity 189.
No previous studies appear to have reported the effects of performing YE on cardiovascular
fitness after six weeks, as was done in Study II. However, a recent larger study investigating
the effects of three months of YE with a dose of 60 min./week plus home training (165
min/week) showed improvements in VO2max. The trial covered most of the demanding hatha
yogic standing postures, seated postures, inversions, back-bends and plank poses, but with no
SS. Since the study included 57 postures performed over 60 minutes, the speed was in all
likelihood dynamic and vigorous. The results are new and interesting and represents one of
the largest studies measuring VO2max after YE with a gas analyzer. Naturally, the results from
this study, which included a larger dose than Study II, can more easily show that
improvements in VO2max may increase following dynamic YE in somewhat older (mean age
52) healthy participants. Furthermore, a meta-analysis has reported improved aerobic fitness
in subjects favoring yoga over comparison activities, such as resistance training and
cycling190. Yet, other investigators measuring VO2max found no effect from using large
muscle-group movement YE three times a week at 40 min. per session 191. It's clear that the
nature of YE and speed of movement are important factors to consider if the aim is to increase
cardiovascular fitness. While the nature of many of the YE seem to achieve a high HR, it's
probably not enough to improve on VO2max. Using HR as a way to measure the intensity of
YE may not be appropriate (unpublished data), due to the intermittent head down position
(inversion). The occasional inversion in YE increases the relaxation counts (HRV) and gives a
restorative effect with alternating lowered HR and increased baroreflex. Unpublished data (by
author) has shown that when measuring oxygen consumption, the intensity is not linear to the
HR, and maby there is anaerobic activity. Hitherto, there seem to exist no reports of the
relationship between HR and oxygen consumption during YE and, consequently, the use of
HR as a measurement of YE intensity remains inappropriate 113. However, it has been
suggested 32 108 109 that the practice of SS, as included in Study II, can be used to maintain or
improve cardiovascular fitness in the form of increased VO2max 108 with elevated HR in unfit
individuals 109, providing low to moderate stress (above three MET) to the cardiovascular
system. Tran et. al. have also reported getting somewhat contradictory results 32 from using a
mixture of dynamic and static YE, with a 6% increase in VO2max in a group similar to the
participants in Study II. The study discusses that the effect on the cardiorespiratory fitness
could perhaps be related to the “frog pose”, dynamic lunges and a few rounds of SS 32. Back
bending YE and inversions are reported at a relative intensity of 41% of VO2max 112 (19
mL/kg/min). Also recommended is an intensity of 40% of VO2max (13 mL/kg/min) 113 after
SS. High HR was noted during the yogic push-up (chatturanga) 112, and exercise which is
included in the SS investigated in Study II. Interestingly enough, the above mentioned
intensities nearly achieve the minimum relative intensity required to achieve cardiovascular
training effects as suggested by the American College of Sports Medicine and the American
No previous studies appear to have reported the effects of performing YE on cardiovascular
fitness after six weeks, as was done in Study II. However, a recent larger study investigating
the effects of three months of YE with a dose of 60 min./week plus home training (165
min/week) showed improvements in VO2max. The trial covered most of the demanding hatha
yogic standing postures, seated postures, inversions, back-bends and plank poses, but with no
SS. Since the study included 57 postures performed over 60 minutes, the speed was in all
likelihood dynamic and vigorous. The results are new and interesting and represents one of
the largest studies measuring VO2max after YE with a gas analyzer. Naturally, the results from
this study, which included a larger dose than Study II, can more easily show that
improvements in VO2max may increase following dynamic YE in somewhat older (mean age
52) healthy participants. Furthermore, a meta-analysis has reported improved aerobic fitness
in subjects favoring yoga over comparison activities, such as resistance training and
cycling190. Yet, other investigators measuring VO2max found no effect from using large
muscle-group movement YE three times a week at 40 min. per session 191. It's clear that the
nature of YE and speed of movement are important factors to consider if the aim is to increase
cardiovascular fitness. While the nature of many of the YE seem to achieve a high HR, it's
probably not enough to improve on VO2max. Using HR as a way to measure the intensity of
YE may not be appropriate (unpublished data), due to the intermittent head down position
(inversion). The occasional inversion in YE increases the relaxation counts (HRV) and gives a
restorative effect with alternating lowered HR and increased baroreflex. Unpublished data (by
author) has shown that when measuring oxygen consumption, the intensity is not linear to the
HR, and maby there is anaerobic activity. Hitherto, there seem to exist no reports of the
relationship between HR and oxygen consumption during YE and, consequently, the use of
HR as a measurement of YE intensity remains inappropriate 113. However, it has been
suggested 32 108 109 that the practice of SS, as included in Study II, can be used to maintain or
improve cardiovascular fitness in the form of increased VO2max 108 with elevated HR in unfit
individuals 109, providing low to moderate stress (above three MET) to the cardiovascular
system. Tran et. al. have also reported getting somewhat contradictory results 32 from using a
mixture of dynamic and static YE, with a 6% increase in VO2max in a group similar to the
participants in Study II. The study discusses that the effect on the cardiorespiratory fitness
could perhaps be related to the “frog pose”, dynamic lunges and a few rounds of SS 32. Back
bending YE and inversions are reported at a relative intensity of 41% of VO2max 112 (19
mL/kg/min). Also recommended is an intensity of 40% of VO2max (13 mL/kg/min) 113 after
SS. High HR was noted during the yogic push-up (chatturanga) 112, and exercise which is
included in the SS investigated in Study II. Interestingly enough, the above mentioned
intensities nearly achieve the minimum relative intensity required to achieve cardiovascular
training effects as suggested by the American College of Sports Medicine and the American
55
55
Heart Association. However, other studies have suggested that if VO2max falls below 40%
there might be improvements achieved with low-intensity activities.
Heart Association. However, other studies have suggested that if VO2max falls below 40%
there might be improvements achieved with low-intensity activities.
Others measuring VO2max 192 have noted low intensities (9.9-26.5% of VO2max) when using
YE not including dynamic poses such as SS. These lower figures are fall far below the
minimum recommendations. Even though there emerged no statistical effect in Study II, 5
participants (24%) in the YE group and 3 participants (13%) in the control group improved
their MCID by 2 mL/kg/min., while there also emerged a few non-responders in each group
(Table D).
Others measuring VO2max 192 have noted low intensities (9.9-26.5% of VO2max) when using
YE not including dynamic poses such as SS. These lower figures are fall far below the
minimum recommendations. Even though there emerged no statistical effect in Study II, 5
participants (24%) in the YE group and 3 participants (13%) in the control group improved
their MCID by 2 mL/kg/min., while there also emerged a few non-responders in each group
(Table D).
Additionally, the biomechanics and techniques used during the practice of YE is an important
issue which suggests that longer interventions would be needed to improve one's skills. The
speed of the SS has to be somewhat dynamic and fast for improvements to occur, and the aim
in Study II was 2-5 seconds per movement. For an unfit individual, these types of exercises
may be sufficient in order to put stress to the cardiovascular system. However, the dose was
still insufficient, being only six weeks with no home training, to improve VO2max. The rhythm
of SS (12 poses) varies between different styles of yoga 44 193, with the faster performances
often carried out by famous gurus (Krischnamacharya, BKS Iyengar 1968 (YouTube old
films)) and the slower speeds being preferred by those looking to meditate. Reported speeds
for each SS pose differs from 1-40 seconds (1.25-6.25 s. 108 40 s. 194 0.63-1.67 s. 195).
Additionally, the biomechanics and techniques used during the practice of YE is an important
issue which suggests that longer interventions would be needed to improve one's skills. The
speed of the SS has to be somewhat dynamic and fast for improvements to occur, and the aim
in Study II was 2-5 seconds per movement. For an unfit individual, these types of exercises
may be sufficient in order to put stress to the cardiovascular system. However, the dose was
still insufficient, being only six weeks with no home training, to improve VO2max. The rhythm
of SS (12 poses) varies between different styles of yoga 44 193, with the faster performances
often carried out by famous gurus (Krischnamacharya, BKS Iyengar 1968 (YouTube old
films)) and the slower speeds being preferred by those looking to meditate. Reported speeds
for each SS pose differs from 1-40 seconds (1.25-6.25 s. 108 40 s. 194 0.63-1.67 s. 195).
6.5 Duration, dose and intensity
6.5 Duration, dose and intensity
In Study I, YE participants rated the exercises “Fairly light to somewhat hard” (RPE 12–13)
on the RPE-20 Borg scale. In Study II, the RPE rating was 14, indicating moderate to
vigorous intensity. The primary aim of Study II was to increase cardiovascular
fitness/endurance. An RPE rating of 14 is defined as “Somewhat hard to very hard” (RPE 14–
17). Converting the RPE rating to the absolute intensity (by age) to MET (metabolic
equivalents) is suggested to 7.2 to 10.1 MET5 indicating sufficient intensity (i.e above 3
MET) for cardiovascular improvements to occur. While we did not measure MET
specifically, the RPE ratings in Study I - 12-13 - are suggestive of a range between 4.0 to 5.9
MET (absolute intensity by age) 5. According to this, Study I also achieved sufficient absolute
intensity for cardiovascular improvements to occur, however we did not measure VO2max in
Study I. The dose in Study II was however too low and the participants did not perform
enough home training for cardiovascular endurance changes to occur. Study III was rated as a
light intensity program (RPE median 10) equivalent to 2.0-3.9 MET (absolute intensity by
age)5. Since RPE ratings were not given for all participants, considering such measurements
were not carried out in every class, consequently the results have to be taken with a grain of
caution. More data is needed to measure the intensities across the many diverse styles of YE.
However, a recent meta-analysis did classify YE as equivalent to 3.3±1.6 MET 189, individual
yogic postures averaging 2.2 METs and breathing exercises 1.3 METs. Most YE have been
classified as light (under 3 METs) to moderate aerobic intensity (3-6 METs)189. Still, the
majority of the studies proved that light intensity physical activity could be achieved with YE,
and the SS has been classified as vigorous. Study II was somewhat of a brave experiment with
very high intensity that required high motivation and skill from the participants. The
In Study I, YE participants rated the exercises “Fairly light to somewhat hard” (RPE 12–13)
on the RPE-20 Borg scale. In Study II, the RPE rating was 14, indicating moderate to
vigorous intensity. The primary aim of Study II was to increase cardiovascular
fitness/endurance. An RPE rating of 14 is defined as “Somewhat hard to very hard” (RPE 14–
17). Converting the RPE rating to the absolute intensity (by age) to MET (metabolic
equivalents) is suggested to 7.2 to 10.1 MET5 indicating sufficient intensity (i.e above 3
MET) for cardiovascular improvements to occur. While we did not measure MET
specifically, the RPE ratings in Study I - 12-13 - are suggestive of a range between 4.0 to 5.9
MET (absolute intensity by age) 5. According to this, Study I also achieved sufficient absolute
intensity for cardiovascular improvements to occur, however we did not measure VO2max in
Study I. The dose in Study II was however too low and the participants did not perform
enough home training for cardiovascular endurance changes to occur. Study III was rated as a
light intensity program (RPE median 10) equivalent to 2.0-3.9 MET (absolute intensity by
age)5. Since RPE ratings were not given for all participants, considering such measurements
were not carried out in every class, consequently the results have to be taken with a grain of
caution. More data is needed to measure the intensities across the many diverse styles of YE.
However, a recent meta-analysis did classify YE as equivalent to 3.3±1.6 MET 189, individual
yogic postures averaging 2.2 METs and breathing exercises 1.3 METs. Most YE have been
classified as light (under 3 METs) to moderate aerobic intensity (3-6 METs)189. Still, the
majority of the studies proved that light intensity physical activity could be achieved with YE,
and the SS has been classified as vigorous. Study II was somewhat of a brave experiment with
very high intensity that required high motivation and skill from the participants. The
56
56
recommendation is to perform YE at an intensity above 3 METs (sessions of at least 10 min.)
for it to be used as a form of physical activity 189.
recommendation is to perform YE at an intensity above 3 METs (sessions of at least 10 min.)
for it to be used as a form of physical activity 189.
In Study II the total YE training dose during the whole intervention (both home and classes)
averaged 390 min. This corresponds to a weekly average of 65 min. The RPE rating of the YE
(range 14–17) was at a sufficient exertion level, but the total time spent was at the lower end
of the limit and therefore unable to affect any improvements 5. Higher RPEs (14-16) requires
at least 75 min. of exertion while lower RPEs (12-13) requires 150 min. for there to be any
noticeable health effects on the cardiovascular system5 196.
In Study II the total YE training dose during the whole intervention (both home and classes)
averaged 390 min. This corresponds to a weekly average of 65 min. The RPE rating of the YE
(range 14–17) was at a sufficient exertion level, but the total time spent was at the lower end
of the limit and therefore unable to affect any improvements 5. Higher RPEs (14-16) requires
at least 75 min. of exertion while lower RPEs (12-13) requires 150 min. for there to be any
noticeable health effects on the cardiovascular system5 196.
In Study III the YE was of a lower intensity than the conventional training (CTP). This may
relate to the YE not including any cardiovascular/endurance training nor any strength-training
machines and probably results from other differences between the CTP and YE.
Thus, one could see a significant increase in walking distance in the YE group, which may
have involved more efficient breathing patterns, reduced dyspnea, better coordination and
improved control of breathing as well as other psychophysiological factors 192. Study III did
however include exercises for the lower limbs (movements similar to deep squats
(utkatasana)), and in this respect may have been somewhat similar to conventional training.
Nevertheless, with more COPD participants in the YE group, improvements in this group was
limited when compared to the asthma participants who constituted the majority of the CTP
group. With YE sometimes being thought of as a form of exercise training, intensity standards
have yet to be determined 5. Still, considering the dynamic intensity applied in Study II with
1–3 seconds per exercise plus the SS, a longer intervention could have generated difficulties
for unfit participants with regards to motivation, and the total YE time would likely have been
an issue as well.
Most studies use a time frame of 6 to 24 weeks, with 12 weeks with two or more sessions a
week being the most common. Depending on expectations, hatha yogic interventions seem to
have the best effect when carried out two or more times a week. However, there have been
larger effects reported from engagement in more intense interventions taking place 5 days a
week 197, and whenever participants have been able to continue with the training at home.
Participation in a retreat may also have potential effects, but in that case maintenance is
required since the effects seem to diminish in the same pattern as regular physical activity,
often after 1 week. Moreover, in smaller studies seven days of intensive yoga have been
shown to be able to reduce pain and improve spinal flexibility in participants with chronic
lower back pain at a more satisfactory level than physical exercise 197 198. For example, with
regards to functional disability and pain outcomes in participants with back pain there were no
difference detected between one or two sessions 199 a week.
Long-term follow-ups of the effects of YE are still lacking, and in Study III no significant
effect could be detected past the 6-month follow-up. However, some recommendations for
YE do exist, and the American College of Sports Medicine labels yoga as a form of
multimodal exercise training involving motor skills that are multifaceted. The
recommendation is a frequency of ≥2-3 days a week at ≥20-30 min. per session. Yet, there has
been no determination of effective intensity, volume, pattern and progression of multimodal
exercise 5. To recommend an intensity for YE could possibly in the future be used to improve
strength 200 201, balance 136 202, flexibility, vagal tone fitness (HRV, baroreceptor sensitivity,
In Study III the YE was of a lower intensity than the conventional training (CTP). This may
relate to the YE not including any cardiovascular/endurance training nor any strength-training
machines and probably results from other differences between the CTP and YE.
Thus, one could see a significant increase in walking distance in the YE group, which may
have involved more efficient breathing patterns, reduced dyspnea, better coordination and
improved control of breathing as well as other psychophysiological factors 192. Study III did
however include exercises for the lower limbs (movements similar to deep squats
(utkatasana)), and in this respect may have been somewhat similar to conventional training.
Nevertheless, with more COPD participants in the YE group, improvements in this group was
limited when compared to the asthma participants who constituted the majority of the CTP
group. With YE sometimes being thought of as a form of exercise training, intensity standards
have yet to be determined 5. Still, considering the dynamic intensity applied in Study II with
1–3 seconds per exercise plus the SS, a longer intervention could have generated difficulties
for unfit participants with regards to motivation, and the total YE time would likely have been
an issue as well.
Most studies use a time frame of 6 to 24 weeks, with 12 weeks with two or more sessions a
week being the most common. Depending on expectations, hatha yogic interventions seem to
have the best effect when carried out two or more times a week. However, there have been
larger effects reported from engagement in more intense interventions taking place 5 days a
week 197, and whenever participants have been able to continue with the training at home.
Participation in a retreat may also have potential effects, but in that case maintenance is
required since the effects seem to diminish in the same pattern as regular physical activity,
often after 1 week. Moreover, in smaller studies seven days of intensive yoga have been
shown to be able to reduce pain and improve spinal flexibility in participants with chronic
lower back pain at a more satisfactory level than physical exercise 197 198. For example, with
regards to functional disability and pain outcomes in participants with back pain there were no
difference detected between one or two sessions 199 a week.
Long-term follow-ups of the effects of YE are still lacking, and in Study III no significant
effect could be detected past the 6-month follow-up. However, some recommendations for
YE do exist, and the American College of Sports Medicine labels yoga as a form of
multimodal exercise training involving motor skills that are multifaceted. The
recommendation is a frequency of ≥2-3 days a week at ≥20-30 min. per session. Yet, there has
been no determination of effective intensity, volume, pattern and progression of multimodal
exercise 5. To recommend an intensity for YE could possibly in the future be used to improve
strength 200 201, balance 136 202, flexibility, vagal tone fitness (HRV, baroreceptor sensitivity,
57
57
HR), mental health and health related quality of life 46, though probably not cardiovascular
fitness 203.
HR), mental health and health related quality of life 46, though probably not cardiovascular
fitness 203.
Regarding the RPE-20 Borg rating during YE, participants rated it as “Fairly light to
somewhat hard” (RPE 12–13) in Study I. In Study II, the RPE rating was 14, indicating
moderate to vigorous intensity. In Study II the primary aim was to increase cardiovascular
fitness/endurance and the RPE rating were 14 (vigorous) and is “Somewhat hard to very hard”
(RPE 14–17). Converting this to the absolute intensity by age in MET (metabolic equivalents)
is suggested to 7.2 to 10.1 MET5 indicating sufficient intensity (i.e above 3 MET) for
cardiovascular improvements to occur. Unfortunately we did not measure MET but the
intensity for improvement in cardiovascular endurance is proposed above 3 MET and the
ratings in Study I of RPE 12-13 is suggested to range between 4.0 to 5.9 MET (absolute
intensity by age)5. According to this, Study I also had sufficient absolute intensity for
cardiovascular improvements to occur, however we did not measure VO2max in Study I.
However in Study II the dose was too low and the participants did not perform enough home
training for cardiovascular endurance changes to occur. Study III was rated as light intensity
(RPE median 10) equivalent to 2.0-3.9 MET (absolute intensity by age)5. However RPE
ratings were not measured for all participants in any of the studies since they were not
measured in every class, consequently the results have to be taken with caution. Yet, more
data are needed to measure intensities in different ways of diverse styles of YE. However, a
recent meta-analysis classifies YE to be equivalent to 3.3±1.6 MET 189 and individual yogic
postures averaged 2.2 METs and breathing exercises 1.3 METs. Though, most YE are
reported as light (less than 3 METs) to moderate aerobic intensity (3-6 METs) 189. Still, the
majority of the studies showed light intensity physical activity with YE and the SS classified
as vigorous. Study II was somewhat of a brave experiment with very high intensity that
required high motivation and skill from the participants. The recommendation is to perform
YE with the intensity being higher than 3 MET (with sessions of at least 10 min.) for it to be
used as a form of physical activity 189.
Regarding the RPE-20 Borg rating during YE, participants rated it as “Fairly light to
somewhat hard” (RPE 12–13) in Study I. In Study II, the RPE rating was 14, indicating
moderate to vigorous intensity. In Study II the primary aim was to increase cardiovascular
fitness/endurance and the RPE rating were 14 (vigorous) and is “Somewhat hard to very hard”
(RPE 14–17). Converting this to the absolute intensity by age in MET (metabolic equivalents)
is suggested to 7.2 to 10.1 MET5 indicating sufficient intensity (i.e above 3 MET) for
cardiovascular improvements to occur. Unfortunately we did not measure MET but the
intensity for improvement in cardiovascular endurance is proposed above 3 MET and the
ratings in Study I of RPE 12-13 is suggested to range between 4.0 to 5.9 MET (absolute
intensity by age)5. According to this, Study I also had sufficient absolute intensity for
cardiovascular improvements to occur, however we did not measure VO2max in Study I.
However in Study II the dose was too low and the participants did not perform enough home
training for cardiovascular endurance changes to occur. Study III was rated as light intensity
(RPE median 10) equivalent to 2.0-3.9 MET (absolute intensity by age)5. However RPE
ratings were not measured for all participants in any of the studies since they were not
measured in every class, consequently the results have to be taken with caution. Yet, more
data are needed to measure intensities in different ways of diverse styles of YE. However, a
recent meta-analysis classifies YE to be equivalent to 3.3±1.6 MET 189 and individual yogic
postures averaged 2.2 METs and breathing exercises 1.3 METs. Though, most YE are
reported as light (less than 3 METs) to moderate aerobic intensity (3-6 METs) 189. Still, the
majority of the studies showed light intensity physical activity with YE and the SS classified
as vigorous. Study II was somewhat of a brave experiment with very high intensity that
required high motivation and skill from the participants. The recommendation is to perform
YE with the intensity being higher than 3 MET (with sessions of at least 10 min.) for it to be
used as a form of physical activity 189.
In Study II the total YE training dose during the whole intervention (both home and classes)
was on average 390 min. This corresponds to a weekly average of 65 min. The RPE rating in
YE (range 14–17) was at a sufficient exertion but the total time was on the lower limit to
show any improvements5. Higher RPE (14-16) requires at least 75 min of duration and lower
RPE (12-13) requires 150 minutes for health effects on the cardiovascular system 5 196.
In Study II the total YE training dose during the whole intervention (both home and classes)
was on average 390 min. This corresponds to a weekly average of 65 min. The RPE rating in
YE (range 14–17) was at a sufficient exertion but the total time was on the lower limit to
show any improvements5. Higher RPE (14-16) requires at least 75 min of duration and lower
RPE (12-13) requires 150 minutes for health effects on the cardiovascular system 5 196.
In Study III the YE was of a lower intensity than the conventional training (CTP). This may
relate to the YE not including any cardiovascular/endurance training and strength-training
machines and probably results from other differences between the CTP and YE.
Thus, walk distance increased significantly in YE and may perhaps involve a more efficient
breathing pattern, less dyspnea, better coordination and control of breathing and other
psychophysiological factors 192. However exercises for the lower limbs (movements similar to
deep squats (utkatasana)) were included in Study III and in this aspect somewhat similar to
conventional training. Nevertheless, with more COPD participants in the YE-group,
improvements in this group may be limited as compared to the asthma participants who
In Study III the YE was of a lower intensity than the conventional training (CTP). This may
relate to the YE not including any cardiovascular/endurance training and strength-training
machines and probably results from other differences between the CTP and YE.
Thus, walk distance increased significantly in YE and may perhaps involve a more efficient
breathing pattern, less dyspnea, better coordination and control of breathing and other
psychophysiological factors 192. However exercises for the lower limbs (movements similar to
deep squats (utkatasana)) were included in Study III and in this aspect somewhat similar to
conventional training. Nevertheless, with more COPD participants in the YE-group,
improvements in this group may be limited as compared to the asthma participants who
58
58
constituted the majority in CTP-group. Nonetheless, with YE sometimes being a form of
exercise training, no intensity standards have been determined 5. Still, the dynamic intensity in
Study II with 1–3 seconds per exercise using SS a longer intervention would perhaps
generated difficulties with motivation for unfit participants and total YE time was likely to be
an issue.
Most studies are using a time frame from 6 weeks to 24 weeks, however, 12 weeks with two
or more sessions a week being the most common. Depending on expected effects of hatha
yogic interventions it seems to have the best effect with 2 or more sessions a week. However
there have been large effects from using intense interventions as 5 days 197 and from where
participants can continue with home training. Participation in a retreat can have potential
effects but maintenance is required since the effect seems to diminish in the same pattern as
regular physical activity, and probably after 1 week. Moreover, in smaller studies, seven days
of intensive yoga can reduced pain and improve spinal flexibility in participants with chronic
lower back pain better than a physical exercise 197 198. For example, on functional disability
and pain outcomes in participants with back- pain there was no difference between one and
two sessions 199 a week.
Moreover, long-term follow-ups are lacking of YE and in Study III no significant effects
persisted after the 6-month follow-up. However, some recommendations for YE exist, and
American College of Sports Medicine labels yoga as a form of multimodal exercise training
involving motor skills that are multifaceted. The recommendation is a frequency of ≥2-3 days
a week with ≥20-30 min a session. Yet, an effective intensity, volume, pattern and
progression of multimodal exercise have not been determined 5. To recommend an intensity
for YE would possibly in the future be to improve strength 200 201, balance 136 202, flexibility,
vagal tone fitness (HRV, baroreceptor sensitivity, HR), mental health and health related
quality of life 46 but probably not for cardiovascular fitness 203.
constituted the majority in CTP-group. Nonetheless, with YE sometimes being a form of
exercise training, no intensity standards have been determined 5. Still, the dynamic intensity in
Study II with 1–3 seconds per exercise using SS a longer intervention would perhaps
generated difficulties with motivation for unfit participants and total YE time was likely to be
an issue.
Most studies are using a time frame from 6 weeks to 24 weeks, however, 12 weeks with two
or more sessions a week being the most common. Depending on expected effects of hatha
yogic interventions it seems to have the best effect with 2 or more sessions a week. However
there have been large effects from using intense interventions as 5 days 197 and from where
participants can continue with home training. Participation in a retreat can have potential
effects but maintenance is required since the effect seems to diminish in the same pattern as
regular physical activity, and probably after 1 week. Moreover, in smaller studies, seven days
of intensive yoga can reduced pain and improve spinal flexibility in participants with chronic
lower back pain better than a physical exercise 197 198. For example, on functional disability
and pain outcomes in participants with back- pain there was no difference between one and
two sessions 199 a week.
Moreover, long-term follow-ups are lacking of YE and in Study III no significant effects
persisted after the 6-month follow-up. However, some recommendations for YE exist, and
American College of Sports Medicine labels yoga as a form of multimodal exercise training
involving motor skills that are multifaceted. The recommendation is a frequency of ≥2-3 days
a week with ≥20-30 min a session. Yet, an effective intensity, volume, pattern and
progression of multimodal exercise have not been determined 5. To recommend an intensity
for YE would possibly in the future be to improve strength 200 201, balance 136 202, flexibility,
vagal tone fitness (HRV, baroreceptor sensitivity, HR), mental health and health related
quality of life 46 but probably not for cardiovascular fitness 203.
6.6 Blood pressure (BP)
6.6 Blood pressure (BP)
Despite previous studies showing significant effects on BP after 3-8 weeks of yoga in
hypertensive individuals 88 90 204 205 , no such effects were observed after YE in either of the
Studies I-III. In Study III, the CTP group, but not the YE group, was associated with a
significant decrease in diastolic blood pressure by 5.7 units mmHg following the intervention.
The clinically relevant decrease, approx. 4-5 mm Hg systolic, did not emerge in any of the
groups. This is in contrast with other findings showing that yoga lowers BP. However, the
participants included in Study I-III were normotensive and consequently larger BP changes
could not be detected. But such findings typically emanate from studies without active
comparison groups where time would likely have had an effect. This means that further
studies are needed.
Despite previous studies showing significant effects on BP after 3-8 weeks of yoga in
hypertensive individuals 88 90 204 205 , no such effects were observed after YE in either of the
Studies I-III. In Study III, the CTP group, but not the YE group, was associated with a
significant decrease in diastolic blood pressure by 5.7 units mmHg following the intervention.
The clinically relevant decrease, approx. 4-5 mm Hg systolic, did not emerge in any of the
groups. This is in contrast with other findings showing that yoga lowers BP. However, the
participants included in Study I-III were normotensive and consequently larger BP changes
could not be detected. But such findings typically emanate from studies without active
comparison groups where time would likely have had an effect. This means that further
studies are needed.
In addition, other studies have reported both systolic and diastolic decreases after yogic
interventions 87 92-94, similar to usual care, in participants with mild to moderate hypertension
88 89 90 91
. Moreover, a systolic decrease range of 4-9.6 mm Hg and a diastolic decrease range
of 3-7.2 mm Hg have been shown following YE 206 . A recent meta-analysis 207 showed the
clinically important effects of YE on cardiovascular risk factors as compared to usual care.
Moreover, hyperventilation is a common factor in hypertension, and inhibition of the
In addition, other studies have reported both systolic and diastolic decreases after yogic
interventions 87 92-94, similar to usual care, in participants with mild to moderate hypertension
88 89 90 91
. Moreover, a systolic decrease range of 4-9.6 mm Hg and a diastolic decrease range
of 3-7.2 mm Hg have been shown following YE 206 . A recent meta-analysis 207 showed the
clinically important effects of YE on cardiovascular risk factors as compared to usual care.
Moreover, hyperventilation is a common factor in hypertension, and inhibition of the
59
59
baroreflex can represent a possible mechanism while breathing fast 208 which elevates blood
pressure. A smaller study on patients with essential hypertension showed the restoration of the
malfunctioning baroreflex mechanism with the lowering of blood pressure (29 units systolic
and 17 units diastolic) after 3 weeks of yogic postures (including inversions)88.
baroreflex can represent a possible mechanism while breathing fast 208 which elevates blood
pressure. A smaller study on patients with essential hypertension showed the restoration of the
malfunctioning baroreflex mechanism with the lowering of blood pressure (29 units systolic
and 17 units diastolic) after 3 weeks of yogic postures (including inversions)88.
6.7 Hand-grip strength
6.7 Hand-grip strength
Prior research suggests the presence of increased hand-grip-strength following YE 209 157 210.
Study I included hand-grip strength measurements and the results did show significant
improvements, thereby aligning with previous research. Specifically, Study I showed an
increase of 4 units (kg).
Prior research suggests the presence of increased hand-grip-strength following YE 209 157 210.
Study I included hand-grip strength measurements and the results did show significant
improvements, thereby aligning with previous research. Specifically, Study I showed an
increase of 4 units (kg).
6.8 Apolipoproteins
6.8 Apolipoproteins
Study II was the first study to measure apolipoproteins levels following YE. While the YE
dose was small and the baseline levels were low and within normal range, there still emerged
a significant effect on ApoA1 in the YE group with no between-groups effect. The
mechanism behind the increased ApoA1 in the YE group seems to be similar that of physical
activity, showing increased levels 124 with an improved metabolic response. Other studies
have shown favorable and increased levels of HDL cholesterol (main component of ApoA)207
with decreasing triglycerides 211 and uncertain effects on LDL cholesterol 93.
Study II was the first study to measure apolipoproteins levels following YE. While the YE
dose was small and the baseline levels were low and within normal range, there still emerged
a significant effect on ApoA1 in the YE group with no between-groups effect. The
mechanism behind the increased ApoA1 in the YE group seems to be similar that of physical
activity, showing increased levels 124 with an improved metabolic response. Other studies
have shown favorable and increased levels of HDL cholesterol (main component of ApoA)207
with decreasing triglycerides 211 and uncertain effects on LDL cholesterol 93.
6.9 Adiponectin, leptin and cytokines
6.9 Adiponectin, leptin and cytokines
In Study II, the YE group showed increased adiponectin levels six weeks after the
intervention. Similar effects were not found in the control group, though there was no
significant between-groups effect. This indicates that the type of YE used in Study II is
effective in low doses, with a potential anti-inflammatory effect and improved immunologic
response in healthy individuals.
Regarding leptin, Study II saw no changes after six weeks. Still, others have reported positive
effects on leptin rather than adiponectin levels 12 weeks following YE 131. The levels may
change differently. It could be that the adiponectin levels were changing faster than the leptin
levels, while in other cases the opposite has been reported 131, i.e. no effect on adiponectin
levels after 12 weeks. Interestingly, adiponectin and leptin levels vary between the sexes, with
women having higher adiponectin and leptin levels212 and leaner persons having higher
adiponectin levels 213-215. Studies need to remember to account for such differences.
Additionally, body mass index (BMI) has a suggested connection to diastolic blood pressure
179
, though participant BMI was within normal range in Study II (22).
In Study II, the YE group showed increased adiponectin levels six weeks after the
intervention. Similar effects were not found in the control group, though there was no
significant between-groups effect. This indicates that the type of YE used in Study II is
effective in low doses, with a potential anti-inflammatory effect and improved immunologic
response in healthy individuals.
Regarding leptin, Study II saw no changes after six weeks. Still, others have reported positive
effects on leptin rather than adiponectin levels 12 weeks following YE 131. The levels may
change differently. It could be that the adiponectin levels were changing faster than the leptin
levels, while in other cases the opposite has been reported 131, i.e. no effect on adiponectin
levels after 12 weeks. Interestingly, adiponectin and leptin levels vary between the sexes, with
women having higher adiponectin and leptin levels212 and leaner persons having higher
adiponectin levels 213-215. Studies need to remember to account for such differences.
Additionally, body mass index (BMI) has a suggested connection to diastolic blood pressure
179
, though participant BMI was within normal range in Study II (22).
6.10 Physical function: walk distance
6.10 Physical function: walk distance
The main findings in Study III showed that both the YE and CTP group had improved in the
6MWD after 12 weeks of intervention, with no between-group differences. Other studies and
meta-analyses have reported similar findings with other yogic exercise programs 115 117 160. In
a recent study of coal miners with COPD, researchers found significant and clinically relevant
effects on 6MWD after a yoga therapy intervention (including yogic counseling and lectures)
216
. Granted, this group was not fully comparable to the ones in Study III, since oxygen
saturation was low and yogic exercises were performed 6 days a week at 90 minutes per
session for 12 weeks. This represents a much larger dose than the one used in Study III.
The main findings in Study III showed that both the YE and CTP group had improved in the
6MWD after 12 weeks of intervention, with no between-group differences. Other studies and
meta-analyses have reported similar findings with other yogic exercise programs 115 117 160. In
a recent study of coal miners with COPD, researchers found significant and clinically relevant
effects on 6MWD after a yoga therapy intervention (including yogic counseling and lectures)
216
. Granted, this group was not fully comparable to the ones in Study III, since oxygen
saturation was low and yogic exercises were performed 6 days a week at 90 minutes per
session for 12 weeks. This represents a much larger dose than the one used in Study III.
60
60
Perhaps a higher dose would indeed have produced even larger effects. However, there can be
a ceiling effect in the walk-test, what with the YE group having significant higher baseline
levels compared to the CTP group. This means that the CTP group had a larger capacity for
improvement. Yet, some MCID differences emerged in each group (Table F) for 30 meters
and 50 meters. Moreover, recent findings show similar improvements in 6MWD after 12
weeks of Thai yoga (similar to hatha yoga) compared to Thai Chi and control 217. A 3 month
pilot study of COPD patients also showed improvements in 6MWD at 19 meters in the yoga
group and 8.5 meters in the usual care group 160. The YE group rated the RPE lower than the
CTP group, the mechanism for which might be an increased awareness of the breathing with
better coordination and control over the breathing 192. This is confirmed in Study IV.
However, with more COPD participants in the YE group, increases in this group may be
limited when compared to the participants with asthma who constituted the majority of the
CTP group. Improved effects on lung function and respiratory muscle strength parameters
could not be found in the YE group, and there may be other psychophysiological factors that
could explain the 6MWD improvement. Yet, the YE program included a few strength
exercises for the upper limbs that may have helped the participants to increase their deep
breathing, but not to the same degree as the CTP.
Perhaps a higher dose would indeed have produced even larger effects. However, there can be
a ceiling effect in the walk-test, what with the YE group having significant higher baseline
levels compared to the CTP group. This means that the CTP group had a larger capacity for
improvement. Yet, some MCID differences emerged in each group (Table F) for 30 meters
and 50 meters. Moreover, recent findings show similar improvements in 6MWD after 12
weeks of Thai yoga (similar to hatha yoga) compared to Thai Chi and control 217. A 3 month
pilot study of COPD patients also showed improvements in 6MWD at 19 meters in the yoga
group and 8.5 meters in the usual care group 160. The YE group rated the RPE lower than the
CTP group, the mechanism for which might be an increased awareness of the breathing with
better coordination and control over the breathing 192. This is confirmed in Study IV.
However, with more COPD participants in the YE group, increases in this group may be
limited when compared to the participants with asthma who constituted the majority of the
CTP group. Improved effects on lung function and respiratory muscle strength parameters
could not be found in the YE group, and there may be other psychophysiological factors that
could explain the 6MWD improvement. Yet, the YE program included a few strength
exercises for the upper limbs that may have helped the participants to increase their deep
breathing, but not to the same degree as the CTP.
6.11 Dyspnea-related distress (DD-index)
6.11 Dyspnea-related distress (DD-index)
Dyspnea-related distress is a new measure that shows fatigue after 6MWT. To date only one
pilot study investigating YE and patients with COPD have shown significant effects on the
DD-index 160. Study III found no significant improvements in DD-index after the 6MWT,
neither in the groups or between-groups. However, MCID emerged for 16% of patients in the
YE and 41% of the patients in the CTP group (Table F). The DD-index is related to the RPE
Borg-scale with 6MWD, meaning this measure may more adequately reflect pulmonary
disease improvements.
Dyspnea-related distress is a new measure that shows fatigue after 6MWT. To date only one
pilot study investigating YE and patients with COPD have shown significant effects on the
DD-index 160. Study III found no significant improvements in DD-index after the 6MWT,
neither in the groups or between-groups. However, MCID emerged for 16% of patients in the
YE and 41% of the patients in the CTP group (Table F). The DD-index is related to the RPE
Borg-scale with 6MWD, meaning this measure may more adequately reflect pulmonary
disease improvements.
6.12 Disease specific quality of life – chronic respiratory disease
questionnaire (CRQ)
6.12 Disease specific quality of life – chronic respiratory disease
questionnaire (CRQ)
Both groups in Study III exhibited immediate effects after the intervention (12 weeks) on
MCID (0.5 points) in CRQ, though there was a larger effect found in the CTP group.
Interaction (group x time) showed significance in CRQ fatigue and CRQ emotional favouring
the CTP group. This probably relates to the CTP group having had improved effects when
comparing the baseline to the point in time after the follow-up. The YE group showed
significance in the CRQ mastery domain, however no significant between-group effects
emerged after the 12 week long intervention.
This evidence follows from earlier research 218, and the interviews conducted in Study IV
qualitatively confirms the large effects shown in the YE group with regards to the mastery
domain. Previously, diaphragmatic breathing and YE have had positive effects on diseasespecific quality of life among patients with COPD 62 79 186, while other studies have reported
no effects 160. A pilot trial investigating patients with COPD and pulmonary arterial
hypertension, which usually develops late in patients with severe COPD, found improvements
in the fatigue, dyspnea and emotional domains following yoga intervention 218. Moreover, the
Both groups in Study III exhibited immediate effects after the intervention (12 weeks) on
MCID (0.5 points) in CRQ, though there was a larger effect found in the CTP group.
Interaction (group x time) showed significance in CRQ fatigue and CRQ emotional favouring
the CTP group. This probably relates to the CTP group having had improved effects when
comparing the baseline to the point in time after the follow-up. The YE group showed
significance in the CRQ mastery domain, however no significant between-group effects
emerged after the 12 week long intervention.
This evidence follows from earlier research 218, and the interviews conducted in Study IV
qualitatively confirms the large effects shown in the YE group with regards to the mastery
domain. Previously, diaphragmatic breathing and YE have had positive effects on diseasespecific quality of life among patients with COPD 62 79 186, while other studies have reported
no effects 160. A pilot trial investigating patients with COPD and pulmonary arterial
hypertension, which usually develops late in patients with severe COPD, found improvements
in the fatigue, dyspnea and emotional domains following yoga intervention 218. Moreover, the
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per-protocol analysis suggested the presence of significant additional improvements in the
CRQ emotional domain in the YE group (results not shown).
per-protocol analysis suggested the presence of significant additional improvements in the
CRQ emotional domain in the YE group (results not shown).
6.13 Self-reported health
6.13 Self-reported health
In Study III eight participants from each group reported better self-reported health after 12
weeks of intervention (data not shown) using the EQ-5D/VAS of MCID (10 units), but no
significance appeared. However, the EQ-5D had decreased significantly in the CTP group at 6
months (Figure 21). Furthermore, a strong correlation emerged in the YE group when
comparing differences in walking distance at baseline and after 12 weeks, indicating that an
increase in walking distance resulted in improved self-reported health (Figure 22). Others
have reported improved EQ-5D following the practise of adapted kundalini yoga for 12 weeks
(once a week) in patients with paroxysmal atrial fibrillation219 when compared to a control
group with no intervention.
In Study III eight participants from each group reported better self-reported health after 12
weeks of intervention (data not shown) using the EQ-5D/VAS of MCID (10 units), but no
significance appeared. However, the EQ-5D had decreased significantly in the CTP group at 6
months (Figure 21). Furthermore, a strong correlation emerged in the YE group when
comparing differences in walking distance at baseline and after 12 weeks, indicating that an
increase in walking distance resulted in improved self-reported health (Figure 22). Others
have reported improved EQ-5D following the practise of adapted kundalini yoga for 12 weeks
(once a week) in patients with paroxysmal atrial fibrillation219 when compared to a control
group with no intervention.
6.14 General effects after 6-months in Study III
6.14 General effects after 6-months in Study III
In Study III, effects after 6-months were compared to baseline levels. This resulted in
significant effects between CTP and YE-group in the six-minute walk test and the CRQemotional domain. This showed that CTP, but not YE, had longer lasting effects in 6MWT
and CRQ emotional domain. This may be related to longer lasting effects in CTP group in
these parameters. To achieve increased compliance after an intervention, it seems vital for
patients with pulmonary diseases to maintain physical activity levels since the effects
otherwise seem to diminish after 6 months. 69 This underscores the importance of researching
how to help patients to maintain physical activity levels.
In Study III, effects after 6-months were compared to baseline levels. This resulted in
significant effects between CTP and YE-group in the six-minute walk test and the CRQemotional domain. This showed that CTP, but not YE, had longer lasting effects in 6MWT
and CRQ emotional domain. This may be related to longer lasting effects in CTP group in
these parameters. To achieve increased compliance after an intervention, it seems vital for
patients with pulmonary diseases to maintain physical activity levels since the effects
otherwise seem to diminish after 6 months. 69 This underscores the importance of researching
how to help patients to maintain physical activity levels.
6.15 Experiences: qualitative content analysis
6.15 Experiences: qualitative content analysis
Study IV saw the participants in the YE group being interviewed face to face. The reported
experiences included being taught new ways of controlling and using their breathing as a way
to counteract symptoms, such as dyspnea and coughing, related to obstructive pulmonary
disease. The participants found “learning by doing” to be helpful in becoming more focused,
which in turn created a calmer and deeper breathing. Participants also reported increased body
awareness, energy and stamina. Study IV represents an important complement to the
traditionally measured effects on biomarkers of physical function. Patients reported increased
empowerment, expressed as increased mastery of the disease. This is a valuable new finding.
Improved awareness of breathing in combination with more efficient breathing techniques
were experienced as an important learning opportunity as well as something that increased
their perceived control over their health.
Study IV saw the participants in the YE group being interviewed face to face. The reported
experiences included being taught new ways of controlling and using their breathing as a way
to counteract symptoms, such as dyspnea and coughing, related to obstructive pulmonary
disease. The participants found “learning by doing” to be helpful in becoming more focused,
which in turn created a calmer and deeper breathing. Participants also reported increased body
awareness, energy and stamina. Study IV represents an important complement to the
traditionally measured effects on biomarkers of physical function. Patients reported increased
empowerment, expressed as increased mastery of the disease. This is a valuable new finding.
Improved awareness of breathing in combination with more efficient breathing techniques
were experienced as an important learning opportunity as well as something that increased
their perceived control over their health.
The main tools and active ingredients of YE involves working with body, breath and mind
simultaneously. These three tools work together to involve the individual fully and are using
both a bottom-up (doing the exercise) and top-down (observing with the mind) perspective43.
This means that the individual is involved in the practise in a more focused way since the
“listening” part is added 35 220 43. The yogic tools fit in with the overall theme in Study IV,
“From limitation to opportunity - to develop awareness and control over one’s breathing”.
Likewise, others report that 221 self-efficacy is an important predictor of behavioural change.
In general this means that the individual takes more charge of self-controlling the symptoms.
The main tools and active ingredients of YE involves working with body, breath and mind
simultaneously. These three tools work together to involve the individual fully and are using
both a bottom-up (doing the exercise) and top-down (observing with the mind) perspective43.
This means that the individual is involved in the practise in a more focused way since the
“listening” part is added 35 220 43. The yogic tools fit in with the overall theme in Study IV,
“From limitation to opportunity - to develop awareness and control over one’s breathing”.
Likewise, others report that 221 self-efficacy is an important predictor of behavioural change.
In general this means that the individual takes more charge of self-controlling the symptoms.
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In Study IV this was reflected in the increased self-control experienced with the help of the
three yogic tools. Increased self-efficacy is an important effect and goal of YE that has been
reported by the participants in Study IV under the category “To experience how one can
influence one's own situation”.
In Study IV this was reflected in the increased self-control experienced with the help of the
three yogic tools. Increased self-efficacy is an important effect and goal of YE that has been
reported by the participants in Study IV under the category “To experience how one can
influence one's own situation”.
Increased awareness seems to be the active ingredient of YE needed for improvements to
occur 222 223, especially as it pertains to patients with pain223 and obstructive pulmonary
diseases 218. The attention part of yoga is an important instrument for these patient groups.
Improved body awareness, control over one's health and pain reduction are a few of the
mechanisms emerging after continuous yogic practice, i.e “learning by doing”, and is
something which has also been reported in other qualitative studies 222-224.
Increased awareness seems to be the active ingredient of YE needed for improvements to
occur 222 223, especially as it pertains to patients with pain223 and obstructive pulmonary
diseases 218. The attention part of yoga is an important instrument for these patient groups.
Improved body awareness, control over one's health and pain reduction are a few of the
mechanisms emerging after continuous yogic practice, i.e “learning by doing”, and is
something which has also been reported in other qualitative studies 222-224.
Furthermore, the participants reported increased stamina and energy, which can be explained
by the style of yoga used and that the program included vigorous poses and breathing
exercises. Improved energy and stamina has been previously reported in patients with lung
disorders 62 115. One participant reported walking faster in daily life. Other studies have
suggested that a better breathing technique may be a mechanism to more energy 192.
Furthermore, the participants reported increased stamina and energy, which can be explained
by the style of yoga used and that the program included vigorous poses and breathing
exercises. Improved energy and stamina has been previously reported in patients with lung
disorders 62 115. One participant reported walking faster in daily life. Other studies have
suggested that a better breathing technique may be a mechanism to more energy 192.
In Study IV participants reported decreased use of bronchodilators and less breathlessness as
well as an increased mastery of dyspnea following YE, specified under the category “To
experience how one can influence one's own situation”.
In Study IV participants reported decreased use of bronchodilators and less breathlessness as
well as an increased mastery of dyspnea following YE, specified under the category “To
experience how one can influence one's own situation”.
A recent Cochrane review reports that yoga to some extent improves quality of life and
asthma symptoms without serious adverse events 114, and it has been suggested to serve as an
alternative rehabilitation choice for patients with obstructive lung diseases 48. Moreover,
asthma symptoms, quality of life, exercise capacity and bronchial hyper reactivity have all
been shown to improve in asthmatics after physical training 225 .
A recent Cochrane review reports that yoga to some extent improves quality of life and
asthma symptoms without serious adverse events 114, and it has been suggested to serve as an
alternative rehabilitation choice for patients with obstructive lung diseases 48. Moreover,
asthma symptoms, quality of life, exercise capacity and bronchial hyper reactivity have all
been shown to improve in asthmatics after physical training 225 .
Using breathing exercises can improve breathing technique 79, which seems to be one of the
important yogic tools to increase awareness that the patients in Study IV experienced. This
has been reported under the category “To experience how one can influence one’s own
situation”. Other yogic interventions 226 using only breathing exercises for 3 weeks - a total of
15 hours - showed significant improvements in sleep patterns when compared to usual care.
This suggests that short interventions can have powerful and non-pharmacological effects.
There were a few reported difficulties and challenges in the beginning of Study IV related to
the synchronization of breathing and movements, but after 5-6 times participants reported that
it became easier.
Using breathing exercises can improve breathing technique 79, which seems to be one of the
important yogic tools to increase awareness that the patients in Study IV experienced. This
has been reported under the category “To experience how one can influence one’s own
situation”. Other yogic interventions 226 using only breathing exercises for 3 weeks - a total of
15 hours - showed significant improvements in sleep patterns when compared to usual care.
This suggests that short interventions can have powerful and non-pharmacological effects.
There were a few reported difficulties and challenges in the beginning of Study IV related to
the synchronization of breathing and movements, but after 5-6 times participants reported that
it became easier.
Social interactions before and after YE may have strengthened the experiences and effects of
YE. However, during class, silence (no conversation) was encouraged. Being in a group
setting with a common goal may have created a positive social atmosphere 218 and may have
increased the participants' personal empowerment 224, as well as having added to their
awareness of the self and the physical body. The importance of a positive atmosphere has
been reported under the category, "To focus and be aware in a new way."
Social interactions before and after YE may have strengthened the experiences and effects of
YE. However, during class, silence (no conversation) was encouraged. Being in a group
setting with a common goal may have created a positive social atmosphere 218 and may have
increased the participants' personal empowerment 224, as well as having added to their
awareness of the self and the physical body. The importance of a positive atmosphere has
been reported under the category, "To focus and be aware in a new way."
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The category, “To experience how one can influence one’s own situation” and the overall
theme to go from limitation to opportunity can be described as a form of improvement in
quality of life, since the patients were able to master their symptoms themselves.
Other qualitative reports have reported improved quality of life (CRQ-fatigue), energy and
breathing capacity with less anxiety and pain; "increased tidal volume with slowing
expiration" with quotes as: "I have an overall feeling of well-being" and "excellent amount of
energy" 218.
Measuring quality of life on the CRQ scale of mastery increased significantly in Study III,
showing that objective and subjective data mirror each other. Rehabilitation that helps patients
self-manage their symptoms and improve quality of life needs to be emphasized for this
patient group.
The category, “To experience how one can influence one’s own situation” and the overall
theme to go from limitation to opportunity can be described as a form of improvement in
quality of life, since the patients were able to master their symptoms themselves.
Other qualitative reports have reported improved quality of life (CRQ-fatigue), energy and
breathing capacity with less anxiety and pain; "increased tidal volume with slowing
expiration" with quotes as: "I have an overall feeling of well-being" and "excellent amount of
energy" 218.
Measuring quality of life on the CRQ scale of mastery increased significantly in Study III,
showing that objective and subjective data mirror each other. Rehabilitation that helps patients
self-manage their symptoms and improve quality of life needs to be emphasized for this
patient group.
7 Methodological considerations
7 Methodological considerations
This thesis includes both objective and subjective data in the form of questionnaires and
interviews.
This thesis includes both objective and subjective data in the form of questionnaires and
interviews.
7.1 Design
7.1 Design
Using an RCT design is considered the best method for evaluating the efficiency of different
interventions and cancel out bias and the placebo effect. Moreover, in order to prevent bias,
the optimal design should avoid passive comparison groups and make sure to blind both
measurers and participants.
Using an RCT design is considered the best method for evaluating the efficiency of different
interventions and cancel out bias and the placebo effect. Moreover, in order to prevent bias,
the optimal design should avoid passive comparison groups and make sure to blind both
measurers and participants.
Missing outcomes and non-compliance is solved by employing the statistical concept
intention-to-treat model (ITT) and there include all participants randomized to each treatment.
If a participant is missing or unwilling to be re-measured, the technique of last observation
carried forward should be used. Alternatively, one could also use more sophisticated
statistical modeling using the available data from each individual. Study III employed an
intention to treat (ITT) model and minimized the risk of bias. However, the principle of last
observation carried forward was not applied to those participants who were unwilling to be
measured, especially after the follow-up 6 months later. In line with ethical principles, those
participants were not included in the ITT calculation if absent or sick. Factors that can occur
after randomization has taken place, e.g. absence and deviations from protocol, were
corrected. The Per-protocol model, which is the most common design in a majority of the
published yoga studies, says to analyze only participants who've completed the full
intervention 227. Although avoided in Study III, Studies I and II did use the per-protocol
model. The ITT analysis resulted in many patients with low adherence in the YE group, while
the low adherence patients in the CTP group were excluded from analysis (3 classes minimum
in YE and 12 minimum in CTP) due to their unwillingness to participate in additional followups. This resulted in higher adherence to CTP than that of YE.
Missing outcomes and non-compliance is solved by employing the statistical concept
intention-to-treat model (ITT) and there include all participants randomized to each treatment.
If a participant is missing or unwilling to be re-measured, the technique of last observation
carried forward should be used. Alternatively, one could also use more sophisticated
statistical modeling using the available data from each individual. Study III employed an
intention to treat (ITT) model and minimized the risk of bias. However, the principle of last
observation carried forward was not applied to those participants who were unwilling to be
measured, especially after the follow-up 6 months later. In line with ethical principles, those
participants were not included in the ITT calculation if absent or sick. Factors that can occur
after randomization has taken place, e.g. absence and deviations from protocol, were
corrected. The Per-protocol model, which is the most common design in a majority of the
published yoga studies, says to analyze only participants who've completed the full
intervention 227. Although avoided in Study III, Studies I and II did use the per-protocol
model. The ITT analysis resulted in many patients with low adherence in the YE group, while
the low adherence patients in the CTP group were excluded from analysis (3 classes minimum
in YE and 12 minimum in CTP) due to their unwillingness to participate in additional followups. This resulted in higher adherence to CTP than that of YE.
Regarding attrition bias – four participants in the YE group dropped out due to severe health
issues, exacerbations and other personal reasons. Moreover, according to selection bias one
cannot exclude that those participants who have a better perceived health always select
themselves, i. self-selection and fulfillment of the full intervention. Perhaps those with lower
Regarding attrition bias – four participants in the YE group dropped out due to severe health
issues, exacerbations and other personal reasons. Moreover, according to selection bias one
cannot exclude that those participants who have a better perceived health always select
themselves, i. self-selection and fulfillment of the full intervention. Perhaps those with lower
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health status are those who are most in need of interventions. Neither response bias can be
excluded. Response bias is when the participants report their symptoms in a more optimistic
way, and in a way they feel is socially acceptable or desirable. This especially applies to faceto-face interviews such as those conducted in Study IV. Additionally, the co-intervention bias
is the tendency of participants to seek out and get treatment that is not part of the trial. Advice
given to the participants during the intervention was to not start any new type of exercise.
The participants were then asked about this at the end of the intervention, but no participants
reported having done so. Being part of a trial or experiment and sign informed consent forms
may also alter people's preconceptions and beliefs and create a placebo effect228. Seasonal
variations could also have had an effect, since many people in Scandinavia are more naturally
active in the spring, which is when all studies were starting.
health status are those who are most in need of interventions. Neither response bias can be
excluded. Response bias is when the participants report their symptoms in a more optimistic
way, and in a way they feel is socially acceptable or desirable. This especially applies to faceto-face interviews such as those conducted in Study IV. Additionally, the co-intervention bias
is the tendency of participants to seek out and get treatment that is not part of the trial. Advice
given to the participants during the intervention was to not start any new type of exercise.
The participants were then asked about this at the end of the intervention, but no participants
reported having done so. Being part of a trial or experiment and sign informed consent forms
may also alter people's preconceptions and beliefs and create a placebo effect228. Seasonal
variations could also have had an effect, since many people in Scandinavia are more naturally
active in the spring, which is when all studies were starting.
7.2 Recruitment
7.2 Recruitment
In Study I the recruitment pool was large – based on two major corporations - however since
the inclusion criteria only allowed for physical activity once a month, only 12 participants
were found. The subsequent studies included a broader inclusion for feasibility purposes. In
Study II, recruitment was done through a website for students (the target group), the problem
with this being that the students who signed up to this website was probably interested in
larger payments for participation in interventions. The recruitment process and the
participants’ preferences and expectations for treatment assignment and positive outcomes
should therefore be considered as limitations of Studies II-IV.
Study III+IV recruited actively from a variety of channels, including websites, email, primary
care general practitioners and posters pasted in hospitals and lung clinics. Seeing as there
were several other research projects running simultaneously on COPD, we found it hard to get
enough participants. Furthermore, the randomization process resulted in more participants
with COPD ending up in the YE group while more asthma participants ended up in the CTP
group. The recruitment of additional patients with COPD was also limited by the rather low
prevalence of registered diagnoses in Sweden, this in turn relating to the low rate of daily
smokers. Moreover, patients with severe obstructions (GOLD-4) were excluded for safety
reasons, meaning that the effects of the YE program on this group remain unknown. Thus the
transfer of our findings to patients with severe obstructions may not be fully realized.
In Study I the recruitment pool was large – based on two major corporations - however since
the inclusion criteria only allowed for physical activity once a month, only 12 participants
were found. The subsequent studies included a broader inclusion for feasibility purposes. In
Study II, recruitment was done through a website for students (the target group), the problem
with this being that the students who signed up to this website was probably interested in
larger payments for participation in interventions. The recruitment process and the
participants’ preferences and expectations for treatment assignment and positive outcomes
should therefore be considered as limitations of Studies II-IV.
Study III+IV recruited actively from a variety of channels, including websites, email, primary
care general practitioners and posters pasted in hospitals and lung clinics. Seeing as there
were several other research projects running simultaneously on COPD, we found it hard to get
enough participants. Furthermore, the randomization process resulted in more participants
with COPD ending up in the YE group while more asthma participants ended up in the CTP
group. The recruitment of additional patients with COPD was also limited by the rather low
prevalence of registered diagnoses in Sweden, this in turn relating to the low rate of daily
smokers. Moreover, patients with severe obstructions (GOLD-4) were excluded for safety
reasons, meaning that the effects of the YE program on this group remain unknown. Thus the
transfer of our findings to patients with severe obstructions may not be fully realized.
Study II-III included a majority of women while Study I included a majority of men.
Study II-III included a majority of women while Study I included a majority of men.
All the Study IV participants engaged in the YE intervention gave their permission to be
interviewed. This together with the wide variety of participants, regarding gender, age and
different levels of obstructive lung diseases, provided a broad view of YE experiences and
thus strengthens the transfer of the findings to a wider sample. However, the information
given to the participants was clear regarding the fact that the study involved two different
conditions with eligible participants being randomized into either yoga or conventional
treatment.
All the Study IV participants engaged in the YE intervention gave their permission to be
interviewed. This together with the wide variety of participants, regarding gender, age and
different levels of obstructive lung diseases, provided a broad view of YE experiences and
thus strengthens the transfer of the findings to a wider sample. However, the information
given to the participants was clear regarding the fact that the study involved two different
conditions with eligible participants being randomized into either yoga or conventional
treatment.
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7.3 Hawthorne/Placebo effect
7.3 Hawthorne/Placebo effect
Being invited to participate in a clinical trial creates beliefs and expectations among the
enrolled participants. This is one of the reasons for including a control group (especially an
active control group). Specifically, a control group allows one to cancel out pure time effects
and placebo effects. This means that if someone is being observed and assessed it can add to
their expectations and beliefs about the treatment having positive effects. This phenomenon is
called placebo and the participants receiving attention is called the Hawthorne effect. To
clarify, the three components in placebo involves: “assessment and observation, a therapeutic
ritual (placebo treatment), and a supportive patient-practitioner relationship”, with the
therapeutic ritual (patient-practitioner) being the most effective ingredient of the placebo
effect 229. Study I was a pilot-study with no controls and thus the results have to be
approached with caution. Study III resulted in positive effects in both groups and they were
both exposed to the Hawthorne effect. Moreover, the Hawthorne effect could have influenced
the subjective measures (e.g. the CRQ scale in Study III), however the placebo effect was
probably cancelled due to both groups being enrolled in an active treatment. Nevertheless,
different people met the participants in the different groups 1-2 times weekly during the
intervention and this could have created a placebo effect by way of the instructors 229.To
avoid the therapeutic ritual part of placebo, the author did not measure or train the participants
in any of the studies. It has been shown that placebo effects can produce statistically and
clinically significant improvements 229, while other meta-analyses have shown no such
significant effects on objective or binary outcomes of placebo. Yet, small effects can emerge
in studies with subjective outcomes and for the treatment of pain 230 and mental disorders 231 .
Being invited to participate in a clinical trial creates beliefs and expectations among the
enrolled participants. This is one of the reasons for including a control group (especially an
active control group). Specifically, a control group allows one to cancel out pure time effects
and placebo effects. This means that if someone is being observed and assessed it can add to
their expectations and beliefs about the treatment having positive effects. This phenomenon is
called placebo and the participants receiving attention is called the Hawthorne effect. To
clarify, the three components in placebo involves: “assessment and observation, a therapeutic
ritual (placebo treatment), and a supportive patient-practitioner relationship”, with the
therapeutic ritual (patient-practitioner) being the most effective ingredient of the placebo
effect 229. Study I was a pilot-study with no controls and thus the results have to be
approached with caution. Study III resulted in positive effects in both groups and they were
both exposed to the Hawthorne effect. Moreover, the Hawthorne effect could have influenced
the subjective measures (e.g. the CRQ scale in Study III), however the placebo effect was
probably cancelled due to both groups being enrolled in an active treatment. Nevertheless,
different people met the participants in the different groups 1-2 times weekly during the
intervention and this could have created a placebo effect by way of the instructors 229.To
avoid the therapeutic ritual part of placebo, the author did not measure or train the participants
in any of the studies. It has been shown that placebo effects can produce statistically and
clinically significant improvements 229, while other meta-analyses have shown no such
significant effects on objective or binary outcomes of placebo. Yet, small effects can emerge
in studies with subjective outcomes and for the treatment of pain 230 and mental disorders 231 .
7.4 Intervention program
7.4 Intervention program
The dose-response relationship during interventions and what duration and frequency is
needed for the treatment to produce optimal effects needs to be established. Yet, for clinical
trials it can be difficult to find a balance between how long people are willing to commit to
participating in interventions and how long it takes to get results. Studies I and II used a once
a week design, while Study III used a twice a week design. All three studies used 1-hour
classes and had 1-2 instructors present during each session. In Study II the large variation in
home exercises was an obvious issue. Yogic interventions can however be more cost-effective
than pulmonary rehabilitation since no equipment is necessary and exercises can be partly
self-taught and practiced at home.
The dose-response relationship during interventions and what duration and frequency is
needed for the treatment to produce optimal effects needs to be established. Yet, for clinical
trials it can be difficult to find a balance between how long people are willing to commit to
participating in interventions and how long it takes to get results. Studies I and II used a once
a week design, while Study III used a twice a week design. All three studies used 1-hour
classes and had 1-2 instructors present during each session. In Study II the large variation in
home exercises was an obvious issue. Yogic interventions can however be more cost-effective
than pulmonary rehabilitation since no equipment is necessary and exercises can be partly
self-taught and practiced at home.
Currently, there are no other RCTs of obstructive pulmonary disease patients using the newly
developed YE program investigated in Study III. Evaluating the efficiency, safety and
feasibility of this new YE program was essential to the thesis and also one of our main study
objectives. The detailed program description of the interventions, as well as the follow-up 6
months after the intervention, represents its main strength.
Another strength of Study III's YE program was to include breathing exercises with prolonged
exhalations and certain other specific YE. Regarding the presentation of the yoga programs
the program was taught by trained yoga instructors and not the author of the thesis.
Furthermore, the interaction between the instructor or measurer and the participant may have
Currently, there are no other RCTs of obstructive pulmonary disease patients using the newly
developed YE program investigated in Study III. Evaluating the efficiency, safety and
feasibility of this new YE program was essential to the thesis and also one of our main study
objectives. The detailed program description of the interventions, as well as the follow-up 6
months after the intervention, represents its main strength.
Another strength of Study III's YE program was to include breathing exercises with prolonged
exhalations and certain other specific YE. Regarding the presentation of the yoga programs
the program was taught by trained yoga instructors and not the author of the thesis.
Furthermore, the interaction between the instructor or measurer and the participant may have
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created a therapeutic benefit. Still, the author trained the teachers in the three different
programs to be able to provide a standardized quality of instruction.
created a therapeutic benefit. Still, the author trained the teachers in the three different
programs to be able to provide a standardized quality of instruction.
The YE program design in Study III varied between CTP and YE. To achieve equal effects on
lung function and respiratory muscle strength, a larger YE dose and a program with a higher
dynamic intensity on the upper and lower body might have added greater benefits.
Moreover, feelings of insecurity appeared when the aim of any breathing exercise was not
clearly understood in Study IV. The YE program could have included more strength training
exercises that are important for breathing, but one reason for there being no improvement in
lung function is probably due to the nature of the YE program and most of the participants in
the YE group having COPD. The follow-up of the YE group in Study III demonstrated no
effects, which may be due to this group including more patients with COPD.
The YE program design in Study III varied between CTP and YE. To achieve equal effects on
lung function and respiratory muscle strength, a larger YE dose and a program with a higher
dynamic intensity on the upper and lower body might have added greater benefits.
Moreover, feelings of insecurity appeared when the aim of any breathing exercise was not
clearly understood in Study IV. The YE program could have included more strength training
exercises that are important for breathing, but one reason for there being no improvement in
lung function is probably due to the nature of the YE program and most of the participants in
the YE group having COPD. The follow-up of the YE group in Study III demonstrated no
effects, which may be due to this group including more patients with COPD.
Experiencing an adverse effect with yogic inversions (head below heart body position) and
sun salutations (including semi-inversions) could increase the risk for gastroesophageal reflux
(preliminary reports), which is why these should be avoided by sensitive individuals.
Experiencing an adverse effect with yogic inversions (head below heart body position) and
sun salutations (including semi-inversions) could increase the risk for gastroesophageal reflux
(preliminary reports), which is why these should be avoided by sensitive individuals.
To describe and keep the intervention as “clean” as possible without interfering factors is
important. For example, some yogic interventions uses background music, which may affect
the results. There are studies showing that listening to music can lower BP and HR 232 233. We
did not include any background music in any of the YE interventions and the room was quiet
and meant exclusively for the YE connected to this thesis. People running around a room
containing many assistant yoga teachers or other people should be avoided, as should
disturbances from next door. Group interventions can give rise to many factors that can
interfere with the results, one example being the strengthening effect that social interaction
can have.
To describe and keep the intervention as “clean” as possible without interfering factors is
important. For example, some yogic interventions uses background music, which may affect
the results. There are studies showing that listening to music can lower BP and HR 232 233. We
did not include any background music in any of the YE interventions and the room was quiet
and meant exclusively for the YE connected to this thesis. People running around a room
containing many assistant yoga teachers or other people should be avoided, as should
disturbances from next door. Group interventions can give rise to many factors that can
interfere with the results, one example being the strengthening effect that social interaction
can have.
In Study II and III all measurements were taken by trained physiotherapists. In Study I, BP
and hand-grip strength was measured by the author for practical reasons due to the
measurements being carried out on site. Breathing frequency was measured with a device
only in Study III.
In Study II and III all measurements were taken by trained physiotherapists. In Study I, BP
and hand-grip strength was measured by the author for practical reasons due to the
measurements being carried out on site. Breathing frequency was measured with a device
only in Study III.
7.5 Measurements
7.5 Measurements
Study I was a small-scale longitudinal pilot study done on naive YE participants, where time
spent on inversions increased from 7 minutes to 20 minutes over an eight week period,
showing that YE increased HRV in the time domain (pNN50%). Yogic exercises can have a
restorative effect on the autonomic nervous system. Moreover, other HRV measures,
including NN50, HF and LF/HF ratio, also showed a trend towards improvement, but not a
significant one. However, larger randomized controlled studies are needed to confirm the
effects of different YE on the sympathetic and parasympathetic nervous system. Furthermore,
in Study I the time domain HRV measures increased whereas the frequency domain HRV
measures did not. Some participants were excluded due to poor ECG recording quality,
therefore resulting in a smaller sample size.
Study I was a small-scale longitudinal pilot study done on naive YE participants, where time
spent on inversions increased from 7 minutes to 20 minutes over an eight week period,
showing that YE increased HRV in the time domain (pNN50%). Yogic exercises can have a
restorative effect on the autonomic nervous system. Moreover, other HRV measures,
including NN50, HF and LF/HF ratio, also showed a trend towards improvement, but not a
significant one. However, larger randomized controlled studies are needed to confirm the
effects of different YE on the sympathetic and parasympathetic nervous system. Furthermore,
in Study I the time domain HRV measures increased whereas the frequency domain HRV
measures did not. Some participants were excluded due to poor ECG recording quality,
therefore resulting in a smaller sample size.
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67
Measurement of oxygen uptake in Study II was done using a Cooper field test, allowing for
limited control over weather conditions (which differed slightly). However, the Golden
Standard for experimental testing of VO2max is direct measurement using a metabolic cart with
a chamber, which would have allowed for more precision. Coopers test was chosen for
practical reasons, since the validity is similar to the oxygen chamber method 152 153 and since
to schedule each individual for laboratory analysis with metabolic cart measurement would
have been impossible.
Measurement of oxygen uptake in Study II was done using a Cooper field test, allowing for
limited control over weather conditions (which differed slightly). However, the Golden
Standard for experimental testing of VO2max is direct measurement using a metabolic cart with
a chamber, which would have allowed for more precision. Coopers test was chosen for
practical reasons, since the validity is similar to the oxygen chamber method 152 153 and since
to schedule each individual for laboratory analysis with metabolic cart measurement would
have been impossible.
Biomarkers used blood analysis and were performed at a certified laboratory. They were
analyzed in direct relation to the intervention in Study II. The obvious strength of Study II lie
in participants being gluco-metabolically healthy (very low HbA1c), and no larger effect on
blood parameters could be detected after high intensity yogic exercises. Perhaps research done
on individuals with lower fitness levels or on patient groups could produce such effects. Both
the ApoA1 and adiponectin levels increased in the YE group, which suggests a positive
metabolic effect on a somewhat active and healthy group. However, large positive effects
were not expected. Yet, the increasing ApoA1 and adiponectin levels along with the lowered
HbA1c in the YE group show a clear trend. The YE dose was too low to produce any
cardiovascular fitness improvements, but still there emerged positive effects on ApoA1 and
adiponectin levels. As regards the biomarkers, there was no correction for variations in
plasma volume shifts, and further details on nutritional status would have added information.
Some of the blood parameters differ between men and women, e.g. adiponectin which was
only calculated for women in Study II. This was not a problem considering the majority of the
participants in Study II were women.
Biomarkers used blood analysis and were performed at a certified laboratory. They were
analyzed in direct relation to the intervention in Study II. The obvious strength of Study II lie
in participants being gluco-metabolically healthy (very low HbA1c), and no larger effect on
blood parameters could be detected after high intensity yogic exercises. Perhaps research done
on individuals with lower fitness levels or on patient groups could produce such effects. Both
the ApoA1 and adiponectin levels increased in the YE group, which suggests a positive
metabolic effect on a somewhat active and healthy group. However, large positive effects
were not expected. Yet, the increasing ApoA1 and adiponectin levels along with the lowered
HbA1c in the YE group show a clear trend. The YE dose was too low to produce any
cardiovascular fitness improvements, but still there emerged positive effects on ApoA1 and
adiponectin levels. As regards the biomarkers, there was no correction for variations in
plasma volume shifts, and further details on nutritional status would have added information.
Some of the blood parameters differ between men and women, e.g. adiponectin which was
only calculated for women in Study II. This was not a problem considering the majority of the
participants in Study II were women.
In Study III there was a statistical imbalance in the 6MWD baseline with higher walk-distance
levels in the YE group, meaning that the range for improvements (ceiling-effect) was
probably smaller when compared to the CTP.
In Study III there was a statistical imbalance in the 6MWD baseline with higher walk-distance
levels in the YE group, meaning that the range for improvements (ceiling-effect) was
probably smaller when compared to the CTP.
Despite variation in compliance between the groups, the overall compliance was large and
allowed for testing of both YE and conventional training programs in Study III and IV. We
chose to include both asthma and COPD in order to investigate the effects on both groups.
Both groups showed positive effects on the validated 6MWT234 and was performed according
to guidelines 235. The walk-test is a powerful indicator of health status impairment 236 237 238 .
The walk-test was performed indoors in the same environment for all three tests. Prior
research suggests that to see improvements in walk-test it should be 54 meters239, but this has
recently been changed to 26 meters for patients with severe COPD115 240.
Despite variation in compliance between the groups, the overall compliance was large and
allowed for testing of both YE and conventional training programs in Study III and IV. We
chose to include both asthma and COPD in order to investigate the effects on both groups.
Both groups showed positive effects on the validated 6MWT234 and was performed according
to guidelines 235. The walk-test is a powerful indicator of health status impairment 236 237 238 .
The walk-test was performed indoors in the same environment for all three tests. Prior
research suggests that to see improvements in walk-test it should be 54 meters239, but this has
recently been changed to 26 meters for patients with severe COPD115 240.
In Study III the YE group increased in the CRQ mastery domain, which may have increased
their health and self-efficacy by teaching them new skills to master their breathlessness, thus
improving their quality of life. Using self-evaluative questionnaires like CRQ represents a
valid 241 242 instrument. However, there are other questionnaires that come recommended by
GOLD, such as the Modified British Medical Research Council questionnaire on
breathlessness or the COPD Assessment Test (CAT)63, both of which could have been used in
Study III to describe the patients' wellbeing.
In Study III the YE group increased in the CRQ mastery domain, which may have increased
their health and self-efficacy by teaching them new skills to master their breathlessness, thus
improving their quality of life. Using self-evaluative questionnaires like CRQ represents a
valid 241 242 instrument. However, there are other questionnaires that come recommended by
GOLD, such as the Modified British Medical Research Council questionnaire on
breathlessness or the COPD Assessment Test (CAT)63, both of which could have been used in
Study III to describe the patients' wellbeing.
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68
The most commonly used parameter for measuring lung function is FEV1 and FVC151, both of
which were used in Study III. Spirometry was performed according to guidelines 151 and is
valid 243 in general practice and satisfactory in comparison with the “gold-standard spirometry
test measured in certified pulmonary function laboratories . However, spirometric indices
relevant to the management of COPD obtained during trained general practices showed a
marginal but statistically significant increase when compared to those measured in certified
pulmonary function laboratories 244. According to GOLD, spirometry should be measured
after administration of an adequate dose of short-acting inhaled bronchodilator to minimize
variability, but this was not done in Study III. Instead patients were asked not to use the
inhaler prior to the spirometry and respiratory strength tests to make sure that the baseline
levels were similar in all the measurements in Study III. Yet, all the participants already had a
diagnosis from a doctor. However, there is a certain learning process associated with
spirometry, and perhaps the participants got increasingly used to the test throughout the study
period. Yet, all the measurements were taken by physiotherapists and not in a laboratory. As
for measurement errors, inadequate inhalation may have induced errors during the breathing
tests. It's important to note that the patients varied largely both in age, disease severity (both
asthma and COPD) and FEV1, however FEV1 is not an optimal measure. Moreover, some of
the patients in the CTP group had previous experience of participating in physiotherapeutic
interventions involving cycling and strength training, which made them familiar with some of
the exercises, while the participants in the YE were all novices. Three participants with more
severe illnesses and one younger woman dropped out from Study III, which may have been
due to either the intensity of the program or personal reasons.
The number of asthma attacks and/or exacerbations as well as the strength required in large
muscle groups during the interventions could have added more information about exercise
interference.
Regarding oximetry, no participants in Study III fell below 92% 245, which meant arterial
oxyhemoglobin saturation (%SaO2) blood gas analysis were not needed and fingertip capillary
gas estimation was performed. This accurately reflects the arterial pressure of C02 and arterial
blood gas tension 246.
The most commonly used parameter for measuring lung function is FEV1 and FVC151, both of
which were used in Study III. Spirometry was performed according to guidelines 151 and is
valid 243 in general practice and satisfactory in comparison with the “gold-standard spirometry
test measured in certified pulmonary function laboratories . However, spirometric indices
relevant to the management of COPD obtained during trained general practices showed a
marginal but statistically significant increase when compared to those measured in certified
pulmonary function laboratories 244. According to GOLD, spirometry should be measured
after administration of an adequate dose of short-acting inhaled bronchodilator to minimize
variability, but this was not done in Study III. Instead patients were asked not to use the
inhaler prior to the spirometry and respiratory strength tests to make sure that the baseline
levels were similar in all the measurements in Study III. Yet, all the participants already had a
diagnosis from a doctor. However, there is a certain learning process associated with
spirometry, and perhaps the participants got increasingly used to the test throughout the study
period. Yet, all the measurements were taken by physiotherapists and not in a laboratory. As
for measurement errors, inadequate inhalation may have induced errors during the breathing
tests. It's important to note that the patients varied largely both in age, disease severity (both
asthma and COPD) and FEV1, however FEV1 is not an optimal measure. Moreover, some of
the patients in the CTP group had previous experience of participating in physiotherapeutic
interventions involving cycling and strength training, which made them familiar with some of
the exercises, while the participants in the YE were all novices. Three participants with more
severe illnesses and one younger woman dropped out from Study III, which may have been
due to either the intensity of the program or personal reasons.
The number of asthma attacks and/or exacerbations as well as the strength required in large
muscle groups during the interventions could have added more information about exercise
interference.
Regarding oximetry, no participants in Study III fell below 92% 245, which meant arterial
oxyhemoglobin saturation (%SaO2) blood gas analysis were not needed and fingertip capillary
gas estimation was performed. This accurately reflects the arterial pressure of C02 and arterial
blood gas tension 246.
Content analysis 164 163 is suggested to report on external validity 247 practical applicability,
relevance and trustworthiness 248 165 . This relates to the content analysis, as used in Study IV,
involving the analysis of interview data. In Study IV credibility in data collection and analysis
was assured by close cooperation within the research group with good competency in using
content analyses163, yoga teacher experiences and clinical experiences of working with
obstructive pulmonary disorders as well as the interviews being performed by an independent
interviewer not involved in the intervention. The interviews were performed directly after the
intervention while the participants had their experiences fresh in mind. The interview guide
used two test interviews in order to strengthen the interview technique. In Study IV all the
participants engaged in the YE intervention accepted to be interviewed and a broad view of
YE experiences emerged.
Content analysis 164 163 is suggested to report on external validity 247 practical applicability,
relevance and trustworthiness 248 165 . This relates to the content analysis, as used in Study IV,
involving the analysis of interview data. In Study IV credibility in data collection and analysis
was assured by close cooperation within the research group with good competency in using
content analyses163, yoga teacher experiences and clinical experiences of working with
obstructive pulmonary disorders as well as the interviews being performed by an independent
interviewer not involved in the intervention. The interviews were performed directly after the
intervention while the participants had their experiences fresh in mind. The interview guide
used two test interviews in order to strengthen the interview technique. In Study IV all the
participants engaged in the YE intervention accepted to be interviewed and a broad view of
YE experiences emerged.
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69
7.6 Statistical considerations
7.6 Statistical considerations
7.6.1 Power calculation
7.6.1 Power calculation
Study I was performed at a workplace with a high percentage of physically active employees.
It was difficult to find sedentary individuals that fit the inclusion criteria, and this was one of
the reasons for the study becoming a pilot study; initially it was planned as a RCT trial. The
sample size and power for study II was sufficient at 96% power (20 was required for each
group). Study III required 24 patients (calculated on DD-index) in each group and therefore a
few more participants were needed to achieve 80% power. However, given the number of
patients we managed to include the statistical power still reached 71%, and additional patient
recruitment was deemed unfeasible. Regarding power in 6MWT in Study III we hypothesized
a difference after the intervention of a MCID of 54 meters in the YE group and 30 meters in
the CTP group, with the same SD (25) in each group and at 80% power. Since 18 participants
were needed in each group the study was therefore powered. Calculating the power on
adiponectin in Study II, we hypothesized a difference of 1 unit and 0.2 in Control group with
SD (0.8) in each group and with 80% power, it required 16 participants in each group and was
therefore powered.
Study I was performed at a workplace with a high percentage of physically active employees.
It was difficult to find sedentary individuals that fit the inclusion criteria, and this was one of
the reasons for the study becoming a pilot study; initially it was planned as a RCT trial. The
sample size and power for study II was sufficient at 96% power (20 was required for each
group). Study III required 24 patients (calculated on DD-index) in each group and therefore a
few more participants were needed to achieve 80% power. However, given the number of
patients we managed to include the statistical power still reached 71%, and additional patient
recruitment was deemed unfeasible. Regarding power in 6MWT in Study III we hypothesized
a difference after the intervention of a MCID of 54 meters in the YE group and 30 meters in
the CTP group, with the same SD (25) in each group and at 80% power. Since 18 participants
were needed in each group the study was therefore powered. Calculating the power on
adiponectin in Study II, we hypothesized a difference of 1 unit and 0.2 in Control group with
SD (0.8) in each group and with 80% power, it required 16 participants in each group and was
therefore powered.
The power for primary outcomes was calculated compared to other studies on HRV in Study
I101, oxygen uptake (VO2max) in Study II32 and DD-index in Study III 160. We chose the
parameters that reported clinically significant findings. In Study I the reason we choose HRV
was that no other reports with similar design similar to yoga to the study planned was
available at that time (2011). Study II used VO2max and was the only trial available with
significant findings on VO2max (with 2 mL/kg/min) at that time, moreover the design of that
study was similar to the one we planned. Study III power calculation was based on a pilot
study of yoga in COPD 160, this was the only yoga trial for this patient category that was
available, although DD-index is a new measure.
The power for primary outcomes was calculated compared to other studies on HRV in Study
I101, oxygen uptake (VO2max) in Study II32 and DD-index in Study III 160. We chose the
parameters that reported clinically significant findings. In Study I the reason we choose HRV
was that no other reports with similar design similar to yoga to the study planned was
available at that time (2011). Study II used VO2max and was the only trial available with
significant findings on VO2max (with 2 mL/kg/min) at that time, moreover the design of that
study was similar to the one we planned. Study III power calculation was based on a pilot
study of yoga in COPD 160, this was the only yoga trial for this patient category that was
available, although DD-index is a new measure.
8 Future perspectives
8 Future perspectives
To achieve effects on cardiovascular parameters such as oxygen uptake and health would
probably require longer YE interventions with more motivated participants. Additional
research is needed into the use of dynamic YE and sun salutations, with a longer duration (a
suggested 12 weeks, 3 times a week for at least 40 minutes) in both trained and naïve
participants.
To achieve effects on cardiovascular parameters such as oxygen uptake and health would
probably require longer YE interventions with more motivated participants. Additional
research is needed into the use of dynamic YE and sun salutations, with a longer duration (a
suggested 12 weeks, 3 times a week for at least 40 minutes) in both trained and naïve
participants.
Measuring baroreceptor sensitivity, heart rate variability (HRV) and heart rate recovery
before, during and immediately after a YE program could be another interesting project.
Measuring baroreceptor sensitivity, heart rate variability (HRV) and heart rate recovery
before, during and immediately after a YE program could be another interesting project.
Moreover, focusing solely on inversions to detect associated changes in the autonomic
nervous system (HRV) and their effect on energy/fatigue/recovery/stress tolerance would be
another very interesting approach to take.
Moreover, focusing solely on inversions to detect associated changes in the autonomic
nervous system (HRV) and their effect on energy/fatigue/recovery/stress tolerance would be
another very interesting approach to take.
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A detailed description of the program (perhaps with film) is warranted and further
interventions should introduce fewer exercises in the beginning of the intervention. Due to the
heterogeneity of the available studies there exists an unequal representation of body, breath
and mind exercises. To investigate which of the main components (body, breath, mind) that is
the most powerful of the YE is a warranted approach for future investigations. Determining
what type of YE is needed to improve walking distance and pulmonary function is another
interesting perspective.
A detailed description of the program (perhaps with film) is warranted and further
interventions should introduce fewer exercises in the beginning of the intervention. Due to the
heterogeneity of the available studies there exists an unequal representation of body, breath
and mind exercises. To investigate which of the main components (body, breath, mind) that is
the most powerful of the YE is a warranted approach for future investigations. Determining
what type of YE is needed to improve walking distance and pulmonary function is another
interesting perspective.
Patients requiring specific effects could possibly come to influence which intervention one
would chose to use.
Patients requiring specific effects could possibly come to influence which intervention one
would chose to use.
To determine to what extent self-efficacy is strengthened after a long/short yoga intervention
28
using self-efficacy scales.
To determine to what extent self-efficacy is strengthened after a long/short yoga intervention
28
using self-efficacy scales.
Systematic monitoring of subjective indicators as sleep-quality, perceived stress and mental
health are needed to complement qualitative data.
Systematic monitoring of subjective indicators as sleep-quality, perceived stress and mental
health are needed to complement qualitative data.
Future studies would be recommended to use a YE dose of 2-3 times a week to achieve
optimal results and to improve breathing performance/improvements in diseased populations’
probably daily practice is needed.
Future studies would be recommended to use a YE dose of 2-3 times a week to achieve
optimal results and to improve breathing performance/improvements in diseased populations’
probably daily practice is needed.
Regarding the effects of YE on breathing there's a lot to be investigated, such as for example
breathing frequency, breath holding time, diaphragmatic mobilization, chest expansion and
the use of breathing quality self-evaluations 183 184, as well as more frequent measurements of
oxygen saturation.
Regarding the effects of YE on breathing there's a lot to be investigated, such as for example
breathing frequency, breath holding time, diaphragmatic mobilization, chest expansion and
the use of breathing quality self-evaluations 183 184, as well as more frequent measurements of
oxygen saturation.
The effects of using diaphragmatic mobilisation techniques 121 in yogic practice and the
specific yogic breathing exercise bhramari (i.e humming with sound) and its long and shortterm effect on health and blood pressure. Bhramari was used extensively in Study III and has
been shown to increase exhaled Nitric Monoxide (NO) 249, distend capillaries and induce
relaxation. Using NO as a biomarker for eosinophilic inflammation in pulmonary patients
with exacerbation, pulmonary function impairments as progression of airways inflammation
and pulmonary arterial hypertension might come to represent an advantageous novel
biomarker.
The effects of using diaphragmatic mobilisation techniques 121 in yogic practice and the
specific yogic breathing exercise bhramari (i.e humming with sound) and its long and shortterm effect on health and blood pressure. Bhramari was used extensively in Study III and has
been shown to increase exhaled Nitric Monoxide (NO) 249, distend capillaries and induce
relaxation. Using NO as a biomarker for eosinophilic inflammation in pulmonary patients
with exacerbation, pulmonary function impairments as progression of airways inflammation
and pulmonary arterial hypertension might come to represent an advantageous novel
biomarker.
Future clinical trials are needed for different patient groups as well as for healthy participants
to further evaluate the long-term effects of yogic practice.
Future clinical trials are needed for different patient groups as well as for healthy participants
to further evaluate the long-term effects of yogic practice.
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9 Practical implications
9 Practical implications
The use of yogic exercises among both healthy and diseased populations can be implemented
as a complementary treatment in addition to other established methods. This pertains in
particular to participants with breathing disorders, poor cardiovascular health, elevated stress
levels and poor quality of life and lower-back pain. The YE can be used to empower
participants as well as to improve symptoms, well-being and health.
The use of yogic exercises among both healthy and diseased populations can be implemented
as a complementary treatment in addition to other established methods. This pertains in
particular to participants with breathing disorders, poor cardiovascular health, elevated stress
levels and poor quality of life and lower-back pain. The YE can be used to empower
participants as well as to improve symptoms, well-being and health.
10 Clinical implications
10 Clinical implications
Because of the pilot design in Study I, the results have to be approached with caution.
However, other studies have shown that YE increase HRV and programs such as the one used
in Study I and II produce similar effects as those of physical exercise, with no reported
adverse effects.
Yogic exercises may be added to other established physical training programs as a
complementary treatment for healthy individuals that require higher intensities. Physical
therapists may use the program for additional benefits in the treatment of patients and healthy
individuals.
With the results from Study III showing similar effects in both the YE and CTP group with
regards to walking distance after 12 weeks of intervention, YE seems like feasible and safe
short-form version of physical exercise for patients with pulmonary disease.
While the long-term effects (after follow-up) on CRQ and walk-tests were greater in the CTP
group, the YE group showed greater increases in mastery of symptoms and respiratory rates.
As part of rehabilitation YE may then constitute an alternative to other physical activities or
training and may be a useful addition to traditional rehabilitation programs 48, especially
considering it has no reported adverse effects.
However, the randomized distribution of more patients with asthma in the CTP group and
more patients with COPD in the YE group means that the results have to be interpreted
cautiously. Study IV revealed the recognition of yoga as a treatment of COPD and asthma in
medical practice, and its contribution to the empowerment of patients in their everyday
practice is an important new finding.
Because of the pilot design in Study I, the results have to be approached with caution.
However, other studies have shown that YE increase HRV and programs such as the one used
in Study I and II produce similar effects as those of physical exercise, with no reported
adverse effects.
Yogic exercises may be added to other established physical training programs as a
complementary treatment for healthy individuals that require higher intensities. Physical
therapists may use the program for additional benefits in the treatment of patients and healthy
individuals.
With the results from Study III showing similar effects in both the YE and CTP group with
regards to walking distance after 12 weeks of intervention, YE seems like feasible and safe
short-form version of physical exercise for patients with pulmonary disease.
While the long-term effects (after follow-up) on CRQ and walk-tests were greater in the CTP
group, the YE group showed greater increases in mastery of symptoms and respiratory rates.
As part of rehabilitation YE may then constitute an alternative to other physical activities or
training and may be a useful addition to traditional rehabilitation programs 48, especially
considering it has no reported adverse effects.
However, the randomized distribution of more patients with asthma in the CTP group and
more patients with COPD in the YE group means that the results have to be interpreted
cautiously. Study IV revealed the recognition of yoga as a treatment of COPD and asthma in
medical practice, and its contribution to the empowerment of patients in their everyday
practice is an important new finding.
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11 Conclusions
11 Conclusions
The conclusions of this thesis were drawn from an evaluation of different yogic exercise
programs on health and show that:
The conclusions of this thesis were drawn from an evaluation of different yogic exercise
programs on health and show that:


Yogic inversions in naïve and untrained healthy persons increased heart rate
variability but had no effect on blood pressure, however results have to be taken with
caution due to the study's pilot design.
High intensity sun salutations in healthy students showed no effect on cardiovascular
fitness or any significant effect compared to control, but the yoga group showed
increased levels of adiponectin and apolipoproteinA1.
 Yogic exercises (YE) for obstructive pulmonary disease patients using a customized


program showed no significant effect after 12 weeks when compared to conventional
treatment (CTP) in terms of improved walking distance. Both groups improved
walking distance after 12 weeks. The CTP group showed improvement in all CRQ
domains after 12 weeks, the YE group showed improvement in the mastery domain. In
conclusion, the short term effects (after 12 weeks) of YE included improved walking
distance, lowered respiratory rate, improved mastery of the disease and increased
oxygen saturation.
The detailed program description of the interventions (I-III) and the follow-up carried
out 6 months after the intervention represent the main strengths of Study III. However,
the long-term effects of YE were not as significant as those of CTP and more longterm follow-ups are needed for YE.
Yogic exercises performed in Study I-III were feasible and safe with no documented
adverse effects.
 The experiences of people with obstructive pulmonary disease who'd used YE
revealed the importance and power of practicing (learning by doing). This appeared as
a central component for facilitating self-awareness and learning new ways of
breathing. The control of symptoms and breathlessness through YE practice can serve
as an efficient tool for strengthening self-efficacy and mastery of the disease.
73


Yogic inversions in naïve and untrained healthy persons increased heart rate
variability but had no effect on blood pressure, however results have to be taken with
caution due to the study's pilot design.
High intensity sun salutations in healthy students showed no effect on cardiovascular
fitness or any significant effect compared to control, but the yoga group showed
increased levels of adiponectin and apolipoproteinA1.
 Yogic exercises (YE) for obstructive pulmonary disease patients using a customized


program showed no significant effect after 12 weeks when compared to conventional
treatment (CTP) in terms of improved walking distance. Both groups improved
walking distance after 12 weeks. The CTP group showed improvement in all CRQ
domains after 12 weeks, the YE group showed improvement in the mastery domain. In
conclusion, the short term effects (after 12 weeks) of YE included improved walking
distance, lowered respiratory rate, improved mastery of the disease and increased
oxygen saturation.
The detailed program description of the interventions (I-III) and the follow-up carried
out 6 months after the intervention represent the main strengths of Study III. However,
the long-term effects of YE were not as significant as those of CTP and more longterm follow-ups are needed for YE.
Yogic exercises performed in Study I-III were feasible and safe with no documented
adverse effects.
 The experiences of people with obstructive pulmonary disease who'd used YE
revealed the importance and power of practicing (learning by doing). This appeared as
a central component for facilitating self-awareness and learning new ways of
breathing. The control of symptoms and breathlessness through YE practice can serve
as an efficient tool for strengthening self-efficacy and mastery of the disease.
73
12 Acknowledgements
12 Acknowledgements
The work of this thesis was carried out at the Department of Neurobiology Care Sciences and
Society, Division of family medicine, Karolinska Institutet, Stockholm, Sweden.
The work of this thesis was carried out at the Department of Neurobiology Care Sciences and
Society, Division of family medicine, Karolinska Institutet, Stockholm, Sweden.
I wish to express my appreciation to all persons who in different ways have supported and
helped me make this work possible.
I wish to express my appreciation to all persons who in different ways have supported and
helped me make this work possible.
Especially I want to thank all participants for voluntary participation in the different
interventions. For showing up and were interested and willing to test the different programs
Especially I want to thank all participants for voluntary participation in the different
interventions. For showing up and were interested and willing to test the different programs
Professor, M.D Per Wändell my main supervisor and co-author that has helped, pushed,
supported, inspired and educated me with the greatest excellent deep knowledge. Your energy
and enthusiasm are the greatest. Thanks for taking me in.
Professor, M.D Per Wändell my main supervisor and co-author that has helped, pushed,
supported, inspired and educated me with the greatest excellent deep knowledge. Your energy
and enthusiasm are the greatest. Thanks for taking me in.
Professor Petra Lindfors, my co-supervisor and co-author for being so excellent support, your
excellent English, clear corrections, patience with my writing, advice and the incredible help
you did, you are simply the best
Professor Petra Lindfors, my co-supervisor and co-author for being so excellent support, your
excellent English, clear corrections, patience with my writing, advice and the incredible help
you did, you are simply the best
PhD, RPT Malin Nygren-Bonnier, my co-supervisor and co-author for your excellent
intelligent comments and suggestions when I was stuck, I am impressed of your great energy
and for taking the time and patience with me and not the least your enormous help. Also for
convincing me to include pulmonary patients into my last study.
PhD, RPT Malin Nygren-Bonnier, my co-supervisor and co-author for your excellent
intelligent comments and suggestions when I was stuck, I am impressed of your great energy
and for taking the time and patience with me and not the least your enormous help. Also for
convincing me to include pulmonary patients into my last study.
PhD Lennart Gullstrand, my co-supervisor and co-author for important help with the oxygen
measures and with constructive feedback.
PhD Lennart Gullstrand, my co-supervisor and co-author for important help with the oxygen
measures and with constructive feedback.
M.D Niklas Storck my co-author and for all the helpful discussions and help with HRV
analyses
M.D Niklas Storck my co-author and for all the helpful discussions and help with HRV
analyses
Associate professor, RPT Annette Heijne, my mentor and friend for always being available all
these years. I am inspired of your great energy, support and encouragement.
Associate professor, RPT Annette Heijne, my mentor and friend for always being available all
these years. I am inspired of your great energy, support and encouragement.
MSci, RPT Maria Henriques my co-author for the interesting qualitative discussions
MSci, RPT Maria Henriques my co-author for the interesting qualitative discussions
MSci, RPT Gabriele Biguet my co-author for valuable constructive feedback and your
incredible energy for reading all the versions
MSci, RPT Gabriele Biguet my co-author for valuable constructive feedback and your
incredible energy for reading all the versions
All the physiotherapists both in training and working at the Karolinska University Hospital for
help with the measurements
All the physiotherapists both in training and working at the Karolinska University Hospital for
help with the measurements
The yoga teachers instructing the programs for your willingness to learn and teach the
designed programs especially I want to thank Ulrika Hedlund that was involved in 2
interventions. Thanks for your patience, generosity and time and for making it possible
The yoga teachers instructing the programs for your willingness to learn and teach the
designed programs especially I want to thank Ulrika Hedlund that was involved in 2
interventions. Thanks for your patience, generosity and time and for making it possible
Staff at KI health promotion unit for all the help and also with recruitment hints for the
interventions and for teaching yoga to KI staff
Staff at KI health promotion unit for all the help and also with recruitment hints for the
interventions and for teaching yoga to KI staff
Anne Claesson for inviting me to teach yogic interventions and all the interesting discussions
Anne Claesson for inviting me to teach yogic interventions and all the interesting discussions
Angela Gompaki for all the help
Angela Gompaki for all the help
Pollyanna Von Knorring for help with illustrations and the great trips to the mountains, you
are the best
Pollyanna Von Knorring for help with illustrations and the great trips to the mountains, you
are the best
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74
MSci, RPT Sibylle Westerling for convincing me to include pulmonary patients in my
research and your great interest in yoga
MSci, RPT Sibylle Westerling for convincing me to include pulmonary patients in my
research and your great interest in yoga
Professor Sven-Erik Johansson for all the help with statistics
Professor Sven-Erik Johansson for all the help with statistics
Mirja Ghosh for your interest in yoga and all our enriching conversations throughout the years
and the help you did for Study I
Mirja Ghosh for your interest in yoga and all our enriching conversations throughout the years
and the help you did for Study I
Professor, PhD Johnny Nilsson who introduced me to research on physical activity and Jesper
Magnusson for all the work preparing for my first research in the 90:s.
Professor, PhD Johnny Nilsson who introduced me to research on physical activity and Jesper
Magnusson for all the work preparing for my first research in the 90:s.
Auckland University recreation Centre New Zealand staff that was willing to test my research
ideas while living in New Zealand
Auckland University recreation Centre New Zealand staff that was willing to test my research
ideas while living in New Zealand
Artur Forsberg for inviting me to write articles in “Svensk Idrottsforskning” about yoga
research that helped me to continue with my research
Artur Forsberg for inviting me to write articles in “Svensk Idrottsforskning” about yoga
research that helped me to continue with my research
Stefan Lundström my dear friend for all the time that with great patience were sitting and
studying with me and teaching me all about computers and other hard subjects necessary to go
further into my studies
Stefan Lundström my dear friend for all the time that with great patience were sitting and
studying with me and teaching me all about computers and other hard subjects necessary to go
further into my studies
PhD, M.D Martin Ugander read my article in “Svensk Idrottsmedicin” and called me from US
to encourage me to continue with research on yoga and helped me to find my main supervisor
PhD, M.D Martin Ugander read my article in “Svensk Idrottsmedicin” and called me from US
to encourage me to continue with research on yoga and helped me to find my main supervisor
MSci Klas Nevrin for sharing all your knowledge on yoga philosophy
MSci Klas Nevrin for sharing all your knowledge on yoga philosophy
Yvonne Sigurd for help with coordinating the measurements for Study I
Yvonne Sigurd for help with coordinating the measurements for Study I
Anna Hansson my dear friend and for believing in the power of yoga and helping me to
initiate some of my first “pilot” studies, but also all the fun we had both at work and privately
Anna Hansson my dear friend and for believing in the power of yoga and helping me to
initiate some of my first “pilot” studies, but also all the fun we had both at work and privately
Josephine for inviting me all these years to spread research on yoga
Josephine for inviting me all these years to spread research on yoga
All my yoga teachers especially Mande in NZ and Dona in Italy who got me interested in and
introduced me to intense yogic practices
All my yoga teachers especially Mande in NZ and Dona in Italy who got me interested in and
introduced me to intense yogic practices
My sister Kitty for always supporting me in hard times and for making me do all the long
head- and handstands when growing up, without you I would not be doing this
My sister Kitty for always supporting me in hard times and for making me do all the long
head- and handstands when growing up, without you I would not be doing this
MSci Birger Andrén my husband and life and mountain guide taking me to the most beautiful
places in the world, you have the greatest power for making my life interesting. Thanks for
your patience and support and always being there but also for all the help with statistics.
MSci Birger Andrén my husband and life and mountain guide taking me to the most beautiful
places in the world, you have the greatest power for making my life interesting. Thanks for
your patience and support and always being there but also for all the help with statistics.
My dear friends Leif Hornsved, Rosita Georghi, Christina and Gunilla for always being there
My dear friends Leif Hornsved, Rosita Georghi, Christina and Gunilla for always being there
My family in Sweden and Hungary
My family in Sweden and Hungary
All the persons interested in yoga over the years, thanks for your willingness to participate in
my pilot studies and tests and for being interested in intensive yogic exercise
All the persons interested in yoga over the years, thanks for your willingness to participate in
my pilot studies and tests and for being interested in intensive yogic exercise
Anyone that I forgot to mention here is as important!
Anyone that I forgot to mention here is as important!
Funding for this thesis was partly by Stockholm County Council, Karolinska University hospital, Karolinska
Institutet health promotion and funds from Per Wändell and mpwork
Funding for this thesis was partly by Stockholm County Council, Karolinska University hospital, Karolinska
Institutet health promotion and funds from Per Wändell and mpwork
Marian Papp is an experienced certified and registered yoga teacher and yoga therapist (E-RYT, C-IAYT)
Marian Papp is an experienced certified and registered yoga teacher and yoga therapist (E-RYT, C-IAYT)
75
75
13 References
13 References
1. Organization WH. International Classification of Functioning, Disability and Health: ICF: World
Health Organization, 2001.
2. Eriksson M, Lindström B. A salutogenic interpretation of the Ottawa Charter. Health promotion
international 2008;23(2):190-99.
3. Kickbusch I. The contribution of the World Health Organization to a new public health and
health promotion. American journal of public health 2003;93(3):383-88.
4. Organization WH. Milestones in health promotion: Statements from global conferences. Geneva,
Switzerland: World Health Organization 2009.
5. Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, et al. American College
of Sports Medicine position stand. Quantity and quality of exercise for developing and
maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently
healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011;43(7):1334-59.
6. Brill PA, Macera CA, Davis DR, Blair SN, Gordon N. Muscular strength and physical function.
Medicine and Science in Sports and Exercise 2000;32(2):412-16.
7. Huang Y, Macera CA, Blair SN, Brill PA, Kohl 3rd H, Kronenfeld JJ. Physical fitness, physical
activity, and functional limitation in adults aged 40 and older. Medicine and Science in
Sports and Exercise 1998;30(9):1430-35.
8. Garber CE, Greaney ML, Riebe D, Nigg CR, Burbank PA, Clark PG. Physical and mental healthrelated correlates of physical function in community dwelling older adults: a cross sectional
study. BMC geriatrics 2010;10(1):6.
9. Fried LP, Bandeen-Roche K, Chaves P, Johnson BA. Preclinical mobility disability predicts incident
mobility disability in older women. Journals of Gerontology-Biological Sciences and
Medical Sciences 2000;55(1):M43.
10. Fried LP, Bandeen-Roche K, Kasper JD, Guralnik JM. Association of comorbidity with disability
in older women: the Women’s Health and Aging Study. Journal of clinical epidemiology
1999;52(1):27-37.
11. Peeters G, Dobson AJ, Deeg DJ, Brown WJ. A life-course perspective on physical functioning in
women. Bulletin of the World Health Organization 2013;91(9):661-70.
12. Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. Canadian
medical association journal 2006;174(6):801-09.
13. Sullivan M, Karlsson J, Ware JE, Jr. The Swedish SF-36 Health Survey--I. Evaluation of data
quality, scaling assumptions, reliability and construct validity across general populations in
Sweden. Soc Sci Med 1995;41(10):1349-58.
14. Kalache A, Kickbusch I. A global strategy for healthy ageing. World health 1997;50(4):4-5.
15. Caspersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness:
definitions and distinctions for health-related research. Public health reports
1985;100(2):126.
16. Cooper R, Kuh D, Cooper C, Gale CR, Lawlor DA, Matthews F, et al. Objective measures of
physical capability and subsequent health: a systematic review. Age and ageing
2011;40(1):14-23.
17. Williams PT. Physical fitness and activity as separate heart disease risk factors: a meta-analysis.
Medicine and Science in Sports and Exercise 2001;33(5):754.
18. Warburton DE, Charlesworth S, Ivey A, Nettlefold L, Bredin SS. A systematic review of the
evidence for Canada's Physical Activity Guidelines for Adults. International Journal of
Behavioral Nutrition and Physical Activity 2010;7(1):1.
19. Committee PAGA. Physical activity guidelines advisory committee report, 2008. Washington,
DC: US Department of Health and Human Services 2008;2008:A1-H14.
20. Organization WH. Global recommendations on physical activity for health. 2010.
1. Organization WH. International Classification of Functioning, Disability and Health: ICF: World
Health Organization, 2001.
2. Eriksson M, Lindström B. A salutogenic interpretation of the Ottawa Charter. Health promotion
international 2008;23(2):190-99.
3. Kickbusch I. The contribution of the World Health Organization to a new public health and
health promotion. American journal of public health 2003;93(3):383-88.
4. Organization WH. Milestones in health promotion: Statements from global conferences. Geneva,
Switzerland: World Health Organization 2009.
5. Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, et al. American College
of Sports Medicine position stand. Quantity and quality of exercise for developing and
maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently
healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011;43(7):1334-59.
6. Brill PA, Macera CA, Davis DR, Blair SN, Gordon N. Muscular strength and physical function.
Medicine and Science in Sports and Exercise 2000;32(2):412-16.
7. Huang Y, Macera CA, Blair SN, Brill PA, Kohl 3rd H, Kronenfeld JJ. Physical fitness, physical
activity, and functional limitation in adults aged 40 and older. Medicine and Science in
Sports and Exercise 1998;30(9):1430-35.
8. Garber CE, Greaney ML, Riebe D, Nigg CR, Burbank PA, Clark PG. Physical and mental healthrelated correlates of physical function in community dwelling older adults: a cross sectional
study. BMC geriatrics 2010;10(1):6.
9. Fried LP, Bandeen-Roche K, Chaves P, Johnson BA. Preclinical mobility disability predicts incident
mobility disability in older women. Journals of Gerontology-Biological Sciences and
Medical Sciences 2000;55(1):M43.
10. Fried LP, Bandeen-Roche K, Kasper JD, Guralnik JM. Association of comorbidity with disability
in older women: the Women’s Health and Aging Study. Journal of clinical epidemiology
1999;52(1):27-37.
11. Peeters G, Dobson AJ, Deeg DJ, Brown WJ. A life-course perspective on physical functioning in
women. Bulletin of the World Health Organization 2013;91(9):661-70.
12. Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. Canadian
medical association journal 2006;174(6):801-09.
13. Sullivan M, Karlsson J, Ware JE, Jr. The Swedish SF-36 Health Survey--I. Evaluation of data
quality, scaling assumptions, reliability and construct validity across general populations in
Sweden. Soc Sci Med 1995;41(10):1349-58.
14. Kalache A, Kickbusch I. A global strategy for healthy ageing. World health 1997;50(4):4-5.
15. Caspersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness:
definitions and distinctions for health-related research. Public health reports
1985;100(2):126.
16. Cooper R, Kuh D, Cooper C, Gale CR, Lawlor DA, Matthews F, et al. Objective measures of
physical capability and subsequent health: a systematic review. Age and ageing
2011;40(1):14-23.
17. Williams PT. Physical fitness and activity as separate heart disease risk factors: a meta-analysis.
Medicine and Science in Sports and Exercise 2001;33(5):754.
18. Warburton DE, Charlesworth S, Ivey A, Nettlefold L, Bredin SS. A systematic review of the
evidence for Canada's Physical Activity Guidelines for Adults. International Journal of
Behavioral Nutrition and Physical Activity 2010;7(1):1.
19. Committee PAGA. Physical activity guidelines advisory committee report, 2008. Washington,
DC: US Department of Health and Human Services 2008;2008:A1-H14.
20. Organization WH. Global recommendations on physical activity for health. 2010.
76
76
21. Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT. Effect of physical inactivity on
major non-communicable diseases worldwide: an analysis of burden of disease and life
expectancy. Lancet 2012;380(9838):219-29.
22. Kohl HW, Craig CL, Lambert EV, Inoue S, Alkandari JR, Leetongin G, et al. The pandemic of
physical inactivity: global action for public health. The Lancet 2012;380(9838):294-305.
23. Wang H, Naghavi M, Allen C, Barber RM, Bhutta ZA, Carter A, et al. Global, regional, and
national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of
death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015. The
Lancet 2016;388(10053):1459-544.
24. Uebelacker LA, Epstein-Lubow G, Gaudiano BA, Tremont G, Battle CL, Miller IW. Hatha yoga for
depression: critical review of the evidence for efficacy, plausible mechanisms of action, and
directions for future research. Journal of Psychiatric Practice® 2010;16(1):22-33.
25. Feuerstein G. The Shambhala encyclopedia of yoga: Shambhala Publications, 1997.
26. Bryant EF. The yoga sutras of Patanjali: A new edition, translation, and commentary: North
Point Press, 2015.
27. Newcombe S. The development of modern yoga: A survey of the field. Religion Compass
2009;3(6):986-1002.
28. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga SelfEfficacy Scale (YSES). BMC complementary and alternative medicine 2016;16(1):3.
29. Desikachar K, Bragdon L, Bossart C. The yoga of healing: Exploring yoga's holistic model for
health and well-being. International journal of yoga therapy 2005;15(1):17-39.
30. Govindaraj R, Karmani S, Varambally S, Gangadhar B. Yoga and physical exercise–a review and
comparison. International Review of Psychiatry 2016:1-12.
31. Cramer H. The Efficacy and Safety of Yoga in Managing Hypertension. Experimental and Clinical
Endocrinology & Diabetes 2016;124(02):65-70.
32. Tran MD, Holly RG, Lashbrook J, Amsterdam EA. Effects of Hatha Yoga Practice on the HealthRelated Aspects of Physical Fitness. Prev Cardiol 2001;4(4):165-70.
33. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A systematic
review of associations of yoga style and conclusions in randomized yoga trials.
Complementary therapies in medicine 2016.
34. Pandurangi AK, Keshavan MS, Ganapathy V, Gangadhar BN. Yoga: Past and Present. Am J
Psychiatry 2017;174(1):16-17.
35. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and cardiopulmonary
function: a literature review. Journal of alternative and complementary medicine
2002;8(6):797-812.
36. Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies.
Journal of alternative and complementary medicine 2010;16(1):3-12.
37. Cramer H, Ward L, Saper R, Fishbein D, Dobos G, Lauche R. The Safety of Yoga: A Systematic
Review and Meta-Analysis of Randomized Controlled Trials. Am J Epidemiol
2015;182(4):281-93.
38. Elwy AR, Groessl EJ, Eisen SV, Riley KE, Maiya M, Lee JP, et al. A systematic scoping review of
yoga intervention components and study quality. American Journal of Preventive Medicine
2014;47(2):220-32.
39. Eliade M, Trask WR, White DG. Yoga: Immortality and freedom: Princeton University Press,
2009.
40. Mallinson J. Haṭha Yoga. Britt encyclopedia of hinduism, 2011:770-81.
41. Feuerstein G, Wilber K. The yoga tradition: its history, literature, philosophy, and practice:
Bhavana Books New Delhi, India, 2002.
42. Georg F. The Shambhala Encyclopedia of Yoga. London: Shambhala, 2000.
43. Gard T, Noggle JJ, Park CL, Vago DR, Wilson A. Potential self-regulatory mechanisms of yoga for
psychological health. Frontiers in human neuroscience 2014;8:770.
21. Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT. Effect of physical inactivity on
major non-communicable diseases worldwide: an analysis of burden of disease and life
expectancy. Lancet 2012;380(9838):219-29.
22. Kohl HW, Craig CL, Lambert EV, Inoue S, Alkandari JR, Leetongin G, et al. The pandemic of
physical inactivity: global action for public health. The Lancet 2012;380(9838):294-305.
23. Wang H, Naghavi M, Allen C, Barber RM, Bhutta ZA, Carter A, et al. Global, regional, and
national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of
death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015. The
Lancet 2016;388(10053):1459-544.
24. Uebelacker LA, Epstein-Lubow G, Gaudiano BA, Tremont G, Battle CL, Miller IW. Hatha yoga for
depression: critical review of the evidence for efficacy, plausible mechanisms of action, and
directions for future research. Journal of Psychiatric Practice® 2010;16(1):22-33.
25. Feuerstein G. The Shambhala encyclopedia of yoga: Shambhala Publications, 1997.
26. Bryant EF. The yoga sutras of Patanjali: A new edition, translation, and commentary: North
Point Press, 2015.
27. Newcombe S. The development of modern yoga: A survey of the field. Religion Compass
2009;3(6):986-1002.
28. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga SelfEfficacy Scale (YSES). BMC complementary and alternative medicine 2016;16(1):3.
29. Desikachar K, Bragdon L, Bossart C. The yoga of healing: Exploring yoga's holistic model for
health and well-being. International journal of yoga therapy 2005;15(1):17-39.
30. Govindaraj R, Karmani S, Varambally S, Gangadhar B. Yoga and physical exercise–a review and
comparison. International Review of Psychiatry 2016:1-12.
31. Cramer H. The Efficacy and Safety of Yoga in Managing Hypertension. Experimental and Clinical
Endocrinology & Diabetes 2016;124(02):65-70.
32. Tran MD, Holly RG, Lashbrook J, Amsterdam EA. Effects of Hatha Yoga Practice on the HealthRelated Aspects of Physical Fitness. Prev Cardiol 2001;4(4):165-70.
33. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A systematic
review of associations of yoga style and conclusions in randomized yoga trials.
Complementary therapies in medicine 2016.
34. Pandurangi AK, Keshavan MS, Ganapathy V, Gangadhar BN. Yoga: Past and Present. Am J
Psychiatry 2017;174(1):16-17.
35. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and cardiopulmonary
function: a literature review. Journal of alternative and complementary medicine
2002;8(6):797-812.
36. Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies.
Journal of alternative and complementary medicine 2010;16(1):3-12.
37. Cramer H, Ward L, Saper R, Fishbein D, Dobos G, Lauche R. The Safety of Yoga: A Systematic
Review and Meta-Analysis of Randomized Controlled Trials. Am J Epidemiol
2015;182(4):281-93.
38. Elwy AR, Groessl EJ, Eisen SV, Riley KE, Maiya M, Lee JP, et al. A systematic scoping review of
yoga intervention components and study quality. American Journal of Preventive Medicine
2014;47(2):220-32.
39. Eliade M, Trask WR, White DG. Yoga: Immortality and freedom: Princeton University Press,
2009.
40. Mallinson J. Haṭha Yoga. Britt encyclopedia of hinduism, 2011:770-81.
41. Feuerstein G, Wilber K. The yoga tradition: its history, literature, philosophy, and practice:
Bhavana Books New Delhi, India, 2002.
42. Georg F. The Shambhala Encyclopedia of Yoga. London: Shambhala, 2000.
43. Gard T, Noggle JJ, Park CL, Vago DR, Wilson A. Potential self-regulatory mechanisms of yoga for
psychological health. Frontiers in human neuroscience 2014;8:770.
77
77
44. Hewitt J. The Complete Yoga Book: The Yoga of Breathing, Posture and Meditation: Random
House, 2012.
45. Feuerstein G. The Yoga-sūtra of Patañjali: A new translation and commentary. 1982.
46. McCall MC, Ward A, Roberts NW, Heneghan C. Overview of systematic reviews: yoga as a
therapeutic intervention for adults with acute and chronic health conditions. Evid Based
Complement Alternat Med 2013;2013:945895.
47. Cramer H, Ward L, Steel A, Lauche R, Dobos G, Zhang Y. Prevalence, Patterns, and Predictors of
Yoga Use. American Journal of Preventive Medicine 2016;50(2):230-35.
48. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease: A
Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
49. Boehm K, Ostermann T, Milazzo S, Bussing A. Effects of yoga interventions on fatigue: a metaanalysis. Evid Based Complement Alternat Med 2012;2012:124703.
50. Birdee GS, Legedza AT, Saper RB, Bertisch SM, Eisenberg DM, Phillips RS. Characteristics of yoga
users: results of a national survey. J Gen Intern Med 2008;23(10):1653-8.
51. Tracey KJ. The inflammatory reflex. Nature 2002;420(6917):853-9.
52. Telles S, Singh N, Balkrishna A. Heart rate variability changes during high frequency yoga
breathing and breath awareness. Biopsychosoc Med 2011;5:4.
53. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan MM, Ford GA. Effects of aerobic exercise
training and yoga on the baroreflex in healthy elderly persons. Eur J Clin Invest
1997;27(5):443-9.
54. Cole RJ. Nonpharmacologic techniques for promoting sleep. Clin Sports Med 2005;24(2):343-53,
xi.
55. Joseph CN, Porta C, Casucci G, Casiraghi N, Maffeis M, Rossi M, et al. Slow breathing improves
arterial baroreflex sensitivity and decreases blood pressure in essential hypertension.
Hypertension 2005;46(4):714-8.
56. Cramer H, Lauche R, Klose P, Lange S, Langhorst J, Dobos GJ. Yoga for improving health-related
quality of life, mental health and cancer-related symptoms in women diagnosed with
breast cancer. Cochrane Database Syst Rev 2017;1:CD010802.
57. Hofmann SG, Andreoli G, Carpenter JK, Curtiss J. Effect of Hatha Yoga on Anxiety: A MetaAnalysis. J Evid Based Med 2016.
58. Cramer H, Lauche R, Langhorst J, Dobos G. Yoga for depression: a systematic review and metaanalysis. Depress Anxiety 2013;30(11):1068-83.
59. Wu WW, Kwong E, Lan XY, Jiang XY. The Effect of a Meditative Movement Intervention on
Quality of Sleep in the Elderly: A Systematic Review and Meta-Analysis. J Altern
Complement Med 2015;21(9):509-19.
60. Nathan RA, Sorkness CA, Kosinski M, Schatz M, Li JT, Marcus P, et al. Development of the
asthma control test: a survey for assessing asthma control. Journal of Allergy and Clinical
Immunology 2004;113(1):59-65.
61. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease: a
systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
62. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014.
63. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2013;187(4):347-65.
64. Danielsson P, Olafsdottir IS, Benediktsdottir B, Gislason T, Janson C. The prevalence of chronic
obstructive pulmonary disease in Uppsala, Sweden--the Burden of Obstructive Lung
Disease (BOLD) study: cross-sectional population-based study. Clin Respir J 2012;6(2):1207.
44. Hewitt J. The Complete Yoga Book: The Yoga of Breathing, Posture and Meditation: Random
House, 2012.
45. Feuerstein G. The Yoga-sūtra of Patañjali: A new translation and commentary. 1982.
46. McCall MC, Ward A, Roberts NW, Heneghan C. Overview of systematic reviews: yoga as a
therapeutic intervention for adults with acute and chronic health conditions. Evid Based
Complement Alternat Med 2013;2013:945895.
47. Cramer H, Ward L, Steel A, Lauche R, Dobos G, Zhang Y. Prevalence, Patterns, and Predictors of
Yoga Use. American Journal of Preventive Medicine 2016;50(2):230-35.
48. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease: A
Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
49. Boehm K, Ostermann T, Milazzo S, Bussing A. Effects of yoga interventions on fatigue: a metaanalysis. Evid Based Complement Alternat Med 2012;2012:124703.
50. Birdee GS, Legedza AT, Saper RB, Bertisch SM, Eisenberg DM, Phillips RS. Characteristics of yoga
users: results of a national survey. J Gen Intern Med 2008;23(10):1653-8.
51. Tracey KJ. The inflammatory reflex. Nature 2002;420(6917):853-9.
52. Telles S, Singh N, Balkrishna A. Heart rate variability changes during high frequency yoga
breathing and breath awareness. Biopsychosoc Med 2011;5:4.
53. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan MM, Ford GA. Effects of aerobic exercise
training and yoga on the baroreflex in healthy elderly persons. Eur J Clin Invest
1997;27(5):443-9.
54. Cole RJ. Nonpharmacologic techniques for promoting sleep. Clin Sports Med 2005;24(2):343-53,
xi.
55. Joseph CN, Porta C, Casucci G, Casiraghi N, Maffeis M, Rossi M, et al. Slow breathing improves
arterial baroreflex sensitivity and decreases blood pressure in essential hypertension.
Hypertension 2005;46(4):714-8.
56. Cramer H, Lauche R, Klose P, Lange S, Langhorst J, Dobos GJ. Yoga for improving health-related
quality of life, mental health and cancer-related symptoms in women diagnosed with
breast cancer. Cochrane Database Syst Rev 2017;1:CD010802.
57. Hofmann SG, Andreoli G, Carpenter JK, Curtiss J. Effect of Hatha Yoga on Anxiety: A MetaAnalysis. J Evid Based Med 2016.
58. Cramer H, Lauche R, Langhorst J, Dobos G. Yoga for depression: a systematic review and metaanalysis. Depress Anxiety 2013;30(11):1068-83.
59. Wu WW, Kwong E, Lan XY, Jiang XY. The Effect of a Meditative Movement Intervention on
Quality of Sleep in the Elderly: A Systematic Review and Meta-Analysis. J Altern
Complement Med 2015;21(9):509-19.
60. Nathan RA, Sorkness CA, Kosinski M, Schatz M, Li JT, Marcus P, et al. Development of the
asthma control test: a survey for assessing asthma control. Journal of Allergy and Clinical
Immunology 2004;113(1):59-65.
61. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease: a
systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
62. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014.
63. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2013;187(4):347-65.
64. Danielsson P, Olafsdottir IS, Benediktsdottir B, Gislason T, Janson C. The prevalence of chronic
obstructive pulmonary disease in Uppsala, Sweden--the Burden of Obstructive Lung
Disease (BOLD) study: cross-sectional population-based study. Clin Respir J 2012;6(2):1207.
78
78
65. Hagstad S, Backman H, Bjerg A, Ekerljung L, Ye X, Hedman L, et al. Prevalence and risk factors of
COPD among never-smokers in two areas of Sweden - Occupational exposure to gas, dust
or fumes is an important risk factor. Respir Med 2015;109(11):1439-45.
66. Bousquet J, Clark T, Hurd S, Khaltaev N, Lenfant C, O'byrne P, et al. GINA guidelines on asthma
and beyond. Allergy 2007;62(2):102-12.
67. Chapman K, Boulet L, Rea RM, Franssen E. Suboptimal asthma control: prevalence, detection
and consequences in general practice. European Respiratory Journal 2008;31(2):320-25.
68. Berry MJ, Rejeski WJ, Adair NE, Zaccaro D. Exercise rehabilitation and chronic obstructive
pulmonary disease stage. Am J Respir Crit Care Med 1999;160(4):1248-53.
69. Spruit MA, Singh SJ, Garvey C, ZuWallack R, Nici L, Rochester C, et al. An official American
Thoracic Society/European Respiratory Society statement: key concepts and advances in
pulmonary rehabilitation. American journal of respiratory and critical care medicine
2013;188(8):e13-64.
70. Troosters T, Sciurba F, Battaglia S, Langer D, Valluri SR, Martino L, et al. Physical inactivity in
patients with COPD, a controlled multi-center pilot-study. Respir Med 2010;104(7):1005-11.
71. Gysels MH, Higginson IJ. Self-management for breathlessness in COPD: the role of pulmonary
rehabilitation. Chron Respir Dis 2009;6(3):133-40.
72. Lucas SR, Platts-Mills TA. Physical activity and exercise in asthma: relevance to etiology and
treatment. Journal of Allergy and Clinical Immunology 2005;115(5):928-34.
73. Gibson PG, Powell H, Wilson A, Abramson MJ, Haywood P, Bauman A, et al. Self‐management
education and regular practitioner review for adults with asthma. The Cochrane Library
2002.
74. Rabe KF, Hurd S, Anzueto A, Barnes PJ, Buist SA, Calverley P, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2007;176(6):532-55.
75. Osadnik CR, Rodrigues FMM, Camillo CA, Loeckx M, Janssens W, Dooms C, et al. Principles of
Rehabilitation and Reactivation. Respiration 2015;89(1):2-11.
76. Dressendorfer R, Haykowsky M, Eves N. Exercise for persons with chronic obstructive
pulmonary disease. ACSM. Retrieved August 2014;14.
77. Satta A. Exercise training in asthma. Journal of Sports Medicine and Physical Fitness
2000;40(4):277.
78. Brumpton BM, Langhammer A, Henriksen AH, Camargo CA, Chen Y, Romundstad PR, et al.
Physical activity and lung function decline in adults with asthma: The HUNT Study.
Respirology 2016.
79. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of controlled
breathing exercises and respiratory muscle training in people with chronic obstructive
pulmonary disease: results from evaluating the quality of evidence in systematic reviews.
BMC Pulm Med 2014;14:184.
80. Courtney R. The functions of breathing and its dysfunctions and their relationship to breathing
therapy. International Journal of Osteopathic Medicine 2009;12(3):78-85.
81. Wadell K, Janaudis Ferreira T, Arne M, Lisspers K, Stallberg B, Emtner M. Hospital-based
pulmonary rehabilitation in patients with COPD in Sweden--a national survey. Respir Med
2013;107(8):1195-200.
82. Fischer MJ, Scharloo M, Abbink JJ, Thijs-Van A, Rudolphus A, Snoei L, et al. Participation and
drop-out in pulmonary rehabilitation: a qualitative analysis of the patient's perspective.
Clin Rehabil 2007;21(3):212-21.
83. Incorvaia C, Russo A, Foresi A, Berra D, Elia R, Passalacqua G, et al. Effects of pulmonary
rehabilitation on lung function in chronic obstructive pulmonary disease: the FIRST study.
Eur J Phys Rehabil Med 2014;50(4):419-26.
65. Hagstad S, Backman H, Bjerg A, Ekerljung L, Ye X, Hedman L, et al. Prevalence and risk factors of
COPD among never-smokers in two areas of Sweden - Occupational exposure to gas, dust
or fumes is an important risk factor. Respir Med 2015;109(11):1439-45.
66. Bousquet J, Clark T, Hurd S, Khaltaev N, Lenfant C, O'byrne P, et al. GINA guidelines on asthma
and beyond. Allergy 2007;62(2):102-12.
67. Chapman K, Boulet L, Rea RM, Franssen E. Suboptimal asthma control: prevalence, detection
and consequences in general practice. European Respiratory Journal 2008;31(2):320-25.
68. Berry MJ, Rejeski WJ, Adair NE, Zaccaro D. Exercise rehabilitation and chronic obstructive
pulmonary disease stage. Am J Respir Crit Care Med 1999;160(4):1248-53.
69. Spruit MA, Singh SJ, Garvey C, ZuWallack R, Nici L, Rochester C, et al. An official American
Thoracic Society/European Respiratory Society statement: key concepts and advances in
pulmonary rehabilitation. American journal of respiratory and critical care medicine
2013;188(8):e13-64.
70. Troosters T, Sciurba F, Battaglia S, Langer D, Valluri SR, Martino L, et al. Physical inactivity in
patients with COPD, a controlled multi-center pilot-study. Respir Med 2010;104(7):1005-11.
71. Gysels MH, Higginson IJ. Self-management for breathlessness in COPD: the role of pulmonary
rehabilitation. Chron Respir Dis 2009;6(3):133-40.
72. Lucas SR, Platts-Mills TA. Physical activity and exercise in asthma: relevance to etiology and
treatment. Journal of Allergy and Clinical Immunology 2005;115(5):928-34.
73. Gibson PG, Powell H, Wilson A, Abramson MJ, Haywood P, Bauman A, et al. Self‐management
education and regular practitioner review for adults with asthma. The Cochrane Library
2002.
74. Rabe KF, Hurd S, Anzueto A, Barnes PJ, Buist SA, Calverley P, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2007;176(6):532-55.
75. Osadnik CR, Rodrigues FMM, Camillo CA, Loeckx M, Janssens W, Dooms C, et al. Principles of
Rehabilitation and Reactivation. Respiration 2015;89(1):2-11.
76. Dressendorfer R, Haykowsky M, Eves N. Exercise for persons with chronic obstructive
pulmonary disease. ACSM. Retrieved August 2014;14.
77. Satta A. Exercise training in asthma. Journal of Sports Medicine and Physical Fitness
2000;40(4):277.
78. Brumpton BM, Langhammer A, Henriksen AH, Camargo CA, Chen Y, Romundstad PR, et al.
Physical activity and lung function decline in adults with asthma: The HUNT Study.
Respirology 2016.
79. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of controlled
breathing exercises and respiratory muscle training in people with chronic obstructive
pulmonary disease: results from evaluating the quality of evidence in systematic reviews.
BMC Pulm Med 2014;14:184.
80. Courtney R. The functions of breathing and its dysfunctions and their relationship to breathing
therapy. International Journal of Osteopathic Medicine 2009;12(3):78-85.
81. Wadell K, Janaudis Ferreira T, Arne M, Lisspers K, Stallberg B, Emtner M. Hospital-based
pulmonary rehabilitation in patients with COPD in Sweden--a national survey. Respir Med
2013;107(8):1195-200.
82. Fischer MJ, Scharloo M, Abbink JJ, Thijs-Van A, Rudolphus A, Snoei L, et al. Participation and
drop-out in pulmonary rehabilitation: a qualitative analysis of the patient's perspective.
Clin Rehabil 2007;21(3):212-21.
83. Incorvaia C, Russo A, Foresi A, Berra D, Elia R, Passalacqua G, et al. Effects of pulmonary
rehabilitation on lung function in chronic obstructive pulmonary disease: the FIRST study.
Eur J Phys Rehabil Med 2014;50(4):419-26.
79
79
84. Greulich T, Koczulla AR, Nell C, Kehr K, Vogelmeier CF, Stojanovic D, et al. Effect of a ThreeWeek Inpatient Rehabilitation Program on 544 Consecutive Patients with Very Severe
COPD: A Retrospective Analysis. Respiration 2015;90(4):287-92.
85. Chu P, Gotink RA, Yeh GY, Goldie SJ, Hunink MM. The effectiveness of yoga in modifying risk
factors for cardiovascular disease and metabolic syndrome: A systematic review and metaanalysis of randomized controlled trials. European journal of preventive cardiology
2016;23(3):291-307.
86. Kwong JS, Lau HL, Yeung F, Chau PH, Woo J. Yoga for secondary prevention of coronary heart
disease. Cochrane Database Syst Rev 2015(6):CD009506.
87. Hagins M, States R, Selfe T, Innes K. Effectiveness of yoga for hypertension: systematic review
and meta-analysis. Evidence-based complementary and alternative medicine : eCAM
2013;2013:649836.
88. Selvamurthy W, Sridharan K, Ray US, Tiwary RS, Hegde KS, Radhakrishan U, et al. A new
physiological approach to control essential hypertension. Indian J Physiol Pharmacol
1998;42(2):205-13.
89. Murugesan R, Govindarajulu N, Bera T. Effect of selected yogic practices on the management of
hypertension. Indian Journal of Physiology and Pharmacology 2000;44(2):207-10.
90. McCaffrey R, Ruknui P, Hatthakit U, Kasetsomboon P. The effects of yoga on hypertensive
persons in Thailand. Holistic nursing practice 2005;19(4):173-80.
91. Patel C. 12-month follow-up of yoga and bio-feedback in the management of hypertension. The
Lancet 1975;305(7898):62-64.
92. Cramer H, Haller H, Lauche R, Steckhan N, Michalsen A, Dobos G. A systematic review and
meta-analysis of yoga for hypertension. Am J Hypertens 2014;27(9):1146-51.
93. Hartley L, Dyakova M, Holmes J, Clarke A, Lee MS, Ernst E, et al. Yoga for the primary
prevention of cardiovascular disease. Cochrane Database Syst Rev 2014(5):CD010072.
94. Cramer H, Langhorst J, Dobos G, Lauche R. Yoga for metabolic syndrome: A systematic review
and meta-analysis. Eur J Prev Cardiol 2016.
95. Gomes-Neto M, Rodrigues-Jr ES, Silva-Jr WM, Carvalho VO. Effects of Yoga in Patients with
Chronic Heart Failure: A Meta-Analysis. Arq Bras Cardiol 2014;103(5):433-39.
96. Duren CM, Cress ME, McCully KK. The influence of physical activity and yoga on central arterial
stiffness. Dynamic Medicine 2008;7(1):1.
97. Cheema BS, Houridis A, Busch L, Raschke-Cheema V, Melville GW, Marshall PW, et al. Effect of
an office worksite-based yoga program on heart rate variability: outcomes of a randomized
controlled trial. BMC complementary and alternative medicine 2013;13(1):1.
98. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic meditation
and supine rest. Appl Psychophysiol Biofeedback 2010;35(2):135-40.
99. Chu IH, Wu WL, Lin IM, Chang YK, Lin YJ, Yang PC. Effects of Yoga on Heart Rate Variability and
Depressive Symptoms in Women: A Randomized Controlled Trial. J Altern Complement
Med 2017.
100. Telles S, Gaur V, Balkrishna A. Effect of a yoga practice session and a yoga theory session on
state anxiety. Perceptual and motor skills 2009;109(3):924-30.
101. Mueck-Weymann M, Janshoff G, Mueck H. Stretching increases heart rate variability in
healthy athletes complaining about limited muscular flexibility. Clinical Autonomic
Research 2004;14(1):15-18.
102. Tai YP, Colaco CB. Upside-down position for paroxysmal supraventricular tachycardia. Lancet
1981;2(8258):1289.
103. DEBBINDU K, Latha R, Bhuvaneswaran J. Cardiovascular responses to head-down-body-up
postural exercise (Sarvangasana). Indian J Phyaiol Pharmacol 2000;44(4):392-400.
104. Razin A. Upside-down position to terminate tachycardia of Wolff-Parkinson-White syndrome.
The New England journal of medicine 1977;296(26):1535-36.
105. Constantiniu I. An unusual treatment of paroxysmal supraventricular tachycardia. The
American journal of cardiology 1972;30(3):310.
84. Greulich T, Koczulla AR, Nell C, Kehr K, Vogelmeier CF, Stojanovic D, et al. Effect of a ThreeWeek Inpatient Rehabilitation Program on 544 Consecutive Patients with Very Severe
COPD: A Retrospective Analysis. Respiration 2015;90(4):287-92.
85. Chu P, Gotink RA, Yeh GY, Goldie SJ, Hunink MM. The effectiveness of yoga in modifying risk
factors for cardiovascular disease and metabolic syndrome: A systematic review and metaanalysis of randomized controlled trials. European journal of preventive cardiology
2016;23(3):291-307.
86. Kwong JS, Lau HL, Yeung F, Chau PH, Woo J. Yoga for secondary prevention of coronary heart
disease. Cochrane Database Syst Rev 2015(6):CD009506.
87. Hagins M, States R, Selfe T, Innes K. Effectiveness of yoga for hypertension: systematic review
and meta-analysis. Evidence-based complementary and alternative medicine : eCAM
2013;2013:649836.
88. Selvamurthy W, Sridharan K, Ray US, Tiwary RS, Hegde KS, Radhakrishan U, et al. A new
physiological approach to control essential hypertension. Indian J Physiol Pharmacol
1998;42(2):205-13.
89. Murugesan R, Govindarajulu N, Bera T. Effect of selected yogic practices on the management of
hypertension. Indian Journal of Physiology and Pharmacology 2000;44(2):207-10.
90. McCaffrey R, Ruknui P, Hatthakit U, Kasetsomboon P. The effects of yoga on hypertensive
persons in Thailand. Holistic nursing practice 2005;19(4):173-80.
91. Patel C. 12-month follow-up of yoga and bio-feedback in the management of hypertension. The
Lancet 1975;305(7898):62-64.
92. Cramer H, Haller H, Lauche R, Steckhan N, Michalsen A, Dobos G. A systematic review and
meta-analysis of yoga for hypertension. Am J Hypertens 2014;27(9):1146-51.
93. Hartley L, Dyakova M, Holmes J, Clarke A, Lee MS, Ernst E, et al. Yoga for the primary
prevention of cardiovascular disease. Cochrane Database Syst Rev 2014(5):CD010072.
94. Cramer H, Langhorst J, Dobos G, Lauche R. Yoga for metabolic syndrome: A systematic review
and meta-analysis. Eur J Prev Cardiol 2016.
95. Gomes-Neto M, Rodrigues-Jr ES, Silva-Jr WM, Carvalho VO. Effects of Yoga in Patients with
Chronic Heart Failure: A Meta-Analysis. Arq Bras Cardiol 2014;103(5):433-39.
96. Duren CM, Cress ME, McCully KK. The influence of physical activity and yoga on central arterial
stiffness. Dynamic Medicine 2008;7(1):1.
97. Cheema BS, Houridis A, Busch L, Raschke-Cheema V, Melville GW, Marshall PW, et al. Effect of
an office worksite-based yoga program on heart rate variability: outcomes of a randomized
controlled trial. BMC complementary and alternative medicine 2013;13(1):1.
98. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic meditation
and supine rest. Appl Psychophysiol Biofeedback 2010;35(2):135-40.
99. Chu IH, Wu WL, Lin IM, Chang YK, Lin YJ, Yang PC. Effects of Yoga on Heart Rate Variability and
Depressive Symptoms in Women: A Randomized Controlled Trial. J Altern Complement
Med 2017.
100. Telles S, Gaur V, Balkrishna A. Effect of a yoga practice session and a yoga theory session on
state anxiety. Perceptual and motor skills 2009;109(3):924-30.
101. Mueck-Weymann M, Janshoff G, Mueck H. Stretching increases heart rate variability in
healthy athletes complaining about limited muscular flexibility. Clinical Autonomic
Research 2004;14(1):15-18.
102. Tai YP, Colaco CB. Upside-down position for paroxysmal supraventricular tachycardia. Lancet
1981;2(8258):1289.
103. DEBBINDU K, Latha R, Bhuvaneswaran J. Cardiovascular responses to head-down-body-up
postural exercise (Sarvangasana). Indian J Phyaiol Pharmacol 2000;44(4):392-400.
104. Razin A. Upside-down position to terminate tachycardia of Wolff-Parkinson-White syndrome.
The New England journal of medicine 1977;296(26):1535-36.
105. Constantiniu I. An unusual treatment of paroxysmal supraventricular tachycardia. The
American journal of cardiology 1972;30(3):310.
80
80
106. American College of Sports Medicine, editor. ACSM Guidelines for Exercise Testing and
Prescription. 5th ed. Baltimore, MD: Williams and Wilkins, 1995.
107. Broad WJ. The Science of Yoga, 2012.
108. Mody BS. Acute effects of Surya Namaskar on the cardiovascular & metabolic system. Journal
of bodywork and movement therapies 2011;15(3):343-7.
109. Hagins M, Moore W, Rundle A. Does practicing hatha yoga satisfy recommendations for
intensity of physical activity which improves and maintains health and cardiovascular
fitness? BMC complementary and alternative medicine 2007;7:40.
110. Ha MS, Baek YH, Kim JW, Kim DY. Effects of yoga exercise on maximum oxygen uptake,
cortisol level, and creatine kinase myocardial bond activity in female patients with skeletal
muscle pain syndrome. J Phys Ther Sci 2015;27(5):1451-3.
111. Lau C, Yu R, Woo J. Effects of a 12-week hatha yoga intervention on cardiorespiratory
endurance, muscular strength and endurance, and flexibility in Hong Kong Chinese adults:
a controlled clinical trial. Evidence-Based Complementary and Alternative Medicine
2015;2015.
112. Sinha B, Ray US, Pathak A, Selvamurthy W. Energy cost and cardiorespiratory changes during
the practice of Surya Namaskar. Indian J Physiol Pharmacol 2004;48(2):184-90.
113. Clay CC, Lloyd LK, Walker JL, Sharp KR, Pankey RB. The metabolic cost of hatha yoga. Journal
of strength and conditioning research / National Strength & Conditioning Association
2005;19(3):604-10.
114. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma. Cochrane
Database Syst Rev 2016;4:CD010346.
115. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients with chronic
obstructive pulmonary disease: a systematic review and meta-analysis. J Thorac Dis
2014;6(6):795-802.
116. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014;112(6):503-10 e5.
117. Holland AE, Hill CJ, Jones AY, McDonald CF. Breathing exercises for chronic obstructive
pulmonary disease. Cochrane Database Syst Rev 2012;10:CD008250.
118. Fagevik Olsén M, Lannefors L, Westerdahl E. Positive expiratory pressure – Common clinical
applications and physiological effects. Respiratory Medicine 2015;109(3):297-307.
119. Fried R. The psychology and physiology of breathing: In behavioral medicine, clinical
psychology, and psychiatry: Springer Science & Business Media, 1993.
120. Cahalin LP, Braga M, Matsuo Y, Hernandez ED. Efficacy of diaphragmatic breathing in persons
with chronic obstructive pulmonary disease: a review of the literature. J Cardiopulm
Rehabil 2002;22(1):7-21.
121. Rocha T, Souza H, Brandao DC, Rattes C, Ribeiro L, Campos SL, et al. The Manual Diaphragm
Release Technique improves diaphragmatic mobility, inspiratory capacity and exercise
capacity in people with chronic obstructive pulmonary disease: a randomised trial. J
Physiother 2015;61(4):182-9.
122. Golbidi S, Laher I. Exercise induced adipokine changes and the metabolic syndrome. Journal of
diabetes research 2014;2014.
123. Bouassida A, Chamari K, Zaouali M, Feki Y, Zbidi A, Tabka Z. Review on leptin and adiponectin
responses and adaptations to acute and chronic exercise. British journal of sports medicine
2010;44(9):620-30.
124. Gleeson M, Bishop NC, Stensel DJ, Lindley MR, Mastana SS, Nimmo MA. The antiinflammatory effects of exercise: mechanisms and implications for the prevention and
treatment of disease. Nature reviews. Immunology 2011;11(9):607-15.
125. Kiecolt-Glaser JK, Christian LM, Andridge R, Hwang BS, Malarkey WB, Belury MA, et al.
Adiponectin, leptin, and yoga practice. Physiology & behavior 2012;107(5):809-13.
106. American College of Sports Medicine, editor. ACSM Guidelines for Exercise Testing and
Prescription. 5th ed. Baltimore, MD: Williams and Wilkins, 1995.
107. Broad WJ. The Science of Yoga, 2012.
108. Mody BS. Acute effects of Surya Namaskar on the cardiovascular & metabolic system. Journal
of bodywork and movement therapies 2011;15(3):343-7.
109. Hagins M, Moore W, Rundle A. Does practicing hatha yoga satisfy recommendations for
intensity of physical activity which improves and maintains health and cardiovascular
fitness? BMC complementary and alternative medicine 2007;7:40.
110. Ha MS, Baek YH, Kim JW, Kim DY. Effects of yoga exercise on maximum oxygen uptake,
cortisol level, and creatine kinase myocardial bond activity in female patients with skeletal
muscle pain syndrome. J Phys Ther Sci 2015;27(5):1451-3.
111. Lau C, Yu R, Woo J. Effects of a 12-week hatha yoga intervention on cardiorespiratory
endurance, muscular strength and endurance, and flexibility in Hong Kong Chinese adults:
a controlled clinical trial. Evidence-Based Complementary and Alternative Medicine
2015;2015.
112. Sinha B, Ray US, Pathak A, Selvamurthy W. Energy cost and cardiorespiratory changes during
the practice of Surya Namaskar. Indian J Physiol Pharmacol 2004;48(2):184-90.
113. Clay CC, Lloyd LK, Walker JL, Sharp KR, Pankey RB. The metabolic cost of hatha yoga. Journal
of strength and conditioning research / National Strength & Conditioning Association
2005;19(3):604-10.
114. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma. Cochrane
Database Syst Rev 2016;4:CD010346.
115. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients with chronic
obstructive pulmonary disease: a systematic review and meta-analysis. J Thorac Dis
2014;6(6):795-802.
116. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014;112(6):503-10 e5.
117. Holland AE, Hill CJ, Jones AY, McDonald CF. Breathing exercises for chronic obstructive
pulmonary disease. Cochrane Database Syst Rev 2012;10:CD008250.
118. Fagevik Olsén M, Lannefors L, Westerdahl E. Positive expiratory pressure – Common clinical
applications and physiological effects. Respiratory Medicine 2015;109(3):297-307.
119. Fried R. The psychology and physiology of breathing: In behavioral medicine, clinical
psychology, and psychiatry: Springer Science & Business Media, 1993.
120. Cahalin LP, Braga M, Matsuo Y, Hernandez ED. Efficacy of diaphragmatic breathing in persons
with chronic obstructive pulmonary disease: a review of the literature. J Cardiopulm
Rehabil 2002;22(1):7-21.
121. Rocha T, Souza H, Brandao DC, Rattes C, Ribeiro L, Campos SL, et al. The Manual Diaphragm
Release Technique improves diaphragmatic mobility, inspiratory capacity and exercise
capacity in people with chronic obstructive pulmonary disease: a randomised trial. J
Physiother 2015;61(4):182-9.
122. Golbidi S, Laher I. Exercise induced adipokine changes and the metabolic syndrome. Journal of
diabetes research 2014;2014.
123. Bouassida A, Chamari K, Zaouali M, Feki Y, Zbidi A, Tabka Z. Review on leptin and adiponectin
responses and adaptations to acute and chronic exercise. British journal of sports medicine
2010;44(9):620-30.
124. Gleeson M, Bishop NC, Stensel DJ, Lindley MR, Mastana SS, Nimmo MA. The antiinflammatory effects of exercise: mechanisms and implications for the prevention and
treatment of disease. Nature reviews. Immunology 2011;11(9):607-15.
125. Kiecolt-Glaser JK, Christian LM, Andridge R, Hwang BS, Malarkey WB, Belury MA, et al.
Adiponectin, leptin, and yoga practice. Physiology & behavior 2012;107(5):809-13.
81
81
126. Kiecolt-Glaser JK, Bennett JM, Andridge R, Peng J, Shapiro CL, Malarkey WB, et al. Yoga's
Impact on Inflammation, Mood, and Fatigue in Breast Cancer Survivors: A Randomized
Controlled Trial. J Clin Oncol 2014.
127. Kiecolt-Glaser JK, Christian L, Preston H, Houts CR, Malarkey WB, Emery CF, et al. Stress,
inflammation, and yoga practice. Psychosomatic medicine 2010;72(2):113-21.
128. Lee J-A, Kim J-W, Kim D-Y. Effects of yoga exercise on serum adiponectin and metabolic
syndrome factors in obese postmenopausal women. Menopause 2012;19(3):296-301.
129. Sarvottam K, Magan D, Yadav RK, Mehta N, Mahapatra SC. Adiponectin, interleukin-6, and
cardiovascular disease risk factors are modified by a short-term yoga-based lifestyle
intervention in overweight and obese men. The journal of alternative and complementary
medicine 2013;19(5):397-402.
130. Yadav RK, Magan D, Mehta N, Sharma R, Mahapatra SC. Efficacy of a short-term yoga-based
lifestyle intervention in reducing stress and inflammation: preliminary results. The journal
of alternative and complementary medicine 2012;18(7):662-67.
131. Yadav R, Yadav RK, Khadgawat R, Mehta N. OS 28-06 BENEFICIAL EFFECTS OF A 12-WEEK
YOGA-BASED LIFESTYLE INTERVENTION ON CARDIO-METABOLIC RISK FACTORS AND
ADIPOKINES IN SUBJECTS WITH PRE-HYPERTENSION OR HYPERTENSION. Journal of
hypertension 2016;34:e252.
132. Cui J, Yan JH, Yan LM, Pan L, Le JJ, Guo YZ. Effects of yoga in adults with type 2 diabetes
mellitus: A meta-analysis. J Diabetes Investig 2016.
133. Kumar V, Jagannathan A, Philip M, Thulasi A, Angadi P, Raghuram N. Role of yoga for patients
with type II diabetes mellitus: A systematic review and meta-analysis. Complement Ther
Med 2016;25:104-12.
134. Vizcaino M, Stover E. The effect of yoga practice on glycemic control and other health
parameters in Type 2 diabetes mellitus patients: A systematic review and meta-analysis.
Complement Ther Med 2016;28:57-66.
135. Morgan N, Irwin MR, Chung M, Wang C. The effects of mind-body therapies on the immune
system: meta-analysis. PLoS One 2014;9(7):e100903.
136. Youkhana S, Dean CM, Wolff M, Sherrington C, Tiedemann A. Yoga-based exercise improves
balance and mobility in people aged 60 and over: a systematic review and meta-analysis.
Age Ageing 2016;45(1):21-9.
137. Sharma M. Yoga as an alternative and complementary approach for arthritis: a systematic
review. J Evid Based Complementary Altern Med 2014;19(1):51-8.
138. Kim SD. Effects of yoga on chronic neck pain: a systematic review of randomized controlled
trials. J Phys Ther Sci 2016;28(7):2171-4.
139. Cramer H, Lauche R, Haller H, Dobos G. A systematic review and meta-analysis of yoga for low
back pain. Clin J Pain 2013;29(5):450-60.
140. Holtzman S, Beggs RT. Yoga for chronic low back pain: a meta-analysis of randomized
controlled trials. Pain Res Manag 2013;18(5):267-72.
141. Mist SD, Firestone KA, Jones KD. Complementary and alternative exercise for fibromyalgia: a
meta-analysis. J Pain Res 2013;6:247-60.
142. Gothe NP, McAuley E. Yoga and Cognition: A Meta-Analysis of Chronic and Acute Effects.
Psychosom Med 2015;77(7):784-97.
143. Boccia M, Piccardi L, Guariglia P. The Meditative Mind: A Comprehensive Meta-Analysis of
MRI Studies. Biomed Res Int 2015;2015:419808.
144. Swain TA, McGwin G. Yoga-Related Injuries in the United States From 2001 to 2014.
Orthopaedic Journal of Sports Medicine 2016;4(11):2325967116671703.
145. CZURA CJ, ROSAS–BALLINA M, TRACEY KJ. Cholinergic regulation of inflammation.
Psychoneuroimmunology, Two-Volume Set 2011.
146. Rosas-Ballina M, Tracey KJ. The neurology of the immune system: neural reflexes regulate
immunity. Neuron 2009;64(1):28-32.
126. Kiecolt-Glaser JK, Bennett JM, Andridge R, Peng J, Shapiro CL, Malarkey WB, et al. Yoga's
Impact on Inflammation, Mood, and Fatigue in Breast Cancer Survivors: A Randomized
Controlled Trial. J Clin Oncol 2014.
127. Kiecolt-Glaser JK, Christian L, Preston H, Houts CR, Malarkey WB, Emery CF, et al. Stress,
inflammation, and yoga practice. Psychosomatic medicine 2010;72(2):113-21.
128. Lee J-A, Kim J-W, Kim D-Y. Effects of yoga exercise on serum adiponectin and metabolic
syndrome factors in obese postmenopausal women. Menopause 2012;19(3):296-301.
129. Sarvottam K, Magan D, Yadav RK, Mehta N, Mahapatra SC. Adiponectin, interleukin-6, and
cardiovascular disease risk factors are modified by a short-term yoga-based lifestyle
intervention in overweight and obese men. The journal of alternative and complementary
medicine 2013;19(5):397-402.
130. Yadav RK, Magan D, Mehta N, Sharma R, Mahapatra SC. Efficacy of a short-term yoga-based
lifestyle intervention in reducing stress and inflammation: preliminary results. The journal
of alternative and complementary medicine 2012;18(7):662-67.
131. Yadav R, Yadav RK, Khadgawat R, Mehta N. OS 28-06 BENEFICIAL EFFECTS OF A 12-WEEK
YOGA-BASED LIFESTYLE INTERVENTION ON CARDIO-METABOLIC RISK FACTORS AND
ADIPOKINES IN SUBJECTS WITH PRE-HYPERTENSION OR HYPERTENSION. Journal of
hypertension 2016;34:e252.
132. Cui J, Yan JH, Yan LM, Pan L, Le JJ, Guo YZ. Effects of yoga in adults with type 2 diabetes
mellitus: A meta-analysis. J Diabetes Investig 2016.
133. Kumar V, Jagannathan A, Philip M, Thulasi A, Angadi P, Raghuram N. Role of yoga for patients
with type II diabetes mellitus: A systematic review and meta-analysis. Complement Ther
Med 2016;25:104-12.
134. Vizcaino M, Stover E. The effect of yoga practice on glycemic control and other health
parameters in Type 2 diabetes mellitus patients: A systematic review and meta-analysis.
Complement Ther Med 2016;28:57-66.
135. Morgan N, Irwin MR, Chung M, Wang C. The effects of mind-body therapies on the immune
system: meta-analysis. PLoS One 2014;9(7):e100903.
136. Youkhana S, Dean CM, Wolff M, Sherrington C, Tiedemann A. Yoga-based exercise improves
balance and mobility in people aged 60 and over: a systematic review and meta-analysis.
Age Ageing 2016;45(1):21-9.
137. Sharma M. Yoga as an alternative and complementary approach for arthritis: a systematic
review. J Evid Based Complementary Altern Med 2014;19(1):51-8.
138. Kim SD. Effects of yoga on chronic neck pain: a systematic review of randomized controlled
trials. J Phys Ther Sci 2016;28(7):2171-4.
139. Cramer H, Lauche R, Haller H, Dobos G. A systematic review and meta-analysis of yoga for low
back pain. Clin J Pain 2013;29(5):450-60.
140. Holtzman S, Beggs RT. Yoga for chronic low back pain: a meta-analysis of randomized
controlled trials. Pain Res Manag 2013;18(5):267-72.
141. Mist SD, Firestone KA, Jones KD. Complementary and alternative exercise for fibromyalgia: a
meta-analysis. J Pain Res 2013;6:247-60.
142. Gothe NP, McAuley E. Yoga and Cognition: A Meta-Analysis of Chronic and Acute Effects.
Psychosom Med 2015;77(7):784-97.
143. Boccia M, Piccardi L, Guariglia P. The Meditative Mind: A Comprehensive Meta-Analysis of
MRI Studies. Biomed Res Int 2015;2015:419808.
144. Swain TA, McGwin G. Yoga-Related Injuries in the United States From 2001 to 2014.
Orthopaedic Journal of Sports Medicine 2016;4(11):2325967116671703.
145. CZURA CJ, ROSAS–BALLINA M, TRACEY KJ. Cholinergic regulation of inflammation.
Psychoneuroimmunology, Two-Volume Set 2011.
146. Rosas-Ballina M, Tracey KJ. The neurology of the immune system: neural reflexes regulate
immunity. Neuron 2009;64(1):28-32.
82
82
147. Heart rate variability. Standards of measurement, physiological interpretation, and clinical
use. Task Force of the European Society of Cardiology and the North American Society of
Pacing and Electrophysiology. Eur Heart J 1996;17(3):354-81.
148. Ewing DJ, Neilson JM, Travis P. New method for assessing cardiac parasympathetic activity
using 24 hour electrocardiograms. Br Heart J 1984;52(4):396-402.
149. Viskoper R, Shapira I, Priluck R, Mindlin R, Chornia L, Laszt A, et al. Nonpharmacologic
treatment of resistant hypertensives by device-guided slow breathing exercises. Am J
Hypertens 2003;16(6):484-7.
150. ATS/ERS Statement on respiratory muscle testing. American journal of respiratory and critical
care medicine 2002;166(4):518-624.
151. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al. Standardisation of
spirometry. The European respiratory journal 2005;26(2):319-38.
152. Grant S, Corbett K, Amjad AM, Wilson J, Aitchison T. A comparison of methods of predicting
maximum oxygen uptake. British journal of sports medicine 1995;29(3):147-52.
153. Cooper KH. A means of assessing maximal oxygen intake. Correlation between field and
treadmill testing. Jama 1968;203(3):201-4.
154. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc 1982;14(5):377-81.
155. Borg G. Ratings of perceived exertion and heart rates during short-term cycle exercise and
their use in a new cycling strength test. Int J Sports Med 1982;3(3):153-8.
156. Mancia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, et al. 2007 Guidelines
for the management of arterial hypertension: The Task Force for the Management of
Arterial Hypertension of the European Society of Hypertension (ESH) and of the European
Society of Cardiology (ESC). Eur Heart J 2007;28(12):1462-536.
157. Vijayalakshmi P, Madanmohan, Bhavanani AB, Patil A, Babu K. Modulation of stress induced
by isometric handgrip test in hypertensive patients following yogic relaxation training.
Indian J Physiol Pharmacol 2004;48(1):59-64.
158. Tybor DJ, Lichtenstein AH, Dallal GE, Daniels SR, Must A. Independent effects of age-related
changes in waist circumference and BMI z scores in predicting cardiovascular disease risk
factors in a prospective cohort of adolescent females. Am J Clin Nutr 2011;93(2):392-401.
159. Chhabra SK, Gupta AK, Khuma MZ. Evaluation of three scales of dyspnea in chronic
obstructive pulmonary disease. Ann Thorac Med 2009;4(3):128-32.
160. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases dyspnearelated distress and improves functional performance in people with chronic obstructive
pulmonary disease: a pilot study. Journal of alternative and complementary medicine
2009;15(3):225-34.
161. Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality of life
for clinical trials in chronic lung disease. Thorax 1987;42(10):773-8.
162. Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med
2001;33(5):337-43.
163. Graneheim UH, Lundman B. Qualitative content analysis in nursing research: concepts,
procedures and measures to achieve trustworthiness. Nurse Educ Today 2004;24(2):105-12.
164. Elo S, Kyngäs H. The qualitative content analysis process. Journal of Advanced Nursing
2008;62(1):107-15.
165. Elo S, Kaariainen M, Kanste O, Polkki T, Utriainen K, Kyngas H. Qualitative Content Analysis: A
Focus on Trustworthiness. SAGE Open 2014;4(1).
166. Association GAotWM. World Medical Association Declaration of Helsinki: ethical principles for
medical research involving human subjects. The Journal of the American College of Dentists
2014;81(3):14.
167. Donohue JF. Minimal clinically important differences in COPD lung function. COPD
2005;2(1):111-24.
147. Heart rate variability. Standards of measurement, physiological interpretation, and clinical
use. Task Force of the European Society of Cardiology and the North American Society of
Pacing and Electrophysiology. Eur Heart J 1996;17(3):354-81.
148. Ewing DJ, Neilson JM, Travis P. New method for assessing cardiac parasympathetic activity
using 24 hour electrocardiograms. Br Heart J 1984;52(4):396-402.
149. Viskoper R, Shapira I, Priluck R, Mindlin R, Chornia L, Laszt A, et al. Nonpharmacologic
treatment of resistant hypertensives by device-guided slow breathing exercises. Am J
Hypertens 2003;16(6):484-7.
150. ATS/ERS Statement on respiratory muscle testing. American journal of respiratory and critical
care medicine 2002;166(4):518-624.
151. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al. Standardisation of
spirometry. The European respiratory journal 2005;26(2):319-38.
152. Grant S, Corbett K, Amjad AM, Wilson J, Aitchison T. A comparison of methods of predicting
maximum oxygen uptake. British journal of sports medicine 1995;29(3):147-52.
153. Cooper KH. A means of assessing maximal oxygen intake. Correlation between field and
treadmill testing. Jama 1968;203(3):201-4.
154. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc 1982;14(5):377-81.
155. Borg G. Ratings of perceived exertion and heart rates during short-term cycle exercise and
their use in a new cycling strength test. Int J Sports Med 1982;3(3):153-8.
156. Mancia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, et al. 2007 Guidelines
for the management of arterial hypertension: The Task Force for the Management of
Arterial Hypertension of the European Society of Hypertension (ESH) and of the European
Society of Cardiology (ESC). Eur Heart J 2007;28(12):1462-536.
157. Vijayalakshmi P, Madanmohan, Bhavanani AB, Patil A, Babu K. Modulation of stress induced
by isometric handgrip test in hypertensive patients following yogic relaxation training.
Indian J Physiol Pharmacol 2004;48(1):59-64.
158. Tybor DJ, Lichtenstein AH, Dallal GE, Daniels SR, Must A. Independent effects of age-related
changes in waist circumference and BMI z scores in predicting cardiovascular disease risk
factors in a prospective cohort of adolescent females. Am J Clin Nutr 2011;93(2):392-401.
159. Chhabra SK, Gupta AK, Khuma MZ. Evaluation of three scales of dyspnea in chronic
obstructive pulmonary disease. Ann Thorac Med 2009;4(3):128-32.
160. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases dyspnearelated distress and improves functional performance in people with chronic obstructive
pulmonary disease: a pilot study. Journal of alternative and complementary medicine
2009;15(3):225-34.
161. Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality of life
for clinical trials in chronic lung disease. Thorax 1987;42(10):773-8.
162. Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med
2001;33(5):337-43.
163. Graneheim UH, Lundman B. Qualitative content analysis in nursing research: concepts,
procedures and measures to achieve trustworthiness. Nurse Educ Today 2004;24(2):105-12.
164. Elo S, Kyngäs H. The qualitative content analysis process. Journal of Advanced Nursing
2008;62(1):107-15.
165. Elo S, Kaariainen M, Kanste O, Polkki T, Utriainen K, Kyngas H. Qualitative Content Analysis: A
Focus on Trustworthiness. SAGE Open 2014;4(1).
166. Association GAotWM. World Medical Association Declaration of Helsinki: ethical principles for
medical research involving human subjects. The Journal of the American College of Dentists
2014;81(3):14.
167. Donohue JF. Minimal clinically important differences in COPD lung function. COPD
2005;2(1):111-24.
83
83
168. Telles S, Sharma SK, Gupta RK, Bhardwaj AK, Balkrishna A. Heart rate variability in chronic low
back pain patients randomized to yoga or standard care. BMC complementary and
alternative medicine 2016;16(1):279.
169. Posadzki P, Kuzdzal A, Lee MS, Ernst E. Yoga for heart rate variability: A systematic review and
meta-analysis of randomized clinical trials. Applied psychophysiology and biofeedback
2015;40(3):239-49.
170. Pahlm O, Sˆrnmo L. Elektrokardiologi: klinik och teknik. 2006.
171. Bernardi L, Sleight P, Bandinelli G, Cencetti S. Effect of rosary prayer and yoga mantras on
autonomic cardiovascular rhythms: comparative study. British Medical Journal
2001;323(7327):1446.
172. Cole RJ. Postural baroreflex stimuli may affect EEG arousal and sleep in humans. Journal of
Applied Physiology 1989;67(6):2369-75.
173. Ingemansson M, Holm M, Olsson S. Autonomic modulation of the atrial cycle length by the
head up tilt test: non-invasive evaluation in patients with chronic atrial fibrillation. Heart
1998;80(1):71-76.
174. Krittayaphong R, Cascio WE, Light KC, Sheffield D, Golden RN, Finkel JB, et al. Heart rate
variability in patients with coronary artery disease: differences in patients with higher and
lower depression scores. Psychosomatic medicine 1997;59(3):231-35.
175. Broadley AJ, Frenneaux MP, Moskvina V, Jones CJ, Korszun A. Baroreflex sensitivity is reduced
in depression. Psychosomatic medicine 2005;67(4):648-51.
176. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart-rate recovery immediately
after exercise as a predictor of mortality. New England Journal of Medicine
1999;341(18):1351-57.
177. Moodithaya SS, Avadhany ST. Comparison of cardiac autonomic activity between pre and post
menopausal women using heart rate variability. 2009.
178. Farinatti PT, Brandao C, Soares PP, Duarte AF. Acute effects of stretching exercise on the heart
rate variability in subjects with low flexibility levels. Journal of strength and conditioning
research / National Strength & Conditioning Association 2011;25(6):1579-85.
179. Pal GK, Chandrasekaran A, Hariharan AP, Dutta TK, Pal P, Nanda N, et al. Body mass index
contributes to sympathovagal imbalance in prehypertensives. BMC Cardiovascular
Disorders 2012;12(1).
180. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of yoga
breathing in patients with chronic obstructive pulmonary disease: a pilot study. J
Cardiopulm Rehabil Prev 2009;29(2):133-7.
181. Jones M, Harvey A, Marston L, O'Connell NE. Breathing exercises for dysfunctional
breathing/hyperventilation syndrome in adults. Cochrane Database Syst Rev
2013;5:CD009041.
182. Bezerra LA, de Melo HF, Garay AP, Reis VM, Aidar FJ, Bodas AR, et al. Do 12-week yoga
program influence respiratory function of elderly women? J Hum Kinet 2014;43:177-84.
183. Courtney R, van Dixhoorn J, Greenwood KM, Anthonissen EL. Medically unexplained dyspnea:
partly moderated by dysfunctional (thoracic dominant) breathing pattern. J Asthma
2011;48(3):259-65.
184. Courtney R, Greenwood KM, Cohen M. Relationships between measures of dysfunctional
breathing in a population with concerns about their breathing. Journal of bodywork and
movement therapies 2011;15(1):24-34.
185. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary function in
healthy individuals: a literature review. Journal of alternative and complementary
medicine 2013;19(3):185-90.
186. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in chronic
obstructive pulmonary disease. American journal of therapeutics 2012;19(2):96-100.
187. Passino C, Beutler E, Beltrami FG, Boutellier U, Spengler CM. Effect of Regular Yoga Practice on
Respiratory Regulation and Exercise Performance. Plos One 2016;11(4):e0153159.
168. Telles S, Sharma SK, Gupta RK, Bhardwaj AK, Balkrishna A. Heart rate variability in chronic low
back pain patients randomized to yoga or standard care. BMC complementary and
alternative medicine 2016;16(1):279.
169. Posadzki P, Kuzdzal A, Lee MS, Ernst E. Yoga for heart rate variability: A systematic review and
meta-analysis of randomized clinical trials. Applied psychophysiology and biofeedback
2015;40(3):239-49.
170. Pahlm O, Sˆrnmo L. Elektrokardiologi: klinik och teknik. 2006.
171. Bernardi L, Sleight P, Bandinelli G, Cencetti S. Effect of rosary prayer and yoga mantras on
autonomic cardiovascular rhythms: comparative study. British Medical Journal
2001;323(7327):1446.
172. Cole RJ. Postural baroreflex stimuli may affect EEG arousal and sleep in humans. Journal of
Applied Physiology 1989;67(6):2369-75.
173. Ingemansson M, Holm M, Olsson S. Autonomic modulation of the atrial cycle length by the
head up tilt test: non-invasive evaluation in patients with chronic atrial fibrillation. Heart
1998;80(1):71-76.
174. Krittayaphong R, Cascio WE, Light KC, Sheffield D, Golden RN, Finkel JB, et al. Heart rate
variability in patients with coronary artery disease: differences in patients with higher and
lower depression scores. Psychosomatic medicine 1997;59(3):231-35.
175. Broadley AJ, Frenneaux MP, Moskvina V, Jones CJ, Korszun A. Baroreflex sensitivity is reduced
in depression. Psychosomatic medicine 2005;67(4):648-51.
176. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart-rate recovery immediately
after exercise as a predictor of mortality. New England Journal of Medicine
1999;341(18):1351-57.
177. Moodithaya SS, Avadhany ST. Comparison of cardiac autonomic activity between pre and post
menopausal women using heart rate variability. 2009.
178. Farinatti PT, Brandao C, Soares PP, Duarte AF. Acute effects of stretching exercise on the heart
rate variability in subjects with low flexibility levels. Journal of strength and conditioning
research / National Strength & Conditioning Association 2011;25(6):1579-85.
179. Pal GK, Chandrasekaran A, Hariharan AP, Dutta TK, Pal P, Nanda N, et al. Body mass index
contributes to sympathovagal imbalance in prehypertensives. BMC Cardiovascular
Disorders 2012;12(1).
180. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of yoga
breathing in patients with chronic obstructive pulmonary disease: a pilot study. J
Cardiopulm Rehabil Prev 2009;29(2):133-7.
181. Jones M, Harvey A, Marston L, O'Connell NE. Breathing exercises for dysfunctional
breathing/hyperventilation syndrome in adults. Cochrane Database Syst Rev
2013;5:CD009041.
182. Bezerra LA, de Melo HF, Garay AP, Reis VM, Aidar FJ, Bodas AR, et al. Do 12-week yoga
program influence respiratory function of elderly women? J Hum Kinet 2014;43:177-84.
183. Courtney R, van Dixhoorn J, Greenwood KM, Anthonissen EL. Medically unexplained dyspnea:
partly moderated by dysfunctional (thoracic dominant) breathing pattern. J Asthma
2011;48(3):259-65.
184. Courtney R, Greenwood KM, Cohen M. Relationships between measures of dysfunctional
breathing in a population with concerns about their breathing. Journal of bodywork and
movement therapies 2011;15(1):24-34.
185. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary function in
healthy individuals: a literature review. Journal of alternative and complementary
medicine 2013;19(3):185-90.
186. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in chronic
obstructive pulmonary disease. American journal of therapeutics 2012;19(2):96-100.
187. Passino C, Beutler E, Beltrami FG, Boutellier U, Spengler CM. Effect of Regular Yoga Practice on
Respiratory Regulation and Exercise Performance. Plos One 2016;11(4):e0153159.
84
84
188. Lorenc AB, Wang Y, Madge SL, Hu X, Mian AM, Robinson N. Meditative movement for
respiratory function: a systematic review. Respiratory care 2014;59(3):427-40.
189. Larson-Meyer DE. A Systematic Review of the Energy Cost and Metabolic Intensity of Yoga.
Medicine & Science in Sports & Exercise 2016.
190. Patel NK, Newstead AH, Ferrer RL. The effects of yoga on physical functioning and health
related quality of life in older adults: a systematic review and meta-analysis. The journal of
alternative and complementary medicine 2012;18(10):902-17.
191. Ha M-S, Baek Y-H, Kim J-W, Kim D-Y. Effects of yoga exercise on maximum oxygen uptake,
cortisol level, and creatine kinase myocardial bond activity in female patients with skeletal
muscle pain syndrome. Journal of physical therapy science 2015;27(5):1451.
192. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes
and intensity of exercise. Evidence-based complementary and alternative medicine : eCAM
2011;2011:241294.
193. Saraswati SS. Surya namaskara: a technique of solar vitalization: Bihar School of Yoga, 1996.
194. Bhavanani AB, Udupa K, Ravindra P. A comparative study of slow and fast suryanamaskar on
physiological function. International journal of yoga 2011;4(2):71.
195. Choudhary R, Stec K. The Effects of Dynamic Suryanamaskar on Flexibility of University
Students.
196. O'Donovan G, Blazevich AJ, Boreham C, Cooper AR, Crank H, Ekelund U, et al. The ABC of
Physical Activity for Health: a consensus statement from the British Association of Sport
and Exercise Sciences. J Sports Sci 2010;28(6):573-91.
197. Telles S, Naveen KV, Gaur V, Balkrishna A. Effect of one week of yoga on function and severity
in rheumatoid arthritis. BMC research notes 2011;4(1):1.
198. Tekur P, Singphow C, Nagendra HR, Raghuram N. Effect of short-term intensive yoga program
on pain, functional disability and spinal flexibility in chronic low back pain: a randomized
control study. The journal of alternative and complementary medicine 2008;14(6):637-44.
199. Saper R, Boah A, Keosaian J, Weinberg J, Sherman K. OA10. 01. The Yoga Dosing Study:
comparing once vs. twice per week yoga classes for chronic low back pain in predominantly
low income minority populations. BMC complementary and alternative medicine
2012;12(1):1.
200. Bhutkar MV, Bhutkar PM, Taware GB, Surdi AD. How effective is sun salutation in improving
muscle strength, general body endurance and body composition? Asian J Sports Med
2011;2(4):259-66.
201. Kim S, Bemben MG, Bemben DA. Effects of an 8-month yoga intervention on arterial
compliance and muscle strength in premenopausal women. J Sports Sci Med
2012;11(2):322-30.
202. Ni M, Mooney K, Richards L, Balachandran A, Sun M, Harriell K, et al. Comparative impacts of
tai chi, balance training, and a specially-designed yoga program on balance in older fallers.
Archives of physical medicine and rehabilitation 2014;95(9):1620-28. e30.
203. Papp ME, Lindfors P, Nygren-Bonnier M, Gullstrand L, Wandell PE. Effects of High-Intensity
Hatha Yoga on Cardiovascular Fitness, Adipocytokines, and Apolipoproteins in Healthy
Students: A Randomized Controlled Study. J Altern Complement Med 2016;22(1):81-7.
204. Sujatha T, Judie A. Effectiveness of a 12-week yoga program on physiopsychological
parameters in patients with hypertension. Int. J. Pharm. Clin. Res. 2014;6(4):329-35.
205. Cohen DL, Bloedon LT, Rothman RL, Farrar JT, Galantino ML, Volger S, et al. Iyengar Yoga
versus Enhanced Usual Care on Blood Pressure in Patients with Prehypertension to Stage I
Hypertension: a Randomized Controlled Trial. Evid Based Complement Alternat Med
2011;2011:546428.
206. Cohen DL, Boudhar S, Bowler A, Townsend RR. Blood Pressure Effects of Yoga, Alone or in
Combination With Lifestyle Measures: Results of the Lifestyle Modification and Blood
Pressure Study (LIMBS). The Journal of Clinical Hypertension 2016.
188. Lorenc AB, Wang Y, Madge SL, Hu X, Mian AM, Robinson N. Meditative movement for
respiratory function: a systematic review. Respiratory care 2014;59(3):427-40.
189. Larson-Meyer DE. A Systematic Review of the Energy Cost and Metabolic Intensity of Yoga.
Medicine & Science in Sports & Exercise 2016.
190. Patel NK, Newstead AH, Ferrer RL. The effects of yoga on physical functioning and health
related quality of life in older adults: a systematic review and meta-analysis. The journal of
alternative and complementary medicine 2012;18(10):902-17.
191. Ha M-S, Baek Y-H, Kim J-W, Kim D-Y. Effects of yoga exercise on maximum oxygen uptake,
cortisol level, and creatine kinase myocardial bond activity in female patients with skeletal
muscle pain syndrome. Journal of physical therapy science 2015;27(5):1451.
192. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes
and intensity of exercise. Evidence-based complementary and alternative medicine : eCAM
2011;2011:241294.
193. Saraswati SS. Surya namaskara: a technique of solar vitalization: Bihar School of Yoga, 1996.
194. Bhavanani AB, Udupa K, Ravindra P. A comparative study of slow and fast suryanamaskar on
physiological function. International journal of yoga 2011;4(2):71.
195. Choudhary R, Stec K. The Effects of Dynamic Suryanamaskar on Flexibility of University
Students.
196. O'Donovan G, Blazevich AJ, Boreham C, Cooper AR, Crank H, Ekelund U, et al. The ABC of
Physical Activity for Health: a consensus statement from the British Association of Sport
and Exercise Sciences. J Sports Sci 2010;28(6):573-91.
197. Telles S, Naveen KV, Gaur V, Balkrishna A. Effect of one week of yoga on function and severity
in rheumatoid arthritis. BMC research notes 2011;4(1):1.
198. Tekur P, Singphow C, Nagendra HR, Raghuram N. Effect of short-term intensive yoga program
on pain, functional disability and spinal flexibility in chronic low back pain: a randomized
control study. The journal of alternative and complementary medicine 2008;14(6):637-44.
199. Saper R, Boah A, Keosaian J, Weinberg J, Sherman K. OA10. 01. The Yoga Dosing Study:
comparing once vs. twice per week yoga classes for chronic low back pain in predominantly
low income minority populations. BMC complementary and alternative medicine
2012;12(1):1.
200. Bhutkar MV, Bhutkar PM, Taware GB, Surdi AD. How effective is sun salutation in improving
muscle strength, general body endurance and body composition? Asian J Sports Med
2011;2(4):259-66.
201. Kim S, Bemben MG, Bemben DA. Effects of an 8-month yoga intervention on arterial
compliance and muscle strength in premenopausal women. J Sports Sci Med
2012;11(2):322-30.
202. Ni M, Mooney K, Richards L, Balachandran A, Sun M, Harriell K, et al. Comparative impacts of
tai chi, balance training, and a specially-designed yoga program on balance in older fallers.
Archives of physical medicine and rehabilitation 2014;95(9):1620-28. e30.
203. Papp ME, Lindfors P, Nygren-Bonnier M, Gullstrand L, Wandell PE. Effects of High-Intensity
Hatha Yoga on Cardiovascular Fitness, Adipocytokines, and Apolipoproteins in Healthy
Students: A Randomized Controlled Study. J Altern Complement Med 2016;22(1):81-7.
204. Sujatha T, Judie A. Effectiveness of a 12-week yoga program on physiopsychological
parameters in patients with hypertension. Int. J. Pharm. Clin. Res. 2014;6(4):329-35.
205. Cohen DL, Bloedon LT, Rothman RL, Farrar JT, Galantino ML, Volger S, et al. Iyengar Yoga
versus Enhanced Usual Care on Blood Pressure in Patients with Prehypertension to Stage I
Hypertension: a Randomized Controlled Trial. Evid Based Complement Alternat Med
2011;2011:546428.
206. Cohen DL, Boudhar S, Bowler A, Townsend RR. Blood Pressure Effects of Yoga, Alone or in
Combination With Lifestyle Measures: Results of the Lifestyle Modification and Blood
Pressure Study (LIMBS). The Journal of Clinical Hypertension 2016.
85
85
207. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A, Dobos G. Effects of yoga on
cardiovascular disease risk factors: A systematic review and meta-analysis. Int J Cardiol
2014.
208. Van de Borne P, Mezzetti S, Montano N, Narkiewicz K, Degaute JP, Somers VK.
Hyperventilation alters arterial baroreflex control of heart rate and muscle sympathetic
nerve activity. American Journal of Physiology-Heart and Circulatory Physiology
2000;279(2):H536-H41.
209. Dash M, Telles S. Improvement in hand grip strength in normal volunteers and rheumatoid
arthritis patients following yoga training. Indian Journal of Physiology and Pharmacology
2001;45(3):355-60.
210. BHAVANANI AB. Effect of yoga training on handgrip, respiratory pressures and pulmonary
function. Indian J Physiol Pharmacol 2003;47(4):387-92.
211. Posadzki P, AlBedah AM, Khalil MM, AlQaed MS. Complementary and alternative medicine for
lowering blood lipid levels: A systematic review of systematic reviews. Complementary
therapies in medicine 2016;29:141-51.
212. Hickey MS, Israel RG, Gardiner SN, Considine RV, McCammon MR, Tyndall GL, et al. Gender
differences in serum leptin levels in humans. Biochemical and molecular medicine
1996;59(1):1-6.
213. Böttner A, Kratzsch Jr, Müller G, Kapellen TM, Blüher S, Keller E, et al. Gender differences of
adiponectin levels develop during the progression of puberty and are related to serum
androgen levels. The Journal of Clinical Endocrinology & Metabolism 2004;89(8):4053-61.
214. Trujillo M, Scherer P. Adiponectin–journey from an adipocyte secretory protein to biomarker
of the metabolic syndrome. Journal of internal medicine 2005;257(2):167-75.
215. Inoue M, Maehata E, Yano M, Taniyama M, Suzuki S. Correlation between the adiponectinleptin ratio and parameters of insulin resistance in patients with type 2 diabetes.
Metabolism 2005;54(3):281-86.
216. Ranjita R, Hankey A, Nagendra H, Mohanty S. Yoga-based pulmonary rehabilitation for the
management of dyspnea in coal miners with chronic obstructive pulmonary disease: A
randomized controlled trial. Journal of Ayurveda and integrative medicine 2016;7(3):15866.
217. Noradechanunt C, Worsley A, Groeller H. Thai Yoga improves physical function and well-being
in older adults: A randomised controlled trial. Journal of Science and Medicine in Sport
2016.
218. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects of
Iyengar yoga practice on the health-related quality of life of patients with chronic
respiratory diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
219. Wahlstrom M, Rydell Karlsson M, Medin J, Frykman V. Effects of yoga in patients with
paroxysmal atrial fibrillation - a randomized controlled study. Eur J Cardiovasc Nurs 2016.
220. Selman L, McDermott K, Donesky D, Citron T, Howie-Esquivel J. Appropriateness and
acceptability of a Tele-Yoga intervention for people with heart failure and chronic
obstructive pulmonary disease: qualitative findings from a controlled pilot study. BMC
complementary and alternative medicine 2015;15:21.
221. Bandura A. Health Promotion by Social Cognitive Means. Health Education & Behavior
2004;31(2):143-64.
222. Keosaian JE, Lemaster CM, Dresner D, Godersky ME, Paris R, Sherman KJ, et al. "We're all in
this together": A qualitative study of predominantly low income minority participants in a
yoga trial for chronic low back pain. Complementary therapies in medicine 2016;24:34-9.
223. Cramer H, Lauche R, Haller H, Langhorst J, Dobos G, Berger B. "I'm more in balance": a
qualitative study of yoga for patients with chronic neck pain. Journal of alternative and
complementary medicine 2013;19(6):536-42.
207. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A, Dobos G. Effects of yoga on
cardiovascular disease risk factors: A systematic review and meta-analysis. Int J Cardiol
2014.
208. Van de Borne P, Mezzetti S, Montano N, Narkiewicz K, Degaute JP, Somers VK.
Hyperventilation alters arterial baroreflex control of heart rate and muscle sympathetic
nerve activity. American Journal of Physiology-Heart and Circulatory Physiology
2000;279(2):H536-H41.
209. Dash M, Telles S. Improvement in hand grip strength in normal volunteers and rheumatoid
arthritis patients following yoga training. Indian Journal of Physiology and Pharmacology
2001;45(3):355-60.
210. BHAVANANI AB. Effect of yoga training on handgrip, respiratory pressures and pulmonary
function. Indian J Physiol Pharmacol 2003;47(4):387-92.
211. Posadzki P, AlBedah AM, Khalil MM, AlQaed MS. Complementary and alternative medicine for
lowering blood lipid levels: A systematic review of systematic reviews. Complementary
therapies in medicine 2016;29:141-51.
212. Hickey MS, Israel RG, Gardiner SN, Considine RV, McCammon MR, Tyndall GL, et al. Gender
differences in serum leptin levels in humans. Biochemical and molecular medicine
1996;59(1):1-6.
213. Böttner A, Kratzsch Jr, Müller G, Kapellen TM, Blüher S, Keller E, et al. Gender differences of
adiponectin levels develop during the progression of puberty and are related to serum
androgen levels. The Journal of Clinical Endocrinology & Metabolism 2004;89(8):4053-61.
214. Trujillo M, Scherer P. Adiponectin–journey from an adipocyte secretory protein to biomarker
of the metabolic syndrome. Journal of internal medicine 2005;257(2):167-75.
215. Inoue M, Maehata E, Yano M, Taniyama M, Suzuki S. Correlation between the adiponectinleptin ratio and parameters of insulin resistance in patients with type 2 diabetes.
Metabolism 2005;54(3):281-86.
216. Ranjita R, Hankey A, Nagendra H, Mohanty S. Yoga-based pulmonary rehabilitation for the
management of dyspnea in coal miners with chronic obstructive pulmonary disease: A
randomized controlled trial. Journal of Ayurveda and integrative medicine 2016;7(3):15866.
217. Noradechanunt C, Worsley A, Groeller H. Thai Yoga improves physical function and well-being
in older adults: A randomised controlled trial. Journal of Science and Medicine in Sport
2016.
218. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects of
Iyengar yoga practice on the health-related quality of life of patients with chronic
respiratory diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
219. Wahlstrom M, Rydell Karlsson M, Medin J, Frykman V. Effects of yoga in patients with
paroxysmal atrial fibrillation - a randomized controlled study. Eur J Cardiovasc Nurs 2016.
220. Selman L, McDermott K, Donesky D, Citron T, Howie-Esquivel J. Appropriateness and
acceptability of a Tele-Yoga intervention for people with heart failure and chronic
obstructive pulmonary disease: qualitative findings from a controlled pilot study. BMC
complementary and alternative medicine 2015;15:21.
221. Bandura A. Health Promotion by Social Cognitive Means. Health Education & Behavior
2004;31(2):143-64.
222. Keosaian JE, Lemaster CM, Dresner D, Godersky ME, Paris R, Sherman KJ, et al. "We're all in
this together": A qualitative study of predominantly low income minority participants in a
yoga trial for chronic low back pain. Complementary therapies in medicine 2016;24:34-9.
223. Cramer H, Lauche R, Haller H, Langhorst J, Dobos G, Berger B. "I'm more in balance": a
qualitative study of yoga for patients with chronic neck pain. Journal of alternative and
complementary medicine 2013;19(6):536-42.
86
86
224. McCall M, Thorne S, Ward A, Heneghan C. Yoga in adult cancer: an exploratory, qualitative
analysis of the patient experience. BMC complementary and alternative medicine
2015;15(1).
225. Eichenberger PA, Diener SN, Kofmehl R, Spengler CM. Effects of Exercise Training on Airway
Hyperreactivity in Asthma: A Systematic Review and Meta-Analysis. Sports Medicine
2013;43(11):1157-70.
226. Sendhilkumar R, Gupta A, Nagarathna R, Taly AB. “Effect of pranayama and meditation as an
add-on therapy in rehabilitation of patients with Guillain-Barré syndrome—a randomized
control pilot study”. Disability and Rehabilitation 2012;35(1):57-62.
227. Gupta SK. Intention-to-treat concept: a review. Perspectives in clinical research 2011;2(3):109.
228. Hróbjartsson A, Kaptchuk TJ, Miller FG. Placebo effect studies are susceptible to response bias
and to other types of biases. Journal of clinical epidemiology 2011;64(11):1223-29.
229. Kaptchuk TJ, Kelley JM, Conboy LA, Davis RB, Kerr CE, Jacobson EE, et al. Components of
placebo effect: randomised controlled trial in patients with irritable bowel syndrome. Bmj
2008;336(7651):999-1003.
230. Hróbjartsson A, Gøtzsche PC. Is the placebo powerless? An analysis of clinical trials comparing
placebo with no treatment. New England Journal of Medicine 2001;344(21):1594-602.
231. Beauregard M. Mind does really matter: Evidence from neuroimaging studies of emotional
self-regulation, psychotherapy, and placebo effect. Progress in neurobiology
2007;81(4):218-36.
232. Knight WE, Rickard NS. Relaxing music prevents stress-induced increases in subjective anxiety,
systolic blood pressure, and heart rate in healthy males and females. Journal of music
therapy 2001;38(4):254-72.
233. Loomba RS, Arora R, Shah PH, Chandrasekar S, Molnar J. Effects of music on systolic blood
pressure, diastolic blood pressure, and heart rate: a meta-analysis. Indian heart journal
2012;64(3):309-13.
234. Guyatt GH, Sullivan MJ, Thompson PJ, Fallen EL, Pugsley SO, Taylor DW, et al. The 6-minute
walk: a new measure of exercise capacity in patients with chronic heart failure. Canadian
medical association journal 1985;132(8):919.
235. Laboratories ACoPSfCPF. ATS statement: guidelines for the six-minute walk test. American
journal of respiratory and critical care medicine 2002;166(1):111.
236. Pinto-Plata V, Cote C, Cabral H, Taylor J, Celli B. The 6‐min walk distance: change over time
and value as a predictor of survival in severe COPD. European Respiratory Journal
2004;23(1):28-33.
237. Bellet RN, Adams L, Morris NR. The 6-minute walk test in outpatient cardiac rehabilitation:
validity, reliability and responsiveness--a systematic review. Physiotherapy 2012;98(4):27786.
238. Hamilton DM, Haennel R. Validity and reliability of the 6-minute walk test in a cardiac
rehabilitation population. J Cardiopulm Rehabil Prev 2000;20(3):156-64.
239. Redelmeier DA, Bayoumi AM, Goldstein RS, Guyatt GH. Interpreting small differences in
functional status: the Six Minute Walk test in chronic lung disease patients. American
journal of respiratory and critical care medicine 1997;155(4):1278-82.
240. Puhan MA, Chandra D, Mosenifar Z, Ries A, Make B, Hansel NN, et al. The minimal important
difference of exercise tests in severe COPD. The European respiratory journal
2011;37(4):784-90.
241. Guyatt GH, King DR, Feeny DH, Stubbing D, Goldstein RS. Generic and specific measurement of
health-related quality of life in a clinical trial of respiratory rehabilitation. Journal of clinical
epidemiology 1999;52(3):187-92.
242. Jones PW. Health status measurement in chronic obstructive pulmonary disease. Thorax
2001;56(11):880-87.
224. McCall M, Thorne S, Ward A, Heneghan C. Yoga in adult cancer: an exploratory, qualitative
analysis of the patient experience. BMC complementary and alternative medicine
2015;15(1).
225. Eichenberger PA, Diener SN, Kofmehl R, Spengler CM. Effects of Exercise Training on Airway
Hyperreactivity in Asthma: A Systematic Review and Meta-Analysis. Sports Medicine
2013;43(11):1157-70.
226. Sendhilkumar R, Gupta A, Nagarathna R, Taly AB. “Effect of pranayama and meditation as an
add-on therapy in rehabilitation of patients with Guillain-Barré syndrome—a randomized
control pilot study”. Disability and Rehabilitation 2012;35(1):57-62.
227. Gupta SK. Intention-to-treat concept: a review. Perspectives in clinical research 2011;2(3):109.
228. Hróbjartsson A, Kaptchuk TJ, Miller FG. Placebo effect studies are susceptible to response bias
and to other types of biases. Journal of clinical epidemiology 2011;64(11):1223-29.
229. Kaptchuk TJ, Kelley JM, Conboy LA, Davis RB, Kerr CE, Jacobson EE, et al. Components of
placebo effect: randomised controlled trial in patients with irritable bowel syndrome. Bmj
2008;336(7651):999-1003.
230. Hróbjartsson A, Gøtzsche PC. Is the placebo powerless? An analysis of clinical trials comparing
placebo with no treatment. New England Journal of Medicine 2001;344(21):1594-602.
231. Beauregard M. Mind does really matter: Evidence from neuroimaging studies of emotional
self-regulation, psychotherapy, and placebo effect. Progress in neurobiology
2007;81(4):218-36.
232. Knight WE, Rickard NS. Relaxing music prevents stress-induced increases in subjective anxiety,
systolic blood pressure, and heart rate in healthy males and females. Journal of music
therapy 2001;38(4):254-72.
233. Loomba RS, Arora R, Shah PH, Chandrasekar S, Molnar J. Effects of music on systolic blood
pressure, diastolic blood pressure, and heart rate: a meta-analysis. Indian heart journal
2012;64(3):309-13.
234. Guyatt GH, Sullivan MJ, Thompson PJ, Fallen EL, Pugsley SO, Taylor DW, et al. The 6-minute
walk: a new measure of exercise capacity in patients with chronic heart failure. Canadian
medical association journal 1985;132(8):919.
235. Laboratories ACoPSfCPF. ATS statement: guidelines for the six-minute walk test. American
journal of respiratory and critical care medicine 2002;166(1):111.
236. Pinto-Plata V, Cote C, Cabral H, Taylor J, Celli B. The 6‐min walk distance: change over time
and value as a predictor of survival in severe COPD. European Respiratory Journal
2004;23(1):28-33.
237. Bellet RN, Adams L, Morris NR. The 6-minute walk test in outpatient cardiac rehabilitation:
validity, reliability and responsiveness--a systematic review. Physiotherapy 2012;98(4):27786.
238. Hamilton DM, Haennel R. Validity and reliability of the 6-minute walk test in a cardiac
rehabilitation population. J Cardiopulm Rehabil Prev 2000;20(3):156-64.
239. Redelmeier DA, Bayoumi AM, Goldstein RS, Guyatt GH. Interpreting small differences in
functional status: the Six Minute Walk test in chronic lung disease patients. American
journal of respiratory and critical care medicine 1997;155(4):1278-82.
240. Puhan MA, Chandra D, Mosenifar Z, Ries A, Make B, Hansel NN, et al. The minimal important
difference of exercise tests in severe COPD. The European respiratory journal
2011;37(4):784-90.
241. Guyatt GH, King DR, Feeny DH, Stubbing D, Goldstein RS. Generic and specific measurement of
health-related quality of life in a clinical trial of respiratory rehabilitation. Journal of clinical
epidemiology 1999;52(3):187-92.
242. Jones PW. Health status measurement in chronic obstructive pulmonary disease. Thorax
2001;56(11):880-87.
87
87
243. Finkelstein SM, Lindgren B, Prasad B, Snyder M, Edin C, Wielinski C, et al. Reliability and
validity of spirometry measurements in a paperless home monitoring diary program for
lung transplantation. Heart Lung 1993;22(6):523-33.
244. Schermer T, Jacobs J, Chavannes N, Hartman J, Folgering H, Bottema B, et al. Validity of
spirometric testing in a general practice population of patients with chronic obstructive
pulmonary disease (COPD). Thorax 2003;58(10):861-66.
245. Kelly A-M, McAlpine R, Kyle E. How accurate are pulse oximeters in patients with acute
exacerbations of chronic obstructive airways disease? Respiratory Medicine
2001;95(5):336-40.
246. Zavorsky GS, Cao J, Mayo NE, Gabbay R, Murias JM. Arterial versus capillary blood gases: a
meta-analysis. Respir Physiol Neurobiol 2007;155(3):268-79.
247. Downe‐Wamboldt B. Content analysis: method, applications, and issues. Health care for
women international 1992;13(3):313-21.
248. Hsieh H-F, Shannon SE. Three approaches to qualitative content analysis. Qualitative health
research 2005;15(9):1277-88.
249. Maniscalco M. Exhaled nitric oxide and disease progression in chronic obstructive pulmonary
disease. J Thorac Dis 2015;7(3):E59.
88
243. Finkelstein SM, Lindgren B, Prasad B, Snyder M, Edin C, Wielinski C, et al. Reliability and
validity of spirometry measurements in a paperless home monitoring diary program for
lung transplantation. Heart Lung 1993;22(6):523-33.
244. Schermer T, Jacobs J, Chavannes N, Hartman J, Folgering H, Bottema B, et al. Validity of
spirometric testing in a general practice population of patients with chronic obstructive
pulmonary disease (COPD). Thorax 2003;58(10):861-66.
245. Kelly A-M, McAlpine R, Kyle E. How accurate are pulse oximeters in patients with acute
exacerbations of chronic obstructive airways disease? Respiratory Medicine
2001;95(5):336-40.
246. Zavorsky GS, Cao J, Mayo NE, Gabbay R, Murias JM. Arterial versus capillary blood gases: a
meta-analysis. Respir Physiol Neurobiol 2007;155(3):268-79.
247. Downe‐Wamboldt B. Content analysis: method, applications, and issues. Health care for
women international 1992;13(3):313-21.
248. Hsieh H-F, Shannon SE. Three approaches to qualitative content analysis. Qualitative health
research 2005;15(9):1277-88.
249. Maniscalco M. Exhaled nitric oxide and disease progression in chronic obstructive pulmonary
disease. J Thorac Dis 2015;7(3):E59.
88
14 Appendix
14 Appendix
PROGRAM DESCRIPTIONS
PROGRAM DESCRIPTIONS
STUDY I Intervention (HRV-study)
STUDY I Intervention (HRV-study)
The yoga program was 60 minutes and standardized. The program included general poses, inversions
and semi-inversions. The postures were: cat/cow, shoulder rolls, upper body rotation in cat position,
bridge pose (also on one leg), cobra, wall dog variation, wall dog moving down on the wall, down
dog, half hand stand towards the wall, chest opener – lying on a roll placed under the rib cage, twisted
side angle pose with the knee on the floor, shoulder stand variation to the wall, universal pose,
waterfall pose and horizontal relaxation (5–8 minutes). As the intervention proceeded, the time spent
on inverted poses gradually increased while the time spent on other poses decreased. The total
inversion time for each participant during the last 4 weeks of the intervention was around 1520 minutes. All participants were encouraged to practice at home between classes. If participants had
little time to do so, they were encouraged to practise only the inverted poses.
The yoga program was 60 minutes and standardized. The program included general poses, inversions
and semi-inversions. The postures were: cat/cow, shoulder rolls, upper body rotation in cat position,
bridge pose (also on one leg), cobra, wall dog variation, wall dog moving down on the wall, down
dog, half hand stand towards the wall, chest opener – lying on a roll placed under the rib cage, twisted
side angle pose with the knee on the floor, shoulder stand variation to the wall, universal pose,
waterfall pose and horizontal relaxation (5–8 minutes). As the intervention proceeded, the time spent
on inverted poses gradually increased while the time spent on other poses decreased. The total
inversion time for each participant during the last 4 weeks of the intervention was around 1520 minutes. All participants were encouraged to practice at home between classes. If participants had
little time to do so, they were encouraged to practise only the inverted poses.
Study II – Intervention (sun salutation)
Study II – Intervention (sun salutation)
The yoga program was 60 minutes and standardized. The program included high intensity dynamic
yoga postures with the classical surya namaskar (sun salutation, SS) (30-40 minutes) and other
inversion poses (pincha mayurasana, half hand stand towards the wall, ardha adho mukha vrksasana,
sarvangasana), parivrtta parsvakonasana, gomukasana (around 15 min.) Inversions and semiinversions were performed at the end of the program. The SS is a collection of 12 separate poses
forming a dynamic sequence. The order of the SS was the following (Figure A): tadasana, tadasana
The yoga program was 60 minutes and standardized. The program included high intensity dynamic
yoga postures with the classical surya namaskar (sun salutation, SS) (30-40 minutes) and other
inversion poses (pincha mayurasana, half hand stand towards the wall, ardha adho mukha vrksasana,
sarvangasana), parivrtta parsvakonasana, gomukasana (around 15 min.) Inversions and semiinversions were performed at the end of the program. The SS is a collection of 12 separate poses
forming a dynamic sequence. The order of the SS was the following (Figure A): tadasana, tadasana
89
89
with back bend, uttanasana (with bent knees), crescent pose (right leg back), adho mukha svanasana,
modified chatturanga dandasana (with buttocks up and knees on the ground), urdhva mukha svanasana
(knees on the ground), adho mukha svanasana, crescent pose (right leg forward), uttanasana and
standing back bend tadasana (program similar to 108). The next round was repeated with the left leg
back and forward during the crescent pose. The speed of the SS was somewhat increased during the
six week period with the goal being to perform each pose for 1,5-2 seconds. Relaxation mainly
involved the waterfall pose (viparita karani) or horizontal relaxation (5 minutes). Intensity: an intensity
of 14-17 using the Borg RPE-scale was recommended.
with back bend, uttanasana (with bent knees), crescent pose (right leg back), adho mukha svanasana,
modified chatturanga dandasana (with buttocks up and knees on the ground), urdhva mukha svanasana
(knees on the ground), adho mukha svanasana, crescent pose (right leg forward), uttanasana and
standing back bend tadasana (program similar to 108). The next round was repeated with the left leg
back and forward during the crescent pose. The speed of the SS was somewhat increased during the
six week period with the goal being to perform each pose for 1,5-2 seconds. Relaxation mainly
involved the waterfall pose (viparita karani) or horizontal relaxation (5 minutes). Intensity: an intensity
of 14-17 using the Borg RPE-scale was recommended.
Study III – Intervention (YE and strong breathing study)
Study III – Intervention (YE and strong breathing study)
Dose: Two sessions per week with one session stretching 60-70 min. at a time, for 12 weeks totaling
24 sessions. Starting position: seated on a chair or meditation chair. The room was quiet without music
allowing no other individuals in the room than those participating in the intervention. Props included
yogic blocks and blankets. Exempting questions directed at the teacher, there was no talking during
the yoga class. The majority of the subjects were yoga novices.
Dose: Two sessions per week with one session stretching 60-70 min. at a time, for 12 weeks totaling
24 sessions. Starting position: seated on a chair or meditation chair. The room was quiet without music
allowing no other individuals in the room than those participating in the intervention. Props included
yogic blocks and blankets. Exempting questions directed at the teacher, there was no talking during
the yoga class. The majority of the subjects were yoga novices.
Asanas: (eyes open) Important instruction communicated during class; to rest when needed by
switching into the child pose (balasana), alternatively to lean forward on the chair with the legs apart
(uttanasana variation), and to work at their own capacity. General postural instructions and centering
in the beginning of the class: long spine with lateral movement, widening of the waist during
inhalation. Keeping hands on the waist with thumbs pointing backward.
Asanas: (eyes open) Important instruction communicated during class; to rest when needed by
switching into the child pose (balasana), alternatively to lean forward on the chair with the legs apart
(uttanasana variation), and to work at their own capacity. General postural instructions and centering
in the beginning of the class: long spine with lateral movement, widening of the waist during
inhalation. Keeping hands on the waist with thumbs pointing backward.
General breathing instructions: Extended exhalations, all breathing done through nostrils (if possible).
Complete a deep yogic breath using the diaphragm extensively during all asanas. Uddiyana bandha
(pulling stomach in using first the pelvic floor muscles and then the navel—light pull in towards
spine—during all exhalations) introduced after approx. 6 weeks. Performing complete yogic breaths, 3
levels on inhalation and 3 levels on exhalation. Move hands along with the breathing, inhalation
starting at lower abdominal navel area, moving to the upper waist/middle chest and finishing at the
upper chest below the clavicle. Exhalation starting in upper chest, moving down to middle chest and
finally ending at lower abdominal movement.
General breathing instructions: Extended exhalations, all breathing done through nostrils (if possible).
Complete a deep yogic breath using the diaphragm extensively during all asanas. Uddiyana bandha
(pulling stomach in using first the pelvic floor muscles and then the navel—light pull in towards
spine—during all exhalations) introduced after approx. 6 weeks. Performing complete yogic breaths, 3
levels on inhalation and 3 levels on exhalation. Move hands along with the breathing, inhalation
starting at lower abdominal navel area, moving to the upper waist/middle chest and finishing at the
upper chest below the clavicle. Exhalation starting in upper chest, moving down to middle chest and
finally ending at lower abdominal movement.
Vinyasa with back bending tadasana on inhalation (initially without head back) and deep utkatasana
on exhalation (with arms up and open chest, avoid leaning forward), instruction without arms and
then with arms extended above the head, alternatively keeping the hands resting on the shoulders.
Utkatasana progressed to sitting all the way down into the chair and later by sqatting all the way down
to the floor letting the heels come up. Ardha Chandrasana (standing side stretch, one arm up while
other arm down, other arm supported on thigh). Dynamic and then progressing to static holding
(approx. 30 seconds on each side), alternatively while seated on chair if breathing restriction occurs.
Trikonasana with chair, foot on floor under chair’s seat and hand on chair’s seat or on the back-rest of
the chair. Press hip out to side when going down and extend arm up to ceiling. Rotation of head during
the final pose. Small sun salutation, dog down and dog up, (adho mukha svanasana, urdhva mukha
svanasana) dynamic sequence with the breath, 4-5 times with hands on the seat of the chair. Dog pose
with wall (hands on wall at shoulder height) was also suggested if no weight on upper body is possible
(approx.. 2 min). Parsvakonasana with chair, foot placed under chair’s seat and hand on seat (after 4-5
weeks), emphasis on turning the chest and head if possible to get pressure change in neck.
Bharadvajasana 1, using both seated and standing variations, both legs folded to the left and twist right
first. Standing variation (utthita marichyasana); right side to wall with right leg up on chair and hands
to wall, twist to the right (alternative given with block under heel of standing foot), then changing
sides. Tiger breathing flow, Cat (marjaryasana) and cow, on all fours using extended exhalations.
Strong abdominal draw-in when exhaling. Variation used by some; seated vertically on chair using
simple back flexion and extension (no weight on arms). Another variation of cat pose was with flexion
of wrists on floor (palms down, thumbs facing out and palms up with thumbs facing towards each
other). Sphinx pose (salamba bhujangasana), walk on underarms to the right and then to the left.
Bhujangasana, resting on abdomen, then arms wide with fingertips facing outwards extending up on
Vinyasa with back bending tadasana on inhalation (initially without head back) and deep utkatasana
on exhalation (with arms up and open chest, avoid leaning forward), instruction without arms and
then with arms extended above the head, alternatively keeping the hands resting on the shoulders.
Utkatasana progressed to sitting all the way down into the chair and later by sqatting all the way down
to the floor letting the heels come up. Ardha Chandrasana (standing side stretch, one arm up while
other arm down, other arm supported on thigh). Dynamic and then progressing to static holding
(approx. 30 seconds on each side), alternatively while seated on chair if breathing restriction occurs.
Trikonasana with chair, foot on floor under chair’s seat and hand on chair’s seat or on the back-rest of
the chair. Press hip out to side when going down and extend arm up to ceiling. Rotation of head during
the final pose. Small sun salutation, dog down and dog up, (adho mukha svanasana, urdhva mukha
svanasana) dynamic sequence with the breath, 4-5 times with hands on the seat of the chair. Dog pose
with wall (hands on wall at shoulder height) was also suggested if no weight on upper body is possible
(approx.. 2 min). Parsvakonasana with chair, foot placed under chair’s seat and hand on seat (after 4-5
weeks), emphasis on turning the chest and head if possible to get pressure change in neck.
Bharadvajasana 1, using both seated and standing variations, both legs folded to the left and twist right
first. Standing variation (utthita marichyasana); right side to wall with right leg up on chair and hands
to wall, twist to the right (alternative given with block under heel of standing foot), then changing
sides. Tiger breathing flow, Cat (marjaryasana) and cow, on all fours using extended exhalations.
Strong abdominal draw-in when exhaling. Variation used by some; seated vertically on chair using
simple back flexion and extension (no weight on arms). Another variation of cat pose was with flexion
of wrists on floor (palms down, thumbs facing out and palms up with thumbs facing towards each
other). Sphinx pose (salamba bhujangasana), walk on underarms to the right and then to the left.
Bhujangasana, resting on abdomen, then arms wide with fingertips facing outwards extending up on
90
90
inhalation. Setu bhandasana (bridge pose) with one leg up, progressing to feet on chair to achieve
inversion. Hip resting on block with both legs up (viparita dandasana variation), then one leg lowering
at a time to the floor (stretching hip flexors), then in setu bandha with block. Universal pose: supine
twist to right with initial strong abdominal activity and straight spine. Rotation of head opposite to legs
to improve neck mobility. Fish pose (matsyasana), supported back bend with yoga block (wood) on
thoracic spine behind heart, to increase mobility in chest (chest opener); option of using rolled mat or
blanket under chest. Alternative was given with either weight on elbows or baddha konasana.
inhalation. Setu bhandasana (bridge pose) with one leg up, progressing to feet on chair to achieve
inversion. Hip resting on block with both legs up (viparita dandasana variation), then one leg lowering
at a time to the floor (stretching hip flexors), then in setu bandha with block. Universal pose: supine
twist to right with initial strong abdominal activity and straight spine. Rotation of head opposite to legs
to improve neck mobility. Fish pose (matsyasana), supported back bend with yoga block (wood) on
thoracic spine behind heart, to increase mobility in chest (chest opener); option of using rolled mat or
blanket under chest. Alternative was given with either weight on elbows or baddha konasana.
Yogic breathing exercises (pranayama), seated on a chair or meditation chair, straight spine, chin
slightly lowered (eyes closed), avoid leaning into back of chair (approx. 30 min). Asthma mudra was
used during some of the exercises. Metronome was used during the last 5-6 weeks to get the timing
and awareness of the breathing right during the breathing exercises. Kapalabhati (breath of fire),
starting with 10 times working up to 30 times. Hands on lower abdominals to increase awareness of
the abdominals, pull in during exhalation. Begin slowly then try to speed up. At the end of the course
this involves 20 x 4. Focus on exhalation, no attention to inhalation, 2-3 minutes. Bhastrika, hands on
lower abdominal, 20 times. Alternate nostril breath (nadi shodhana), using nashiki mudra, start
exhalation through left nostril, inhale left, exhale right, inhale right, exhale left (=1 cycle). Begin with
equal inhale and exhale (5 sec. in and 5 sec. out suggested) then try varied lengths of breathing ratios;
2-0-4-0, 6-0-12-0 no pauses, important prolonged exhalation. No pauses after inhalation. Focus on
extended exhalations and if possible a short pause after each exhalation, 5-10 minutes. Sitkari (inhale
through teeth, exhale through nose and closed mouth) to be used only during the first 4-5 weeks.
Bharmari (mmmmm sound on exhalation), humming bee, extended outbreaths –10 minutes, powerful
outbreaths with sound (sometimes with sanmukhi mudra), move sound to upper back palate and
towards third eye. Viloma (Dirgha/3 part breath). Divide inhalation and exhalation into 3 parts,
inhalation starting at abdomen, then same inhalation at middle ribs and final inhalation at collarbones.
Exhalation starts at collarbones, middle ribs, abdomen. 2-3 minutes (sometimes with prana mudra).
Hands moving to the active region of the chest. In the beginning of the course seated while supine, on
back at the end of the course. Sukhasana with forward bend, hands on block or chair. Shavasana (body
scanning, focus on synchronization of equal relaxation between the left and right side of the body and
let the weight drop to the floor), sometimes elevated legs with feet or calves on meditation chair, once
during the intervention patient tried with weight on thighs. Feet closer than arms, keep back of the
shoulders pressed to the floor. Approx. 5-8 min. Home training with this program was provided on
DVD (in Swedish).
Yogic breathing exercises (pranayama), seated on a chair or meditation chair, straight spine, chin
slightly lowered (eyes closed), avoid leaning into back of chair (approx. 30 min). Asthma mudra was
used during some of the exercises. Metronome was used during the last 5-6 weeks to get the timing
and awareness of the breathing right during the breathing exercises. Kapalabhati (breath of fire),
starting with 10 times working up to 30 times. Hands on lower abdominals to increase awareness of
the abdominals, pull in during exhalation. Begin slowly then try to speed up. At the end of the course
this involves 20 x 4. Focus on exhalation, no attention to inhalation, 2-3 minutes. Bhastrika, hands on
lower abdominal, 20 times. Alternate nostril breath (nadi shodhana), using nashiki mudra, start
exhalation through left nostril, inhale left, exhale right, inhale right, exhale left (=1 cycle). Begin with
equal inhale and exhale (5 sec. in and 5 sec. out suggested) then try varied lengths of breathing ratios;
2-0-4-0, 6-0-12-0 no pauses, important prolonged exhalation. No pauses after inhalation. Focus on
extended exhalations and if possible a short pause after each exhalation, 5-10 minutes. Sitkari (inhale
through teeth, exhale through nose and closed mouth) to be used only during the first 4-5 weeks.
Bharmari (mmmmm sound on exhalation), humming bee, extended outbreaths –10 minutes, powerful
outbreaths with sound (sometimes with sanmukhi mudra), move sound to upper back palate and
towards third eye. Viloma (Dirgha/3 part breath). Divide inhalation and exhalation into 3 parts,
inhalation starting at abdomen, then same inhalation at middle ribs and final inhalation at collarbones.
Exhalation starts at collarbones, middle ribs, abdomen. 2-3 minutes (sometimes with prana mudra).
Hands moving to the active region of the chest. In the beginning of the course seated while supine, on
back at the end of the course. Sukhasana with forward bend, hands on block or chair. Shavasana (body
scanning, focus on synchronization of equal relaxation between the left and right side of the body and
let the weight drop to the floor), sometimes elevated legs with feet or calves on meditation chair, once
during the intervention patient tried with weight on thighs. Feet closer than arms, keep back of the
shoulders pressed to the floor. Approx. 5-8 min. Home training with this program was provided on
DVD (in Swedish).
Intervention progression in HY group
Intervention progression in HY group
The time spent in each yoga pose was gradually increased, each pose being held from 5-40 seconds,
each breathing exercise performed for a longer duration with fewer pauses towards the end of the
intervention. Different variations of the poses were gradually introduced (using walls, chairs and
floor). Emphasis was on the synchronisation of the breathing during the exercises. Strength was not
measured in the HY group.
The time spent in each yoga pose was gradually increased, each pose being held from 5-40 seconds,
each breathing exercise performed for a longer duration with fewer pauses towards the end of the
intervention. Different variations of the poses were gradually introduced (using walls, chairs and
floor). Emphasis was on the synchronisation of the breathing during the exercises. Strength was not
measured in the HY group.
BOTH GROUPS - Training maintenance and progression following intervention (approx. 3 months
after intervention): among CTP group (8 responders), 4 did not continue and 4 continued the CTP
program, 8 did other exercise training. Among HY group (12 responders), 5 did not continue the HY
program and 7 did, 10 did other exercise training. One patient in each group used physical activity on
recipe (FaR).
BOTH GROUPS - Training maintenance and progression following intervention (approx. 3 months
after intervention): among CTP group (8 responders), 4 did not continue and 4 continued the CTP
program, 8 did other exercise training. Among HY group (12 responders), 5 did not continue the HY
program and 7 did, 10 did other exercise training. One patient in each group used physical activity on
recipe (FaR).
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91
Conventional training program (CTP) (physiotherapeutic intervention)
Conventional training program (CTP) (physiotherapeutic intervention)
Dose: Two sessions per week with one session stretching 60-70 min. at a time, for 12 weeks totaling
24 sessions. Work using strength training machines (2-4 sets each of 10-20 repetitions) was tested
individually on 70 %.
Dose: Two sessions per week with one session stretching 60-70 min. at a time, for 12 weeks totaling
24 sessions. Work using strength training machines (2-4 sets each of 10-20 repetitions) was tested
individually on 70 %.
Cycling 10-15 minutes at an intensity rating of 12-14 (on Borg 20-scale, approx. 50-60 rpm per
minute).
Cycling 10-15 minutes at an intensity rating of 12-14 (on Borg 20-scale, approx. 50-60 rpm per
minute).
CTP was performed in a gym (with gym equipment and stationary exercise bikes, adjacent to the yoga
room) with background radio/music while two physiotherapists coached the subjects. Subjects were
allowed to talk to each other and to the physiotherapists as well as the other subjects who were
sometimes in the room.
CTP was performed in a gym (with gym equipment and stationary exercise bikes, adjacent to the yoga
room) with background radio/music while two physiotherapists coached the subjects. Subjects were
allowed to talk to each other and to the physiotherapists as well as the other subjects who were
sometimes in the room.
The exercises included: Leg extensions (seated position), standing arm pull-backs with thera-band*,
seated leg press, shoulder press, squats to chair with crossed arms in front of chest*, seated
rowing/arm pull-backs with machine, heel lifts holding back of chair*, triceps press with machine,
torso rotation with machine, standing biceps curls with free weights, seated wide on chair and torso
twists with stick behind chest, hands resting at shoulder height on stick*, seated side stretches with
extended arm* (lower arm resting on hip), shoulder shrugs*, seated big upward swimming arm
movements with arms above head*. Calf stretch with chair*. * refers to exercises that were prescribed
as home exercises.
The exercises included: Leg extensions (seated position), standing arm pull-backs with thera-band*,
seated leg press, shoulder press, squats to chair with crossed arms in front of chest*, seated
rowing/arm pull-backs with machine, heel lifts holding back of chair*, triceps press with machine,
torso rotation with machine, standing biceps curls with free weights, seated wide on chair and torso
twists with stick behind chest, hands resting at shoulder height on stick*, seated side stretches with
extended arm* (lower arm resting on hip), shoulder shrugs*, seated big upward swimming arm
movements with arms above head*. Calf stretch with chair*. * refers to exercises that were prescribed
as home exercises.
The home exercise program for pulmonary rehabilitation was distributed on DVD and the program
written out on paper. This included exercises marked with * plus walking on the spot, shoulder lifts
with theraband, one arm at a time (up to shoulder level), bicep lifts seated on chair with theraband
(foot on theraband), seated rows on floor with straight legs with theraband, maintaining end position.
Therabands were then supplied for the home sessions.
The home exercise program for pulmonary rehabilitation was distributed on DVD and the program
written out on paper. This included exercises marked with * plus walking on the spot, shoulder lifts
with theraband, one arm at a time (up to shoulder level), bicep lifts seated on chair with theraband
(foot on theraband), seated rows on floor with straight legs with theraband, maintaining end position.
Therabands were then supplied for the home sessions.
Intervention progression in strength in CTP group
Intervention progression in strength in CTP group
Load increased during the 12 week period in CTP, during the leg extension by mean 7.81 kg or by 49
% (mean start kg divided by mean kilos increased during the intervention), during straight arm pull
backs by mean 2.8 kg or by 44.6 % using starting kg/kg increased during the intervention and during
leg press by mean 12.3 kg, or by 29.4 % using starting kg/kg increased during the intervention.
Strength was not measured in HY.
Load increased during the 12 week period in CTP, during the leg extension by mean 7.81 kg or by 49
% (mean start kg divided by mean kilos increased during the intervention), during straight arm pull
backs by mean 2.8 kg or by 44.6 % using starting kg/kg increased during the intervention and during
leg press by mean 12.3 kg, or by 29.4 % using starting kg/kg increased during the intervention.
Strength was not measured in HY.
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Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
RESEARCH ARTICLE
Open Access
RESEARCH ARTICLE
Open Access
Increased heart rate variability but no effect on
blood pressure from 8 weeks of hatha yoga –
a pilot study
Increased heart rate variability but no effect on
blood pressure from 8 weeks of hatha yoga –
a pilot study
Marian E Papp1, Petra Lindfors2, Niklas Storck3 and Per E Wändell1*
Marian E Papp1, Petra Lindfors2, Niklas Storck3 and Per E Wändell1*
Abstract
Abstract
Background: Yoga exercises are known to decrease stress and restore autonomic balance. Yet knowledge about
the physiological effects of inversion postures is limited. This study aimed to investigate the effects of inversion
postures (head below the heart) on blood pressure (BP) and heart rate variability (HRV).
Methods: Twelve healthy women and men took part in an 8-week yoga program (60 min once a week). BP was
measured with an automatic Omron mx3 oscillometric monitoring device and HRV with a Holter 24-hour ECG at
baseline and 8 weeks after the intervention.
Background: Yoga exercises are known to decrease stress and restore autonomic balance. Yet knowledge about
the physiological effects of inversion postures is limited. This study aimed to investigate the effects of inversion
postures (head below the heart) on blood pressure (BP) and heart rate variability (HRV).
Methods: Twelve healthy women and men took part in an 8-week yoga program (60 min once a week). BP was
measured with an automatic Omron mx3 oscillometric monitoring device and HRV with a Holter 24-hour ECG at
baseline and 8 weeks after the intervention.
Results: There was no significant effect of inversion postures on BP. Nine out of 12 participants showed a
significant increase in HRV (p < 0.05) at night (2 hours) on pNN50% (12.7 ± 12.5 to 18.2 ± 13.3). There were no
significant changes in other HRV measures such as NN50, LF, HF, LF/HF ratio, LF normalized units (n.u.), HF n.u. and
RMSSD.
Results: There was no significant effect of inversion postures on BP. Nine out of 12 participants showed a
significant increase in HRV (p < 0.05) at night (2 hours) on pNN50% (12.7 ± 12.5 to 18.2 ± 13.3). There were no
significant changes in other HRV measures such as NN50, LF, HF, LF/HF ratio, LF normalized units (n.u.), HF n.u. and
RMSSD.
Conclusion: Eight weeks of hatha yoga improved HRV significantly which suggests an increased vagal tone and
reduced sympathetic activity.
Conclusion: Eight weeks of hatha yoga improved HRV significantly which suggests an increased vagal tone and
reduced sympathetic activity.
Keywords: Autonomic balance, Blood pressure, ECG, Heart rate variability, Yoga
Keywords: Autonomic balance, Blood pressure, ECG, Heart rate variability, Yoga
Background
Yoga is frequently used as a lifestyle intervention to reduce stress and restore autonomic nervous system balance [1]. The National Centre for Complementary and
Alternative Medicine (NCCAM) refers to yoga as a
“mind-body medicine,” with its use being recommended
as a non-pharmacological tool for managing stress [1,2].
Hatha yoga uses psychophysical energy movements including specific body postures (asanas), breathing exercises (pranayama) and concentration exercises (dharana)
for the mind [1]. Due to the continuous focus on the
body, breathing and mind, yoga is psychophysical in
character. Focusing on one’s own breathing while practising yoga body movements, and vice versa, can function as a tool to increase awareness of tension/relaxation
states. Thus, awareness of one’s body’s position in space
* Correspondence: [email protected]
1
Centre for Family Medicine, Karolinska Institutet, Alfred Nobels allé 12,
SE-14183, Huddinge, Sweden
Full list of author information is available at the end of the article
can be used as an effective bio-feedback instrument.
Many of the slow movements in yoga are considered
related to a natural synchronization between breathing
and moving (vinyasa) which, in turn, promotes a slower,
deeper and more even paced breathing. This, in turn,
induces parasympathetic nerve activity and a feeling of
relaxation [3–5] which can influence heart rate, blood
pressure and breathing pace.
A few studies have shown an effect of yoga on the cardiovascular system. For instance, eight to twelve weeks
of yoga for individuals with mild to moderate high blood
pressure was as effective as medication for hypertension
[6–8]. Yoga has been shown to increase parasympathetic
dominance and, as such, often reduces blood pressure,
heart rate and stress while it improves sleep and calms
body and mind [1,2,9]. In studies of aerobic exercise and
hatha yoga, yoga was shown to increase Heart Rate Variation (HRV), i.e. the beat-to-beat time variation in heart
rate [10–13].
© 2013 Papp et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Background
Yoga is frequently used as a lifestyle intervention to reduce stress and restore autonomic nervous system balance [1]. The National Centre for Complementary and
Alternative Medicine (NCCAM) refers to yoga as a
“mind-body medicine,” with its use being recommended
as a non-pharmacological tool for managing stress [1,2].
Hatha yoga uses psychophysical energy movements including specific body postures (asanas), breathing exercises (pranayama) and concentration exercises (dharana)
for the mind [1]. Due to the continuous focus on the
body, breathing and mind, yoga is psychophysical in
character. Focusing on one’s own breathing while practising yoga body movements, and vice versa, can function as a tool to increase awareness of tension/relaxation
states. Thus, awareness of one’s body’s position in space
* Correspondence: [email protected]
1
Centre for Family Medicine, Karolinska Institutet, Alfred Nobels allé 12,
SE-14183, Huddinge, Sweden
Full list of author information is available at the end of the article
can be used as an effective bio-feedback instrument.
Many of the slow movements in yoga are considered
related to a natural synchronization between breathing
and moving (vinyasa) which, in turn, promotes a slower,
deeper and more even paced breathing. This, in turn,
induces parasympathetic nerve activity and a feeling of
relaxation [3–5] which can influence heart rate, blood
pressure and breathing pace.
A few studies have shown an effect of yoga on the cardiovascular system. For instance, eight to twelve weeks
of yoga for individuals with mild to moderate high blood
pressure was as effective as medication for hypertension
[6–8]. Yoga has been shown to increase parasympathetic
dominance and, as such, often reduces blood pressure,
heart rate and stress while it improves sleep and calms
body and mind [1,2,9]. In studies of aerobic exercise and
hatha yoga, yoga was shown to increase Heart Rate Variation (HRV), i.e. the beat-to-beat time variation in heart
rate [10–13].
© 2013 Papp et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
HRV measurement is a very sensitive method of detecting changes, for example after an intervention [14]. In
healthy individuals, the parasympathetic pathway is active
during rest, which is reflected by an increased HRV, while
low HRV indicates poor health and a higher sympathetic
activity [14,15]. However, strong vagal reactivity (high
HRV) is associated with good health [14]. Typically, athletes
have a higher HRV than do physically inactive individuals.
However, intensive training and overtraining can result in a
lower HRV [16]. The effects of yoga on HRV is often similar to that of physical activity [17].
A few studies have shown that acute effects of performing yoga postures increased HRV during the night
in healthy individuals [18,19]. Long-term effects from
5 weeks of yoga practice (90 minutes once a week) involve significantly increased RR intervals [20]. Taken together, findings from small-scale studies suggest a
greater parasympathetic control. Most of the existing research on the effects of yoga has used a mix of yoga postures and breathing exercises, but little is known about
the specific effects of different types of yoga postures. In
view of this, the present study set out to investigate the
long-term effects of specific yoga postures on BP and
HRV, focusing mainly on inversions (head below the
heart) and semi-inversions (with a deep breathing pattern). It was hypothesized that healthy individuals participating in an 8-week program of hatha yoga consisting
mainly of inversions and semi-inversions would show
decreased BP and increased HRV.
Methods
Participants and procedure
The study recruited participants from a medium-sized
organization within the engineering industry. Invitations to
take part in the study were sent through the personnel
manager to 794 employees and were targeted to either inactive women and men or women and men planning to
commence an active lifestyle. Thirty-two individuals
responded and 12 fulfilled the inclusion criteria. None of
the participants were taking any anti-hypertensive medicines, though medication for asthma, allergy and high
cholesterol was used by some participants.
Page 2 of 9
indigestion (reflux) and heartburn, which can affect the performance of inversions, as can recent operations during the
previous 6 months. Additionally, we excluded individuals
with musculoskeletal injuries in the back and/or neck, or
suffering from headaches in the morning or while coughing
or sneezing. Also, participants performing physical activities
more than twice a month and/or at medium or high intensity (out of breath and sweating, Borg >13) were excluded.
Twenty individuals were excluded due to age (5 were
too old), taking medication for high blood pressure (2),
recent surgery (1), current treatment for brain tumor
(1), infection (1), exercising regularly (5), poor possibilities to participate (3), performing mindfulness (1) and
ethical reasons (1).
In all 12 individuals took part in the study but 3 individuals had many artifacts on the Holter recording and
these were excluded from further HRV analysis.
Consequently, the analysis of blood pressure includes 12
individuals while the HRV data come from 9 individuals.
Assessments/outcome measures
Individual measurements were carried out at the workplace at baseline, before starting the yoga program, and
after 8 weeks of yoga exercise. The participants were
instructed not to eat, drink coffee or smoke 2–3 hours
before measurement.
Blood pressure (BP)
BP and heart rate were measured with an automatic
Omron mx3 oscillometric blood pressure monitoring
device. BP was measured while sitting up after at least
5 minutes of rest. To maximize relaxation, the arm used
for measuring BP was firmly supported by the other
arm. BP measurements were performed on both arms,
at the upper arm in the position of the heart. BP was
measured under the same conditions in all participants,
i.e. at the same time during the day, at the same sitting
position, no talking, and when the individual was
relaxed. Mean BP was computed based on readings
obtained from both arms. Machine error/accuracy of
Omron mx3 was ±3 mmHg (or 2%) of the reading and
for the pulse ±5.
Inclusion criteria
Age 25–60 years, having a good general health, having a
lightly elevated blood pressure (no higher than 145/95),
new to yoga, not exercising regularly or physically active
at medium to high intensity (Borg >13).
Exclusion criteria
Age > 60 years, diagnosed with high blood pressure and/or
taking blood pressure medication; suffering from or diagnosed with chronic diseases that could potentially impede
performing yoga such as eye diseases, depression, burnout,
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
HRV measurement is a very sensitive method of detecting changes, for example after an intervention [14]. In
healthy individuals, the parasympathetic pathway is active
during rest, which is reflected by an increased HRV, while
low HRV indicates poor health and a higher sympathetic
activity [14,15]. However, strong vagal reactivity (high
HRV) is associated with good health [14]. Typically, athletes
have a higher HRV than do physically inactive individuals.
However, intensive training and overtraining can result in a
lower HRV [16]. The effects of yoga on HRV is often similar to that of physical activity [17].
A few studies have shown that acute effects of performing yoga postures increased HRV during the night
in healthy individuals [18,19]. Long-term effects from
5 weeks of yoga practice (90 minutes once a week) involve significantly increased RR intervals [20]. Taken together, findings from small-scale studies suggest a
greater parasympathetic control. Most of the existing research on the effects of yoga has used a mix of yoga postures and breathing exercises, but little is known about
the specific effects of different types of yoga postures. In
view of this, the present study set out to investigate the
long-term effects of specific yoga postures on BP and
HRV, focusing mainly on inversions (head below the
heart) and semi-inversions (with a deep breathing pattern). It was hypothesized that healthy individuals participating in an 8-week program of hatha yoga consisting
mainly of inversions and semi-inversions would show
decreased BP and increased HRV.
Methods
Participants and procedure
The study recruited participants from a medium-sized
organization within the engineering industry. Invitations to
take part in the study were sent through the personnel
manager to 794 employees and were targeted to either inactive women and men or women and men planning to
commence an active lifestyle. Thirty-two individuals
responded and 12 fulfilled the inclusion criteria. None of
the participants were taking any anti-hypertensive medicines, though medication for asthma, allergy and high
cholesterol was used by some participants.
Page 2 of 9
indigestion (reflux) and heartburn, which can affect the performance of inversions, as can recent operations during the
previous 6 months. Additionally, we excluded individuals
with musculoskeletal injuries in the back and/or neck, or
suffering from headaches in the morning or while coughing
or sneezing. Also, participants performing physical activities
more than twice a month and/or at medium or high intensity (out of breath and sweating, Borg >13) were excluded.
Twenty individuals were excluded due to age (5 were
too old), taking medication for high blood pressure (2),
recent surgery (1), current treatment for brain tumor
(1), infection (1), exercising regularly (5), poor possibilities to participate (3), performing mindfulness (1) and
ethical reasons (1).
In all 12 individuals took part in the study but 3 individuals had many artifacts on the Holter recording and
these were excluded from further HRV analysis.
Consequently, the analysis of blood pressure includes 12
individuals while the HRV data come from 9 individuals.
Assessments/outcome measures
Individual measurements were carried out at the workplace at baseline, before starting the yoga program, and
after 8 weeks of yoga exercise. The participants were
instructed not to eat, drink coffee or smoke 2–3 hours
before measurement.
Blood pressure (BP)
BP and heart rate were measured with an automatic
Omron mx3 oscillometric blood pressure monitoring
device. BP was measured while sitting up after at least
5 minutes of rest. To maximize relaxation, the arm used
for measuring BP was firmly supported by the other
arm. BP measurements were performed on both arms,
at the upper arm in the position of the heart. BP was
measured under the same conditions in all participants,
i.e. at the same time during the day, at the same sitting
position, no talking, and when the individual was
relaxed. Mean BP was computed based on readings
obtained from both arms. Machine error/accuracy of
Omron mx3 was ±3 mmHg (or 2%) of the reading and
for the pulse ±5.
Inclusion criteria
ECG Holter Analyzer – heart rate variability (HRV)
An Aria-Delmar Holter Analyzer (Spacelabs Healthcare,
WA, USA and United Kingdom), was used to record
HRV under 24 hours. The sampling rate was 2048 Hz.
For all participants, HRV was measured during the
night, but for practical reasons the Holter analyzer was
activated during the day. Data were collected between
02.00 and 04.00 a.m. while participants were asleep to
minimize potential effects of confounding factors such
as alcohol, nicotine or caffeine.
Age 25–60 years, having a good general health, having a
lightly elevated blood pressure (no higher than 145/95),
new to yoga, not exercising regularly or physically active
at medium to high intensity (Borg >13).
Exclusion criteria
Age > 60 years, diagnosed with high blood pressure and/or
taking blood pressure medication; suffering from or diagnosed with chronic diseases that could potentially impede
performing yoga such as eye diseases, depression, burnout,
ECG Holter Analyzer – heart rate variability (HRV)
An Aria-Delmar Holter Analyzer (Spacelabs Healthcare,
WA, USA and United Kingdom), was used to record
HRV under 24 hours. The sampling rate was 2048 Hz.
For all participants, HRV was measured during the
night, but for practical reasons the Holter analyzer was
activated during the day. Data were collected between
02.00 and 04.00 a.m. while participants were asleep to
minimize potential effects of confounding factors such
as alcohol, nicotine or caffeine.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
The difference between each R wave in milliseconds
(RR intervals), were calculated. All intervals between adjacent QRS complexes in the Electrocardiogram (ECG)
resulting from sinus node depolarisations were defined
as NN-intervals [21]. NN50 count denotes the number
of pairs of successive NN intervals differing by more
than 50 ms in the entire recording/sampling. This is
highly correlated with frequency domain measures and
recognized to be strongly dependent on vagal tone. The
pNN50% is a time domain measure of heart rate variability defined as the number of all NN intervals in
which the change in consecutive normal sinus intervals
exceeds 50 milliseconds divided by the total number of
NN intervals measured (pNN50 = (NN50/n-1)*100%)
[21,22]. SDNN is defined as the standard deviation of all
NN intervals. RMSSD is defined as the square root of
the mean of the sum of the squares of the differences
between adjacent NN intervals.
The LF/HF ratio was calculated to assess the
sympatho-vagal balance. HF is the power in the high frequency range and reflects efferent vagal activity whereas
LF is the power in the low frequency range. LF is considered by some researchers to reflect both sympathetic
and parasympathetic modulation while others consider
it a measure of vagal withdrawal [21]. LF and HF were
expressed as measured in normalized units (n.u) which
represents the relative value of each power frequency
range component in relation to the total power minus
the VLF (very low frequency) component. LF and HF in
n.u. emphasize the controlled and balanced activity of
the two branches of the autonomic nervous system [21].
Obvious technical artifacts were deleted from the ECG
and only segments with normal sinus rhythm were
included in the analysis. A text file was constructed
using subsequent RR-intervals from Aria Holter and
imported to Kubios software (filter settings on medium).
Time and frequency domain analyses were calculated
using Kubios software. A time series was calculated from
the RR intervals using spline interpolation with an
interpolation rate of 4 Hz. The linear trend was deleted
and a Welch filter applied. The frequency analysis was
performed using FFT (Fast Fourier Transform).
Hand grip strength
Hand grip strength was measured using an electronic
hand dynamometer (Camry model EH101). The difference in diastolic BP before and after a 2-minute static
(1/3 of maximum hand grip) hand grip strength test was
computed. The hand grip measurement was performed
standing upright with the device in the dominant hand,
the arm held straight out in front of the chest. No other
muscles were engaged but the hands. The grip was statically held at a third of the person’s maximum strength. Since
no printout function was available, data were manually
Page 3 of 9
recorded by the investigator who looked at the monitor of
the device. The BP was measured with the device placed on
the non-dominant hand before and after the hand grip test
(2 minute intervals). A difference in the diastolic BP between the resting BP and the BP after the hand grip test of
at least 10 mm Hg indicated an increased reactivity and
function of the sympathetic nervous system [23]. This
method has been previously suggested to test the efficiency
of the cardiovascular system.
Borg scale (ratings of perceived exertion)
The Borg scale [24], with a range from 6–20, is often
used to measure physical exertion. A rating of ten indicates a heart rate of around 100 beats per minute (bpm).
The Borg scale was used to measure the intensity of the
yoga class to avoid too high exertion.
Waist-hip ratio
Waist-hip ratio (WHR) was used as a complementary
measure of body-mass index (BMI) to facilitate detection
of cardiovascular diseases among participants. WHR has
been used as a tool to measure the degree of obesity
[25]. Waist circumference was measured by placing the
measuring tape in a horizontal plane midway between
the lower rib margin and the hip bone. The hip measurement was taken at the widest point between the two
bony prominences at the front of the hips. The same
procedure was followed throughout the study.
Heart rate
Heart rate measurements were taken using an automatic
blood pressure monitoring device and by reading ECG
profiles.
Intervention
The yoga program was 60 minutes long and standardized
and was performed in the same manner every time. The
program included general poses, inversions and semiinversions. The order of the postures was the following:
cat/cow, shoulder rolls, upper body rotation in cat position,
bridge pose (also on one leg), cobra, wall dog variation, wall
dog moving down on the wall, down dog, half hand stand
towards the wall, chest opener – lying on a roll placed
under the rib cage, twisted side angle pose with the knee
on the floor, shoulder stand variation to the wall, universal
pose, waterfall pose and relaxing lying on the back
(for 5–8 minutes) (Additional file 1). As the intervention
proceeded, the time spent on inverted poses gradually
increased while the time spent on other poses decreased.
The total inversion time for each participant during the last
4 weeks of the intervention was around 15-20 minutes. All
participants were encouraged to practice at home between
classes. If participants had little time they were encouraged
to practise only the inverted poses. All classes were run by
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
The difference between each R wave in milliseconds
(RR intervals), were calculated. All intervals between adjacent QRS complexes in the Electrocardiogram (ECG)
resulting from sinus node depolarisations were defined
as NN-intervals [21]. NN50 count denotes the number
of pairs of successive NN intervals differing by more
than 50 ms in the entire recording/sampling. This is
highly correlated with frequency domain measures and
recognized to be strongly dependent on vagal tone. The
pNN50% is a time domain measure of heart rate variability defined as the number of all NN intervals in
which the change in consecutive normal sinus intervals
exceeds 50 milliseconds divided by the total number of
NN intervals measured (pNN50 = (NN50/n-1)*100%)
[21,22]. SDNN is defined as the standard deviation of all
NN intervals. RMSSD is defined as the square root of
the mean of the sum of the squares of the differences
between adjacent NN intervals.
The LF/HF ratio was calculated to assess the
sympatho-vagal balance. HF is the power in the high frequency range and reflects efferent vagal activity whereas
LF is the power in the low frequency range. LF is considered by some researchers to reflect both sympathetic
and parasympathetic modulation while others consider
it a measure of vagal withdrawal [21]. LF and HF were
expressed as measured in normalized units (n.u) which
represents the relative value of each power frequency
range component in relation to the total power minus
the VLF (very low frequency) component. LF and HF in
n.u. emphasize the controlled and balanced activity of
the two branches of the autonomic nervous system [21].
Obvious technical artifacts were deleted from the ECG
and only segments with normal sinus rhythm were
included in the analysis. A text file was constructed
using subsequent RR-intervals from Aria Holter and
imported to Kubios software (filter settings on medium).
Time and frequency domain analyses were calculated
using Kubios software. A time series was calculated from
the RR intervals using spline interpolation with an
interpolation rate of 4 Hz. The linear trend was deleted
and a Welch filter applied. The frequency analysis was
performed using FFT (Fast Fourier Transform).
Hand grip strength
Hand grip strength was measured using an electronic
hand dynamometer (Camry model EH101). The difference in diastolic BP before and after a 2-minute static
(1/3 of maximum hand grip) hand grip strength test was
computed. The hand grip measurement was performed
standing upright with the device in the dominant hand,
the arm held straight out in front of the chest. No other
muscles were engaged but the hands. The grip was statically held at a third of the person’s maximum strength. Since
no printout function was available, data were manually
Page 3 of 9
recorded by the investigator who looked at the monitor of
the device. The BP was measured with the device placed on
the non-dominant hand before and after the hand grip test
(2 minute intervals). A difference in the diastolic BP between the resting BP and the BP after the hand grip test of
at least 10 mm Hg indicated an increased reactivity and
function of the sympathetic nervous system [23]. This
method has been previously suggested to test the efficiency
of the cardiovascular system.
Borg scale (ratings of perceived exertion)
The Borg scale [24], with a range from 6–20, is often
used to measure physical exertion. A rating of ten indicates a heart rate of around 100 beats per minute (bpm).
The Borg scale was used to measure the intensity of the
yoga class to avoid too high exertion.
Waist-hip ratio
Waist-hip ratio (WHR) was used as a complementary
measure of body-mass index (BMI) to facilitate detection
of cardiovascular diseases among participants. WHR has
been used as a tool to measure the degree of obesity
[25]. Waist circumference was measured by placing the
measuring tape in a horizontal plane midway between
the lower rib margin and the hip bone. The hip measurement was taken at the widest point between the two
bony prominences at the front of the hips. The same
procedure was followed throughout the study.
Heart rate
Heart rate measurements were taken using an automatic
blood pressure monitoring device and by reading ECG
profiles.
Intervention
The yoga program was 60 minutes long and standardized
and was performed in the same manner every time. The
program included general poses, inversions and semiinversions. The order of the postures was the following:
cat/cow, shoulder rolls, upper body rotation in cat position,
bridge pose (also on one leg), cobra, wall dog variation, wall
dog moving down on the wall, down dog, half hand stand
towards the wall, chest opener – lying on a roll placed
under the rib cage, twisted side angle pose with the knee
on the floor, shoulder stand variation to the wall, universal
pose, waterfall pose and relaxing lying on the back
(for 5–8 minutes) (Additional file 1). As the intervention
proceeded, the time spent on inverted poses gradually
increased while the time spent on other poses decreased.
The total inversion time for each participant during the last
4 weeks of the intervention was around 15-20 minutes. All
participants were encouraged to practice at home between
classes. If participants had little time they were encouraged
to practise only the inverted poses. All classes were run by
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
Page 4 of 9
an experienced certified yoga instructor (U.H.) and all
classes took place at the same location, on the same day of
the week and at the same time in the afternoon.
A breathing frequency at a rate of 0.1 Hz (6 breaths/minute) was encouraged but many of the participants found it
hard to breathe at this speed. The majority were breathing
at a rate of 0.2 Hz (12 breaths per minute) though this was
not measured directly and is only a rough estimate. All participants had a 30-min assessment at their workplace before
and after the intervention. The Regional Ethical Review
Board in Stockholm (DNR: 2011/248-31/1) approved the
study and all participants signed informed consent forms.
Data extraction and statistical analysis
Statistical analysis
The Kubios HRV analysis program, Version 2.0 from
Department of Physics, University of Kuopio, Kuopio,
Finland, was used for the ECG analysis. The analysis was
carried out at the physiology laboratory at S:t Göran
hospital in Stockholm in cooperation with their doctors
and the chief executive of the laboratory (N.S). Data
from three individuals were excluded from the analysis
due to artefacts caused by faulty device operation (2)
and electric interference (1).
Wilcoxon’s paired signed-rank tests were used to compare data collected before and after the intervention. It
is a nonparametric statistical test applicable to repeated
measures on individuals belonging to a small sample.
Effect size (ES) (Cohen’s d) was used to measure
change, with an ES of 0.20 regarded as a small change,
an ES of 0.50 as a moderate change and an ES of 0.80 as
a large change [26].
All statistical analyses were performed using MATLAB.
Power analysis We performed both two-tailed and onetailed post-hoc test, the latter as our hypothesis was that
yoga postures could increase HRV. Post –hoc analyses used
the program: STATA/IC 11.2.
Post-hoc statistical power alpha = 0.05, N = 9 (two-tailed)
RR mean 0.07, RR triangular index (triang) 0.10,
SDNN 0.09, NN50 0.20, pNN50% 0.21, RMSSD 0.12
Post-hoc statistical power alpha = 0.05, N = 9 (one-tailed)
RR mean 0.12, RR triang 0.16, SDNN 0.16, NN50 0.32,
pNN50% 0.33, RMSSD 0.19
From Table 1: Post-hoc statistical power alpha = 0.05,
N = 9 (two-tailed)
LF 0.06, HF 0.11, LF/HF ratio 0.06, LF n.u 0.13, HF
n.u 0.13
Post-hoc statistical power alpha = 0.05, N = 9 (one-tailed)
LF 0.08, HF 0.18, LF/HF ratio 0.08, LF n.u 0.22, HF
n.u 0.22
Results
Table 2 shows sample characteristics.
Blood pressure
There was no significant difference in blood pressure between baseline and follow-up (Table 2). In addition,
there were no significant effects on pulse pressure and
mean arterial pressure after 8 weeks of yoga.
ECG Holter analysis – heart rate variability (HRV)
There was a medium (ES 0.45) but significant effect of
yoga on pNN50% (mean 12.7 ± 12.5 to 18.2 ± 13.3;
Table 3). NN50 also increased. The LF/HF ratio
showed a slight but not significant decrease (Table 1).
Additionally, analyses of LF and HF showed a trend
Table 1 Frequency domain power (ms2) – (FFT spectrum) ECG data and HRV (heart rate variability) in study
participants at night (02.00-04.00 am; n = 9)
LF [ms2]
2
HF [ms ]
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
Page 4 of 9
an experienced certified yoga instructor (U.H.) and all
classes took place at the same location, on the same day of
the week and at the same time in the afternoon.
A breathing frequency at a rate of 0.1 Hz (6 breaths/minute) was encouraged but many of the participants found it
hard to breathe at this speed. The majority were breathing
at a rate of 0.2 Hz (12 breaths per minute) though this was
not measured directly and is only a rough estimate. All participants had a 30-min assessment at their workplace before
and after the intervention. The Regional Ethical Review
Board in Stockholm (DNR: 2011/248-31/1) approved the
study and all participants signed informed consent forms.
Data extraction and statistical analysis
Statistical analysis
The Kubios HRV analysis program, Version 2.0 from
Department of Physics, University of Kuopio, Kuopio,
Finland, was used for the ECG analysis. The analysis was
carried out at the physiology laboratory at S:t Göran
hospital in Stockholm in cooperation with their doctors
and the chief executive of the laboratory (N.S). Data
from three individuals were excluded from the analysis
due to artefacts caused by faulty device operation (2)
and electric interference (1).
Wilcoxon’s paired signed-rank tests were used to compare data collected before and after the intervention. It
is a nonparametric statistical test applicable to repeated
measures on individuals belonging to a small sample.
Effect size (ES) (Cohen’s d) was used to measure
change, with an ES of 0.20 regarded as a small change,
an ES of 0.50 as a moderate change and an ES of 0.80 as
a large change [26].
All statistical analyses were performed using MATLAB.
Power analysis We performed both two-tailed and onetailed post-hoc test, the latter as our hypothesis was that
yoga postures could increase HRV. Post –hoc analyses used
the program: STATA/IC 11.2.
Post-hoc statistical power alpha = 0.05, N = 9 (two-tailed)
RR mean 0.07, RR triangular index (triang) 0.10,
SDNN 0.09, NN50 0.20, pNN50% 0.21, RMSSD 0.12
Post-hoc statistical power alpha = 0.05, N = 9 (one-tailed)
RR mean 0.12, RR triang 0.16, SDNN 0.16, NN50 0.32,
pNN50% 0.33, RMSSD 0.19
From Table 1: Post-hoc statistical power alpha = 0.05,
N = 9 (two-tailed)
LF 0.06, HF 0.11, LF/HF ratio 0.06, LF n.u 0.13, HF
n.u 0.13
Post-hoc statistical power alpha = 0.05, N = 9 (one-tailed)
LF 0.08, HF 0.18, LF/HF ratio 0.08, LF n.u 0.22, HF
n.u 0.22
Results
Table 2 shows sample characteristics.
Blood pressure
There was no significant difference in blood pressure between baseline and follow-up (Table 2). In addition,
there were no significant effects on pulse pressure and
mean arterial pressure after 8 weeks of yoga.
ECG Holter analysis – heart rate variability (HRV)
There was a medium (ES 0.45) but significant effect of
yoga on pNN50% (mean 12.7 ± 12.5 to 18.2 ± 13.3;
Table 3). NN50 also increased. The LF/HF ratio
showed a slight but not significant decrease (Table 1).
Additionally, analyses of LF and HF showed a trend
Table 1 Frequency domain power (ms2) – (FFT spectrum) ECG data and HRV (heart rate variability) in study
participants at night (02.00-04.00 am; n = 9)
Before/Baseline
After 8 weeks’ yoga
P-value
Effect Confidence
size
interval
before
Confidence
interval after
8 weeks
Before/Baseline
After 8 weeks’ yoga
P-value
Effect Confidence
size
interval
before
Confidence
interval after
8 weeks
1237.9 ± 1072.6 Md 852
1335.2 ± 989.1 Md 1346
0.82
0.10
412-2064
574-2097
LF [ms2]
1237.9 ± 1072.6 Md 852
1335.2 ± 989.1 Md 1346
0.82
0.10
412-2064
574-2097
560.7 ± 509.0 Md 454
689.2 ± 505.2 Md 666
0.50
0.27
169-953
300-1078
HF [ms2]
560.7 ± 509.0 Md 454
689.2 ± 505.2 Md 666
0.50
0.27
169-953
300-1078
LF/HF ratio 2.5 ± 1.0 Md 2.2
2.4 ± 1.2 Md 2.3
0.36
0.10
1.7-3.3
1.5-3.3
LF/HF ratio 2.5 ± 1.0 Md 2.2
2.4 ± 1.2 Md 2.3
0.36
0.10
1.7-3.3
1.5-3.3
LF n.u.
69.8 ± 7.9 Md 68.5
66.5 ± 13.1 Md 69.5
0.29
0.32
63.7-75.9
56.4-76.6
LF n.u.
69.8 ± 7.9 Md 68.5
66.5 ± 13.1 Md 69.5
0.29
0.32
63.7-75.9
56.4-76.6
HF n.u.
30.2 ± 7.9 Md 31.5
33.5 ± 13.1 Md 30.5
0.29
0.32
24.1-36.3
23.4-43.6
HF n.u.
30.2 ± 7.9 Md 31.5
33.5 ± 13.1 Md 30.5
0.29
0.32
24.1-36.3
23.4-43.6
Data are expressed as means ± SD and, when stated, median.
LF = Power in low frequency range (0.04-0.15 Hz). Some researchers believe this involves both sympathetic and parasympathetic modulation (sympathetic involves
the blood vessels whereas parasympathetic involves the heart). LF measures withdrawal of vagal tone (Goldstein).
HF = Power in high frequency range (0.15-0.4 Hz), indicates efferent vagal activity.
LF/HF ratio = Ratio is correlated with sympatho-vagal balance.
LF n.u = Represents the relative value of LF power component in proportion to the total power minus the VLF (very low frequency) component in normalized
units (n.u).
HF n.u. = Represents the relative value of HF power component in proportion to the total power minus the VLF (very low frequency) component.
n.u. = normalized units.
Confidence interval = 95%.
Md = Median.
Data are expressed as means ± SD and, when stated, median.
LF = Power in low frequency range (0.04-0.15 Hz). Some researchers believe this involves both sympathetic and parasympathetic modulation (sympathetic involves
the blood vessels whereas parasympathetic involves the heart). LF measures withdrawal of vagal tone (Goldstein).
HF = Power in high frequency range (0.15-0.4 Hz), indicates efferent vagal activity.
LF/HF ratio = Ratio is correlated with sympatho-vagal balance.
LF n.u = Represents the relative value of LF power component in proportion to the total power minus the VLF (very low frequency) component in normalized
units (n.u).
HF n.u. = Represents the relative value of HF power component in proportion to the total power minus the VLF (very low frequency) component.
n.u. = normalized units.
Confidence interval = 95%.
Md = Median.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
Page 5 of 9
Table 2 Parameters in whole group (n = 12) and those with ECG measurements (n = 9)
Parameters
P-value (ES)
Age (y)
49.6 ± 6.2
-
Height (m)
1.76 ± 0.08
1.77 ± 0.09
Male
8
Women
4
Weight (kg)
80.0 ± 11.9
80.6 ± 12.0
0.22
84.9 ± 11.9
85.4 ± 12.1
Maximal Handgrip/kg
36.6 ± 8.6
39.0 ± 10.0
0.12 (ES: 0.28)
38.1 ± 9.4
Waist : hip ratio
0.87 ± 0.08
0.87 ± 0.08
1.0
BMI (kg/m2)
26.0 ± 3.7
26.2 ± 3.8
0.23
BP mean from left and right
123.3 ± 12.4
arm Systolic/Diastolic (mm Hg) 79.8 ± 6.3
Md 119.3 80.8
124.1 ± 11.7
82.2 ± 7.6
Md 120.0 83.0
Heart rate from Blood Pressure 66.5 ± 8.4
cuff (bpm)
Md 66.0
67.4 ± 11.0
Md 64.3
Heart rate (from ECG) (n = 10)
(bpm)
61.0 ± 6.2 (n = 10) 62.0 ± 10.0(n = 10)
Md (n = 10) 60.5 Md (n = 10) 62.3
Before/Baseline
(n = 9)
After 8 weeks’
yoga (n = 9)
50.1 ± 4.8
-
P-value (ES)
Parameters
Before/Baseline After 8 weeks’
(n = 12)
yoga (n =12)
P-value (ES)
-
Age (y)
49.6 ± 6.2
-
Height (m)
1.76 ± 0.08
1.77 ± 0.09
6
Male
8
6
3
Women
4
0.39
Weight (kg)
80.0 ± 11.9
80.6 ± 12.0
0.22
84.9 ± 11.9
85.4 ± 12.1
0.39
42.5 ± 10.8
0.02* (ES: 0.46)
Maximal Handgrip/kg
36.6 ± 8.6
39.0 ± 10.0
0.12 (ES: 0.28)
38.1 ± 9.4
42.5 ± 10.8
0.02* (ES: 0.46)
0.88 ± 0.08
0.88 ± 0.08
0.67
Waist : hip ratio
0.87 ± 0.08
0.87 ± 0.08
1.0
0.88 ± 0.08
0.88 ± 0.08
0.67
27.1 ± 3.6
27.3 ± 3.9
0.38
BMI (kg/m2)
26.0 ± 3.7
26.2 ± 3.8
0.23
27.1 ± 3.6
27.3 ± 3.9
0.38
0.62 0.18
123.3 ± 13.2
79 ± 7.4
Md 118.5 75.0
125.8 ± 13.3
83.9 ± 10.7
Md 120.5 83.0
0.89 0.21
BP mean from left and right
123.3 ± 12.4
arm Systolic/Diastolic (mm Hg) 79.8 ± 6.3
Md 119.3 80.8
124.1 ± 11.7
82.2 ± 7.6
Md 120.0 83.0
0.62 0.18
123.3 ± 13.2
79 ± 7.4
Md 118.5 75.0
125.8 ± 13.3
83.9 ± 10.7
Md 120.5 83.0
0.89 0.21
0.83
63.1 ± 4.9
Md 62.0
68.4 ± 12.1
Md 62.0
0.20
Heart rate from Blood Pressure 66.5 ± 8.4
cuff (bpm)
Md 66.0
67.4 ± 11.0
Md 64.3
0.83
63.1 ± 4.9
Md 62.0
68.4 ± 12.1
Md 62.0
0.20
0.77
61.4 ± 6.4
Md 61.0
61.0 ± 10.0
Md 57.3
0.91
Heart rate (from ECG) (n = 10)
(bpm)
0.77
61.4 ± 6.4
Md 61.0
61.0 ± 10.0
Md 57.3
0.91
Data are expressed as means ± SD and, when stated, median.
Y = years, m = meters, bpm = beats per minute, ES = effect size (change/sd).
* = p < 0.05 significant.
Effect size noted when of interest.
Md = Median.
towards a higher HF indicating an increased vagal
tone. No statistically significant differences were found
for SDNN, LF n.u. (normalized units) or HF n.u.
RMSSD (an estimate of short-term components of
HRV data).
After 8 weeks’ yoga
-
Before/Baseline
(n = 9)
After 8 weeks’
yoga (n = 9)
50.1 ± 4.8
-
P-value (ES)
-
3
61.0 ± 6.2 (n = 10) 62.0 ± 10.0(n = 10)
Md (n = 10) 60.5 Md (n = 10) 62.3
Data are expressed as means ± SD and, when stated, median.
Y = years, m = meters, bpm = beats per minute, ES = effect size (change/sd).
* = p < 0.05 significant.
Effect size noted when of interest.
Md = Median.
Hand grip strength
No significant effects of yoga on hand grip strength were
found after analysing the differences in diastolic pressure
before and after the hand grip test. However, and as presented in Table 2, analysis of ECG data that were
Table 3 Time Domain Units – ECG data and HRV (heart rate variability) in study participants at night (02.00-04.00 am)
(n = 9)
Before/Baseline
Page 5 of 9
Table 2 Parameters in whole group (n = 12) and those with ECG measurements (n = 9)
Before/Baseline After 8 weeks’
(n = 12)
yoga (n =12)
-
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
P-value
Effect size
Confidence
interval
before
towards a higher HF indicating an increased vagal
tone. No statistically significant differences were found
for SDNN, LF n.u. (normalized units) or HF n.u.
RMSSD (an estimate of short-term components of
HRV data).
Hand grip strength
No significant effects of yoga on hand grip strength were
found after analysing the differences in diastolic pressure
before and after the hand grip test. However, and as presented in Table 2, analysis of ECG data that were
Table 3 Time Domain Units – ECG data and HRV (heart rate variability) in study participants at night (02.00-04.00 am)
(n = 9)
Confidence
interval after
8 weeks
Before/Baseline
After 8 weeks’ yoga
P-value
Effect size
Confidence
interval
before
Confidence
interval after
8 weeks
RR mean [ms]
996.2 ± 105.4 Md 992.3
1019.8 ± 172.8 Md 1057.1
0.82
0.17
915-1077
887-1153
RR mean [ms]
996.2 ± 105.4 Md 992.3
1019.8 ± 172.8 Md 1057.1
0.82
0.17
915-1077
887-1153
RR triangular index
16.3 ± 4.5 Md18.0
17.5 ± 5.8 Md 17.9
0.50
0.25
12.8-19.7
13.0-22.0
RR triangular index
16.3 ± 4.5 Md18.0
17.5 ± 5.8 Md 17.9
0.50
0.25
12.8-19.7
13.0-22.0
SDNN (stdRR) [ms]
85.6 ± 21.9 Md 83.4
92.7 ± 39.6 Md 95.6
0.57
0.24
68.7-102.5
62.2-123.2
SDNN (stdRR) [ms]
85.6 ± 21.9 Md 83.4
92.7 ± 39.6 Md 95.6
0.57
0.24
68.7-102.5
62.2-123.2
NN50 count
868.4 ± 823.8 Md 731
1208.7 ± 810.0 Md 1497
0.13
0.44
234-1503
585-1832
NN50 count
868.4 ± 823.8 Md 731
1208.7 ± 810.0 Md 1497
0.13
0.44
234-1503
585-1832
pNN50 [%]
12.7 ± 12.5 Md 10.6
18.2 ± 13.3 Md 17.1
*0.035
0.45
3.1-22.3
8.0-28.4
pNN50 [%]
12.7 ± 12.5 Md 10.6
18.2 ± 13.3 Md 17.1
*0.035
0.45
3.1-22.3
8.0-28.4
RMSSD [ms]
42.1 ± 19.4 Md 41.0
47.6 ± 21.2 Md 50.2
0.30
0.29
27.2-57.0
31.3-63.9
RMSSD [ms]
42.1 ± 19.4 Md 41.0
47.6 ± 21.2 Md 50.2
0.30
0.29
27.2-57.0
31.3-63.9
Data are expressed as means ± SD and, when stated, median. ms = milli seconds.
* = P < 0.05 significant.
NN = RR.
RR triangular index = Total number of all NN intervals divided by the height of the histogram of all NN intervals measured on a discrete scale with bins of
7.8125 ms (1/128 s) [21].
SDNN = the standard deviation of all NN intervals.
NN50 count = Number of pairs of adjacent NN intervals differing by more than 50 ms in the entire recording. This is highly correlated with frequency domain
measures and recognized to be strongly dependent on vagal tone.
pNN50% = NN50 count divided by the total number of all NN intervals.
RMSSD = the square root of the mean of the sum of the squares of differences between adjacent NN intervals.
Confidence interval = 95%.
Md = Median.
Data are expressed as means ± SD and, when stated, median. ms = milli seconds.
* = P < 0.05 significant.
NN = RR.
RR triangular index = Total number of all NN intervals divided by the height of the histogram of all NN intervals measured on a discrete scale with bins of
7.8125 ms (1/128 s) [21].
SDNN = the standard deviation of all NN intervals.
NN50 count = Number of pairs of adjacent NN intervals differing by more than 50 ms in the entire recording. This is highly correlated with frequency domain
measures and recognized to be strongly dependent on vagal tone.
pNN50% = NN50 count divided by the total number of all NN intervals.
RMSSD = the square root of the mean of the sum of the squares of differences between adjacent NN intervals.
Confidence interval = 95%.
Md = Median.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
available for nine participants showed a significant increase in maximal hand grip strength (p < 0.02) (Table 2)
with an ES of 0.46.
Borg scale (perceived exertion)
The perceived exertion during yoga class was 12.9 on
the Borg scale for the whole group and 12.8 for the ECG
group. The intensity was at a comfortable level (<13) for
all participants, and many of them reported lower levels
of exertion towards the end of the study
Anthropometric measures
Waist-hip ratio
No significant effect of yoga was found on waist-hip ratio
(WHR), weight or body mass index.
Heart rate
There were no significant changes in heart rate after
8 weeks of yoga (Table 2).
Attendance rate (of a total of 8 sessions) and home practice
The attendance rate during the whole intervention was
5.5 times (69%) for the whole group. and 6.0 times (75%)
for the ECG group. The total number of home practice
sessions was 5.2 during 8 weeks for the whole group and
4.2 for the ECG group.
Discussion
This study of an 8-week hatha yoga program showed no
significant effect on BP but showed a significant medium
effect (ES 0.45) of yoga on HRV, with a significant increase
in pNN50% (12.7 ± 12.5 to 18.2 ± 13.3). In addition, other
measures improved i.e. the NN50, and the HF power component increased, and the LF/HF ratio decreased, but failed
to reach statistical significance.
Few other studies have looked into the effects of yoga
postures (including many inversions) on HRV in healthy
individuals. Specifically, previous findings show that
acute effects include increased HRV at night after having
practiced yoga [18,19]. Long-term effects include
significantly increased RR intervals [20]. Findings from
previous small-scale studies have suggested that yoga
postures and yogic breathing exercises significantly increase cardiac vagal modulation which, in turn, suggests
a greater parasympathetic control.
Despite previous studies showing significant effects on
BP after 3-8 weeks of yoga in hypertensive individuals [6,8],
no such effects were observed in the current study. This
was probably due to participants in the current study being
normotensive, i.e. their blood pressure was low or normal
already at baseline. Consequently, large changes in blood
pressure were not to be expected. Nevertheless, the current
findings are in line with previous research showing that
15 minutes of yoga postures had no effect on blood
Page 6 of 9
pressure but instead had a significant effect on HRV, on
SDNN (square root of variance) [27]. As regards SDNN
comparisons with previous research, the recordings must
be of the same duration. In the current study, the SDNN
recordings were 2 hours long whereas the recordings in an
earlier study were 15 minutes long which means that data
from the two studies are incomparable [21].
HRV is a very sensitive measure and the current study
showed significant effects of yoga on pNN50% at night.
High HRV indicates greater parasympathetic control
[28] and the physiological adaptations to yoga exercises
were similar to those of conventional exercise [13,17].
This was the rationale behind the exclusion of individuals who exercised regularly from the current study.
Since this study focuses on long- term effects of yoga on
HRV after yoga performance, HRV data both during
sleep and yoga practice are not presented. Also, all
participants did not have the Holter monitor on while
practicing yoga. It is well known that exercise and
stretching decreases HRV [29] which means that the
measurement of HRV during physical activity would give
no valuable information of about long term effects of
yoga on HRV.
The current study findings showing a significant effect
of yoga on HRV (pNN50) at night are consistent with
those of previous research [18]. However, the proportions differ, which may result from our recordings being
scheduled during the deepest sleep and during one
period (02.00–04.00 a.m.), but also from the fact that our
total recording time was 1 hour longer than that of Patra
[18]. However, differences in initial pNN50 values are
also due to the characteristics of the participants of the
current study with the present study including a group
of middle-aged healthy participants. The normal number
of intervals with a difference of more than 50 ms is approximately 200 intervals per/hour during the day and
around 400 intervals per hour at night [14,22]. In this
study, an overall increase in pNN50% was detected at
night by the end of the intervention. Other studies have
had shorter HRV recording times than the 2-hour
recording time in the current study. However, as there
were not enough Holter devices for all participants to
use during the exactly the same time period, the recording times may have differed slightly. Consequently, HRV
data cannot be compared during the whole 24-hour
period. However, we are not aware of any yoga intervention studies or other interventions presenting full
24-hour HRV data. Here, data collected from HRV
recordings during night-time when participants were
asleep and wearing the Holter device and thus in a comparable condition, were included in the analysis.
Physical activity have been found important for achieving a high HRV [30]. This was the rationale for choosing
to include only inactive individuals who had not
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
available for nine participants showed a significant increase in maximal hand grip strength (p < 0.02) (Table 2)
with an ES of 0.46.
Borg scale (perceived exertion)
The perceived exertion during yoga class was 12.9 on
the Borg scale for the whole group and 12.8 for the ECG
group. The intensity was at a comfortable level (<13) for
all participants, and many of them reported lower levels
of exertion towards the end of the study
Anthropometric measures
Waist-hip ratio
No significant effect of yoga was found on waist-hip ratio
(WHR), weight or body mass index.
Heart rate
There were no significant changes in heart rate after
8 weeks of yoga (Table 2).
Attendance rate (of a total of 8 sessions) and home practice
The attendance rate during the whole intervention was
5.5 times (69%) for the whole group. and 6.0 times (75%)
for the ECG group. The total number of home practice
sessions was 5.2 during 8 weeks for the whole group and
4.2 for the ECG group.
Discussion
This study of an 8-week hatha yoga program showed no
significant effect on BP but showed a significant medium
effect (ES 0.45) of yoga on HRV, with a significant increase
in pNN50% (12.7 ± 12.5 to 18.2 ± 13.3). In addition, other
measures improved i.e. the NN50, and the HF power component increased, and the LF/HF ratio decreased, but failed
to reach statistical significance.
Few other studies have looked into the effects of yoga
postures (including many inversions) on HRV in healthy
individuals. Specifically, previous findings show that
acute effects include increased HRV at night after having
practiced yoga [18,19]. Long-term effects include
significantly increased RR intervals [20]. Findings from
previous small-scale studies have suggested that yoga
postures and yogic breathing exercises significantly increase cardiac vagal modulation which, in turn, suggests
a greater parasympathetic control.
Despite previous studies showing significant effects on
BP after 3-8 weeks of yoga in hypertensive individuals [6,8],
no such effects were observed in the current study. This
was probably due to participants in the current study being
normotensive, i.e. their blood pressure was low or normal
already at baseline. Consequently, large changes in blood
pressure were not to be expected. Nevertheless, the current
findings are in line with previous research showing that
15 minutes of yoga postures had no effect on blood
Page 6 of 9
pressure but instead had a significant effect on HRV, on
SDNN (square root of variance) [27]. As regards SDNN
comparisons with previous research, the recordings must
be of the same duration. In the current study, the SDNN
recordings were 2 hours long whereas the recordings in an
earlier study were 15 minutes long which means that data
from the two studies are incomparable [21].
HRV is a very sensitive measure and the current study
showed significant effects of yoga on pNN50% at night.
High HRV indicates greater parasympathetic control
[28] and the physiological adaptations to yoga exercises
were similar to those of conventional exercise [13,17].
This was the rationale behind the exclusion of individuals who exercised regularly from the current study.
Since this study focuses on long- term effects of yoga on
HRV after yoga performance, HRV data both during
sleep and yoga practice are not presented. Also, all
participants did not have the Holter monitor on while
practicing yoga. It is well known that exercise and
stretching decreases HRV [29] which means that the
measurement of HRV during physical activity would give
no valuable information of about long term effects of
yoga on HRV.
The current study findings showing a significant effect
of yoga on HRV (pNN50) at night are consistent with
those of previous research [18]. However, the proportions differ, which may result from our recordings being
scheduled during the deepest sleep and during one
period (02.00–04.00 a.m.), but also from the fact that our
total recording time was 1 hour longer than that of Patra
[18]. However, differences in initial pNN50 values are
also due to the characteristics of the participants of the
current study with the present study including a group
of middle-aged healthy participants. The normal number
of intervals with a difference of more than 50 ms is approximately 200 intervals per/hour during the day and
around 400 intervals per hour at night [14,22]. In this
study, an overall increase in pNN50% was detected at
night by the end of the intervention. Other studies have
had shorter HRV recording times than the 2-hour
recording time in the current study. However, as there
were not enough Holter devices for all participants to
use during the exactly the same time period, the recording times may have differed slightly. Consequently, HRV
data cannot be compared during the whole 24-hour
period. However, we are not aware of any yoga intervention studies or other interventions presenting full
24-hour HRV data. Here, data collected from HRV
recordings during night-time when participants were
asleep and wearing the Holter device and thus in a comparable condition, were included in the analysis.
Physical activity have been found important for achieving a high HRV [30]. This was the rationale for choosing
to include only inactive individuals who had not
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
practised yoga before in our study. The program studied
here was different from cyclic meditation (which
involves no inversions and is performed with the eyes
closed) used in an earlier study [18]. Yet, this study [18]
is one of the few HRV studies showing findings that are
comparable to the present results.
Another study [31] showed increased pNN50% during
rest in athletes (body builders) who performed 15 minutes of daily stretching for 28 days. However, the
pNN50% values were calculated using a heart rate monitor which is not as reliable a device as is the Holter analysis, since the heart monitor often fails to record all
true beats from the sinus node. Measures taken after
stretching typically show a rapid increase in parasympathetic activity and a lower heart rate, and many yogic
postures include a stretching component [29]. This may
be one explanation for feelings of relaxation and
increased parasympathetic activity after yoga exercises.
Thus, yoga may enhance the plasticity of the autonomic
nervous system and improve the ability to recover after
stress [18,31]. Some studies have shown that yoga lowered the resting heart rate [32], indicating a vagal dominance [18,31]. However, no such effect on heart rate
was found in the current study.
Other studies have found a decreased LF/HF ratio
(low frequency/high frequency) after yoga, indicating a
switch towards vagal dominance. In the present study,
the LF/HF ratio decreased but this change was not significant [11,12,18] (Table 1). An increased LF/HF ratio is
often seen in older age [30] but has also been related to
depression and stress [33].
The present findings show an increased LF power,
which measures the parasympathetic withdrawal, but
also an increased HF power indicating a higher vagal
tone. However, none of these changes were statistically
significant. LF and HF were also analysed in normalized
units (n.u.) but no significant effects emerged. These
findings were consistent with those of earlier studies
showing an LF n.u. decrease and an HF n.u. increase following a yoga intervention [18].
RMSSD is an estimate of short-term components of
HRV data and was found to increase but not
significantly. This trend suggests an increased HRV after
the 8-week yoga intervention but the non-significant
effect may have been due to the small sample size.
Supine and inverted body postures stimulate the
baroreceptor reflex (from altered negative pressure in
the upper body) and may create a parasympathetic
(vagal) activity [8,34–36] while upright postures inhibit
it [34]. The baroreceptor reflex which regulates heart
rate is closely linked to the parasympathetic nervous
system [14,37].
The increased HRV after stretching may be related to
the release of vasodilative agents (EDRF = Endothelium-
Page 7 of 9
derived relaxing factor) which reduces muscle tone, but
could also result from a general systemic psychicphysical relaxation [31].
Some findings suggest that atrial arrhythmia can be
restored after an inversion program [38] and a 40-minute
program (with 10-minute intervals of posture change that
alternatively stimulate the vagal and the sinus nerve) can be
as effective as medication in 50% of patients with atrial
arrhythmia. This study used inversions in the intervention
program. Other researchers report that the upside down
position can treat paroxysmal supraventricular tachycardia
[35,36,39] when no other methods, such as medication and
manual stimulation of the vagus nerve, work. Tai reported
a case study where a woman with arrhythmia was able to
restore a normal sinus rhythm with a 20-second hand stand
when none of the conventional methods worked. According to the researchers the mechanism may involve vagal
stimulation due to increased carotid sinus pressure that
may possibly restore the baroreceptor reflex function
[2,35,36,39,40].
Patients with essential hypertension seem to be able to
restore the baroreflex mechanism with lowering of the
blood pressure (29 units systolic and 17 units diastolic)
after 3 weeks of yoga postures (also inversions) [8]. The
inversions may reactivate the malfunctioning baroreflex
mechanism by alternating the pressure on the baroreceptors. The baroreflex arc does not function properly in
hypertensive, ageing, stressed, inactive and depressed
individuals [8,14,33,41,42].
Breathing frequency affects HRV, and respiratory sinus
arrhythmia (RSA) has its maximal amplitude with a frequency of 6 breaths per minute; baroreflex sensitivity is also
enhanced with this breathing frequency [4]. There is an
increased RSA in supine posture [14] and perhaps even
more so in an inverted posture [2,14] which might have
created a slower breathing frequency among the participants in our study who performed many inversions.
In this study, breathing frequency was not measured
but deep breathing was encouraged, and this may have
lowered the breathing frequency. There are studies
showing a slower breathing frequency and resting heart
rate after a yoga intervention [32]. Hyperventilation is
common in hypertension, and inhibition of the baroreflex may be a possible mechanism while breathing fast
[43] elevates blood pressure.
Limitations
In this study, the main limitation is the small sample size
with a low power. This was due to difficulties in recruiting study participants who were physically inactive. The
workplace had a high percentage of physically active
employees and consequently the main problem was to
find sedentary individuals. This too was the main reason
for not having enough participants that could fit into the
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
practised yoga before in our study. The program studied
here was different from cyclic meditation (which
involves no inversions and is performed with the eyes
closed) used in an earlier study [18]. Yet, this study [18]
is one of the few HRV studies showing findings that are
comparable to the present results.
Another study [31] showed increased pNN50% during
rest in athletes (body builders) who performed 15 minutes of daily stretching for 28 days. However, the
pNN50% values were calculated using a heart rate monitor which is not as reliable a device as is the Holter analysis, since the heart monitor often fails to record all
true beats from the sinus node. Measures taken after
stretching typically show a rapid increase in parasympathetic activity and a lower heart rate, and many yogic
postures include a stretching component [29]. This may
be one explanation for feelings of relaxation and
increased parasympathetic activity after yoga exercises.
Thus, yoga may enhance the plasticity of the autonomic
nervous system and improve the ability to recover after
stress [18,31]. Some studies have shown that yoga lowered the resting heart rate [32], indicating a vagal dominance [18,31]. However, no such effect on heart rate
was found in the current study.
Other studies have found a decreased LF/HF ratio
(low frequency/high frequency) after yoga, indicating a
switch towards vagal dominance. In the present study,
the LF/HF ratio decreased but this change was not significant [11,12,18] (Table 1). An increased LF/HF ratio is
often seen in older age [30] but has also been related to
depression and stress [33].
The present findings show an increased LF power,
which measures the parasympathetic withdrawal, but
also an increased HF power indicating a higher vagal
tone. However, none of these changes were statistically
significant. LF and HF were also analysed in normalized
units (n.u.) but no significant effects emerged. These
findings were consistent with those of earlier studies
showing an LF n.u. decrease and an HF n.u. increase following a yoga intervention [18].
RMSSD is an estimate of short-term components of
HRV data and was found to increase but not
significantly. This trend suggests an increased HRV after
the 8-week yoga intervention but the non-significant
effect may have been due to the small sample size.
Supine and inverted body postures stimulate the
baroreceptor reflex (from altered negative pressure in
the upper body) and may create a parasympathetic
(vagal) activity [8,34–36] while upright postures inhibit
it [34]. The baroreceptor reflex which regulates heart
rate is closely linked to the parasympathetic nervous
system [14,37].
The increased HRV after stretching may be related to
the release of vasodilative agents (EDRF = Endothelium-
Page 7 of 9
derived relaxing factor) which reduces muscle tone, but
could also result from a general systemic psychicphysical relaxation [31].
Some findings suggest that atrial arrhythmia can be
restored after an inversion program [38] and a 40-minute
program (with 10-minute intervals of posture change that
alternatively stimulate the vagal and the sinus nerve) can be
as effective as medication in 50% of patients with atrial
arrhythmia. This study used inversions in the intervention
program. Other researchers report that the upside down
position can treat paroxysmal supraventricular tachycardia
[35,36,39] when no other methods, such as medication and
manual stimulation of the vagus nerve, work. Tai reported
a case study where a woman with arrhythmia was able to
restore a normal sinus rhythm with a 20-second hand stand
when none of the conventional methods worked. According to the researchers the mechanism may involve vagal
stimulation due to increased carotid sinus pressure that
may possibly restore the baroreceptor reflex function
[2,35,36,39,40].
Patients with essential hypertension seem to be able to
restore the baroreflex mechanism with lowering of the
blood pressure (29 units systolic and 17 units diastolic)
after 3 weeks of yoga postures (also inversions) [8]. The
inversions may reactivate the malfunctioning baroreflex
mechanism by alternating the pressure on the baroreceptors. The baroreflex arc does not function properly in
hypertensive, ageing, stressed, inactive and depressed
individuals [8,14,33,41,42].
Breathing frequency affects HRV, and respiratory sinus
arrhythmia (RSA) has its maximal amplitude with a frequency of 6 breaths per minute; baroreflex sensitivity is also
enhanced with this breathing frequency [4]. There is an
increased RSA in supine posture [14] and perhaps even
more so in an inverted posture [2,14] which might have
created a slower breathing frequency among the participants in our study who performed many inversions.
In this study, breathing frequency was not measured
but deep breathing was encouraged, and this may have
lowered the breathing frequency. There are studies
showing a slower breathing frequency and resting heart
rate after a yoga intervention [32]. Hyperventilation is
common in hypertension, and inhibition of the baroreflex may be a possible mechanism while breathing fast
[43] elevates blood pressure.
Limitations
In this study, the main limitation is the small sample size
with a low power. This was due to difficulties in recruiting study participants who were physically inactive. The
workplace had a high percentage of physically active
employees and consequently the main problem was to
find sedentary individuals. This too was the main reason
for not having enough participants that could fit into the
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
inclusion criteria and to perform, as initially planned, a
randomized controlled trial. Even though the findings
showed significant differences between baseline and
follow-up, this may have been due to the study being
conducted in the spring when the weather allows for
more outdoor activities and a more active lifestyle. Also
the interaction with the instructor may have created a
therapeutic benefit. However, in line with the initial
hypothesis, some of the HRV measures increased. With
pNN50% being a very sensitive measure, it was not
surprising that the increase in pNN50% was statistically
significant whereas changes in other HRV measures
were not. Some participants were excluded due to the
low ECG recording quality. Breathing frequency is an
important factor for detecting vagal tone, but this was
not measured as participants were instructed to only
take deep breaths.
Conclusions
This small-scale longitudinal pilot study in naive hatha
yoga participants, where time spent on inversions
increased from 7 minutes to 20 minutes over the eight
week period, showed that yoga increased HRV. This suggests that yoga exercises can have a restorative effect on
the autonomic nervous system. Some HRV measures,
including HF and LF/HF ratio also improved but not significantly. However, larger, randomized controlled studies are needed to confirm the effects of yoga on the
sympathetic and parasympathetic nervous system. Future studies should measure breathing frequency,
baroreceptor sensitivity and heart rate recovery before,
during and immediately after performing different yoga
exercises, perhaps focusing solely on inversions or sun
salutations to detect associated changes in the autonomic nervous system.
Additional file
Additional file 1: Availability of supporting data. See appendix A
(link) for pictures of the yoga program. The data are stored at CeFAM.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
MP, PL and PW designed the study, MP performed the study. MP and NS
carried out ECG analyses. MP and PW analyzed the results. MP wrote the
manuscript assisted by PW and PL, NS was involved in designing the
methods and interpreting the results of the ECG analyses. All authors read
and approved of the final manuscript.
Acknowledgements
We would like to thank Birger Andrén for help with the statistics and data
analysis and Martin Ugander for inspiration to conduct this study.
Author details
1
Centre for Family Medicine, Karolinska Institutet, Alfred Nobels allé 12,
SE-14183, Huddinge, Sweden. 2Department of Psychology, Stockholm
Page 8 of 9
University, Frescati hagväg 14, SE-106 91, Stockholm, Sweden. 3Department
of Clinical Physiology, S:t Göran Hospital, SE-112 19, Stockholm, Sweden.
Received: 1 October 2012 Accepted: 21 December 2012
Published: 11 February 2013
References
1. Raub JA: Psychophysiologic effects of Hatha Yoga on musculoskeletal
and cardiopulmonary function: a literature review. J Altern Complement
Med 2002, 8(6):797–812.
2. Cole RJ: Nonpharmacologic techniques for promoting sleep. Clin Sports
Med 2005, 24(2):343–353. xi.
3. Bernardi L, Gabutti A, Porta C, Spicuzza L: Slow breathing reduces
chemoreflex response to hypoxia and hypercapnia, and increases
baroreflex sensitivity. J Hypertens 2001, 19(12):2221–2229.
4. Bernardi L, Sleight P, Bandinelli G, Cencetti S, Fattorini L, Wdowczyc-Szulc J,
Lagi A: Effect of rosary prayer and yoga mantras on autonomic
cardiovascular rhythms: comparative study. BMJ 2001,
323(7327):1446–1449.
5. Sovik R: The science of breathing–the yogic view. Prog Brain Res 2000,
122:491–505.
6. McCaffrey R, Ruknui P, Hatthakit U, Kasetsomboon P: The effects of yoga
on hypertensive persons in Thailand. Holist Nurs Pract 2005,
19(4):173–180.
7. Patel C, North WR: Randomised controlled trial of yoga and bio-feedback
in management of hypertension. Lancet 1975, 2(7925):93–95.
8. Selvamurthy W, Sridharan K, Ray US, Tiwary RS, Hegde KS, Radhakrishan U,
Sinha KC: A new physiological approach to control essential
hypertension. Indian J Physiol Pharmacol 1998, 42(2):205–213.
9. Vera FM, Manzaneque JM, Maldonado EF, Carranque GA, Rodriguez FM,
Blanca MJ, Morell M: Subjective sleep quality and hormonal modulation
in long-term yoga practitioners. Biol Psychol 2009, 81(3):164–168.
10. Joseph CN, Porta C, Casucci G, Casiraghi N, Maffeis M, Rossi M, Bernardi L:
Slow breathing improves arterial baroreflex sensitivity and decreases
blood pressure in essential hypertension. Hypertension 2005,
46(4):714–718.
11. Santaella DF, Devesa CR, Rojo MR, Amato MB, Drager LF, Casali KR, Montano
N, Lorenzi-Filho G: Yoga respiratory training improves respiratory function
and cardiac sympathovagal balance in elderly subjects: a randomised
controlled trial. BMJ Open 2011, 1(1):e000085.
12. Satyapriya M, Nagendra HR, Nagarathna R, Padmalatha V: Effect of
integrated yoga on stress and heart rate variability in pregnant women.
Int J Gynaecol Obstet 2009, 104(3):218–222.
13. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan MM, Ford GA: Effects
of aerobic exercise training and yoga on the baroreflex in healthy
elderly persons. Eur J Clin Invest 1997, 27(5):443–449.
14. Pahlm O, Sörnmo L: Special methods in electrocardiography (specialmetoder
inom elektrokardiografi; in swedish). Lund: Studentlitteratur; 1998.
15. Sookan T, McKune AJ: Heart rate variability in physically active
individuals: reliability and gender characteristics. Cardiovasc J Afr
2011, 22:1–7.
16. Hynynen E, Vesterinen V, Rusko H, Nummela A: Effects of moderate and
heavy endurance exercise on nocturnal HRV. Int J Sports Med 2010,
31(6):428–432.
17. Ross A, Thomas S: The health benefits of yoga and exercise: a review of
comparison studies. J Altern Complement Med 2010, 16(1):3–12.
18. Patra S, Telles S: Heart rate variability during sleep following the practice
of cyclic meditation and supine rest. Appl Psychophysiol Biofeedback 2010,
35(2):135–140.
19. Telles S, Singh N, Balkrishna A: Heart rate variability changes during high
frequency yoga breathing and breath awareness. Biopsychosoc Med
2011, 5:4.
20. Khattab K, Khattab AA, Ortak J, Richardt G, Bonnemeier H: Iyengar yoga
increases cardiac parasympathetic nervous modulation among healthy
yoga practitioners. Evid Based Complement Alternat Med 2007, 4(4):511–517.
21. Task Force of the European Society of Cardiology and the North American
Society of Pacing and Electrophysiology: Heart rate variability. Standards
of measurement, physiological interpretation, and clinical use. Eur Heart J
1996, 17(3):354–381.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
inclusion criteria and to perform, as initially planned, a
randomized controlled trial. Even though the findings
showed significant differences between baseline and
follow-up, this may have been due to the study being
conducted in the spring when the weather allows for
more outdoor activities and a more active lifestyle. Also
the interaction with the instructor may have created a
therapeutic benefit. However, in line with the initial
hypothesis, some of the HRV measures increased. With
pNN50% being a very sensitive measure, it was not
surprising that the increase in pNN50% was statistically
significant whereas changes in other HRV measures
were not. Some participants were excluded due to the
low ECG recording quality. Breathing frequency is an
important factor for detecting vagal tone, but this was
not measured as participants were instructed to only
take deep breaths.
Conclusions
This small-scale longitudinal pilot study in naive hatha
yoga participants, where time spent on inversions
increased from 7 minutes to 20 minutes over the eight
week period, showed that yoga increased HRV. This suggests that yoga exercises can have a restorative effect on
the autonomic nervous system. Some HRV measures,
including HF and LF/HF ratio also improved but not significantly. However, larger, randomized controlled studies are needed to confirm the effects of yoga on the
sympathetic and parasympathetic nervous system. Future studies should measure breathing frequency,
baroreceptor sensitivity and heart rate recovery before,
during and immediately after performing different yoga
exercises, perhaps focusing solely on inversions or sun
salutations to detect associated changes in the autonomic nervous system.
Additional file
Additional file 1: Availability of supporting data. See appendix A
(link) for pictures of the yoga program. The data are stored at CeFAM.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
MP, PL and PW designed the study, MP performed the study. MP and NS
carried out ECG analyses. MP and PW analyzed the results. MP wrote the
manuscript assisted by PW and PL, NS was involved in designing the
methods and interpreting the results of the ECG analyses. All authors read
and approved of the final manuscript.
Acknowledgements
We would like to thank Birger Andrén for help with the statistics and data
analysis and Martin Ugander for inspiration to conduct this study.
Author details
1
Centre for Family Medicine, Karolinska Institutet, Alfred Nobels allé 12,
SE-14183, Huddinge, Sweden. 2Department of Psychology, Stockholm
Page 8 of 9
University, Frescati hagväg 14, SE-106 91, Stockholm, Sweden. 3Department
of Clinical Physiology, S:t Göran Hospital, SE-112 19, Stockholm, Sweden.
Received: 1 October 2012 Accepted: 21 December 2012
Published: 11 February 2013
References
1. Raub JA: Psychophysiologic effects of Hatha Yoga on musculoskeletal
and cardiopulmonary function: a literature review. J Altern Complement
Med 2002, 8(6):797–812.
2. Cole RJ: Nonpharmacologic techniques for promoting sleep. Clin Sports
Med 2005, 24(2):343–353. xi.
3. Bernardi L, Gabutti A, Porta C, Spicuzza L: Slow breathing reduces
chemoreflex response to hypoxia and hypercapnia, and increases
baroreflex sensitivity. J Hypertens 2001, 19(12):2221–2229.
4. Bernardi L, Sleight P, Bandinelli G, Cencetti S, Fattorini L, Wdowczyc-Szulc J,
Lagi A: Effect of rosary prayer and yoga mantras on autonomic
cardiovascular rhythms: comparative study. BMJ 2001,
323(7327):1446–1449.
5. Sovik R: The science of breathing–the yogic view. Prog Brain Res 2000,
122:491–505.
6. McCaffrey R, Ruknui P, Hatthakit U, Kasetsomboon P: The effects of yoga
on hypertensive persons in Thailand. Holist Nurs Pract 2005,
19(4):173–180.
7. Patel C, North WR: Randomised controlled trial of yoga and bio-feedback
in management of hypertension. Lancet 1975, 2(7925):93–95.
8. Selvamurthy W, Sridharan K, Ray US, Tiwary RS, Hegde KS, Radhakrishan U,
Sinha KC: A new physiological approach to control essential
hypertension. Indian J Physiol Pharmacol 1998, 42(2):205–213.
9. Vera FM, Manzaneque JM, Maldonado EF, Carranque GA, Rodriguez FM,
Blanca MJ, Morell M: Subjective sleep quality and hormonal modulation
in long-term yoga practitioners. Biol Psychol 2009, 81(3):164–168.
10. Joseph CN, Porta C, Casucci G, Casiraghi N, Maffeis M, Rossi M, Bernardi L:
Slow breathing improves arterial baroreflex sensitivity and decreases
blood pressure in essential hypertension. Hypertension 2005,
46(4):714–718.
11. Santaella DF, Devesa CR, Rojo MR, Amato MB, Drager LF, Casali KR, Montano
N, Lorenzi-Filho G: Yoga respiratory training improves respiratory function
and cardiac sympathovagal balance in elderly subjects: a randomised
controlled trial. BMJ Open 2011, 1(1):e000085.
12. Satyapriya M, Nagendra HR, Nagarathna R, Padmalatha V: Effect of
integrated yoga on stress and heart rate variability in pregnant women.
Int J Gynaecol Obstet 2009, 104(3):218–222.
13. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan MM, Ford GA: Effects
of aerobic exercise training and yoga on the baroreflex in healthy
elderly persons. Eur J Clin Invest 1997, 27(5):443–449.
14. Pahlm O, Sörnmo L: Special methods in electrocardiography (specialmetoder
inom elektrokardiografi; in swedish). Lund: Studentlitteratur; 1998.
15. Sookan T, McKune AJ: Heart rate variability in physically active
individuals: reliability and gender characteristics. Cardiovasc J Afr
2011, 22:1–7.
16. Hynynen E, Vesterinen V, Rusko H, Nummela A: Effects of moderate and
heavy endurance exercise on nocturnal HRV. Int J Sports Med 2010,
31(6):428–432.
17. Ross A, Thomas S: The health benefits of yoga and exercise: a review of
comparison studies. J Altern Complement Med 2010, 16(1):3–12.
18. Patra S, Telles S: Heart rate variability during sleep following the practice
of cyclic meditation and supine rest. Appl Psychophysiol Biofeedback 2010,
35(2):135–140.
19. Telles S, Singh N, Balkrishna A: Heart rate variability changes during high
frequency yoga breathing and breath awareness. Biopsychosoc Med
2011, 5:4.
20. Khattab K, Khattab AA, Ortak J, Richardt G, Bonnemeier H: Iyengar yoga
increases cardiac parasympathetic nervous modulation among healthy
yoga practitioners. Evid Based Complement Alternat Med 2007, 4(4):511–517.
21. Task Force of the European Society of Cardiology and the North American
Society of Pacing and Electrophysiology: Heart rate variability. Standards
of measurement, physiological interpretation, and clinical use. Eur Heart J
1996, 17(3):354–381.
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
22. Ewing DJ, Neilson JM, Travis P: New method for assessing cardiac
parasympathetic activity using 24 hour electrocardiograms. Br Heart J
1984, 52(4):396–402.
23. Vijayalakshmi P, Madanmohan, Bhavanani AB, Patil A, Babu K: Modulation
of stress induced by isometric handgrip test in hypertensive patients
following yogic relaxation training. Indian J Physiol Pharmacol 2004,
48(1):59–64.
24. Borg GA: Psychophysical bases of perceived exertion. Med Sci Sports Exerc
1982, 14(5):377–381.
25. Tybor DJ, Lichtenstein AH, Dallal GE, Daniels SR, Must A: Independent
effects of age-related changes in waist circumference and BMI z scores
in predicting cardiovascular disease risk factors in a prospective cohort
of adolescent females. Am J Clin Nutr 2011, 93(2):392–401.
26. Revicki DA, Cella D, Hays RD, Sloan JA, Lenderking WR, Aaronson NK:
Responsiveness and minimal important differences for patient reported
outcomes. Health Qual Life Outcomes 2006, 4:70.
27. Melville GW, Chang D, Colagiuri B, Marshall PW, Cheema BS: Fifteen
minutes of chair-based yoga postures or guided meditation performed
in the office can elicit a relaxation response. Evid Based Complement
Alternat Med 2012, 2012:501986.
28. Cheema BS, Marshall PW, Chang D, Colagiuri B, Machliss B: Effect of an
office worksite-based yoga program on heart rate variability: a
randomized controlled trial. BMC Public Health 2011, 11:578.
29. Farinatti PT, Brandao C, Soares PP, Duarte AF: Acute effects of stretching
exercise on the heart rate variability in subjects with low flexibility
levels. J Strength Cond Res 2011, 25(6):1579–1585.
30. Moodithaya SS, Avadhany ST: Comparison of cardiac autonomic activity
between pre and post menopausal women using heart rate variability.
Indian J Physiol Pharmacol 2009, 53(3):227–234.
31. Mueck-Weymann M, Janshoff G, Mueck H: Stretching increases heart rate
variability in healthy athletes complaining about limited muscular
flexibility. Clin Auton Res 2004, 14(1):15–18.
32. Telles S, Gaur V, Balkrishna A: Effect of a yoga practice session and a yoga
theory session on state anxiety. Percept Mot Skills 2009, 109(3):924–930.
33. Krittayaphong R, Cascio WE, Light KC, Sheffield D, Golden RN, Finkel JB,
Glekas G, Koch GG, Sheps DS: Heart rate variability in patients with
coronary artery disease: differences in patients with higher and lower
depression scores. Psychosom Med 1997, 59(3):231–235.
34. Cole RJ: Postural baroreflex stimuli may affect EEG arousal and sleep in
humans. J Appl Physiol 1989, 67(6):2369–2375.
35. Razin A: Upside-down position to terminate tachycardia of WolffParkinson-White syndrome. N Engl J Med 1977, 296(26):1535–1536.
36. Tai YP, Colaco CB: Upside-down position for paroxysmal supraventricular
tachycardia. Lancet 1981, 2(8258):1289.
37. Pahlm O, Sörnmo L: Electrocardiology – Clinical and technical (Elektrokardiologi –
Klinik och teknik; in Swedish). Lund: Studentlitteratur; 2006.
38. Ingemansson MP, Holm M, Olsson SB: Autonomic modulation of the atrial
cycle length by the head up tilt test: non-invasive evaluation in patients
with chronic atrial fibrillation. Heart 1998, 80(1):71–76.
39. Constantiniu I: An unusual treatment of paroxysmal supraventricular
tachycardia. Am J Cardiol 1972, 30(3):310.
40. Konar D, Latha R, Bhuvaneswaran JS: Cardiovascular responses to headdown-body-up postural exercise (Sarvangasana). Indian J Physiol
Pharmacol 2000, 44(4):392–400.
41. Broadley AJ, Frenneaux MP, Moskvina V, Jones CJ, Korszun A: Baroreflex
sensitivity is reduced in depression. Psychosom Med 2005, 67(4):648–651.
42. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS: Heart-rate
recovery immediately after exercise as a predictor of mortality. N Engl J
Med 1999, 341(18):1351–1357.
43. Van De Borne P, Mezzetti S, Montano N, Narkiewicz K, Degaute JP, Somers
VK: Hyperventilation alters arterial baroreflex control of heart rate and
muscle sympathetic nerve activity. Am J Physiol Heart Circ Physiol 2000,
279(2):H536–H541.
doi:10.1186/1756-0500-6-59
Cite this article as: Papp et al.: Increased heart rate variability but no
effect on blood pressure from 8 weeks of hatha yoga –
a pilot study. BMC Research Notes 2013 6:59.
Page 9 of 9
Submit your next manuscript to BioMed Central
and take full advantage of:
• Convenient online submission
• Thorough peer review
• No space constraints or color figure charges
• Immediate publication on acceptance
• Inclusion in PubMed, CAS, Scopus and Google Scholar
Papp et al. BMC Research Notes 2013, 6:59
http://www.biomedcentral.com/1756-0500/6/59
22. Ewing DJ, Neilson JM, Travis P: New method for assessing cardiac
parasympathetic activity using 24 hour electrocardiograms. Br Heart J
1984, 52(4):396–402.
23. Vijayalakshmi P, Madanmohan, Bhavanani AB, Patil A, Babu K: Modulation
of stress induced by isometric handgrip test in hypertensive patients
following yogic relaxation training. Indian J Physiol Pharmacol 2004,
48(1):59–64.
24. Borg GA: Psychophysical bases of perceived exertion. Med Sci Sports Exerc
1982, 14(5):377–381.
25. Tybor DJ, Lichtenstein AH, Dallal GE, Daniels SR, Must A: Independent
effects of age-related changes in waist circumference and BMI z scores
in predicting cardiovascular disease risk factors in a prospective cohort
of adolescent females. Am J Clin Nutr 2011, 93(2):392–401.
26. Revicki DA, Cella D, Hays RD, Sloan JA, Lenderking WR, Aaronson NK:
Responsiveness and minimal important differences for patient reported
outcomes. Health Qual Life Outcomes 2006, 4:70.
27. Melville GW, Chang D, Colagiuri B, Marshall PW, Cheema BS: Fifteen
minutes of chair-based yoga postures or guided meditation performed
in the office can elicit a relaxation response. Evid Based Complement
Alternat Med 2012, 2012:501986.
28. Cheema BS, Marshall PW, Chang D, Colagiuri B, Machliss B: Effect of an
office worksite-based yoga program on heart rate variability: a
randomized controlled trial. BMC Public Health 2011, 11:578.
29. Farinatti PT, Brandao C, Soares PP, Duarte AF: Acute effects of stretching
exercise on the heart rate variability in subjects with low flexibility
levels. J Strength Cond Res 2011, 25(6):1579–1585.
30. Moodithaya SS, Avadhany ST: Comparison of cardiac autonomic activity
between pre and post menopausal women using heart rate variability.
Indian J Physiol Pharmacol 2009, 53(3):227–234.
31. Mueck-Weymann M, Janshoff G, Mueck H: Stretching increases heart rate
variability in healthy athletes complaining about limited muscular
flexibility. Clin Auton Res 2004, 14(1):15–18.
32. Telles S, Gaur V, Balkrishna A: Effect of a yoga practice session and a yoga
theory session on state anxiety. Percept Mot Skills 2009, 109(3):924–930.
33. Krittayaphong R, Cascio WE, Light KC, Sheffield D, Golden RN, Finkel JB,
Glekas G, Koch GG, Sheps DS: Heart rate variability in patients with
coronary artery disease: differences in patients with higher and lower
depression scores. Psychosom Med 1997, 59(3):231–235.
34. Cole RJ: Postural baroreflex stimuli may affect EEG arousal and sleep in
humans. J Appl Physiol 1989, 67(6):2369–2375.
35. Razin A: Upside-down position to terminate tachycardia of WolffParkinson-White syndrome. N Engl J Med 1977, 296(26):1535–1536.
36. Tai YP, Colaco CB: Upside-down position for paroxysmal supraventricular
tachycardia. Lancet 1981, 2(8258):1289.
37. Pahlm O, Sörnmo L: Electrocardiology – Clinical and technical (Elektrokardiologi –
Klinik och teknik; in Swedish). Lund: Studentlitteratur; 2006.
38. Ingemansson MP, Holm M, Olsson SB: Autonomic modulation of the atrial
cycle length by the head up tilt test: non-invasive evaluation in patients
with chronic atrial fibrillation. Heart 1998, 80(1):71–76.
39. Constantiniu I: An unusual treatment of paroxysmal supraventricular
tachycardia. Am J Cardiol 1972, 30(3):310.
40. Konar D, Latha R, Bhuvaneswaran JS: Cardiovascular responses to headdown-body-up postural exercise (Sarvangasana). Indian J Physiol
Pharmacol 2000, 44(4):392–400.
41. Broadley AJ, Frenneaux MP, Moskvina V, Jones CJ, Korszun A: Baroreflex
sensitivity is reduced in depression. Psychosom Med 2005, 67(4):648–651.
42. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS: Heart-rate
recovery immediately after exercise as a predictor of mortality. N Engl J
Med 1999, 341(18):1351–1357.
43. Van De Borne P, Mezzetti S, Montano N, Narkiewicz K, Degaute JP, Somers
VK: Hyperventilation alters arterial baroreflex control of heart rate and
muscle sympathetic nerve activity. Am J Physiol Heart Circ Physiol 2000,
279(2):H536–H541.
doi:10.1186/1756-0500-6-59
Cite this article as: Papp et al.: Increased heart rate variability but no
effect on blood pressure from 8 weeks of hatha yoga –
a pilot study. BMC Research Notes 2013 6:59.
Page 9 of 9
Submit your next manuscript to BioMed Central
and take full advantage of:
• Convenient online submission
• Thorough peer review
• No space constraints or color figure charges
• Immediate publication on acceptance
• Inclusion in PubMed, CAS, Scopus and Google Scholar
• Research which is freely available for redistribution
• Research which is freely available for redistribution
Submit your manuscript at
www.biomedcentral.com/submit
Submit your manuscript at
www.biomedcentral.com/submit
II
II
THE JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE
Volume 22, Number 1, 2016, pp. 81–87
ª Mary Ann Liebert, Inc.
DOI: 10.1089/acm.2015.0082
THE JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE
Volume 22, Number 1, 2016, pp. 81–87
ª Mary Ann Liebert, Inc.
DOI: 10.1089/acm.2015.0082
Effects of High-Intensity Hatha Yoga
on Cardiovascular Fitness, Adipocytokines,
and Apolipoproteins in Healthy Students:
A Randomized Controlled Study
Effects of High-Intensity Hatha Yoga
on Cardiovascular Fitness, Adipocytokines,
and Apolipoproteins in Healthy Students:
A Randomized Controlled Study
Marian E. Papp, MSc,1 Petra Lindfors, PhD,2 Malin Nygren-Bonnier, PhD,3
Lennart Gullstrand, PhD,4 and Per E. Wändell, MD, PhD1
Marian E. Papp, MSc,1 Petra Lindfors, PhD,2 Malin Nygren-Bonnier, PhD,3
Lennart Gullstrand, PhD,4 and Per E. Wändell, MD, PhD1
Abstract
Abstract
Background: Yoga exercises are often used as a form of body and mind exercise to increase performance.
However, knowledge about the physiologic effects of performing high-intensity Hatha yoga exercises over a
longer time period remains limited.
Objective: To investigate the effects of high-intensity yoga (HIY) on cardiovascular fitness (maximal oxygen
consumption, estimated from the Cooper running test), ratings of perceived exertion (RPE), heart rate (HR),
heart rate recovery (HRR), blood pressure (BP), adipocytokines, apolipoprotein A1 (ApoA1), apolipoprotein B
(ApoB), and glycosylated hemoglobin (HbA1c) in healthy students.
Methods: The 44 participants (38 women and 6 men; median age, 25 years [range, 20–39 years]) were
randomly assigned to an HIY or a control group. The HIY program was held for 6 weeks (60 minutes once a
week). Cardiovascular fitness, RPE, HR, HRR, BP, adipocytokines, HbA1c, ApoA1, and ApoB were measured
at baseline and after 6 weeks in both groups.
Results: HIY had no significant effects on cardiovascular fitness (mean dose: 390 minutes [range, 210–800 minutes]), HR, HRR, BP, or any of the blood parameters. However, ApoA1 (1.47 – 0.17 to 1.55 – 0.16 g/L; p = 0.03) and
adiponectin (8.32 – 3.32 to 9.68 – 3.83 mg/L; p = 0.003) levels increased significantly in the HIY group after 6 weeks.
Conclusions: Six weeks of HIY did not significantly improve cardiovascular fitness. However, ApoA1 and
adiponectin levels increased significantly in the HIY group. This finding suggests that HIY may have positive
effects on blood lipids and an anti-inflammatory effect.
Background: Yoga exercises are often used as a form of body and mind exercise to increase performance.
However, knowledge about the physiologic effects of performing high-intensity Hatha yoga exercises over a
longer time period remains limited.
Objective: To investigate the effects of high-intensity yoga (HIY) on cardiovascular fitness (maximal oxygen
consumption, estimated from the Cooper running test), ratings of perceived exertion (RPE), heart rate (HR),
heart rate recovery (HRR), blood pressure (BP), adipocytokines, apolipoprotein A1 (ApoA1), apolipoprotein B
(ApoB), and glycosylated hemoglobin (HbA1c) in healthy students.
Methods: The 44 participants (38 women and 6 men; median age, 25 years [range, 20–39 years]) were
randomly assigned to an HIY or a control group. The HIY program was held for 6 weeks (60 minutes once a
week). Cardiovascular fitness, RPE, HR, HRR, BP, adipocytokines, HbA1c, ApoA1, and ApoB were measured
at baseline and after 6 weeks in both groups.
Results: HIY had no significant effects on cardiovascular fitness (mean dose: 390 minutes [range, 210–800 minutes]), HR, HRR, BP, or any of the blood parameters. However, ApoA1 (1.47 – 0.17 to 1.55 – 0.16 g/L; p = 0.03) and
adiponectin (8.32 – 3.32 to 9.68 – 3.83 mg/L; p = 0.003) levels increased significantly in the HIY group after 6 weeks.
Conclusions: Six weeks of HIY did not significantly improve cardiovascular fitness. However, ApoA1 and
adiponectin levels increased significantly in the HIY group. This finding suggests that HIY may have positive
effects on blood lipids and an anti-inflammatory effect.
HY is a form of multifaceted neuromotor exercise training10 that uses psychophysical exercises, such as the body
(asana), breathing ( pranayama), locks (bandha), seals
(mudras), and mind concentration (dharana).5,11 Many HY
movements, such as the sun salutations (SS), are among the
most common sequences in HY programs.12
Systematic reviews of HY research have shown significant
and decreasing effects on blood pressure (BP), blood lipids,
and metabolic measures, such as glycosylated hemoglobin
(HbA1c).3,13 Additionally, HY studies have shown effects,
including increased oxygen consumption and uptake;14,15
increased heart rate variability;8,12,16,17 decreased cortisol
levels; and decreasing levels of fatigue, stress, and pain.2
Both physical exercise and HY increase levels of the antiinflammatory protein adiponectin and decrease levels of the
Introduction
P
hysical activity is frequently prescribed by medical professionals in countries such as Sweden and New
Zealand to tackle a range of diseases. To avoid the trend of
increasing inactivity,1 Hatha yoga (HY) has been suggested as
an additional form of physical activity.2,3 HY is also considered a body awareness and body–mind (mindfulness) activity4
and is the basis of most yoga styles. HY originates from India,
is mainly based on the ancient text Hatha Yoga Pradipika
(‘‘light on the forceful yoga’’), and aims to strengthen the body
and mind and prepare for self-realization.5 HY is used as
complementary treatment in traditional Western medicine6
and as a form of exercise to reduce stress and restore autonomic nervous system imbalance.7–9
P
hysical activity is frequently prescribed by medical professionals in countries such as Sweden and New
Zealand to tackle a range of diseases. To avoid the trend of
increasing inactivity,1 Hatha yoga (HY) has been suggested as
an additional form of physical activity.2,3 HY is also considered a body awareness and body–mind (mindfulness) activity4
and is the basis of most yoga styles. HY originates from India,
is mainly based on the ancient text Hatha Yoga Pradipika
(‘‘light on the forceful yoga’’), and aims to strengthen the body
and mind and prepare for self-realization.5 HY is used as
complementary treatment in traditional Western medicine6
and as a form of exercise to reduce stress and restore autonomic nervous system imbalance.7–9
1
1
2
2
Department of Neurobiology Care Sciences and Society, Academic Primary Care Centre, Karolinska Institutet, Huddinge, Sweden.
Department of Psychology, Stockholm University, Stockholm, Sweden.
3
Department of Neurobiology Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm, Sweden.
4
Elite Sports Centre, Swedish Sports Confederation, Lidingö, Sweden.
81
HY is a form of multifaceted neuromotor exercise training10 that uses psychophysical exercises, such as the body
(asana), breathing ( pranayama), locks (bandha), seals
(mudras), and mind concentration (dharana).5,11 Many HY
movements, such as the sun salutations (SS), are among the
most common sequences in HY programs.12
Systematic reviews of HY research have shown significant
and decreasing effects on blood pressure (BP), blood lipids,
and metabolic measures, such as glycosylated hemoglobin
(HbA1c).3,13 Additionally, HY studies have shown effects,
including increased oxygen consumption and uptake;14,15
increased heart rate variability;8,12,16,17 decreased cortisol
levels; and decreasing levels of fatigue, stress, and pain.2
Both physical exercise and HY increase levels of the antiinflammatory protein adiponectin and decrease levels of the
Introduction
Department of Neurobiology Care Sciences and Society, Academic Primary Care Centre, Karolinska Institutet, Huddinge, Sweden.
Department of Psychology, Stockholm University, Stockholm, Sweden.
Department of Neurobiology Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm, Sweden.
4
Elite Sports Centre, Swedish Sports Confederation, Lidingö, Sweden.
3
81
82
proinflammatory marker leptin.18–20 Importantly, these
markers have been associated with metabolic abnormalities
and cardiovascular risk. A recent meta-analysis showed
positive effects after HY on blood lipids, including increases
in high-density lipoprotein (HDL) cholesterol and reductions in low-density lipoprotein cholesterol,3 but research on
the effects of HY on apolipoproteins is lacking.
Taken together, existing research investigating the effects
of HY covers many different body and breathing exercises,
but little is known about the specific effects of high-intensity
yoga exercises (HIY), which mainly consist of vigorous SS
sequences performed at rapid speed with inversions at the
end. To fill this gap, the present study aimed at investigating
the effects of HIY on cardiovascular fitness, heart rate recovery (HRR), BP, apolipoproteins, and adipocytokines.
The study hypothesis was that healthy individuals participating in a 6-week HIY program, mainly including SS,
would show increased cardiovascular fitness in terms of
estimated maximal oxygen consumption (VO2max). In addition, improvements in ratings of perceived exertion (RPE),
heart rate recovery (HRR), adipocytokines, and apolipoproteins were expected.
Materials and Methods
Participants
Participants (n = 260, with 40 men) volunteered to participate and were recruited from university bulletin boards
and websites (Fig. 1). Of these 206, were excluded and 54
were enrolled; 44 participants completed the study. The
analyses were performed as per protocol. The study was
presented via a question as to whether participation in a 6week high-intensity hatha yoga was of interest. Participants
responded by email and received detailed written and oral
information about the study; they were also asked to return a
form that elicited information on the inclusion/exclusion
criteria regarding physical fitness, injuries, and chronic
diseases. Those who fulfilled the inclusion criteria and were
healthy (based on normal-range blood pressure levels, blood
samples, HbA1c, apolipoprotein A1 [ApoA1], apolipoprotein B [ApoB], adiponectin, leptin, and subjective response)
were randomly assigned to an HIY group (with home
FIG. 1. Study flowchart.
PAPP ET AL.
training) or to a control group (no treatment, no yoga or
home exercises, and no change in exercise behavior other
than was allowed in the inclusion criteria).
Inclusion criteria involved being a healthy student aged
20–40 years performing physical exercise no more than 2
hours per week at a medium intensity or 1 hour a week at a
high intensity. Exclusion criteria included chronic disease,
injuries, recent operations, or taking medication that can
affect performance. Participants who had headaches in the
morning were also excluded. Medication for asthma and
allergies was not an exclusion criterion and was used by
some participants.
Randomization was performed by a person not involved
in the research project. Blank papers were scattered on a
table with participants’ identification codes (face down). To
prevent unequal group sizes, every other identification code
was placed in the HIY or control group.
Participants were given information on the testing procedure and how to use the RPE-Borg scale. Suggestions on how
to improve their technique and achieve their best and true
performance during the Cooper test were also included. On the
measurement day (performed at a 400-meter sport and track
field arena), participants were instructed not to eat, drink
coffee, or smoke 2–3 hours before the test and not to exercise.
A total of five test leaders were involved, who measured the
same participant during the intervention. The HIY program
was carried out during the spring and late summer/fall of 2013.
The present study used a randomized controlled design and
was approved by the Regional Ethical Review Board in
Stockholm, Sweden (reference number: 2011/248-31/1). All
participants signed informed consent forms.
The study conformed to the Declaration of Helsinki
concerning human rights and informed consent and followed correct procedures concerning treatment of humans.
Measures
Cardiorespiratory fitness (estimated VO2max) was measured by using the Cooper walk/run test. Compared to
the treadmill test, this test has a correlation and reliability of 0.9–0.92 with true VO2max measurements.21,22 This
distance- and time-dependent tool is based on the original
82
proinflammatory marker leptin.18–20 Importantly, these
markers have been associated with metabolic abnormalities
and cardiovascular risk. A recent meta-analysis showed
positive effects after HY on blood lipids, including increases
in high-density lipoprotein (HDL) cholesterol and reductions in low-density lipoprotein cholesterol,3 but research on
the effects of HY on apolipoproteins is lacking.
Taken together, existing research investigating the effects
of HY covers many different body and breathing exercises,
but little is known about the specific effects of high-intensity
yoga exercises (HIY), which mainly consist of vigorous SS
sequences performed at rapid speed with inversions at the
end. To fill this gap, the present study aimed at investigating
the effects of HIY on cardiovascular fitness, heart rate recovery (HRR), BP, apolipoproteins, and adipocytokines.
The study hypothesis was that healthy individuals participating in a 6-week HIY program, mainly including SS,
would show increased cardiovascular fitness in terms of
estimated maximal oxygen consumption (VO2max). In addition, improvements in ratings of perceived exertion (RPE),
heart rate recovery (HRR), adipocytokines, and apolipoproteins were expected.
Materials and Methods
Participants
Participants (n = 260, with 40 men) volunteered to participate and were recruited from university bulletin boards
and websites (Fig. 1). Of these 206, were excluded and 54
were enrolled; 44 participants completed the study. The
analyses were performed as per protocol. The study was
presented via a question as to whether participation in a 6week high-intensity hatha yoga was of interest. Participants
responded by email and received detailed written and oral
information about the study; they were also asked to return a
form that elicited information on the inclusion/exclusion
criteria regarding physical fitness, injuries, and chronic
diseases. Those who fulfilled the inclusion criteria and were
healthy (based on normal-range blood pressure levels, blood
samples, HbA1c, apolipoprotein A1 [ApoA1], apolipoprotein B [ApoB], adiponectin, leptin, and subjective response)
were randomly assigned to an HIY group (with home
FIG. 1. Study flowchart.
PAPP ET AL.
training) or to a control group (no treatment, no yoga or
home exercises, and no change in exercise behavior other
than was allowed in the inclusion criteria).
Inclusion criteria involved being a healthy student aged
20–40 years performing physical exercise no more than 2
hours per week at a medium intensity or 1 hour a week at a
high intensity. Exclusion criteria included chronic disease,
injuries, recent operations, or taking medication that can
affect performance. Participants who had headaches in the
morning were also excluded. Medication for asthma and
allergies was not an exclusion criterion and was used by
some participants.
Randomization was performed by a person not involved
in the research project. Blank papers were scattered on a
table with participants’ identification codes (face down). To
prevent unequal group sizes, every other identification code
was placed in the HIY or control group.
Participants were given information on the testing procedure and how to use the RPE-Borg scale. Suggestions on how
to improve their technique and achieve their best and true
performance during the Cooper test were also included. On the
measurement day (performed at a 400-meter sport and track
field arena), participants were instructed not to eat, drink
coffee, or smoke 2–3 hours before the test and not to exercise.
A total of five test leaders were involved, who measured the
same participant during the intervention. The HIY program
was carried out during the spring and late summer/fall of 2013.
The present study used a randomized controlled design and
was approved by the Regional Ethical Review Board in
Stockholm, Sweden (reference number: 2011/248-31/1). All
participants signed informed consent forms.
The study conformed to the Declaration of Helsinki
concerning human rights and informed consent and followed correct procedures concerning treatment of humans.
Measures
Cardiorespiratory fitness (estimated VO2max) was measured by using the Cooper walk/run test. Compared to
the treadmill test, this test has a correlation and reliability of 0.9–0.92 with true VO2max measurements.21,22 This
distance- and time-dependent tool is based on the original
YOGA AND CARDIOVASCULAR FITNESS
83
Cooper calculation ([d12 – 505]/45, where d12 is the distance
covered in 12 minutes). Before the measurement, participants were familiarized with the test. During the test, test
leaders gave similar verbal encouragement and registered
the time, RPE, and HRR for all participants. After the HIY
program, the Cooper test and measurements were repeated.
The test leaders were blinded to the group allocation of the
participants.
The difference between maximal heart rate (HR) at the
end of the Cooper test and 1 minute after was registered
and called HRR. HR was measured with a Polar heart rate
monitor (RCX5, Polar Electro Oy, Kempele, Finland). The
Borg RPE 20 scale23 was used to provide RPE to ensure
maximal performance of the Cooper test and during the
HIY exercises. Fatigue was measured for breathing (central) and for the legs (peripheral). All participants were
asked to note their physical activity levels in a weekly
activity diary.
BP was measured by using a Welch Allyn Durashock 2hose nonautomated aneroid sphygmomanometer (AJM8001-00l, 12 · 35 cm; AJ Medical, Lidingö, Sweden), with
an inflatable cuff and a screw valve using a stethoscope
(Panascope Combination Stethoscope, Matsuoka Meditech
Corp., Tokyo, Japan) for auscultation. BP, MEAN, MID and
pulse pressure BP were computed by using readings obtained from both arms. Machine error/accuracy of AJM8001-001 was –3 mmHg (2%).
All blood samples were collected via a catheter and analyzed immediately. Adiponectin and leptin samples were
frozen and analyzed after approximately 6 months. ApoA1/
ApoB samples were analyzed with DXC/LX (BeckmanCoulter) with a measurement interval 0.21–3.2 g/L and 8%
measurement uncertainty. Adiponectin was determined by
using radioimmunoassay (EMD Millipore, [St. Charles,
MO] by Electra-Box [Farsta, Sweden]); the measurement
interval was 0.8–200 lg/L), with 10% measurement uncertainty. Leptin was determined by using a radioimmunoassay
(Millipore/Linco), with a measurement interval of 0.78–
100 lg/L and 10% measurement uncertainty. HbA1c was
determined by using Variant II Turbo (Bio-Rad, Hercules,
CA), with a measurement interval of 15–184 mmol/mol and
2.5% measurement uncertainty.
Intervention with HIY
Participants (who were naive to yoga) performed a standardized 60-minute HIY program once weekly for 6 weeks,
with additional home training. The control group did not
receive any intervention. See Appendix A for a description
of the HIY program.
Statistical analysis
Sample size was calculated to show a difference in
VO2max. An improvement of 2.2 mL/kg per min (6%) with a
power of 0.8 and a two-sided a value of 0.05 required at
least 20 participants with a standard deviation of 2.5 in the
HIY and a standard deviation of 1 in the control group.
Depending on skewness, Wilcoxon signed-rank tests or
t tests were computed to analyze differences at baseline and
follow-up within and between groups. Wilcoxon signed-rank
tests were used to analyze differences in Borg RPE measurements. Confidence intervals (CIs) were included where
applicable. Statistically significant skewness emerged for the
following parameters: Cooper value, age, height, body–mass
index, systolic BP, leptin, and adiponectin/leptin ratio. Depending on skewness, Spearman (rs) correlation coefficients
or Pearson (rp) coefficients were computed. The significance
level was set to p < 0.05. Analyses were performed by using
Stata software (Stata Corp., College Station, TX)/Version 11.
Results
There were no significant group differences at baseline in
any of the parameters (Tables 1 and 2). Both ApoA1 (change
of 0.08 g/L; 95% CI, 0.0–0.1 g/L) and adiponectin (change of
1.35 mg/L; 95% CI, 0.5– 2.2 mg/L) increased significantly in
the HIY group; no other significant effect was seen between
the HIY and the control groups. There were no significant
HbA1c changes in the control group, but in the HIY group
HbA1c was lowered and nearly significantly (Table 2).
Borg scale (ratings of perceived exertion) RPE
During the HIY program, the median central RPE was 14
(range, 9–17) after 25 minutes and 15 (range, 10–18) after 45
minutes. The median peripheral RPE was 13 (range, 9–16)
YOGA AND CARDIOVASCULAR FITNESS
Cooper calculation ([d12 – 505]/45, where d12 is the distance
covered in 12 minutes). Before the measurement, participants were familiarized with the test. During the test, test
leaders gave similar verbal encouragement and registered
the time, RPE, and HRR for all participants. After the HIY
program, the Cooper test and measurements were repeated.
The test leaders were blinded to the group allocation of the
participants.
The difference between maximal heart rate (HR) at the
end of the Cooper test and 1 minute after was registered
and called HRR. HR was measured with a Polar heart rate
monitor (RCX5, Polar Electro Oy, Kempele, Finland). The
Borg RPE 20 scale23 was used to provide RPE to ensure
maximal performance of the Cooper test and during the
HIY exercises. Fatigue was measured for breathing (central) and for the legs (peripheral). All participants were
asked to note their physical activity levels in a weekly
activity diary.
BP was measured by using a Welch Allyn Durashock 2hose nonautomated aneroid sphygmomanometer (AJM8001-00l, 12 · 35 cm; AJ Medical, Lidingö, Sweden), with
an inflatable cuff and a screw valve using a stethoscope
(Panascope Combination Stethoscope, Matsuoka Meditech
Corp., Tokyo, Japan) for auscultation. BP, MEAN, MID and
pulse pressure BP were computed by using readings obtained from both arms. Machine error/accuracy of AJM8001-001 was –3 mmHg (2%).
All blood samples were collected via a catheter and analyzed immediately. Adiponectin and leptin samples were
frozen and analyzed after approximately 6 months. ApoA1/
ApoB samples were analyzed with DXC/LX (BeckmanCoulter) with a measurement interval 0.21–3.2 g/L and 8%
measurement uncertainty. Adiponectin was determined by
using radioimmunoassay (EMD Millipore, [St. Charles,
MO] by Electra-Box [Farsta, Sweden]); the measurement
interval was 0.8–200 lg/L), with 10% measurement uncertainty. Leptin was determined by using a radioimmunoassay
(Millipore/Linco), with a measurement interval of 0.78–
100 lg/L and 10% measurement uncertainty. HbA1c was
determined by using Variant II Turbo (Bio-Rad, Hercules,
CA), with a measurement interval of 15–184 mmol/mol and
2.5% measurement uncertainty.
Table 1. Anthropometric Measures for High-Intensity Hatha Yoga and Control Groups
at Baseline and After 6 Weeks
Variable
HIY group
(n = 21)
HIY group
after 6 wk
Women/men (n/n)
18/3
Age (y)
25 (20–37)
Height (m)
1.66 (1.59–1.93)
Weight (kg)
65.4 – 12.8
65.5 – 12.7
Body–mass
22.2 (16.9–34.8) 22.0 (16.9–34.8)
2
index (kg/m )
Waist-to-hip ratio
0.76 – 0.06
0.75 – 0.07
Waist
75.52 – 9.34
75.0 – 9.72
circumference (cm)
p-Value:
HIY
0.76
0.74
0.44
0.26
Control
group (n = 23)
Control group
after 6 wk
20/3
25 (20–39)
1.68 (1.53–1.91)
62.8 – 8.5
62.4 – 8.6
21.9 (18.6–25.3) 22.2 (18.3–25.2)
0.75 – 0.05
73.72 – 6.42
0.75 – 0.04
74.22 – 5.53
p-Value:
control
83
Intervention with HIY
Participants (who were naive to yoga) performed a standardized 60-minute HIY program once weekly for 6 weeks,
with additional home training. The control group did not
receive any intervention. See Appendix A for a description
of the HIY program.
Statistical analysis
Sample size was calculated to show a difference in
VO2max. An improvement of 2.2 mL/kg per min (6%) with a
power of 0.8 and a two-sided a value of 0.05 required at
least 20 participants with a standard deviation of 2.5 in the
HIY and a standard deviation of 1 in the control group.
Depending on skewness, Wilcoxon signed-rank tests or
t tests were computed to analyze differences at baseline and
follow-up within and between groups. Wilcoxon signed-rank
tests were used to analyze differences in Borg RPE measurements. Confidence intervals (CIs) were included where
applicable. Statistically significant skewness emerged for the
following parameters: Cooper value, age, height, body–mass
index, systolic BP, leptin, and adiponectin/leptin ratio. Depending on skewness, Spearman (rs) correlation coefficients
or Pearson (rp) coefficients were computed. The significance
level was set to p < 0.05. Analyses were performed by using
Stata software (Stata Corp., College Station, TX)/Version 11.
Results
There were no significant group differences at baseline in
any of the parameters (Tables 1 and 2). Both ApoA1 (change
of 0.08 g/L; 95% CI, 0.0–0.1 g/L) and adiponectin (change of
1.35 mg/L; 95% CI, 0.5– 2.2 mg/L) increased significantly in
the HIY group; no other significant effect was seen between
the HIY and the control groups. There were no significant
HbA1c changes in the control group, but in the HIY group
HbA1c was lowered and nearly significantly (Table 2).
Borg scale (ratings of perceived exertion) RPE
During the HIY program, the median central RPE was 14
(range, 9–17) after 25 minutes and 15 (range, 10–18) after 45
minutes. The median peripheral RPE was 13 (range, 9–16)
Table 1. Anthropometric Measures for High-Intensity Hatha Yoga and Control Groups
at Baseline and After 6 Weeks
p-Value:
HIY vs.
control
0.38
0.31
0.38
0.34
0.75
0.41
0.63
0.13
Medians and ranges are shown for skewed measures while means and standard deviation are presented for normally distributed measures.
Wilcoxon signed-rank tests or t-tests were computed to analyze differences at baseline and follow-up within and between groups (depending
on skewness).
HIY, high-intensity yoga.
Variable
HIY group
(n = 21)
HIY group
after 6 wk
Women/men (n/n)
18/3
Age (y)
25 (20–37)
Height (m)
1.66 (1.59–1.93)
Weight (kg)
65.4 – 12.8
65.5 – 12.7
Body–mass
22.2 (16.9–34.8) 22.0 (16.9–34.8)
2
index (kg/m )
Waist-to-hip ratio
0.76 – 0.06
0.75 – 0.07
Waist
75.52 – 9.34
75.0 – 9.72
circumference (cm)
p-Value:
HIY
0.76
0.74
0.44
0.26
Control
group (n = 23)
Control group
after 6 wk
20/3
25 (20–39)
1.68 (1.53–1.91)
62.8 – 8.5
62.4 – 8.6
21.9 (18.6–25.3) 22.2 (18.3–25.2)
0.75 – 0.05
73.72 – 6.42
0.75 – 0.04
74.22 – 5.53
p-Value:
control
p-Value:
HIY vs.
control
0.38
0.31
0.38
0.34
0.75
0.41
0.63
0.13
Medians and ranges are shown for skewed measures while means and standard deviation are presented for normally distributed measures.
Wilcoxon signed-rank tests or t-tests were computed to analyze differences at baseline and follow-up within and between groups (depending
on skewness).
HIY, high-intensity yoga.
84
PAPP ET AL.
Table 2. Cardiovascular Fitness (Maximal Oxygen Consumption, Cooper Test), Blood Pressure,
Apolipoproteins, Glycosylated Hemoglobin, and Adipocytokines at Baseline and After 6 Weeks
for the High-Intensity Yoga and Control Groups
HIY group (n = 21)
Variable
Baseline
6 wk
PAPP ET AL.
Table 2. Cardiovascular Fitness (Maximal Oxygen Consumption, Cooper Test), Blood Pressure,
Apolipoproteins, Glycosylated Hemoglobin, and Adipocytokines at Baseline and After 6 Weeks
for the High-Intensity Yoga and Control Groups
Control group (n = 23)
p-Value
Cooper test (maximal oxygen
37.3 – 7.9
37.5 – 7.9
consumption) (mL/kg per min)
Central RPE
17 (15–20) 17 (14–19)
Peripheral RPE
15 (8–18)
15 (11–17)
HRR
39.9 – 13.1
36.8 – 15.5
Rest HR (beats/min)
81.6 – 18.9
79.6 – 8.2
Systolic BP (mmHg)
118.7 – 5.8
118.3 – 5.2
Diastolic BP (mmHg)
76.8 – 5.9
77.2 – 7.4
MID BP (mmHg)
97.7 – 4.7
97.8 – 5.8
Plasma ApoA1 (g/L)
1.47 – 0.17
1.55 – 0.16
Plasma ApoB (g/L)
0.80 – 0.14
0.81 – 0.15
ApoB/ApoA1
0.55 – 0.12
0.53 – 0.13
Blood glycosylated
32.2 – 2.9
31.3 – 3.8
hemoglobin HbA1C
(mmol/mol)
Serum adiponectin (mg/L)
8.32 – 3.32
9.68 – 3.83
Serum leptin (lg/L)
14.33 – 11.04 14.63 – 10.97
Adiponectin/leptin
1.24 – 1.46
1.33 – 1.52
84
0.78
0.20
0.45
0.39
0.47
0.80
0.73
0.66
0.03a
0.65
0.28
0.07
Baseline
6 wk
38.5 – 7.7
38.3 – 6.6
17 (12–19)
17 (7–19)
14 (9–16)
14 (8–18)
40.8 – 11.8 39.2 – 12.7
81.3 – 13.7 78.5 – 14.5
118.9 – 8.9 117.3 – 6.3
74.8 – 5.8
77.8 – 6.8
96.8 – 6.5
97.5 – 5.9
c
1.59 – 0.22 1.62 – 0.22c
c
0.78 – 0.16 0.81 – 0.18c
0.50 – 0.12 0.51 – 0.14
31.8 – 2.7
31.8 – 4.2
0.003a 9.07 – 3.29b
0.73
10.19 – 7.07b
0.24
1.39 – 0.95b
9.53 – 3.78b
9.43 – 5.48b
1.51 – 1.35b
p-Value:
HIY vs.
p-Value control
0.79
0.87
0.83
0.15
0.56
0.32
0.25
0.01a
0.45
0.37
0.12
0.48
1.0
0.37
0.14
0.82
0.97
0.54
0.15
0.45
0.28
0.46
0.20
0.22
0.18
0.59
0.59
0.37
0.48
0.78
HIY group (n = 21)
Variable
Baseline
6 wk
Control group (n = 23)
p-Value
Cooper test (maximal oxygen
37.3 – 7.9
37.5 – 7.9
consumption) (mL/kg per min)
Central RPE
17 (15–20) 17 (14–19)
Peripheral RPE
15 (8–18)
15 (11–17)
HRR
39.9 – 13.1
36.8 – 15.5
Rest HR (beats/min)
81.6 – 18.9
79.6 – 8.2
Systolic BP (mmHg)
118.7 – 5.8
118.3 – 5.2
Diastolic BP (mmHg)
76.8 – 5.9
77.2 – 7.4
MID BP (mmHg)
97.7 – 4.7
97.8 – 5.8
Plasma ApoA1 (g/L)
1.47 – 0.17
1.55 – 0.16
Plasma ApoB (g/L)
0.80 – 0.14
0.81 – 0.15
ApoB/ApoA1
0.55 – 0.12
0.53 – 0.13
Blood glycosylated
32.2 – 2.9
31.3 – 3.8
hemoglobin HbA1C
(mmol/mol)
Serum adiponectin (mg/L)
8.32 – 3.32
9.68 – 3.83
Serum leptin (lg/L)
14.33 – 11.04 14.63 – 10.97
Adiponectin/leptin
1.24 – 1.46
1.33 – 1.52
0.78
0.20
0.45
0.39
0.47
0.80
0.73
0.66
0.03a
0.65
0.28
0.07
Baseline
6 wk
38.5 – 7.7
38.3 – 6.6
17 (12–19)
17 (7–19)
14 (9–16)
14 (8–18)
40.8 – 11.8 39.2 – 12.7
81.3 – 13.7 78.5 – 14.5
118.9 – 8.9 117.3 – 6.3
74.8 – 5.8
77.8 – 6.8
96.8 – 6.5
97.5 – 5.9
c
1.59 – 0.22 1.62 – 0.22c
c
0.78 – 0.16 0.81 – 0.18c
0.50 – 0.12 0.51 – 0.14
31.8 – 2.7
31.8 – 4.2
0.003a 9.07 – 3.29b
0.73
10.19 – 7.07b
0.24
1.39 – 0.95b
9.53 – 3.78b
9.43 – 5.48b
1.51 – 1.35b
p-Value:
HIY vs.
p-Value control
0.79
0.87
0.83
0.15
0.56
0.32
0.25
0.01a
0.45
0.37
0.12
0.48
1.0
0.37
0.14
0.82
0.97
0.54
0.15
0.45
0.28
0.46
0.20
0.22
0.18
0.59
0.59
0.37
0.48
0.78
Data are expressed as means – standard deviations or medians (ranges). Confidence intervals are presented in text. Wilcoxon signed-rank
tests or t-tests were computed to analyze differences at baseline and follow-up within and between groups (depending on skewness).
Wilcoxon signed-rank tests were used to analyze differences in ratings of perceived exertion at the end of the Cooper test (RPE).
Leptin and adiponectin was calculated for women only (majority of the sample) showing significance in adiponectin in yoga group.
a
Statistically significant.
b
n = 17 in the control group.
c
ApoA1, apolipoprotein A1; ApoB, apolipoprotein B (n = 21 in the control group).
RPE, ratings of perceived exertion immediately at the end of the Cooper test; HRR, heart rate recovery (differences in heart beats after 1
minute); rest HR, resting heart rate; BP, blood pressure; MID BP, systol + diastol/2.
Data are expressed as means – standard deviations or medians (ranges). Confidence intervals are presented in text. Wilcoxon signed-rank
tests or t-tests were computed to analyze differences at baseline and follow-up within and between groups (depending on skewness).
Wilcoxon signed-rank tests were used to analyze differences in ratings of perceived exertion at the end of the Cooper test (RPE).
Leptin and adiponectin was calculated for women only (majority of the sample) showing significance in adiponectin in yoga group.
a
Statistically significant.
b
n = 17 in the control group.
c
ApoA1, apolipoprotein A1; ApoB, apolipoprotein B (n = 21 in the control group).
RPE, ratings of perceived exertion immediately at the end of the Cooper test; HRR, heart rate recovery (differences in heart beats after 1
minute); rest HR, resting heart rate; BP, blood pressure; MID BP, systol + diastol/2.
after 25 minutes and 14 (range, 10–18) after 45 minutes. Positive correlations (differences) emerged between peripheral
RPE and during the Cooper test in the HIY group (rs = 0.47;
p = 0.03). After the intervention, positive correlations (Spearman) emerged between HR and central RPE (rs = 0.53;
p = 0.02) in the HIY group. This finding verifies that the participants understood and used the RPE scale accurately.
after 25 minutes and 14 (range, 10–18) after 45 minutes. Positive correlations (differences) emerged between peripheral
RPE and during the Cooper test in the HIY group (rs = 0.47;
p = 0.03). After the intervention, positive correlations (Spearman) emerged between HR and central RPE (rs = 0.53;
p = 0.02) in the HIY group. This finding verifies that the participants understood and used the RPE scale accurately.
An intervention with a 6-week HIY program showed no
significant effect on cardiovascular fitness as compared to a
control group. However, for blood parameters within the HIY
group, significant effects emerged for ApoA1 and adiponectin.
total time performing HIY but also to the fact that the participants were not untrained. However, no previous studies
seem to have reported effects of 6 weeks of HIY on cardiovascular fitness. Previous findings have shown that acute effects include increased VO2max14 and elevated HR24 during
HIY that are sufficient for cardiovascular fitness effects.
Some researchers14,15,24 have suggested that the practice
of SS, as included in HIY, can be used to maintain or improve cardiovascular fitness. One study15 using a mixture of
dynamic and static exercises on a group similar to that included in the present study measured oxygen uptake after 8
weeks of HY and showed a 6% increase. This effect on
cardiorespiratory fitness could perhaps be related to the frog
pose, dynamic lunges, and SS.15
Others have shown an intensity of 41% (19 mL/kg per min)
of VO2max25 from the back-bending yogic exercises and inversions (included in the present study) and have shown high
oxygen consumption. This is close to the minimum limit
required to achieve cardiovascular training effects. However,
this study also showed high heart rates using the ‘‘yoga pushup’’ (chatturanga) included in HIY. Clay et al.26 have reported an intensity of 40% of VO2max (13 mL/kg per min)
from SS, while others27 have noted an intensity of 9.9%–
26.5% of VO2max from HY postures (no SS). These lower
figures are far from the minimum recommendations.
An intervention with a 6-week HIY program showed no
significant effect on cardiovascular fitness as compared to a
control group. However, for blood parameters within the HIY
group, significant effects emerged for ApoA1 and adiponectin.
total time performing HIY but also to the fact that the participants were not untrained. However, no previous studies
seem to have reported effects of 6 weeks of HIY on cardiovascular fitness. Previous findings have shown that acute effects include increased VO2max14 and elevated HR24 during
HIY that are sufficient for cardiovascular fitness effects.
Some researchers14,15,24 have suggested that the practice
of SS, as included in HIY, can be used to maintain or improve cardiovascular fitness. One study15 using a mixture of
dynamic and static exercises on a group similar to that included in the present study measured oxygen uptake after 8
weeks of HY and showed a 6% increase. This effect on
cardiorespiratory fitness could perhaps be related to the frog
pose, dynamic lunges, and SS.15
Others have shown an intensity of 41% (19 mL/kg per min)
of VO2max25 from the back-bending yogic exercises and inversions (included in the present study) and have shown high
oxygen consumption. This is close to the minimum limit
required to achieve cardiovascular training effects. However,
this study also showed high heart rates using the ‘‘yoga pushup’’ (chatturanga) included in HIY. Clay et al.26 have reported an intensity of 40% of VO2max (13 mL/kg per min)
from SS, while others27 have noted an intensity of 9.9%–
26.5% of VO2max from HY postures (no SS). These lower
figures are far from the minimum recommendations.
VO2max
Apolipoproteins
VO2max
Apolipoproteins
The present study found no differences between or within
groups for VO2max. This could relate to low intensity and
While previous research has investigated HDL and shown
increasing levels after HY,3 the present study seems to be
The present study found no differences between or within
groups for VO2max. This could relate to low intensity and
While previous research has investigated HDL and shown
increasing levels after HY,3 the present study seems to be
Blood pressure
For BP, no significant differences emerged between
baseline and follow-up between groups (Table 2). Diastolic
BP increased significantly within the control group, with
changes of 3.0 mmHg (95% CI, 0.9–5.0 mmHg). After 6
weeks, no significant effects emerged for pulse pressure or
mean arterial pressure (not shown).
HIY dose
For findings related to HIY dose, see Appendix A.
Discussion
Blood pressure
For BP, no significant differences emerged between
baseline and follow-up between groups (Table 2). Diastolic
BP increased significantly within the control group, with
changes of 3.0 mmHg (95% CI, 0.9–5.0 mmHg). After 6
weeks, no significant effects emerged for pulse pressure or
mean arterial pressure (not shown).
HIY dose
For findings related to HIY dose, see Appendix A.
Discussion
YOGA AND CARDIOVASCULAR FITNESS
the first to measure apolipoproteins, the main component of
HDL and LDL. Even though the HIY dose was relatively
small and baseline levels of ApoA1 were low and within the
normal range, a significant effect emerged for ApoA1.
However, ApoA1 levels increased in the HIY group only.
The mechanism relating to the ApoA1 findings in the HIY
group perhaps relates to HIY being more of a mindful
physical exercise, which is different from other types of
regular exercise, while the control group continued with their
regular exercise and did no systematic mindful physical
training. However, the ApoA1 findings follow research
showing that ApoA1 typically increases with physical exercise.20 Yet, a higher yoga dose might have resulted in significant group effects. A possible limitation of the present
study on ApoA1 levels is that the control group did not add a
additional group activity to their regular physical activity
schedule as the HIY group did.
Adiponectin and leptin (adipocytokines)
Although baseline levels were within the normal range,
the present study replicated previous findings18,20 showing
increased adiponectin levels after HIY. However, the present study showed no effect on leptin. This is possibly due to
the short time period and the fact that the participants had
levels within the normal range, but another possible reason
is that this is not a sensitive enough biomarker. Previous
research has shown higher adiponectin levels and lower
leptin levels among yoga experts as compared to inexperienced participants, showing a better immunologic response
and an anti-inflammatory effect.19,28,29 The physiologic
mechanism relating to the increase in adiponectin, but not
leptin, found in the present study is probably due to adiponectin levels changing faster than do leptin levels.
Heart rate
A lowered HR was observed in both groups investigated
here, but this finding was not statistically significant. Generally, a high HR is seen during some HY exercises. But
when oxygen consumption is measured, the intensity is not
linear to HR (unpublished data). However, there seem to be
no reports of HR and oxygen consumption during HIY and,
consequently, the use of HR as a measure of HY intensity
seems inappropriate.26 Some studies measuring HR24 have
mentioned that yogic exercises put a low to moderate stress
on the cardiovascular system and have noted that SS (included in HIY) may be intensive enough to improve cardiorespiratory fitness in unfit participants. Others have
shown lowered resting HR8,30 after HY, thus indicating a
vagal dominance.31–33 While the present study included no
HR measurement during HIY, RPE was above 14 (HR, 140
beats/min) and thus within the cardiovascular training zone.
Duration and intensity
The total HIY training dose (both at home and during
classes) was on average 390 minutes (6.5 hours [range,
210–800 minutes]) distributed over 6 weeks (Appendix A).
This corresponds to a weekly average of 65 minutes. Effects
on the cardiovascular system require at least 75 minutes at
RPE of 14–16. The RPE rating (14–17) was at a sufficient
exertion, but the total time was on the lower limit to show
any improvements.10 After 45 minutes into the 60-minute
85
HIY, RPE during the HIY class was at the recommended
ratings. This shows that the time (75 minutes at 14–16 or
150 minutes at 12–13) was on the verge of health effects on
the cardiovascular system.34 Yet, with HY being a form of
mindful exercise training, no intensity standards have been
determined.10 However, the dynamic intensity (1–3 seconds
per exercise) using a longer intervention would have created difficulties with technique and motivation for unfit
participants. In the present study, the total HIY time was
likely to be an issue. The exercise dose did not differ between the groups at baseline. The control group did not
report any changes in exercise behavior during the intervention period.
Blood pressure
The participants included in the present study were young
and normotensive (i.e., their BP was already within the
normal range at baseline), and consequently large BP
changes were not detected. A larger HIY dose could perhaps
show the lowered BP effect, which has been reported in
previous research.13 This relates to HY exercises performed
with the head below the heart, which lowers HR and induces
baroreceptor firing.35
Although a recent meta-analysis3 shows clinically important effects of HY on cardiovascular risk factors as compared to usual care, many people do HY as a form of
exercise. There is further need to evaluate its effects and to
introduce an additional form of exercise to avoid the trend of
increasing inactivity. Others studies have shown strength
benefits of SS.36 and future research should evaluate these
effects further.
Limitations
Considering the limitations of the present study, the large
variation in home training and home exercises is an obvious
issue. Even though RPE measurements showed that the
home training was performed at a sufficient intensity, this
was probably not the case. This is likely the result of unfamiliarity in using the RPE scale at home; whenever possible, electronic monitoring should probably be used
alongside RPE ratings. Another issue relates to this study
being a field study, which allowed limited control over some
factors.
For instance, weather conditions differed slightly during the
Cooper tests, and obviously experimental testing (i.e., direct
measurements of VO2max) would have allowed for more precise
measurement of various markers. With regard to the biomarkers, there was no correction for variations in plasma volume
shifts, and details on nutritional status would have added information. In addition, it would have been ideal to include
sagittal abdominal diameter measures. Although the sample
size and power were sufficient, the use of pseudorandomization
to obtain equal group sizes might be an issue. We chose to
measure apolipoproteins instead of total cholesterol, HDL
cholesterol, and triglycerides, meaning that the participants did
not have to be in the fasting state.
Positive effects
The obvious strengths lie in participants being glucometabolically healthy (very low HbA1c), and a larger effect on
YOGA AND CARDIOVASCULAR FITNESS
the first to measure apolipoproteins, the main component of
HDL and LDL. Even though the HIY dose was relatively
small and baseline levels of ApoA1 were low and within the
normal range, a significant effect emerged for ApoA1.
However, ApoA1 levels increased in the HIY group only.
The mechanism relating to the ApoA1 findings in the HIY
group perhaps relates to HIY being more of a mindful
physical exercise, which is different from other types of
regular exercise, while the control group continued with their
regular exercise and did no systematic mindful physical
training. However, the ApoA1 findings follow research
showing that ApoA1 typically increases with physical exercise.20 Yet, a higher yoga dose might have resulted in significant group effects. A possible limitation of the present
study on ApoA1 levels is that the control group did not add a
additional group activity to their regular physical activity
schedule as the HIY group did.
Adiponectin and leptin (adipocytokines)
Although baseline levels were within the normal range,
the present study replicated previous findings18,20 showing
increased adiponectin levels after HIY. However, the present study showed no effect on leptin. This is possibly due to
the short time period and the fact that the participants had
levels within the normal range, but another possible reason
is that this is not a sensitive enough biomarker. Previous
research has shown higher adiponectin levels and lower
leptin levels among yoga experts as compared to inexperienced participants, showing a better immunologic response
and an anti-inflammatory effect.19,28,29 The physiologic
mechanism relating to the increase in adiponectin, but not
leptin, found in the present study is probably due to adiponectin levels changing faster than do leptin levels.
Heart rate
A lowered HR was observed in both groups investigated
here, but this finding was not statistically significant. Generally, a high HR is seen during some HY exercises. But
when oxygen consumption is measured, the intensity is not
linear to HR (unpublished data). However, there seem to be
no reports of HR and oxygen consumption during HIY and,
consequently, the use of HR as a measure of HY intensity
seems inappropriate.26 Some studies measuring HR24 have
mentioned that yogic exercises put a low to moderate stress
on the cardiovascular system and have noted that SS (included in HIY) may be intensive enough to improve cardiorespiratory fitness in unfit participants. Others have
shown lowered resting HR8,30 after HY, thus indicating a
vagal dominance.31–33 While the present study included no
HR measurement during HIY, RPE was above 14 (HR, 140
beats/min) and thus within the cardiovascular training zone.
Duration and intensity
The total HIY training dose (both at home and during
classes) was on average 390 minutes (6.5 hours [range,
210–800 minutes]) distributed over 6 weeks (Appendix A).
This corresponds to a weekly average of 65 minutes. Effects
on the cardiovascular system require at least 75 minutes at
RPE of 14–16. The RPE rating (14–17) was at a sufficient
exertion, but the total time was on the lower limit to show
any improvements.10 After 45 minutes into the 60-minute
85
HIY, RPE during the HIY class was at the recommended
ratings. This shows that the time (75 minutes at 14–16 or
150 minutes at 12–13) was on the verge of health effects on
the cardiovascular system.34 Yet, with HY being a form of
mindful exercise training, no intensity standards have been
determined.10 However, the dynamic intensity (1–3 seconds
per exercise) using a longer intervention would have created difficulties with technique and motivation for unfit
participants. In the present study, the total HIY time was
likely to be an issue. The exercise dose did not differ between the groups at baseline. The control group did not
report any changes in exercise behavior during the intervention period.
Blood pressure
The participants included in the present study were young
and normotensive (i.e., their BP was already within the
normal range at baseline), and consequently large BP
changes were not detected. A larger HIY dose could perhaps
show the lowered BP effect, which has been reported in
previous research.13 This relates to HY exercises performed
with the head below the heart, which lowers HR and induces
baroreceptor firing.35
Although a recent meta-analysis3 shows clinically important effects of HY on cardiovascular risk factors as compared to usual care, many people do HY as a form of
exercise. There is further need to evaluate its effects and to
introduce an additional form of exercise to avoid the trend of
increasing inactivity. Others studies have shown strength
benefits of SS.36 and future research should evaluate these
effects further.
Limitations
Considering the limitations of the present study, the large
variation in home training and home exercises is an obvious
issue. Even though RPE measurements showed that the
home training was performed at a sufficient intensity, this
was probably not the case. This is likely the result of unfamiliarity in using the RPE scale at home; whenever possible, electronic monitoring should probably be used
alongside RPE ratings. Another issue relates to this study
being a field study, which allowed limited control over some
factors.
For instance, weather conditions differed slightly during the
Cooper tests, and obviously experimental testing (i.e., direct
measurements of VO2max) would have allowed for more precise
measurement of various markers. With regard to the biomarkers, there was no correction for variations in plasma volume
shifts, and details on nutritional status would have added information. In addition, it would have been ideal to include
sagittal abdominal diameter measures. Although the sample
size and power were sufficient, the use of pseudorandomization
to obtain equal group sizes might be an issue. We chose to
measure apolipoproteins instead of total cholesterol, HDL
cholesterol, and triglycerides, meaning that the participants did
not have to be in the fasting state.
Positive effects
The obvious strengths lie in participants being glucometabolically healthy (very low HbA1c), and a larger effect on
86
PAPP ET AL.
blood parameters was not detected after HIY. Perhaps research on older people or those with lower fitness levels or
on patient groups is needed to detect such effects.
Both the ApoA1 and adiponectin levels increased in HIY,
which suggests a positive metabolic effect on a somewhat
active and healthy group. However, large positive effects
were not expected. Yet, the increasing ApoA1 and adiponectin levels along with the lowered HbA1c in the HIY
show a clear trend. The HIY dose-response was low for any
cardiovascular fitness improvements, but this study still
found positive effects on ApoA1 and adiponectin.
Conclusions
Contrary to the initial hypothesis, this 6-week HIY program had no significant effect on estimated VO2max. This
probably relates to insufficiencies and variations regarding
both HIY dose and intensity. The weather conditions also
varied slightly during the Cooper tests. An additional limitation involves the use of pseudo-randomization to obtain
equal group sizes. However, apolipoprotein A1 and adiponectin levels increased significantly in the HIY group, which
suggests that HIY can potentially be effective in low doses.
Acknowledgments
The authors thank all who volunteered to participate.
They also thank Birger Andrén for helping out with the
statistics, the yoga instructors (Ulrika Hedlund, Maddalena
Maresca, and Vera Engdahl), and the test leaders (Matilda
Johansson, Agnes Karlsson-Pyk, Maria Andersson, Johanna
Öster, and Catarina Levin) for helping out with measurements. No funding was received for this study. All data are
stored at an academic primary care center.
Author Disclosure Statement
No competing financial interests exist.
References
1. Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT. Effect of physical inactivity on major noncommunicable diseases worldwide: an analysis of burden
of disease and life expectancy. Lancet 2012;380:219–229.
2. Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies. J Altern Complement
Med 2010;16:3–12.
3. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A,
Dobos G. Effects of yoga on cardiovascular disease risk
factors: a systematic review and meta-analysis. Int J Cardiol 2014;173:170–183.
4. Shelov DV, Suchday S, Friedberg JP. A pilot study measuring the impact of yoga on the trait of mindfulness. Behav Cogn Psychother 2009;37:595–598.
5. Georg F. The Shambhala Encyclopedia of Yoga. London:
Shambhala, 2000.
6. Mustian KM, Sprod LK, Janelsins M, et al. Multicenter,
randomized controlled trial of yoga for sleep quality among
cancer survivors. J Clin Oncol 2013;31:3233–3241.
7. Santaella DF, Devesa CR, Rojo MR, et al. Yoga respiratory
training improves respiratory function and cardiac sympathovagal balance in elderly subjects: a randomised controlled trial. BMJ Open 2011;1:e000085.
8. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic meditation and supine rest.
Appl Psychophysiol Biofeedback 2010;35:135–140.
9. National Center for Complementary and Integrative Health.
Homepage on Internet: https://nccih.nih.gov, accessed
January 12, 2015.
10. Garber CE, Blissmer B, Deschenes MR, et al. American
College of Sports Medicine position stand. Quantity and
quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in
apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011;43(7):1334–1359.
11. Raub JA. Psychophysiologic effects of Hatha Yoga on
musculoskeletal and cardiopulmonary function: a literature
review. J Altern Complement Med 2002;8:797–812.
12. Broad WJ. The Science of Yoga: The Risks and Rewards.
New York: Simon & Schuster, 2012.
13. Hagins M, States R, Selfe T, Innes K. Effectiveness of yoga
for hypertension: systematic review and meta-analysis.
Evid Based Complement Alternat Med 2013;2013:649836.
14. Mody BS. Acute effects of Surya Namaskar on the cardiovascular & metabolic system. J Bodyw Mov Ther 2011;
15:343–347.
15. Tran MD, Holly RG, Lashbrook J, Amsterdam EA. Effects
of Hatha yoga practice on the health-related aspects of
physical fitness. Prev Cardiol 2001;4:165–170.
16. Joseph CN, Porta C, Casucci G, et al. Slow breathing improves arterial baroreflex sensitivity and decreases blood
pressure in essential hypertension. Hypertension 2005;46:
714–718.
17. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan
MM, Ford GA. Effects of aerobic exercise training and
yoga on the baroreflex in healthy elderly persons. Eur J Clin
Invest 1997;27:443–449.
18. Bouassida A, Chamari K, Zaouali M, Feki Y, Zbidi A,
Tabka Z. Review on leptin and adiponectin responses and
adaptations to acute and chronic exercise. Br J Sports Med
2010;44:620–630.
19. Kiecolt-Glaser JK, Christian L, Preston H, et al. Stress,
inflammation, and yoga practice. Psychosom Med 2010;72:
113–121.
20. Gleeson M, Bishop NC, Stensel DJ, Lindley MR, Mastana
SS, Nimmo MA. The anti-inflammatory effects of exercise:
mechanisms and implications for the prevention and treatment of disease. Nat Rev Immunol 2011;11:607–615.
21. Grant S, Corbett K, Amjad AM, Wilson J, Aitchison T. A
comparison of methods of predicting maximum oxygen
uptake. Br J Sports Med 1995;29(3):147–152.
22. Cooper KH. A means of assessing maximal oxygen intake.
Correlation between field and treadmill testing. JAMA
1968;203:201–204.
23. Borg G. Ratings of perceived exertion and heart rates
during short-term cycle exercise and their use in a new
cycling strength test. Int J Sports Med 1982;3:153–158.
24. Hagins M, Moore W, Rundle A. Does practicing hatha
yoga satisfy recommendations for intensity of physical
activity which improves and maintains health and cardiovascular fitness? BMC Complement Altern Med 2007;7:40.
25. Sinha B, Ray US, Pathak A, Selvamurthy W. Energy cost
and cardiorespiratory changes during the practice of Surya
Namaskar. Indian J Physiol Pharmacol 2004;48:184–190.
26. Clay CC, Lloyd LK, Walker JL, Sharp KR, Pankey RB.
The metabolic cost of hatha yoga. J Strength Cond Res 2005;
19(3):604–610.
86
PAPP ET AL.
blood parameters was not detected after HIY. Perhaps research on older people or those with lower fitness levels or
on patient groups is needed to detect such effects.
Both the ApoA1 and adiponectin levels increased in HIY,
which suggests a positive metabolic effect on a somewhat
active and healthy group. However, large positive effects
were not expected. Yet, the increasing ApoA1 and adiponectin levels along with the lowered HbA1c in the HIY
show a clear trend. The HIY dose-response was low for any
cardiovascular fitness improvements, but this study still
found positive effects on ApoA1 and adiponectin.
Conclusions
Contrary to the initial hypothesis, this 6-week HIY program had no significant effect on estimated VO2max. This
probably relates to insufficiencies and variations regarding
both HIY dose and intensity. The weather conditions also
varied slightly during the Cooper tests. An additional limitation involves the use of pseudo-randomization to obtain
equal group sizes. However, apolipoprotein A1 and adiponectin levels increased significantly in the HIY group, which
suggests that HIY can potentially be effective in low doses.
Acknowledgments
The authors thank all who volunteered to participate.
They also thank Birger Andrén for helping out with the
statistics, the yoga instructors (Ulrika Hedlund, Maddalena
Maresca, and Vera Engdahl), and the test leaders (Matilda
Johansson, Agnes Karlsson-Pyk, Maria Andersson, Johanna
Öster, and Catarina Levin) for helping out with measurements. No funding was received for this study. All data are
stored at an academic primary care center.
Author Disclosure Statement
No competing financial interests exist.
References
1. Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT. Effect of physical inactivity on major noncommunicable diseases worldwide: an analysis of burden
of disease and life expectancy. Lancet 2012;380:219–229.
2. Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies. J Altern Complement
Med 2010;16:3–12.
3. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A,
Dobos G. Effects of yoga on cardiovascular disease risk
factors: a systematic review and meta-analysis. Int J Cardiol 2014;173:170–183.
4. Shelov DV, Suchday S, Friedberg JP. A pilot study measuring the impact of yoga on the trait of mindfulness. Behav Cogn Psychother 2009;37:595–598.
5. Georg F. The Shambhala Encyclopedia of Yoga. London:
Shambhala, 2000.
6. Mustian KM, Sprod LK, Janelsins M, et al. Multicenter,
randomized controlled trial of yoga for sleep quality among
cancer survivors. J Clin Oncol 2013;31:3233–3241.
7. Santaella DF, Devesa CR, Rojo MR, et al. Yoga respiratory
training improves respiratory function and cardiac sympathovagal balance in elderly subjects: a randomised controlled trial. BMJ Open 2011;1:e000085.
8. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic meditation and supine rest.
Appl Psychophysiol Biofeedback 2010;35:135–140.
9. National Center for Complementary and Integrative Health.
Homepage on Internet: https://nccih.nih.gov, accessed
January 12, 2015.
10. Garber CE, Blissmer B, Deschenes MR, et al. American
College of Sports Medicine position stand. Quantity and
quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in
apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011;43(7):1334–1359.
11. Raub JA. Psychophysiologic effects of Hatha Yoga on
musculoskeletal and cardiopulmonary function: a literature
review. J Altern Complement Med 2002;8:797–812.
12. Broad WJ. The Science of Yoga: The Risks and Rewards.
New York: Simon & Schuster, 2012.
13. Hagins M, States R, Selfe T, Innes K. Effectiveness of yoga
for hypertension: systematic review and meta-analysis.
Evid Based Complement Alternat Med 2013;2013:649836.
14. Mody BS. Acute effects of Surya Namaskar on the cardiovascular & metabolic system. J Bodyw Mov Ther 2011;
15:343–347.
15. Tran MD, Holly RG, Lashbrook J, Amsterdam EA. Effects
of Hatha yoga practice on the health-related aspects of
physical fitness. Prev Cardiol 2001;4:165–170.
16. Joseph CN, Porta C, Casucci G, et al. Slow breathing improves arterial baroreflex sensitivity and decreases blood
pressure in essential hypertension. Hypertension 2005;46:
714–718.
17. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan
MM, Ford GA. Effects of aerobic exercise training and
yoga on the baroreflex in healthy elderly persons. Eur J Clin
Invest 1997;27:443–449.
18. Bouassida A, Chamari K, Zaouali M, Feki Y, Zbidi A,
Tabka Z. Review on leptin and adiponectin responses and
adaptations to acute and chronic exercise. Br J Sports Med
2010;44:620–630.
19. Kiecolt-Glaser JK, Christian L, Preston H, et al. Stress,
inflammation, and yoga practice. Psychosom Med 2010;72:
113–121.
20. Gleeson M, Bishop NC, Stensel DJ, Lindley MR, Mastana
SS, Nimmo MA. The anti-inflammatory effects of exercise:
mechanisms and implications for the prevention and treatment of disease. Nat Rev Immunol 2011;11:607–615.
21. Grant S, Corbett K, Amjad AM, Wilson J, Aitchison T. A
comparison of methods of predicting maximum oxygen
uptake. Br J Sports Med 1995;29(3):147–152.
22. Cooper KH. A means of assessing maximal oxygen intake.
Correlation between field and treadmill testing. JAMA
1968;203:201–204.
23. Borg G. Ratings of perceived exertion and heart rates
during short-term cycle exercise and their use in a new
cycling strength test. Int J Sports Med 1982;3:153–158.
24. Hagins M, Moore W, Rundle A. Does practicing hatha
yoga satisfy recommendations for intensity of physical
activity which improves and maintains health and cardiovascular fitness? BMC Complement Altern Med 2007;7:40.
25. Sinha B, Ray US, Pathak A, Selvamurthy W. Energy cost
and cardiorespiratory changes during the practice of Surya
Namaskar. Indian J Physiol Pharmacol 2004;48:184–190.
26. Clay CC, Lloyd LK, Walker JL, Sharp KR, Pankey RB.
The metabolic cost of hatha yoga. J Strength Cond Res 2005;
19(3):604–610.
YOGA AND CARDIOVASCULAR FITNESS
87
27. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes and intensity of exercise. Evid Based Complement Alternat Med 2011;2011:
241–294.
28. Kiecolt-Glaser JK, Christian LM, et al. Adiponectin, leptin,
and yoga practice. Physiol Behav 2012;107:809–813.
29. Kiecolt-Glaser JK, Bennett JM, Andridge R, et al. Yoga’s
impact on inflammation, mood, and fatigue in breast cancer
survivors: a randomized controlled trial. J Clin Oncol 2014;
32:1040–1049.
30. Telles S, Singh N, Balkrishna A. Heart rate variability
changes during high frequency yoga breathing and breath
awareness. Biopsychosoc Med 2011;5:4.
31. Tai YP, Colaco CB. Upside-down position for paroxysmal
supraventricular tachycardia. Lancet 1981;2:1289.
32. Selvamurthy W, Sridharan K, Ray US, et al. A new physiological approach to control essential hypertension. Indian
J Physiol Pharmacol 1998;42:205–213.
33. Farinatti PT, Brandao C, Soares PP, Duarte AF. Acute effects of stretching exercise on the heart rate variability in
subjects with low flexibility levels. J Strength Cond Res
2011;25:1579–1585.
34. O’Donovan G, Blazevich AJ, Boreham C, et al. The ABC
of physical activity for health: a consensus statement from
the British Association of Sport and Exercise Sciences. J
Sports Sci 2010;28:573–591.
35. Cole RJ. Nonpharmacologic techniques for promoting
sleep. Clin Sports Med 2005;24:343–353, xi.
36. Bhutkar MV, Bhutkar PM, Taware GB, Surdi AD. How
effective is sun salutation in improving muscle strength,
general body endurance and body composition? Asian J
Sports Med 2011;2:259–266.
Appendix A: Intervention with High Intensity
Yoga Program
All classes were run by three experienced certified yoga
instructors on the same day of the week and at the same time
in the afternoon. The instructors received a DVD with the
HIY program and practiced it together for several months to
get synchronized in their instruction of the program.
During the HIY classes and during home practice, the
participants were encouraged to fill in their perceived exertion (central and peripheral), with the aim of working at an
intensity of 14–17 using the RPE scale. The HIY group
received a 55-minute DVD with the same content as the
HIY class and was encouraged to participate in home
training at least twice a week. The control group received
the HIY DVD after the intervention.
HIY program
The high-intensity yoga (HIY) program included highintensity dynamic yoga postures with 30–40 min of classical
surya namaskar, that is, SS, and 15 min of other poses
( pincha mayurasana); half hand stand toward the wall (ardha
adho mukha vrksasana), parivrtta parsvakonasana, gomukasana, and sarvangasana. The SS involves a collection of 12
separate exercises forming a dynamic sequence using tadasana, tadasana with back bend, uttanasana (with bent
knees), crescent pose (right leg back), adho mukha svanasana, modified chatturanga dandasana (with buttocks up and
knees and chest on ground), urdhva mukha svanasana (knees
on ground), adho mukha svanasana, crescent pose (right leg
forward), uttanasana, tadasana with back bend and tadasana,
SS sequence similar to that described elsewhere.14
The next round was repeated with the left leg back and
forward during the crescent pose. The speed of the SS was
somewhat increased during the 6-week period, with the goal
of performing each pose for 1.5–2 seconds. Relaxation (5
minutes) used the waterfall pose (viparita karani) or lying
on the back (shavasana).
Address correspondence to:
Marian E. Papp, MSc
Department of Neurobiology Care Sciences and Society
Academic Primary Care Centre
Karolinska Institutet
Alfred Nobels alle 12
S-141 83, Huddinge
Sweden
E-mail: [email protected]
HIY dose
The average HIY dose for the teacher-led classes was 240
minutes (range, 60–360 minutes) from a total of 360 minutes
(1 class weekly for 6 weeks), including an average of four
classes during the intervention. During the 6 weeks, the home
training was an average of 135 minutes (range, 0–560 minutes) while the recommendation was 120 minutes a week. The
average total HIY time (classes and home training) was 390
minutes (range, 210–800 minutes).
YOGA AND CARDIOVASCULAR FITNESS
87
27. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes and intensity of exercise. Evid Based Complement Alternat Med 2011;2011:
241–294.
28. Kiecolt-Glaser JK, Christian LM, et al. Adiponectin, leptin,
and yoga practice. Physiol Behav 2012;107:809–813.
29. Kiecolt-Glaser JK, Bennett JM, Andridge R, et al. Yoga’s
impact on inflammation, mood, and fatigue in breast cancer
survivors: a randomized controlled trial. J Clin Oncol 2014;
32:1040–1049.
30. Telles S, Singh N, Balkrishna A. Heart rate variability
changes during high frequency yoga breathing and breath
awareness. Biopsychosoc Med 2011;5:4.
31. Tai YP, Colaco CB. Upside-down position for paroxysmal
supraventricular tachycardia. Lancet 1981;2:1289.
32. Selvamurthy W, Sridharan K, Ray US, et al. A new physiological approach to control essential hypertension. Indian
J Physiol Pharmacol 1998;42:205–213.
33. Farinatti PT, Brandao C, Soares PP, Duarte AF. Acute effects of stretching exercise on the heart rate variability in
subjects with low flexibility levels. J Strength Cond Res
2011;25:1579–1585.
34. O’Donovan G, Blazevich AJ, Boreham C, et al. The ABC
of physical activity for health: a consensus statement from
the British Association of Sport and Exercise Sciences. J
Sports Sci 2010;28:573–591.
35. Cole RJ. Nonpharmacologic techniques for promoting
sleep. Clin Sports Med 2005;24:343–353, xi.
36. Bhutkar MV, Bhutkar PM, Taware GB, Surdi AD. How
effective is sun salutation in improving muscle strength,
general body endurance and body composition? Asian J
Sports Med 2011;2:259–266.
Appendix A: Intervention with High Intensity
Yoga Program
All classes were run by three experienced certified yoga
instructors on the same day of the week and at the same time
in the afternoon. The instructors received a DVD with the
HIY program and practiced it together for several months to
get synchronized in their instruction of the program.
During the HIY classes and during home practice, the
participants were encouraged to fill in their perceived exertion (central and peripheral), with the aim of working at an
intensity of 14–17 using the RPE scale. The HIY group
received a 55-minute DVD with the same content as the
HIY class and was encouraged to participate in home
training at least twice a week. The control group received
the HIY DVD after the intervention.
HIY program
The high-intensity yoga (HIY) program included highintensity dynamic yoga postures with 30–40 min of classical
surya namaskar, that is, SS, and 15 min of other poses
( pincha mayurasana); half hand stand toward the wall (ardha
adho mukha vrksasana), parivrtta parsvakonasana, gomukasana, and sarvangasana. The SS involves a collection of 12
separate exercises forming a dynamic sequence using tadasana, tadasana with back bend, uttanasana (with bent
knees), crescent pose (right leg back), adho mukha svanasana, modified chatturanga dandasana (with buttocks up and
knees and chest on ground), urdhva mukha svanasana (knees
on ground), adho mukha svanasana, crescent pose (right leg
forward), uttanasana, tadasana with back bend and tadasana,
SS sequence similar to that described elsewhere.14
The next round was repeated with the left leg back and
forward during the crescent pose. The speed of the SS was
somewhat increased during the 6-week period, with the goal
of performing each pose for 1.5–2 seconds. Relaxation (5
minutes) used the waterfall pose (viparita karani) or lying
on the back (shavasana).
Address correspondence to:
Marian E. Papp, MSc
Department of Neurobiology Care Sciences and Society
Academic Primary Care Centre
Karolinska Institutet
Alfred Nobels alle 12
S-141 83, Huddinge
Sweden
E-mail: [email protected]
HIY dose
The average HIY dose for the teacher-led classes was 240
minutes (range, 60–360 minutes) from a total of 360 minutes
(1 class weekly for 6 weeks), including an average of four
classes during the intervention. During the 6 weeks, the home
training was an average of 135 minutes (range, 0–560 minutes) while the recommendation was 120 minutes a week. The
average total HIY time (classes and home training) was 390
minutes (range, 210–800 minutes).
III
III
Title: Effects of yogic exercises on functional capacity, lung function and
Title: Effects of yogic exercises on functional capacity, lung function and
quality of life in participants with obstructive pulmonary disease – A
quality of life in participants with obstructive pulmonary disease – A
randomized controlled study
randomized controlled study
Authors:
Authors:
Marian E Papp
1*
Marian E Papp1*
Per E Wändell1 email: [email protected]
Per E Wändell1 email: [email protected]
Petra Lindfors2 email: [email protected]
Petra Lindfors2 email: [email protected]
Malin Nygren-Bonnier3 email: [email protected]
Malin Nygren-Bonnier3 email: [email protected]
Correspondence to: Marian Papp, Department of Neurobiology Care Sciences and Society,
Correspondence to: Marian Papp, Department of Neurobiology Care Sciences and Society,
Division of Family Medicine, Karolinska Institutet, Alfred Nobels alle 23, S-141 83,
Division of Family Medicine, Karolinska Institutet, Alfred Nobels alle 23, S-141 83,
Huddinge, Sweden; e-mail: [email protected], [email protected]
Huddinge, Sweden; e-mail: [email protected], [email protected]
Author affiliations: 1Department of Neurobiology Care Sciences and Society, Division of
Author affiliations: 1Department of Neurobiology Care Sciences and Society, Division of
family medicine, Karolinska Institutet, Stockholm, Sweden; 2Department of Psychology,
family medicine, Karolinska Institutet, Stockholm, Sweden; 2Department of Psychology,
Stockholm University, Stockholm, Sweden; 3Department of Neurobiology Care Sciences and
Stockholm University, Stockholm, Sweden; 3Department of Neurobiology Care Sciences and
Society, Division of Physiotherapy, Karolinska Institutet, Stockholm, Sweden and Functional
Society, Division of Physiotherapy, Karolinska Institutet, Stockholm, Sweden and Functional
Area Occupational therapy and Physiotherapy, Allied Health Professionals Function,
Area Occupational therapy and Physiotherapy, Allied Health Professionals Function,
Karolinska University Hospital, Huddinge, Sweden.
Karolinska University Hospital, Huddinge, Sweden.
Author contributions: MP and PW performed the literature search, MP, PL, PW and MNB
Author contributions: MP and PW performed the literature search, MP, PL, PW and MNB
designed the study, MP and MNB performed the study with data collection. MP, MNB and
designed the study, MP and MNB performed the study with data collection. MP, MNB and
PW analyzed the data. MP wrote the manuscript assisted by PW, PL and MNB. All authors
PW analyzed the data. MP wrote the manuscript assisted by PW, PL and MNB. All authors
read and approved of the final version of the manuscript.
read and approved of the final version of the manuscript.
ABSTRACT
ABSTRACT
BACKGROUND: Knowledge of hatha yogic exercises, the most used yoga style, to increase
BACKGROUND: Knowledge of hatha yogic exercises, the most used yoga style, to increase
functional capacity in patients with obstructive pulmonary diseases remains limited.
functional capacity in patients with obstructive pulmonary diseases remains limited.
AIM: The aim was to evaluate the effects and feasibility of hatha yoga (HY) compared to a
AIM: The aim was to evaluate the effects and feasibility of hatha yoga (HY) compared to a
conventional training program (CTP) on functional capacity, lung function and quality of life
conventional training program (CTP) on functional capacity, lung function and quality of life
in patients/persons with obstructive pulmonary diseases.
in patients/persons with obstructive pulmonary diseases.
DESIGN: RCT (randomized clinical trial)
DESIGN: RCT (randomized clinical trial)
SETTING: The study was performed at the Karolinska University Hospital, Stockholm,
SETTING: The study was performed at the Karolinska University Hospital, Stockholm,
Sweden among outpatients.
Sweden among outpatients.
POPULATION: Thirty-six patients with obstructive pulmonary disease.
POPULATION: Thirty-six patients with obstructive pulmonary disease.
METHODS: Forty patients were randomized with 36 (24 women, median age=64, age range:
METHODS: Forty patients were randomized with 36 (24 women, median age=64, age range:
40-84 yrs) participating in HY (n=19) or CTP (n=17). Both HY and CTP involved a 12-week
40-84 yrs) participating in HY (n=19) or CTP (n=17). Both HY and CTP involved a 12-week
program with a 6-month follow-up. Functional capacity (using 6-minute walk test, 6MWT),
program with a 6-month follow-up. Functional capacity (using 6-minute walk test, 6MWT),
lung function (spirometry), respiratory muscle strength (respiratory pressure meter), oxygen
lung function (spirometry), respiratory muscle strength (respiratory pressure meter), oxygen
saturation (SpO2), breathlessness (Borg), respiratory rate (f) and disease-specific quality of life
saturation (SpO2), breathlessness (Borg), respiratory rate (f) and disease-specific quality of life
(CRQ) were measured at baseline, at 12 weeks and at a 6-month follow-up.
(CRQ) were measured at baseline, at 12 weeks and at a 6-month follow-up.
RESULTS: Testing for interaction (group x time) with ANOVA analysis showed significant
RESULTS: Testing for interaction (group x time) with ANOVA analysis showed significant
results on CRQ domains fatigue (p=0.04) and CRQ domain emotional (p=0.02), showing
results on CRQ domains fatigue (p=0.04) and CRQ domain emotional (p=0.02), showing
improvements within the CTP group after the 12-week intervention (p=0.02 and 0.01,
improvements within the CTP group after the 12-week intervention (p=0.02 and 0.01,
respectively) but not in the HY group. Within each group, significant improvements emerged
respectively) but not in the HY group. Within each group, significant improvements emerged
on 6-minute walk distance (6MWD) after 12-week intervention (HY: mean difference 32.6 m;
on 6-minute walk distance (6MWD) after 12-week intervention (HY: mean difference 32.6 m;
CI 10.1-55.1, p=0.014; CTP: mean difference 42.4 m; CI 17.9-67.0, p=0.006). Within-group
CI 10.1-55.1, p=0.014; CTP: mean difference 42.4 m; CI 17.9-67.0, p=0.006). Within-group
improvements in the CRQ appeared in both groups. Within the HY group, the respiratory rate
improvements in the CRQ appeared in both groups. Within the HY group, the respiratory rate
(f) decreased and SpO2 increased. Improved effects after follow-up was only for the CTP
(f) decreased and SpO2 increased. Improved effects after follow-up was only for the CTP
group in 6MWD (p=0.04), diastolic blood pressure (p=0.05) and CRQ domain emotional
group in 6MWD (p=0.04), diastolic blood pressure (p=0.05) and CRQ domain emotional
(p=0.01).
(p=0.01).
CONCLUSIONS: After 12 weeks, 6MWD improved significantly within both groups. Within
CONCLUSIONS: After 12 weeks, 6MWD improved significantly within both groups. Within
the HY group improvements in the CRQ mastery domain, f and SpO2 emerged and within the
the HY group improvements in the CRQ mastery domain, f and SpO2 emerged and within the
CTP group improvements in lung function parameter forced vital capacity (FVC), respiratory
CTP group improvements in lung function parameter forced vital capacity (FVC), respiratory
muscle strength and across all CRQ-domains appeared. The CTP showed remaining effects
muscle strength and across all CRQ-domains appeared. The CTP showed remaining effects
after 6-months follow up in CRQ
after 6-months follow up in CRQ
CLINICAL REHABILITATION IMPACT: Similar effects of HY and CTP show that HY
CLINICAL REHABILITATION IMPACT: Similar effects of HY and CTP show that HY
seems feasible and safe as a form of physical exercise for pulmonary disease patients. As part
seems feasible and safe as a form of physical exercise for pulmonary disease patients. As part
of the rehabilitation, HY may constitute an alternative to other physical training activities and
of the rehabilitation, HY may constitute an alternative to other physical training activities and
may be a useful addition to formal rehabilitation programs.
may be a useful addition to formal rehabilitation programs.
Keywords: Asthma; Pulmonary Disease, Chronic Obstructive; Meditative Movement; Yoga
Keywords: Asthma; Pulmonary Disease, Chronic Obstructive; Meditative Movement; Yoga
Registration number: NCT02233114
Registration number: NCT02233114
Abbreviations: HY- yogic exercises based on hatha yoga; CTP - individualized program of
Abbreviations: HY- yogic exercises based on hatha yoga; CTP - individualized program of
strength and endurance training based on physiotherapy
strength and endurance training based on physiotherapy
CRQ-SAS = Chronic Respiratory Questionnaire self-reported disease-specific quality of life;
CRQ-SAS = Chronic Respiratory Questionnaire self-reported disease-specific quality of life;
f = respiratory rate; 6MWT = six minute walk test; 6MWD= six minute walk distance; SpO2 =
f = respiratory rate; 6MWT = six minute walk test; 6MWD= six minute walk distance; SpO2 =
peripheral oxygen saturation; FEV1= forced expiratory volume in one second; FVC=forced
peripheral oxygen saturation; FEV1= forced expiratory volume in one second; FVC=forced
vital capacity; DD-index= dyspnea related distress; COPD= Pulmonary disease, chronic
vital capacity; DD-index= dyspnea related distress; COPD= Pulmonary disease, chronic
obstructive
obstructive
1. Introduction
1. Introduction
Chronic Obstructive Pulmonary Disease (COPD) and obstructive asthma have an estimated
worldwide prevalence of 8-10%
1-3
with both involving chronic inflammation and airflow
limitations in the lung tissue. The prevalence of diagnosed COPD and asthma in the
Stockholm County is 1.8% and 5.9% respectively.
4
However, COPD involves permanent
Chronic Obstructive Pulmonary Disease (COPD) and obstructive asthma have an estimated
worldwide prevalence of 8-10% 1-3 with both involving chronic inflammation and airflow
limitations in the lung tissue. The prevalence of diagnosed COPD and asthma in the
Stockholm County is 1.8% and 5.9% respectively. 4 However, COPD involves permanent
structural changes 3 with varied causes 5 6 and is considered to be largely under-diagnosed. 5
structural changes 3 with varied causes 5 6 and is considered to be largely under-diagnosed. 5
Asthma involves episodic smooth muscle contraction of genetic or environmental cause.
Asthma involves episodic smooth muscle contraction of genetic or environmental cause.
COPD and asthma treatments are both pharmacologic and non-pharmacologic. 3 Pulmonary
COPD and asthma treatments are both pharmacologic and non-pharmacologic. 3 Pulmonary
rehabilitation is an important component of the non-pharmacologic treatment. 7 However,
rehabilitation is an important component of the non-pharmacologic treatment. 7 However,
additional RCT-studies of breathing control and pulmonary rehabilitation exercises 8 are
additional RCT-studies of breathing control and pulmonary rehabilitation exercises 8 are
needed for patients with breathing disorders. Such rehabilitation may include yogic exercises
needed for patients with breathing disorders. Such rehabilitation may include yogic exercises
and involve both long-term and short-term physiotherapeutic interventions.
9 10
Yogic
and involve both long-term and short-term physiotherapeutic interventions. 9 10 Yogic
exercises based on hatha yoga (HY), the most used yoga style 11, involve physical activity
exercises based on hatha yoga (HY), the most used yoga style 11, involve physical activity
using body-mind-awareness/self-efficacy techniques 12, meditative movements 13 14 and
using body-mind-awareness/self-efficacy techniques 12, meditative movements 13 14 and
attention based (psychophysical) activities. 15 Reported effects of HY include improved
attention based (psychophysical) activities. 15 Reported effects of HY include improved
functional capacity and fewer respiratory complaints 16 in patients with reduced breathing
functional capacity and fewer respiratory complaints 16 in patients with reduced breathing
capacity 17-19and in healthy persons. 20 Others report that HY interventions improve quality of
capacity 17-19and in healthy persons. 20 Others report that HY interventions improve quality of
life 2 8 21 sleep quality 13, cardio-metabolic health 22 23, functional ability24, reduce perceived
life 2 8 21 sleep quality 13, cardio-metabolic health 22 23, functional ability24, reduce perceived
stress and mental disease. 25 Also, HY is reported to improve breathing techniques, chest
stress and mental disease. 25 Also, HY is reported to improve breathing techniques, chest
expansion and lung functions in both patients with COPD and healthy persons. 2 20 26
expansion and lung functions in both patients with COPD and healthy persons. 2 20 26
Moreover, pilot yoga interventions have been shown to improve lung function reflected in
Moreover, pilot yoga interventions have been shown to improve lung function reflected in
forced expiratory volumes (FEV), dyspnea-related distress (DD-index) 18 and improved
forced expiratory volumes (FEV), dyspnea-related distress (DD-index) 18 and improved
oxygen saturation (SpO2). 26
oxygen saturation (SpO2). 26
Individualized physical conventional training programs (CTPs), including strength and
Individualized physical conventional training programs (CTPs), including strength and
endurance training, are physiotherapeutic interventions forming part of pulmonary
endurance training, are physiotherapeutic interventions forming part of pulmonary
rehabilitation. CTP is an effective, established and evaluated treatment for lung disorders,
rehabilitation. CTP is an effective, established and evaluated treatment for lung disorders,
which decreases disease progression in patients with lung diseases
7 27-29
, reduces dyspnea and
which decreases disease progression in patients with lung diseases 7 27-29, reduces dyspnea and
depression, increases functional capacity and quality of life. 29-31
depression, increases functional capacity and quality of life. 29-31
Today patients ask for alternative rehabilitation treatments that involve other methods of
Today patients ask for alternative rehabilitation treatments that involve other methods of
rehabilitation than do conventional treatments. However, research of the effects of yogic
rehabilitation than do conventional treatments. However, research of the effects of yogic
exercises on obstructive lung diseases is limited, involving smaller RCT and pilot studies with
exercises on obstructive lung diseases is limited, involving smaller RCT and pilot studies with
inadequate program descriptions. Besides, long-term follow-ups are lacking. To make HY
inadequate program descriptions. Besides, long-term follow-ups are lacking. To make HY
available for patients, evaluations of its efficiency and safety are needed. The main objective
available for patients, evaluations of its efficiency and safety are needed. The main objective
of this intervention study was to evaluate the efficiency and feasibility of regularly practicing
of this intervention study was to evaluate the efficiency and feasibility of regularly practicing
a newly developed HY-program in both patients with COPD and asthma on functional
a newly developed HY-program in both patients with COPD and asthma on functional
capacity, lung function and disease specific quality of life after 12 weeks and 6 months as
capacity, lung function and disease specific quality of life after 12 weeks and 6 months as
compared to an active control group participating in a conventional training program (CTP).
compared to an active control group participating in a conventional training program (CTP).
2. Methods
2. Methods
The study was approved by the Regional Ethical Review Board in Stockholm (Ref. No.:
The study was approved by the Regional Ethical Review Board in Stockholm (Ref. No.:
2011/248-31/1). All participants provided written informed consent.
2011/248-31/1). All participants provided written informed consent.
Patients were recruited from the Stockholm county area via medical doctors, nurses and
Patients were recruited from the Stockholm county area via medical doctors, nurses and
physiotherapists and via bulletin boards, social media and email-lists from academic primary
physiotherapists and via bulletin boards, social media and email-lists from academic primary
care centres (approx. 1,000 persons were approached). Invitation letters were sent to 168
care centres (approx. 1,000 persons were approached). Invitation letters were sent to 168
eligible persons. Inclusion criteria were; age 35-85 years with diagnosed (according to
eligible persons. Inclusion criteria were; age 35-85 years with diagnosed (according to
electronic patient records) obstructive pulmonary disease as COPD with mild to severe
electronic patient records) obstructive pulmonary disease as COPD with mild to severe
obstructions with GOLD 1-3, FEV1/FVC < 0.70 or diagnosed asthma with FEV1 and FEV1%
obstructions with GOLD 1-3, FEV1/FVC < 0.70 or diagnosed asthma with FEV1 and FEV1%
of predicted respiratory function of; 30% ≤ FEV1 ≤ 90%, (FVC=forced vital capacity).
of predicted respiratory function of; 30% ≤ FEV1 ≤ 90%, (FVC=forced vital capacity).
Exclusion criteria included severe neurological, orthopedic or rheumatologic injuries or
Exclusion criteria included severe neurological, orthopedic or rheumatologic injuries or
diseases (all patients were examined and their eligibility to perform the exercises was
diseases (all patients were examined and their eligibility to perform the exercises was
evaluated); inability to walk less than 200 meters; decreased mobility and chronic diseases
evaluated); inability to walk less than 200 meters; decreased mobility and chronic diseases
that can affect performance; surgery within 6 months; severe mental disease diagnosis (incl.
that can affect performance; surgery within 6 months; severe mental disease diagnosis (incl.
medication affecting attention); heart infarction within the last 12 months and change of
medication affecting attention); heart infarction within the last 12 months and change of
medications during the last 6 weeks.
medications during the last 6 weeks.
Sixty-two persons responded to the invitation letter while 65 (totalling 127) responded to calls
Sixty-two persons responded to the invitation letter while 65 (totalling 127) responded to calls
via social media, e-mail and telephone (Fig. 1). According to the ethical approval and
via social media, e-mail and telephone (Fig. 1). According to the ethical approval and
inclusion criteria, fifty-three patients were accepted for baseline measurements and fit the
inclusion criteria, fifty-three patients were accepted for baseline measurements and fit the
inclusion criteria while 74 did not. The causes for exclusion covered (total n=33) hypertension
inclusion criteria while 74 did not. The causes for exclusion covered (total n=33) hypertension
32
according to guidelines , upcoming surgery (n=2), mental disorder (n=5), chronic illness
according to guidelines32, upcoming surgery (n=2), mental disorder (n=5), chronic illness
(n=13), lack of time (n=6), language problems (n=5), time unsuitable (n=7), and no specific
(n=13), lack of time (n=6), language problems (n=5), time unsuitable (n=7), and no specific
personal reason (n=3). This resulted in 40 eligible patients who were randomized for
personal reason (n=3). This resulted in 40 eligible patients who were randomized for
participation with 20 in each group. Randomization was performed by an external person.
participation with 20 in each group. Randomization was performed by an external person.
Blank papers were scattered on a table with each participants’ identification code facing
Blank papers were scattered on a table with each participants’ identification code facing
down. Then one paper was randomly categorized into the HY group while the next was
down. Then one paper was randomly categorized into the HY group while the next was
categorized into the CTP group and so on. Table 1 presents patients’ baseline characteristics.
categorized into the CTP group and so on. Table 1 presents patients’ baseline characteristics.
As for medication, the patients used pulmonary inhaler treatments including corticosteroids,
As for medication, the patients used pulmonary inhaler treatments including corticosteroids,
short and long acting bronchodilators (β2-adrenergic drugs). Patients were instructed not to
short and long acting bronchodilators (β2-adrenergic drugs). Patients were instructed not to
change their medication during the intervention period. Some took statins, anticoagulants,
change their medication during the intervention period. Some took statins, anticoagulants,
blood pressure medication and anti-arrhythmic medication. Six patients in the HY-group had
blood pressure medication and anti-arrhythmic medication. Six patients in the HY-group had
diabetes while the CTP-group included three diabetics. One CTP-patient had bronchiectasis
diabetes while the CTP-group included three diabetics. One CTP-patient had bronchiectasis
(included in the COPD-group) while two in each group had both asthma and COPD (included
(included in the COPD-group) while two in each group had both asthma and COPD (included
in the COPD-group).
in the COPD-group).
Figure 1: Participant flow chart. ITT= intention to treat
Figure 1: Participant flow chart. ITT= intention to treat
2.1 Measurements
2.1 Measurements
Outcomes
Outcomes
The objective measures expected to change were functional capacity, assessed using the 6-
The objective measures expected to change were functional capacity, assessed using the 6-
minute walk test (6MWT), FEV1, FVC and the ratio of FEV1/FVC, respiratory muscle
minute walk test (6MWT), FEV1, FVC and the ratio of FEV1/FVC, respiratory muscle
strength (maximal inspiratory pressure (PImax), maximal expiratory pressure (PEmax)),
strength (maximal inspiratory pressure (PImax), maximal expiratory pressure (PEmax)),
respiratory rate (f) and oxygen saturation (SpO2). Haemodynamic assessments including blood
respiratory rate (f) and oxygen saturation (SpO2). Haemodynamic assessments including blood
pressure were expected to improve both after HY and CTP.
pressure were expected to improve both after HY and CTP.
Subjective measures expected to improve included disease specific quality of life (Chronic
Subjective measures expected to improve included disease specific quality of life (Chronic
Respiratory disease Questionnaire, CRQ-SAS), perceived exertion, breathlessness and
Respiratory disease Questionnaire, CRQ-SAS), perceived exertion, breathlessness and
dyspnea-related distress (DD-index) and self-reported health (EQ-5D/VAS).
dyspnea-related distress (DD-index) and self-reported health (EQ-5D/VAS).
All measurements and the interventions took place at the Karolinska University Hospital,
All measurements and the interventions took place at the Karolinska University Hospital,
Sweden. All measurements at baseline, at 12 weeks, and at 6 months after ending the
Sweden. All measurements at baseline, at 12 weeks, and at 6 months after ending the
intervention were performed in the same order and took place about one week before and one
intervention were performed in the same order and took place about one week before and one
week after the intervention. Patients were asked to refrain from caffeine, nicotine, and
week after the intervention. Patients were asked to refrain from caffeine, nicotine, and
physical activity during the measurement days. Pre-bronchodilator measurements were made
physical activity during the measurement days. Pre-bronchodilator measurements were made
at baseline before inclusion. For safety reasons, patients continued taking all their regular
at baseline before inclusion. For safety reasons, patients continued taking all their regular
medication. However, they were asked to refrain from short-acting bronchodilators 4 hours
medication. However, they were asked to refrain from short-acting bronchodilators 4 hours
before measurements. At baseline, any deviation was noted with the patient being asked to
before measurements. At baseline, any deviation was noted with the patient being asked to
behave similarly before the 12-week and 6-month measurements to minimize variation.
behave similarly before the 12-week and 6-month measurements to minimize variation.
Physiotherapists working at the hospital were test leaders and performed all the
Physiotherapists working at the hospital were test leaders and performed all the
measurements. Each patient met three different physiotherapists at one of three stations. The
measurements. Each patient met three different physiotherapists at one of three stations. The
first station included measurement of weight, blood pressure, f, heart rate, HRV measures and
first station included measurement of weight, blood pressure, f, heart rate, HRV measures and
general questions and the distribution of an enveloped questionnaire. The second station
general questions and the distribution of an enveloped questionnaire. The second station
included spirometry and respiratory muscle strength while the third included measurement of
included spirometry and respiratory muscle strength while the third included measurement of
6MWD, perceived exertion, breathlessness and SpO2.
6MWD, perceived exertion, breathlessness and SpO2.
Blood pressure (BP) was measured
32
while seated, after at least 5 minutes of rest, using an
Blood pressure (BP) was measured 32 while seated, after at least 5 minutes of rest, using an
automatic Omron mx3 oscillometric BP monitoring device. To maximize relaxation, a pillow
automatic Omron mx3 oscillometric BP monitoring device. To maximize relaxation, a pillow
supported the arm with the monitor being placed in the position of the heart on the upper arm.
supported the arm with the monitor being placed in the position of the heart on the upper arm.
The measurement was standardized for all patients; i.e., in the right arm, at the same time
The measurement was standardized for all patients; i.e., in the right arm, at the same time
during the day, in the same position (seated, back supported, legs firmly on the floor), no
during the day, in the same position (seated, back supported, legs firmly on the floor), no
talking or crossing of arms or legs were allowed. Machine error/accuracy of Omron mx3 was
talking or crossing of arms or legs were allowed. Machine error/accuracy of Omron mx3 was
±3mmHg (or 2%) of the reading.
±3mmHg (or 2%) of the reading.
Respiratory rate (f) was measured using RESPeRATE ultra Omron. 33 A belt around the
Respiratory rate (f) was measured using RESPeRATE ultra Omron. 33 A belt around the
lower chest was connected to a device placed on a separate table next to the patient in the
lower chest was connected to a device placed on a separate table next to the patient in the
supine position. Manual measurements were performed to validate the results of the
supine position. Manual measurements were performed to validate the results of the
apparatus. Heart rate variability (HRV) was recorded for 5 minutes during respiratory rate
apparatus. Heart rate variability (HRV) was recorded for 5 minutes during respiratory rate
measurement with a Polar heart rate Monitor
34 35
(RCX5, Polar Electro Oy, Kempele,
measurement with a Polar heart rate Monitor 34 35 (RCX5, Polar Electro Oy, Kempele,
Finland). Analysis used the Polar pro 5 software with default automated protocols for editing
Finland). Analysis used the Polar pro 5 software with default automated protocols for editing
of artefacts (sampling frequency 1000 Hz, 1 ms for each RR-interval). Recording and
of artefacts (sampling frequency 1000 Hz, 1 ms for each RR-interval). Recording and
analyses for variability of time domain parameters; proportion of pNN50% measure is defined
analyses for variability of time domain parameters; proportion of pNN50% measure is defined
as the number of all normal sinus intervals (NN) in which the change in consecutive normal
as the number of all normal sinus intervals (NN) in which the change in consecutive normal
sinus intervals exceeds 50 milliseconds divided by the total number of NN intervals
sinus intervals exceeds 50 milliseconds divided by the total number of NN intervals
measured. We computed Square root of the mean of the sum of the squares between adjacent
measured. We computed Square root of the mean of the sum of the squares between adjacent
NN intervals as RMSSD (since the recording time was short).
NN intervals as RMSSD (since the recording time was short).
At the first station, an enveloped questionnaire was distributed. The majority completed this
At the first station, an enveloped questionnaire was distributed. The majority completed this
self-report questionnaire in 30 minutes and returned it enveloped before leaving the hospital.
self-report questionnaire in 30 minutes and returned it enveloped before leaving the hospital.
Self-reports covered smoking, medication, disease onset, quality of life and overall health
Self-reports covered smoking, medication, disease onset, quality of life and overall health
status.
status.
Chronic Respiratory disease Questionnaire Self-Administrative Standardized activities
(CRQ-SAS)
36
includes 20 questions divided into 4 domains (dyspnea, fatigue, emotional
Chronic Respiratory disease Questionnaire Self-Administrative Standardized activities
(CRQ-SAS) 36 includes 20 questions divided into 4 domains (dyspnea, fatigue, emotional
function and mastery over breathing difficulties). The response format ranged from 1-7
function and mastery over breathing difficulties). The response format ranged from 1-7
(dyspnea domain with 5) with higher scores indicating less severity. Minimal clinical
(dyspnea domain with 5) with higher scores indicating less severity. Minimal clinical
important difference (MCID) required 0.5 points per domain.
important difference (MCID) required 0.5 points per domain.
37
Self-reported health was assessed using EuroQoL-5D (EQ-5D) asking the respondents to
Self-reported health was assessed using EuroQoL-5D (EQ-5D)37 asking the respondents to
indicate their health today along a 10 cm visual analogue scale (VAS) ranging from 0-100
indicate their health today along a 10 cm visual analogue scale (VAS) ranging from 0-100
with 100 being excellent health, and to write down this number and ticking the scale.
with 100 being excellent health, and to write down this number and ticking the scale.
Lung function was measured using Spirometry, Micro Loop, CareFusion and Micro
Lung function was measured using Spirometry, Micro Loop, CareFusion and Micro
spirometry, (Micro. Direct. Inc., Gold standard) 31 38 measuring FEV1, FVC and FEV1/FVC,
spirometry, (Micro. Direct. Inc., Gold standard) 31 38 measuring FEV1, FVC and FEV1/FVC,
presenting values in Liters and %. All breathing measurements, including three trials of
presenting values in Liters and %. All breathing measurements, including three trials of
flow/strength, were performed with the patient seated using a nose clip and a personal
flow/strength, were performed with the patient seated using a nose clip and a personal
disposable mouthpiece before taking short-acting bronchodilators (β2-adrenergic drugs).
disposable mouthpiece before taking short-acting bronchodilators (β2-adrenergic drugs).
Respiratory muscle strength was measured using maximal inspiratory pressure (PImax) and
Respiratory muscle strength was measured using maximal inspiratory pressure (PImax) and
maximal expiratory pressure (PEmax) with MicroRPM™ (Respiratory Pressure
maximal expiratory pressure (PEmax) with MicroRPM™ (Respiratory Pressure
Meter, Cat. No. RPM01, CareFusion Germany 234 GmbH, Hoechberg).
presented in cm H2O.
31
Values are
Meter, Cat. No. RPM01, CareFusion Germany 234 GmbH, Hoechberg). 31 Values are
presented in cm H2O.
The six-minute walk test (6MWT) 31 was standardized and took place in a quiet 50 meter
The six-minute walk test (6MWT) 31 was standardized and took place in a quiet 50 meter
corridor at the hospital, with markings every two meters and cues every minute. Cones were
corridor at the hospital, with markings every two meters and cues every minute. Cones were
placed at the end on the inside so the turns were within the end markings. The patients were
placed at the end on the inside so the turns were within the end markings. The patients were
instructed to walk as long distance as possible in six minutes.
instructed to walk as long distance as possible in six minutes.
Ratings of perceived exertion were registered before 6MWT (sitting) and directly after the
Ratings of perceived exertion were registered before 6MWT (sitting) and directly after the
6MWT (standing) using Borg CR-10 for fatigue in breathing and legs and Borg 20-RPE for
6MWT (standing) using Borg CR-10 for fatigue in breathing and legs and Borg 20-RPE for
general tiredness.
39 40
Both rating scales were used during training sessions (approx. 15+45
min. during training sessions/2x during the intervention).
DD-index
18 41
min. during training sessions/2x during the intervention).
was calculated dividing CR-10 Borg scores at the end of 6MWT by the total
distance walked in feet during 6MWT x 1000. Meters were transformed to feet. Minimum
clinical important difference (MCID) required one point.
general tiredness. 39 40 Both rating scales were used during training sessions (approx. 15+45
18
DD-index 18 41 was calculated dividing CR-10 Borg scores at the end of 6MWT by the total
distance walked in feet during 6MWT x 1000. Meters were transformed to feet. Minimum
clinical important difference (MCID) required one point. 18
Oxygen saturation (%) (SpO2) was measured using a Saturation- and pulse oximeter (Ohmeda
Oxygen saturation (%) (SpO2) was measured using a Saturation- and pulse oximeter (Ohmeda
tuffsat, Accuracy of PureSAT Signal Processing Technology, The ONYX II: Nonin Medical,
tuffsat, Accuracy of PureSAT Signal Processing Technology, The ONYX II: Nonin Medical,
Inc.; 2006 model 9550) before (sitting) and after the 6MWT (standing) in the ring or middle
Inc.; 2006 model 9550) before (sitting) and after the 6MWT (standing) in the ring or middle
finger. Heart rate was recorded.
finger. Heart rate was recorded.
2.2 Intervention (Appendix A)
2.2 Intervention (Appendix A)
The interventions (CTP, HY) were performed at the hospital in a well-ventilated and light
The interventions (CTP, HY) were performed at the hospital in a well-ventilated and light
room, twice a week (60-70 min for each session) during 12 weeks (from mid-March to June
room, twice a week (60-70 min for each session) during 12 weeks (from mid-March to June
2015, with recruitment from January to March). The maximal dose was 24 sessions. A home
2015, with recruitment from January to March). The maximal dose was 24 sessions. A home
training program was distributed (on DVD and paper) and recommended. Physical activity on
training program was distributed (on DVD and paper) and recommended. Physical activity on
recipe (“FaR”) was prescribed for both groups after the intervention with encouragement to
recipe (“FaR”) was prescribed for both groups after the intervention with encouragement to
continue the intervention programs. The program was safe to perform and no injuries or other
continue the intervention programs. The program was safe to perform and no injuries or other
side-effects occurred in either group during the interventions.
side-effects occurred in either group during the interventions.
Yogic exercises based on hatha yoga (HY)
Yogic exercises based on hatha yoga (HY)
The starting position involved sitting on a chair. The yoga classes (adjacent to gym) were
The starting position involved sitting on a chair. The yoga classes (adjacent to gym) were
partly based on prior research
18
and designed by first author. The classes were held by an
partly based on prior research 18 and designed by first author. The classes were held by an
experienced yoga teacher, not involved in the measurements, who was trained in the HY
experienced yoga teacher, not involved in the measurements, who was trained in the HY
program (by the first author that is a certified yoga teacher). The majority of the patients were
program (by the first author that is a certified yoga teacher). The majority of the patients were
novice to yoga.
novice to yoga.
Conventional training program (CTP; physiotherapeutic intervention)
Conventional training program (CTP; physiotherapeutic intervention)
CTP involved low intensity cycling and strength training and was performed in a gym (with
CTP involved low intensity cycling and strength training and was performed in a gym (with
gym equipment and stationary exercise bikes, adjacent to the yoga room) and instructed by
gym equipment and stationary exercise bikes, adjacent to the yoga room) and instructed by
physiotherapists. Strength training was tested individually on 70% of 1 RM using 2-4 sets
physiotherapists. Strength training was tested individually on 70% of 1 RM using 2-4 sets
with 10-20 repetitions of each exercise (total 10-12 exercises); Cycling 10-15 minutes per
with 10-20 repetitions of each exercise (total 10-12 exercises); Cycling 10-15 minutes per
session intensity ratings of 12-14 (on Borg 20-scale, approx. 50-60 rpm per minute).
session intensity ratings of 12-14 (on Borg 20-scale, approx. 50-60 rpm per minute).
A physiotherapist designed (last author) the CTP, which involved adjusting the load and
A physiotherapist designed (last author) the CTP, which involved adjusting the load and
repetitions individually during the training period for each participant. Some had previous
repetitions individually during the training period for each participant. Some had previous
individualized training programs from physiotherapy clinics. All were instructed to refrain
individualized training programs from physiotherapy clinics. All were instructed to refrain
from yoga during the intervention period.
from yoga during the intervention period.
2.3 Statistical analysis
2.3 Statistical analysis
A power calculation was performed using the dyspnea distress index (DD-index) and required
A power calculation was performed using the dyspnea distress index (DD-index) and required
24 persons in each group (alfa=0.05, 80% power, two-sided test) for a significant effect on the
24 persons in each group (alfa=0.05, 80% power, two-sided test) for a significant effect on the
DD-index of 1.3 compared to another study
18
compared to 0 (SD 2.0 versus 1.0). We tested
DD-index of 1.3 compared to another study 18 compared to 0 (SD 2.0 versus 1.0). We tested
interaction (group x time) including three time points (T1, T2, T3) on all dependent variables
interaction (group x time) including three time points (T1, T2, T3) on all dependent variables
using two-way repeated measure analysis of variance (ANOVA) combined with Huynh-Feldt
using two-way repeated measure analysis of variance (ANOVA) combined with Huynh-Feldt
post hoc test, and students t-test or Wilcoxon rank-sum test within and between groups.
post hoc test, and students t-test or Wilcoxon rank-sum test within and between groups.
Analyses of results were performed by intention-to-treat-analysis. Due to skewness either
Analyses of results were performed by intention-to-treat-analysis. Due to skewness either
Wilcoxon rank-sum tests or t-tests (two-tailed) were computed to analyze differences at
Wilcoxon rank-sum tests or t-tests (two-tailed) were computed to analyze differences at
baseline (T1), 12 weeks (T2) and 6-months (T3) within and between groups (Table 2).
baseline (T1), 12 weeks (T2) and 6-months (T3) within and between groups (Table 2).
Wilcoxon rank-sum tests were used to analyze ordinal data, differences in self-reported health
Wilcoxon rank-sum tests were used to analyze ordinal data, differences in self-reported health
(VAS), DD-index, CRQ-scale and Borg RPE measurements. The test for normality used the
(VAS), DD-index, CRQ-scale and Borg RPE measurements. The test for normality used the
Belanger and D´Agostino (1990) and the Shapiro-Wilk (1965) methods. Variance comparison
Belanger and D´Agostino (1990) and the Shapiro-Wilk (1965) methods. Variance comparison
test used the standard stata command (sdtest). The following parameters had skewed
test used the standard stata command (sdtest). The following parameters had skewed
distributions: DD-index, EQ-5D/VAS, SpO2, Systolic BP, RMSSD and pNN50%, 6MWD.
distributions: DD-index, EQ-5D/VAS, SpO2, Systolic BP, RMSSD and pNN50%, 6MWD.
Fischer’s exact test was calculated for p-values in baseline table on age, BMI, COPD, asthma
Fischer’s exact test was calculated for p-values in baseline table on age, BMI, COPD, asthma
and year smoking. Depending on skewness either Spearman (rs) coefficients or Pearson (rp)
and year smoking. Depending on skewness either Spearman (rs) coefficients or Pearson (rp)
coefficients were computed. Correlations included age, 6MWD, FEV1, EQ-5D/VAS, SpO2
coefficients were computed. Correlations included age, 6MWD, FEV1, EQ-5D/VAS, SpO2
and having more than two diseases. The significance level was set to p< 0.05 and confidence
and having more than two diseases. The significance level was set to p< 0.05 and confidence
interval to 95 %. Excluding outliers (one in each group) produced similar findings.
interval to 95 %. Excluding outliers (one in each group) produced similar findings.
The analyses were performed using STATA 14 (College Station, TX).
The analyses were performed using STATA 14 (College Station, TX).
3. Results
3. Results
Significant effects in 6MWD emerged between the groups at baseline (Fig. 1, Table 1). No
Significant effects in 6MWD emerged between the groups at baseline (Fig. 1, Table 1). No
other significant between-group effects emerged for any of the parameters at baseline.
other significant between-group effects emerged for any of the parameters at baseline.
Testing for interaction (group x time) with ANOVA analysis showed significant results on
Testing for interaction (group x time) with ANOVA analysis showed significant results on
CRQ domains fatigue (p=0.04) and CRQ domain emotional (p=0.02) (Table 2), and also for
CRQ domains fatigue (p=0.04) and CRQ domain emotional (p=0.02) (Table 2), and also for
diastolic BP (0.04) (in text). No other significant ANOVA-interaction emerged. After 12
diastolic BP (0.04) (in text). No other significant ANOVA-interaction emerged. After 12
weeks (T2), significant within-group effects in HY-group (Tables 2 and 3) emerged for CRQ
weeks (T2), significant within-group effects in HY-group (Tables 2 and 3) emerged for CRQ
domain mastery, and in all CRQ domains in the CTP i.e fatigue, dyspnea, mastery and
domain mastery, and in all CRQ domains in the CTP i.e fatigue, dyspnea, mastery and
emotional. After 12 weeks (T2) and at 6-months (T3) effects on MCID in CRQ appeared in
emotional. After 12 weeks (T2) and at 6-months (T3) effects on MCID in CRQ appeared in
both groups in all domains in CTP (somewhat larger for HY in mastery and fatigue for CTP),
both groups in all domains in CTP (somewhat larger for HY in mastery and fatigue for CTP),
(Table 3).
(Table 3).
Analyzing pairwise test between T1-T3 between CTP and HY for improved effects show
Analyzing pairwise test between T1-T3 between CTP and HY for improved effects show
significance in CRQ emotional domain (p=0.01), 6MWD (p=0.04) and diastolic BP (p=0.05)
significance in CRQ emotional domain (p=0.01), 6MWD (p=0.04) and diastolic BP (p=0.05)
favoring CTP (Table 2). No significance emerged in fatigue domain comparing the time
favoring CTP (Table 2). No significance emerged in fatigue domain comparing the time
intervals T1-T3 or the other two CRQ-domains mastery or dysphnea between HY and CTP.
intervals T1-T3 or the other two CRQ-domains mastery or dysphnea between HY and CTP.
Within each group, significant improvements emerged on walk distance (6MWD), (HY: mean
Within each group, significant improvements emerged on walk distance (6MWD), (HY: mean
difference 32.6 m; CI 10.1-55.1, p=0.014; CTP: mean difference 42.4 m; CI 17.9-67.0,
difference 32.6 m; CI 10.1-55.1, p=0.014; CTP: mean difference 42.4 m; CI 17.9-67.0,
p=0.006) after the 12-week intervention (T2) (Table. 2, Fig.2).
p=0.006) after the 12-week intervention (T2) (Table. 2, Fig.2).
More within-group analysis showed significant differences over time were found for HY on
More within-group analysis showed significant differences over time were found for HY on
SpO2 at rest and respiratory rate (f). Within the CTP group differences over time were found
SpO2 at rest and respiratory rate (f). Within the CTP group differences over time were found
for FVC and respiratory muscle strength (PEmax, PImax).
for FVC and respiratory muscle strength (PEmax, PImax).
Figure 2: Six minute walk test distance in meters (6MWD) at the three points in time.
Figure 2: Six minute walk test distance in meters (6MWD) at the three points in time.
In the HY, significant associations were found for differences in 6MWD and differences in
In the HY, significant associations were found for differences in 6MWD and differences in
EQ-5D/VAS (HY: rp=0.59, p=0.01), (CTP: rp=0.03, p=0.90). In the CTP, there were
EQ-5D/VAS (HY: rp=0.59, p=0.01), (CTP: rp=0.03, p=0.90). In the CTP, there were
significant correlations between differences in SpO2 and differences in FEV1 (0.61 rp, p=0.01)
significant correlations between differences in SpO2 and differences in FEV1 (0.61 rp, p=0.01)
(HY 0.06 rp, p=0.82).
(HY 0.06 rp, p=0.82).
The mean of yoga class adherence was 16 classes for HY (range: 3-24) while CTP attended
The mean of yoga class adherence was 16 classes for HY (range: 3-24) while CTP attended
19 (range: 12-22) training sessions.
19 (range: 12-22) training sessions.
Training maintenance and progression after the intervention (before 6-month follow-up)
Training maintenance and progression after the intervention (before 6-month follow-up)
In CTP (8 responding), 4 continued the CTP-program while 4 discontinued the program, 8 did
In CTP (8 responding), 4 continued the CTP-program while 4 discontinued the program, 8 did
other training. In HY (12 responding), 7 continued the program while 5 discontinued and 10
other training. In HY (12 responding), 7 continued the program while 5 discontinued and 10
did other training.
did other training.
Ratings of perceived exertion (CR-10) during CTP and HY (medians and ranges) were as
Ratings of perceived exertion (CR-10) during CTP and HY (medians and ranges) were as
follows for the CTP-group: breathlessness during cycling, 3.5 (range: 2.5-4.5); during strength
follows for the CTP-group: breathlessness during cycling, 3.5 (range: 2.5-4.5); during strength
training, 3.25 (range: 1-9); leg tiredness during cycling, 3 (range: 1-7); leg tiredness during
training, 3.25 (range: 1-9); leg tiredness during cycling, 3 (range: 1-7); leg tiredness during
strength training, 4.0 (range: 1.75-9). For the HY-group comparable figures was as follows:
strength training, 4.0 (range: 1.75-9). For the HY-group comparable figures was as follows:
breathlessness during yoga, 3 (range: 0-5.5); leg tiredness, 2.1 (range: 0.5-4.67). In the CTP,
breathlessness during yoga, 3 (range: 0-5.5); leg tiredness, 2.1 (range: 0.5-4.67). In the CTP,
general exertion (Borg 20) was 13.0 (range: 11-15) during cycling and 13.75 (range: 10-17)
general exertion (Borg 20) was 13.0 (range: 11-15) during cycling and 13.75 (range: 10-17)
during strength training. For HY during yoga sessions, general exertion was 10.15 (range: 3.5-
during strength training. For HY during yoga sessions, general exertion was 10.15 (range: 3.5-
14).
14).
For BP, significant between-group effects emerged with the CTP-group showing significantly
For BP, significant between-group effects emerged with the CTP-group showing significantly
(p=0.04) lower diastolic BP after 12 weeks (T2; mean decrease: HY=0.3 units; CTP=5.7) and
(p=0.04) lower diastolic BP after 12 weeks (T2; mean decrease: HY=0.3 units; CTP=5.7) and
after 6 months (T3; mean increase: HY=3.7 units; CTP=1.9). The decrease in diastolic BP
after 6 months (T3; mean increase: HY=3.7 units; CTP=1.9). The decrease in diastolic BP
was significant within the CTP-group (p=0.001). For systolic BP after 12 weeks (T2; mean
was significant within the CTP-group (p=0.001). For systolic BP after 12 weeks (T2; mean
decrease: CTP=4.2 units; HY=2.8), after 6 months (T3) a significant increase only in HY=9.1
decrease: CTP=4.2 units; HY=2.8), after 6 months (T3) a significant increase only in HY=9.1
units (p=0.014); CTP=6.1.
units (p=0.014); CTP=6.1.
Heart rate and heart rate variability were analysed showing no significant results.
Heart rate and heart rate variability were analysed showing no significant results.
Comparing baseline (T1) with the after follow-up measures, (T3), t-tests showed a significant
Comparing baseline (T1) with the after follow-up measures, (T3), t-tests showed a significant
effect with the CTP-group, as compared to the HY, exhibiting a significant increase in
effect with the CTP-group, as compared to the HY, exhibiting a significant increase in
6MWD (p=0.04) and CRQ-emotion (p=0.01) (Table 2).
6MWD (p=0.04) and CRQ-emotion (p=0.01) (Table 2).
4. Discussion
4. Discussion
The main findings showed that both HY and CTP-groups had improved in the 6MWD after
The main findings showed that both HY and CTP-groups had improved in the 6MWD after
the 12-week intervention, with remaining effects only in CTP group after follow-up (T3).
the 12-week intervention, with remaining effects only in CTP group after follow-up (T3).
Interaction (group x time) showed significance on CRQ fatigue and CRQ emotional, which
Interaction (group x time) showed significance on CRQ fatigue and CRQ emotional, which
probably relates to that the CTP had improved effects comparing baseline (T1) to the time
probably relates to that the CTP had improved effects comparing baseline (T1) to the time
point after the follow-up (T3). However, comparing the time points T1-T3 showed
point after the follow-up (T3). However, comparing the time points T1-T3 showed
significance only in emotional domain, favoring CTP between HY and CTP group.
significance only in emotional domain, favoring CTP between HY and CTP group.
Findings on 6MWD have reported similar findings with other yogic exercise programs. 17-19
Findings on 6MWD have reported similar findings with other yogic exercise programs. 17-19
As for recommendations regarding the minimal clinical important difference (MCID) for
As for recommendations regarding the minimal clinical important difference (MCID) for
6MWD, a meta-analysis
42
17
suggests a new MCID of 26 meters for patients with severe COPD.
This may replace the previously suggested 54 meters. 43 Using this new recommendation
6MWD, a meta-analysis 17 suggests a new MCID of 26 meters for patients with severe COPD.
42
This may replace the previously suggested 54 meters. 43 Using this new recommendation
for the 6MWD results in seven (37%) in HY and ten (59%) in CTP participants having a
for the 6MWD results in seven (37%) in HY and ten (59%) in CTP participants having a
MCID >30 meters, and with five (26%) in HY and nine (53%) in CTP having a MCID of >50
MCID >30 meters, and with five (26%) in HY and nine (53%) in CTP having a MCID of >50
meters. This suggests similar effects of both HY and CTP, with significant and clinically
meters. This suggests similar effects of both HY and CTP, with significant and clinically
important effects indicating an increased endurance and functional capacity after the 12-week
important effects indicating an increased endurance and functional capacity after the 12-week
intervention. However patients with severe COPD were excluded in this study due to ethical
intervention. However patients with severe COPD were excluded in this study due to ethical
considerations deeming that the HY program was not suitable for this group.
considerations deeming that the HY program was not suitable for this group.
According to the Borg ratings, the HY is of a lower intensity than the CTP. Thus, one reason
According to the Borg ratings, the HY is of a lower intensity than the CTP. Thus, one reason
for increased functional capacity in HY may involve a more efficient breathing pattern, less
for increased functional capacity in HY may involve a more efficient breathing pattern, less
dysphnea, better coordination and control of breathing and psychophysiological factors. 44
dysphnea, better coordination and control of breathing and psychophysiological factors. 44
Also exercises for the lower limbs (utkatasana vinyasa involving similar movements to deep
Also exercises for the lower limbs (utkatasana vinyasa involving similar movements to deep
squats) were included in the newly developed HY program (Appendix A). But, with more
squats) were included in the newly developed HY program (Appendix A). But, with more
COPD participants in the HY, improvements in this group may be limited as compared to the
COPD participants in the HY, improvements in this group may be limited as compared to the
asthma participants who constituted the majority in CTP-group. Since HY had no improving
asthma participants who constituted the majority in CTP-group. Since HY had no improving
effects on lung function and respiratory muscle strength parameters, other factors including
effects on lung function and respiratory muscle strength parameters, other factors including
the greater breathing control and the increased coordination of breathing practiced during HY
the greater breathing control and the increased coordination of breathing practiced during HY
may explain the 6MWD improvement. However, the HY program included some strength
may explain the 6MWD improvement. However, the HY program included some strength
exercises for the upper limbs that are important for breathing but not to the same extent as the
exercises for the upper limbs that are important for breathing but not to the same extent as the
CTP.
CTP.
In the CTP-group, the MCID of 0.5 points in each CRQ-domain was fulfilled (Table 3) for all
In the CTP-group, the MCID of 0.5 points in each CRQ-domain was fulfilled (Table 3) for all
four domains. Both groups exhibited immediate and remaining effects on MCID in CRQ
four domains. Both groups exhibited immediate and remaining effects on MCID in CRQ
(Table 3). Yet, the CTP had a larger effect for the fatigue (64%) and emotional (53%) domain,
(Table 3). Yet, the CTP had a larger effect for the fatigue (64%) and emotional (53%) domain,
while the larger effect in the HY emerged for the mastery domain (63%). The greater number
while the larger effect in the HY emerged for the mastery domain (63%). The greater number
of patients in the HY showing MCID in the mastery domain is perhaps related to an increased
of patients in the HY showing MCID in the mastery domain is perhaps related to an increased
21
self-efficacy. This suggestion follows from previous research , and interviews (manuscript
self-efficacy. This suggestion follows from previous research 21, and interviews (manuscript
in preparation) with the same patient group. Also, the per-protocol analysis suggested
in preparation) with the same patient group. Also, the per-protocol analysis suggested
significant additional improvements in the CRQ-emotional domain in the HY-group (results
significant additional improvements in the CRQ-emotional domain in the HY-group (results
not shown). Previously, HY using diaphragmatic breathing have shown positive effects on
not shown). Previously, HY using diaphragmatic breathing have shown positive effects on
disease-specific quality of life among patients with COPD.
2 8 45
However, others report no
effects. 18 This discrepancy may relate to different interpretations of how to analyze the data
disease-specific quality of life among patients with COPD. 2 8 45 However, others report no
effects. 18 This discrepancy may relate to different interpretations of how to analyze the data
according to guidelines for CRQ-calculations. Specifically, using the CRQ, a pilot trial of
according to guidelines for CRQ-calculations. Specifically, using the CRQ, a pilot trial of
patients with COPD and pulmonary arterial hypertension reported significant findings of
patients with COPD and pulmonary arterial hypertension reported significant findings of
clinical importance on the fatigue domain and clinically important effects on dyspnea and
clinical importance on the fatigue domain and clinically important effects on dyspnea and
emotional domains, including anxiety.
21
emotional domains, including anxiety. 21
Within the HY-group, but not in the CTP, there was a significant increase after the
Within the HY-group, but not in the CTP, there was a significant increase after the
intervention (12-weeks, T2) on SpO2 (however values were within normal range). Higher SpO2
intervention (12-weeks, T2) on SpO2 (however values were within normal range). Higher SpO2
26
26
have been reported in smaller sample studies of obstructive patients after yoga
interventions. Patients with COPD and asthma usually have a rapid, poorly coordinated and
shallow breathing pattern (dysfunctional breathing).
46 47
Using diaphragmatic breathing is
have been reported in smaller sample studies of obstructive patients after yoga
interventions. Patients with COPD and asthma usually have a rapid, poorly coordinated and
shallow breathing pattern (dysfunctional breathing). 46 47 Using diaphragmatic breathing is
similar to the complete yogic three-part breath and lowers f and improves SpO2 26 in COPD
similar to the complete yogic three-part breath and lowers f and improves SpO2 26 in COPD
during and after yoga. 17 48 This intervention used the complete yogic breath, which involves
during and after yoga. 17 48 This intervention used the complete yogic breath, which involves
the diaphragm (Appendix A). The f was significantly lowered within the HY while the SpO2 at
the diaphragm (Appendix A). The f was significantly lowered within the HY while the SpO2 at
rest was significantly higher within HY after the intervention (T2). A slower and deeper
rest was significantly higher within HY after the intervention (T2). A slower and deeper
breathing pattern is an advantage for obstructive patients 26 49 and raises SpO2 levels. Slow
breathing pattern is an advantage for obstructive patients 26 49 and raises SpO2 levels. Slow
yogic breathing, yogic exercises 50 and stretching 51 has been reported to increase heart rate
yogic breathing, yogic exercises 50 and stretching 51 has been reported to increase heart rate
variability (pNN50%). However, this was not found in the present intervention but was shown
variability (pNN50%). However, this was not found in the present intervention but was shown
in our prior study.
52
Diaphragmatic breathing creates a deeper breathing pattern, improves the
in our prior study. 52 Diaphragmatic breathing creates a deeper breathing pattern, improves the
breathing technique 53, prevents partial contraction of the diaphragm 54, encourages the use of
breathing technique 53, prevents partial contraction of the diaphragm 54, encourages the use of
the abdominal wall 7 and greater mobility of the diaphragm increase functional-, and
the abdominal wall 7 and greater mobility of the diaphragm increase functional-, and
inspiratory capacity. 55 Further qualitative data (manuscript in preparation) confirms that
inspiratory capacity. 55 Further qualitative data (manuscript in preparation) confirms that
patients reported better controlling of their dyspnea after HY. Yogic exercises strengthens the
patients reported better controlling of their dyspnea after HY. Yogic exercises strengthens the
torso (e.g., inversions, back-bends and prone poses along with strong breathing exercises) and
torso (e.g., inversions, back-bends and prone poses along with strong breathing exercises) and
46
initiates diaphragmatic breathing that improves performance , lowers f and increases chest
initiates diaphragmatic breathing that improves performance 46, lowers f and increases chest
expansion.
expansion.
However, to achieve chest expansion, more intensive yogic and breathing exercises than those
However, to achieve chest expansion, more intensive yogic and breathing exercises than those
included here are required. With most of the patients being novice to yoga, we refrained from
included here are required. With most of the patients being novice to yoga, we refrained from
including such intensive exercises and from measuring chest expansion.
including such intensive exercises and from measuring chest expansion.
Previous pilot studies have found increased strength and mobility of respiratory muscles in
Previous pilot studies have found increased strength and mobility of respiratory muscles in
both healthy persons and patients with COPD
2 20 26 45
after HY while others show no
both healthy persons and patients with COPD 2 20 26 45 after HY while others show no
improvements. 56 The present study found no effect of HY on respiratory muscle strength
improvements. 56 The present study found no effect of HY on respiratory muscle strength
(PImax and PEmax). However, both inspiratory and expiratory muscle strength and FVC
(PImax and PEmax). However, both inspiratory and expiratory muscle strength and FVC
increased significantly within the CTP at 12-weeks (T2); but no significant between-group
increased significantly within the CTP at 12-weeks (T2); but no significant between-group
effect emerged. The reason for redundant effects within HY on pulmonary function may
effect emerged. The reason for redundant effects within HY on pulmonary function may
relate to HY-exercises being of insufficient dose or intensity or other unknown factors.
relate to HY-exercises being of insufficient dose or intensity or other unknown factors.
However, FEV1 seldom improves in COPD (with more patients in the HY) due to the
However, FEV1 seldom improves in COPD (with more patients in the HY) due to the
hyperinflation or other factors, although pilot studies have reported improved effects on FEV1
hyperinflation or other factors, although pilot studies have reported improved effects on FEV1
14 17
14 17
but no effect on FEV1/FVC-ratio after a yoga intervention in diseased
18 57
or healthy
but no effect on FEV1/FVC-ratio after a yoga intervention in diseased 18 57 or healthy
persons. 20 However, effects are larger among the less fit when performing higher doses of
persons. 20 However, effects are larger among the less fit when performing higher doses of
yogic breathing exercises. 20
yogic breathing exercises. 20
The lack of effects of HY on lung function may relate to the use of the intention-to-treat (ITT)
The lack of effects of HY on lung function may relate to the use of the intention-to-treat (ITT)
model with HY including more patients with COPD (Table 1) whose lung function
model with HY including more patients with COPD (Table 1) whose lung function
parameters seldom improve. Another reason may relate to CTP including approx. 20-30
parameters seldom improve. Another reason may relate to CTP including approx. 20-30
minutes of cardiovascular training (cycling) per week while the HY included none. Yet both
minutes of cardiovascular training (cycling) per week while the HY included none. Yet both
groups had similar effects on the 6MWD. The fact that the randomization resulted in more
groups had similar effects on the 6MWD. The fact that the randomization resulted in more
patients with COPD in the HY-group and more obstructive patients with asthma in CTP-
patients with COPD in the HY-group and more obstructive patients with asthma in CTP-
group can be another explanation. Obviously one limitation relates to groups being unequal
group can be another explanation. Obviously one limitation relates to groups being unequal
with respect to diagnoses meaning that future studies comparing equal numbers of patients
with respect to diagnoses meaning that future studies comparing equal numbers of patients
with similar diagnoses are needed.
with similar diagnoses are needed.
The fact that both groups decreased their FEV1/FVC ratio may follow from several patients in
The fact that both groups decreased their FEV1/FVC ratio may follow from several patients in
both groups having allergic asthma during the second measurement, in the spring with more
both groups having allergic asthma during the second measurement, in the spring with more
pollen in the air, as compared to the baseline measurement in the winter, which suggests
pollen in the air, as compared to the baseline measurement in the winter, which suggests
higher CRP-levels.
58
higher CRP-levels. 58
Others have discussed whether CTP and HY function differently; traditional pulmonary
Others have discussed whether CTP and HY function differently; traditional pulmonary
rehabilitation with different breathing techniques typically focuses on inspiratory muscle
rehabilitation with different breathing techniques typically focuses on inspiratory muscle
training while yogic breathing uses prolonged coordinated expirations as a form of breathing
training while yogic breathing uses prolonged coordinated expirations as a form of breathing
8
control. The yogic exercises in this intervention focused on long exhalations using the
control. 8 The yogic exercises in this intervention focused on long exhalations using the
abdomen to prevent air trapping and dynamic hyperinflation. Pursed lip breathing used in
abdomen to prevent air trapping and dynamic hyperinflation. Pursed lip breathing used in
8
physiotherapy encourages diaphragmatic breathing (without coordination instructions) and is
physiotherapy 8 encourages diaphragmatic breathing (without coordination instructions) and is
used as a form of positive expiratory pressure (PEP) 59 to improve gas exchange and decrease
used as a form of positive expiratory pressure (PEP) 59 to improve gas exchange and decrease
the work of breathing. The HY in this intervention used coordinated slow breathing
the work of breathing. The HY in this intervention used coordinated slow breathing
movements of the upper-, and lower rib cage and the waist to prolong exhalation and
prevented hyperinflation and “air trapping” which is common in obstructive patients.
movements of the upper-, and lower rib cage and the waist to prolong exhalation and
54
These
prevented hyperinflation and “air trapping” which is common in obstructive patients. 54 These
sequential instructions are not included in pursed lip breathing technique 8 or in the CTP
sequential instructions are not included in pursed lip breathing technique 8 or in the CTP
program.
program.
A recommended, MCID of 100 ml
60
for FEV1 associated with other important clinical
A recommended, MCID of 100 ml 60 for FEV1 associated with other important clinical
outcomes is reported when using anchoring techniques. However, this was only found within
outcomes is reported when using anchoring techniques. However, this was only found within
the CTP group at 12-weeks (T2; but non-significant). Dyspnea is more anchored to
the CTP group at 12-weeks (T2; but non-significant). Dyspnea is more anchored to
hyperinflation than FEV1 with recommendations involves associating FEV1 changes with
hyperinflation than FEV1 with recommendations involves associating FEV1 changes with
exertion ratings, residual volumes and inspiratory capacity. 60 Another pilot study of patients
exertion ratings, residual volumes and inspiratory capacity. 60 Another pilot study of patients
with COPD found less dyspnea-related distress (DD-index) and lower dyspnea-intensity at the
with COPD found less dyspnea-related distress (DD-index) and lower dyspnea-intensity at the
end of 6MWT after 12 weeks.
18
The DD-index is related to the Borg-scale with 6MWD,
meaning that this measure may more adequately reflect pulmonary disease improvements.
Yet, the present study showed no significant or MCID (one point)
18
improvements in DD-
end of 6MWT after 12 weeks. 18 The DD-index is related to the Borg-scale with 6MWD,
meaning that this measure may more adequately reflect pulmonary disease improvements.
Yet, the present study showed no significant or MCID (one point) 18 improvements in DD-
index after the 6MWT for neither group. Dyspnea-related distress index is a new measure and
index after the 6MWT for neither group. Dyspnea-related distress index is a new measure and
larger study samples are needed to detect any improvement.
larger study samples are needed to detect any improvement.
Ratings of perceived exertion using the Borg 20-scale showed that the intensity of the HY
Ratings of perceived exertion using the Borg 20-scale showed that the intensity of the HY
program was lower compared to the CTP (10.15 versus 13.4). This relates to the HY not
program was lower compared to the CTP (10.15 versus 13.4). This relates to the HY not
including any cardiovascular/endurance training and probably results from other differences
including any cardiovascular/endurance training and probably results from other differences
between the CTP and HY. For instance, the HY exercises (e.g., attention during training) only
between the CTP and HY. For instance, the HY exercises (e.g., attention during training) only
used persons’ body weight while the more intensive CTP used strength-training machines for
used persons’ body weight while the more intensive CTP used strength-training machines for
the upper body. Such differences can probably explain why the CTP, but not HY, was
the upper body. Such differences can probably explain why the CTP, but not HY, was
associated with a significant decrease in diastolic blood pressure. However, this is in contrast
associated with a significant decrease in diastolic blood pressure. However, this is in contrast
with other findings showing that yoga lowers BP. But such findings typically emanate from
with other findings showing that yoga lowers BP. But such findings typically emanate from
studies without active comparison groups
61
where probably time only has an effect.
studies without active comparison groups 61 where probably time only has an effect.
As suggested in a meta-analysis 19 yogic breathing techniques constitute a safe and
As suggested in a meta-analysis 19 yogic breathing techniques constitute a safe and
complementary alternative to other breathing exercises (but not better than treatment as
complementary alternative to other breathing exercises (but not better than treatment as
usual), and more effective than usual care for asthma control, asthma symptoms, FEV1, PEFR
usual), and more effective than usual care for asthma control, asthma symptoms, FEV1, PEFR
and health-related quality of life.
2
and health-related quality of life. 2
Eight patients in each group reported improved self-reported health after the intervention
Eight patients in each group reported improved self-reported health after the intervention
using (EQ-5D/VAS) of 10 units that is the MCID. However, the EQ-5D decreased
using (EQ-5D/VAS) of 10 units that is the MCID. However, the EQ-5D decreased
significantly in the CTP-group at 6-months (T3; Table 2). This can be explained by no
significantly in the CTP-group at 6-months (T3; Table 2). This can be explained by no
remaining effects on EQ-5D at follow-up, which corresponds to a fast decline in self-reported
remaining effects on EQ-5D at follow-up, which corresponds to a fast decline in self-reported
health.
health.
The patients were encouraged to continue their exercises after the 12-week intervention (T2)
The patients were encouraged to continue their exercises after the 12-week intervention (T2)
and about 40% in each group did so. Interaction (group x time) showed significance on CRQ
and about 40% in each group did so. Interaction (group x time) showed significance on CRQ
fatigue and CRQ emotional, which relates to the fact that the CTP group showed improved
fatigue and CRQ emotional, which relates to the fact that the CTP group showed improved
effects when comparing baseline (T1) to the time point after the follow-up (T3) (Table 2).
effects when comparing baseline (T1) to the time point after the follow-up (T3) (Table 2).
This showed that CTP, but not HY, had long-term effects in CRQ emotional domain. To
This showed that CTP, but not HY, had long-term effects in CRQ emotional domain. To
achieve increased compliance after an intervention, it seems vital for patients with pulmonary
achieve increased compliance after an intervention, it seems vital for patients with pulmonary
diseases to maintain physical activity levels since the effects otherwise seem to diminish after
diseases to maintain physical activity levels since the effects otherwise seem to diminish after
6 months. 7 This underscores the importance of researching how to help patients to maintain
6 months. 7 This underscores the importance of researching how to help patients to maintain
physical activity levels.
physical activity levels.
4.1 Limitations
4.1 Limitations
Differences related to frequency and duration of HY and CTP were due to the fact that the
Differences related to frequency and duration of HY and CTP were due to the fact that the
CTP was more intense, including both strength and endurance training. However, our
CTP was more intense, including both strength and endurance training. However, our
intention was to include an active comparison group using conventional training. Calculating
intention was to include an active comparison group using conventional training. Calculating
power on the DD-index required a few more patients in each group. However, additional
power on the DD-index required a few more patients in each group. However, additional
patient recruitment was unfeasible. Also, there was a statistical imbalance in the 6MWD
patient recruitment was unfeasible. Also, there was a statistical imbalance in the 6MWD
baseline with higher levels in the HY-group, meaning that the range for improvements
baseline with higher levels in the HY-group, meaning that the range for improvements
(ceiling-effect) was smaller as compared to the CTP. Besides, we had problems in recruiting
(ceiling-effect) was smaller as compared to the CTP. Besides, we had problems in recruiting
additional patients with COPD, probably due to the rather low prevalence of registered
additional patients with COPD, probably due to the rather low prevalence of registered
diagnoses in Sweden, relating to the low rate of daily smokers.
diagnoses in Sweden, relating to the low rate of daily smokers.
The fact that the randomization resulted in more patients with COPD in the HY-group and
The fact that the randomization resulted in more patients with COPD in the HY-group and
more obstructive asthma persons in CTP-group can perhaps explain the findings. For HY,
more obstructive asthma persons in CTP-group can perhaps explain the findings. For HY,
there were no remaining effects (T3), which may relate to this group including more patients
there were no remaining effects (T3), which may relate to this group including more patients
with COPD (Table 1). Moreover, the ITT analysis resulted in many patients with low
with COPD (Table 1). Moreover, the ITT analysis resulted in many patients with low
adherence (3 classes minimum in HY and 12 minimum in CTP) in the HY-group while the
adherence (3 classes minimum in HY and 12 minimum in CTP) in the HY-group while the
low adherence patients in the CTP-group were excluded from the analysis due to their
low adherence patients in the CTP-group were excluded from the analysis due to their
unwillingness to participate in additional follow-ups. Thus the general adherence to CTP
unwillingness to participate in additional follow-ups. Thus the general adherence to CTP
seemed greater than that of the HY.
seemed greater than that of the HY.
The program design varied between CTP and HY. To achieve equal effects on lung function
The program design varied between CTP and HY. To achieve equal effects on lung function
and respiratory muscle strength, a larger HY dose and a program with a higher intensity on
and respiratory muscle strength, a larger HY dose and a program with a higher intensity on
the upper body (i.e. inversions and semi-inversions) is probably needed. Also, the patients
the upper body (i.e. inversions and semi-inversions) is probably needed. Also, the patients
investigated here varied largely in age, disease severity (both Asthma and COPD) and FEV1.
investigated here varied largely in age, disease severity (both Asthma and COPD) and FEV1.
Also, some of the patients in the CTP-group had previous experience of participating in
Also, some of the patients in the CTP-group had previous experience of participating in
physiotherapeutic interventions such as cycling and strength training with the exercises being
physiotherapeutic interventions such as cycling and strength training with the exercises being
familiar, while the participants in yoga were novice. Patients with severe obstructions
familiar, while the participants in yoga were novice. Patients with severe obstructions
(GOLD-4) were excluded for safety reasons meaning that the effects of a high intensity
(GOLD-4) were excluded for safety reasons meaning that the effects of a high intensity
program for this group are unknown.
program for this group are unknown.
Considering this, the number of asthma attacks and/or exacerbations or strength in large
Considering this, the number of asthma attacks and/or exacerbations or strength in large
muscle groups during the interventions should have been measured to allow investigating
muscle groups during the interventions should have been measured to allow investigating
exercise interference. As for measurement errors, inadequate inhalation may have induced
exercise interference. As for measurement errors, inadequate inhalation may have induced
error during the breathing tests. Ideally, to allow for a detailed analysis, future studies should
error during the breathing tests. Ideally, to allow for a detailed analysis, future studies should
measure breath holding time, chest expansion and breathing quality self-evaluations 46 47 and
measure breath holding time, chest expansion and breathing quality self-evaluations 46 47 and
SpO2 during HY and CTP. Also the effects of using diaphragmatic mobilisation techniques55
SpO2 during HY and CTP. Also the effects of using diaphragmatic mobilisation techniques55
during yogic poses should be thoroughly investigated to carefully detail potential
during yogic poses should be thoroughly investigated to carefully detail potential
mechanisms.
mechanisms.
4.2 Strengths
4.2 Strengths
Currently, there are no other RCTs of obstructive pulmonary disease patients using the newly
Currently, there are no other RCTs of obstructive pulmonary disease patients using the newly
developed HY-program investigated here (Appendix A). Despite variation in compliance
developed HY-program investigated here (Appendix A). Despite variation in compliance
between groups, the overall compliance was large and allowed testing both programs.
between groups, the overall compliance was large and allowed testing both programs.
Evaluating the efficiency, safety and feasibility of this new HY program was essential and
Evaluating the efficiency, safety and feasibility of this new HY program was essential and
also our main study objective. We choose to include both asthma and COPD to investigate the
also our main study objective. We choose to include both asthma and COPD to investigate the
effects on both groups. Both groups showed positive effects on the 6MWD, which is a strong
effects on both groups. Both groups showed positive effects on the 6MWD, which is a strong
predictor of functional capacity. The HY-group increased in the CRQ mastery domain, which
predictor of functional capacity. The HY-group increased in the CRQ mastery domain, which
may have increased their health and self-efficacy through them learning new skills to master
may have increased their health and self-efficacy through them learning new skills to master
their breathlessness thus improving their quality of life. Yogic interventions are more cost-
their breathlessness thus improving their quality of life. Yogic interventions are more cost-
effective than pulmonary rehabilitation since no equipment is necessary and exercises can be
effective than pulmonary rehabilitation since no equipment is necessary and exercises can be
self-taught and practiced at home. The detailed program description of the interventions, as
self-taught and practiced at home. The detailed program description of the interventions, as
well as the follow-up 6 months after the intervention, is the main strength of this intervention.
well as the follow-up 6 months after the intervention, is the main strength of this intervention.
4.3 Clinical implications
4.3 Clinical implications
With the results showing similar effects of HY and CTP, HY seems feasible and safe as a
With the results showing similar effects of HY and CTP, HY seems feasible and safe as a
form of physical exercise for patients with pulmonary disease. As part of rehabilitation, hatha
form of physical exercise for patients with pulmonary disease. As part of rehabilitation, hatha
yogic exercises (HY) may constitute an alternative to other physical activities or training and
yogic exercises (HY) may constitute an alternative to other physical activities or training and
may be a useful addition to traditional rehabilitation programs.
62
However the distribution of
may be a useful addition to traditional rehabilitation programs. 62 However the distribution of
patients with more asthma in CTP-group and more patients with COPD in HY-group means
patients with more asthma in CTP-group and more patients with COPD in HY-group means
that the results have to be interpreted cautiously.
that the results have to be interpreted cautiously.
5. Conclusions
5. Conclusions
Twelve weeks of HY and CTP for participants with obstructive pulmonary disease improved
Twelve weeks of HY and CTP for participants with obstructive pulmonary disease improved
functional capacity (6MWD) significantly within both groups. After 12 weeks, within-group
functional capacity (6MWD) significantly within both groups. After 12 weeks, within-group
effects showed HY having improvements on f, SpO2 and CRQ-mastery of the disease while
effects showed HY having improvements on f, SpO2 and CRQ-mastery of the disease while
CTP included improvements on FVC, respiratory muscle strength and all dimensions of
CTP included improvements on FVC, respiratory muscle strength and all dimensions of
disease specific quality of life (CRQ). The CTP showed improved effects after 6-months
disease specific quality of life (CRQ). The CTP showed improved effects after 6-months
follow up in CRQ. Yet, HY and CTP had similar effects on 6MWD after 12-weeks but with
follow up in CRQ. Yet, HY and CTP had similar effects on 6MWD after 12-weeks but with
larger improved effects with CTP. The HY program used here seemed to be feasible and safe
larger improved effects with CTP. The HY program used here seemed to be feasible and safe
for the participants with obstructive pulmonary diseases.
for the participants with obstructive pulmonary diseases.
Acknowledgements: Thanks to all patients who volunteered participation. Additional thanks
Acknowledgements: Thanks to all patients who volunteered participation. Additional thanks
to Birger Andrén and Sven-Erik Johansson for statistics guidance. Thanks also to the yoga
to Birger Andrén and Sven-Erik Johansson for statistics guidance. Thanks also to the yoga
instructor P.K and the test leaders (physiotherapists) who were working at the lung clinic at
instructor P.K and the test leaders (physiotherapists) who were working at the lung clinic at
Karolinska University Hospital, Huddinge for assisting with the measurements.
Karolinska University Hospital, Huddinge for assisting with the measurements.
Conflict of interest: We conformed to the Helsinki Declaration concerning human rights and
Conflict of interest: We conformed to the Helsinki Declaration concerning human rights and
informed consent, and followed correct procedures concerning treatment of humans. Marian
informed consent, and followed correct procedures concerning treatment of humans. Marian
Papp, Petra Lindfors, Malin Nygren-Bonnier and Per Wändell declare that they have no
Papp, Petra Lindfors, Malin Nygren-Bonnier and Per Wändell declare that they have no
conflict of interest.. All data are stored at Department of Neurobiology Care Sciences and
conflict of interest.. All data are stored at Department of Neurobiology Care Sciences and
Society, Division of Family Medicine, Karolinska Institutet
Society, Division of Family Medicine, Karolinska Institutet
Table 1: Baseline values (T1) (N=36), mean, SD, confidence intervals, median (ranges) for
hatha yoga (HY) and the conventional training program (CTP).
Age (Y)
HY (n=19)
CTP (n=17)
p-value
61 (40-76)
69 (43-84)
0.06
55.8; 65.5
62.0; 72.1
Gender F/M
14/5
10/7
BMI
25.5±4.2
28.1±6.4
23.5; 27.6
24.8; 31.4
COPD
8 (42%)
3 (18%)
0.16
Asthma
14 (74%)
15 (88%)
0.41
Year since smoking
21.6
23.1
0.84
10.6; 32.7
10.6; 35.7
11/7/1
8/9/0
Former smoker/never
0.16
0.74/0.50/-
smoked/still smoking
FEV1 (L)
FEV1 expected (%)
FEV1/FVC
FVC (L)
PImax (cm H2O)
PEmax (cm H2O)
SpO2 rest (%)
6MWD (m)
Rest HR, bpm
pNN50 (%)
RMSSD (ms) (5 min)
DD-index breathing
Respiratory rate/min
Dysphnea (CRQ)
Fatigue (CRQ)
Emotional (CRQ)
Mastery (CRQ)
EQ-5D (VAS)
Table 1: Baseline values (T1) (N=36), mean, SD, confidence intervals, median (ranges) for
hatha yoga (HY) and the conventional training program (CTP).
Age (Y)
HY (n=19)
CTP (n=17)
p-value
61 (40-76)
69 (43-84)
0.06
55.8; 65.5
62.0; 72.1
Gender F/M
14/5
10/7
BMI
25.5±4.2
28.1±6.4
23.5; 27.6
24.8; 31.4
COPD
8 (42%)
3 (18%)
0.16
Asthma
14 (74%)
15 (88%)
0.41
Year since smoking
21.6
23.1
0.84
10.6; 32.7
10.6; 35.7
11/7/1
8/9/0
0.74/0.50/-
1.86±0.59
1.58; 2.15
67.6±20.4
57.8; 77.4
0.61±0.13
0.55; 0.67
3.02±0.70
2.68; 3.35
79.5±26.3
66.8; 92.2
101.2±19.9
91.6; 110.7
96.2±2.3
95.1; 97.3
593.5±116.4
537; 650
72.6±11.7
67.0; 78.3
5.5±6.9
2.1; 8.9
37.2±42.0
16.4; 58.1
2.6±2.2
1.6; 3.7
12.8±3.7
11.1; 14.6
5.6 (2.4-7.0)
4.9; 6.2
4.25 (2.5 - 6.5)
3.8; 4.9
4.57 (3.14 - 6.14)
4.2; 5.2
5.25 (2.75-6.75)
4.6; 5.8
70 (30-80)
Q (50 – 75)
1.75±0.52
1.48; 2.01
64.3±15.4
56.4; 72.2
0.64±0.12
0.58; 0.70
2.77±0.75
2.38; 3.16
84.5±29.9
69.1; 99.9
116.9±34.4
99.2; 134.6
95.9±2.0
94.9; 97.0
502.3±136.3
432; 572
70.6±8.5
66.3; 75.0
2.4±5.0
-0.2; 5.0
26.8±19.1
17.0; 36.6
3.3±2.4
2.1; 4.6
14.7±4.5
12.4; 17.1
5.8 (2.6-7.0)
4.6; 6.0
4.0 (1.0 - 6.0)
3.2; 4.9
4.71 (2.29-6.43)
3.9; 5.3
5.5 (2.75-7.0)
4.7; 6.1
70 (18-85)
Q (50 – 80)
0.55
Former smoker/never
0.16
smoked/still smoking
1.86±0.59
1.58; 2.15
67.6±20.4
57.8; 77.4
0.61±0.13
0.55; 0.67
3.02±0.70
2.68; 3.35
79.5±26.3
66.8; 92.2
101.2±19.9
91.6; 110.7
96.2±2.3
95.1; 97.3
593.5±116.4
537; 650
72.6±11.7
67.0; 78.3
5.5±6.9
2.1; 8.9
37.2±42.0
16.4; 58.1
2.6±2.2
1.6; 3.7
12.8±3.7
11.1; 14.6
5.6 (2.4-7.0)
4.9; 6.2
4.25 (2.5 - 6.5)
3.8; 4.9
4.57 (3.14 - 6.14)
4.2; 5.2
5.25 (2.75-6.75)
4.6; 5.8
70 (30-80)
Q (50 – 75)
1.75±0.52
1.48; 2.01
64.3±15.4
56.4; 72.2
0.64±0.12
0.58; 0.70
2.77±0.75
2.38; 3.16
84.5±29.9
69.1; 99.9
116.9±34.4
99.2; 134.6
95.9±2.0
94.9; 97.0
502.3±136.3
432; 572
70.6±8.5
66.3; 75.0
2.4±5.0
-0.2; 5.0
26.8±19.1
17.0; 36.6
3.3±2.4
2.1; 4.6
14.7±4.5
12.4; 17.1
5.8 (2.6-7.0)
4.6; 6.0
4.0 (1.0 - 6.0)
3.2; 4.9
4.71 (2.29-6.43)
3.9; 5.3
5.5 (2.75-7.0)
4.7; 6.1
70 (18-85)
Q (50 – 80)
0.55
FEV1 (L)
0.59
FEV1 expected (%)
0.53
FEV1/FVC
0.31
FVC (L)
0.60
PImax (cm H2O)
0.13
PEmax (cm H2O)
0.72
SpO2 rest (%)
0.04*
6MWD (m)
0.57
Rest HR, bpm
0.53
pNN50 (%)
0.53
RMSSD (ms) (5 min)
0.31
DD-index breathing
0.17
Respiratory rate/min
0.49
Dysphnea (CRQ)
0.71
Fatigue (CRQ)
0.96
Emotional (CRQ)
0.52
Mastery (CRQ)
0.46
EQ-5D (VAS)
* p<0.05; BMI=Body mass index, kg/m2; L=liter; m=meters; Y=years; ms=milli seconds;
FEV1=forced expiratory volume in one second; FEV=forced expiratory volume; FVC=forced vital
capacity; 6MWD=distance during 6 minutes walking; CRQ=chronic respiratory questionnaire; DD-
0.59
0.53
0.31
0.60
0.13
0.72
0.04*
0.57
0.53
0.53
0.31
0.17
0.49
0.71
0.96
0.52
0.46
* p<0.05; BMI=Body mass index, kg/m2; L=liter; m=meters; Y=years; ms=milli seconds;
FEV1=forced expiratory volume in one second; FEV=forced expiratory volume; FVC=forced vital
capacity; 6MWD=distance during 6 minutes walking; CRQ=chronic respiratory questionnaire; DD-
index=perceived exertion using Borg-CR 10-scale at the end of 6MWT divided by feet x 1000;
HR=Heart rate; NN50 count (time domain unit)=Number of pairs of adjacent NN intervals differing
by more than 50 ms in the 5 min recording; pNN50% =NN50 count divided by the total number of all
NN intervals; RMSSD=the square root of the mean of the sum of the squares of differences between
adjacent NN intervals; EQ-5D/VAS=median, range in parenthesis and inter quartile range (Q),
100=optimal health; PImax=maximal inspiratory pressure; PEmax=maximal expiratory pressure;
SpO2=oxygen saturation; FEV1/FVC ratio is calculated on Litre values. Some patients had both asthma
and COPD. One patient with bronchiectasis was included in the COPD group.
index=perceived exertion using Borg-CR 10-scale at the end of 6MWT divided by feet x 1000;
HR=Heart rate; NN50 count (time domain unit)=Number of pairs of adjacent NN intervals differing
by more than 50 ms in the 5 min recording; pNN50% =NN50 count divided by the total number of all
NN intervals; RMSSD=the square root of the mean of the sum of the squares of differences between
adjacent NN intervals; EQ-5D/VAS=median, range in parenthesis and inter quartile range (Q),
100=optimal health; PImax=maximal inspiratory pressure; PEmax=maximal expiratory pressure;
SpO2=oxygen saturation; FEV1/FVC ratio is calculated on Litre values. Some patients had both asthma
and COPD. One patient with bronchiectasis was included in the COPD group.
22
22
0.29
0.41
FEV1/FVC
FVC (L)
PImax
0.82
Rest HR,
0.32
DD-index
-0.53
-0.22; 0.91
-1.31; 0.38
1.00
0.26 (-0.90-2.60)
-11.12; 3.81
-0.10 (-4.47-1.61)
-3.65
-16.52; 12.03
-1.14; 3.34
-2.24
1.1
-4.53; 2.35
-3.29 ; 12.89
-1.09
4.8
-5.49; 6.33
-28.6; 6.9
0.42
-10.9
10.1; 55.1
-9.01; 5.54
32.6
-1.73
-1.94; 12.89
-6.24; 5.04
5.47
-0.60
-3.34; 14.08
-0.29; -0.00
5.37
-0.15
-0.07; 0.27
-0.00; 0.04
-0.03; -0.00
0.10
0.02
-0.02
0.02*
0.33
0.78
0.38
0.88
0.014*
0.14
0.21
0.22
0.04*
0.86
P
T1-T2
HY
0.12
0.31
0.19
0.86
0.22
0.32
0.62
0.82
0.05*
0.13
0.62
P
T2-T3
HY
0.59
-1.60; 0.26
-0.05 (-4.53-2.57)
-10.10; 3.70
-3.20
-1.23; 2,48
0.62
-5.25; 6.55
0.64
17.9; 67.0
42.4
6.30; 28.17
17.24
1.39; 24.49
12.94
-0.07; 0.38
0.22
-0.03; 0.01
-0.01
-0.00; 0.21
0.10
T1-T2
CTP
0.10
-1.17; 0.18
-0.11 (-3.18-1.19)
-5.88; 11.42
2.77
-3.64; 1.91
-0.87
-7.18; 7.31
0.07
-5.5; 29.1
11.8
-14.39; 0.52
-6.93
-11.83; 3.03
-4.40
-0.25; 0.09
-0.08
-0.01; 0.04
0.01
-0.14; 0.11
-0.01
T2-T3
CTP
0.40
0.33
0.27
0.56
0.82
0.006*
0.004*
0.03*
0.01*
0.46
0.06
P
T1-T2
CTP
0.80
0.19
0.51
0.75
0.98
0.14
0.07
0.22
0.34
0.31
0.82
P
T2-T3
CTP
0.51
0.89
0.57
0.26
0.97
0.60
0.13
0.47
0.26
0.48
0.21
P
T1-T2
HY/CTP
0.15
0.09
0.21
0.90
0.41
0.07
0.41
0.66
0.51
0.24
0.90
P
T2-T3
HY/CTP
0.44
0.29
0.41
FEV1/FVC
FVC (L)
PImax
0.82
Rest HR,
0.32
DD-index
SpO2 rest
0.39
0.71
RMSSD
breathing
0.50
pNN50%
bpm
0.08
6MWD (m)
(cm H2O)
PEmax
0.11
-0.11; 0.07
-0.11; 0.12
(cm H2O)
-0-02
0.01
0.37
FEV1 (L)
-0.53
-0.22; 0.91
1.00
0.26 (-0.90-2.60)
-1.31; 0.38
-11.12; 3.81
-0.10 (-4.47-1.61)
-3.65
-16.52; 12.03
-1.14; 3.34
-2.24
1.1
-4.53; 2.35
-3.29 ; 12.89
-1.09
4.8
-5.49; 6.33
-28.6; 6.9
0.42
-10.9
10.1; 55.1
-9.01; 5.54
32.6
-1.73
-1.94; 12.89
-6.24; 5.04
5.47
-0.60
-3.34; 14.08
-0.29; -0.00
-0.07; 0.27
5.37
-0.15
-0.00; 0.04
-0.03; -0.00
0.10
0.02
-0.02
T2-T3
T1-T2
(g x t)
CTP; n=17
HY
HY
P**
HY; n=19
0.02*
0.33
0.78
0.38
0.88
0.014*
0.14
0.21
0.22
0.04*
0.86
P
T1-T2
HY
0.12
0.31
0.19
0.86
0.22
0.32
0.62
0.82
0.05*
0.13
0.62
P
T2-T3
HY
0.59
-1.60; 0.26
-0.05 (-4.53-2.57)
-10.10; 3.70
-3.20
-1.23; 2,48
0.62
-5.25; 6.55
0.64
17.9; 67.0
42.4
6.30; 28.17
17.24
1.39; 24.49
12.94
-0.07; 0.38
0.22
-0.03; 0.01
-0.01
-0.00; 0.21
0.10
T1-T2
CTP
0.10
-1.17; 0.18
-0.11 (-3.18-1.19)
-5.88; 11.42
2.77
-3.64; 1.91
-0.87
-7.18; 7.31
0.07
-5.5; 29.1
11.8
-14.39; 0.52
-6.93
-11.83; 3.03
-4.40
-0.25; 0.09
-0.08
-0.01; 0.04
0.01
-0.14; 0.11
-0.01
T2-T3
CTP
0.40
0.33
0.27
0.56
0.82
0.006*
0.004*
0.03*
0.01*
0.46
0.06
P
T1-T2
CTP
0.80
0.19
0.51
0.75
0.98
0.14
0.07
0.22
0.34
0.31
0.82
P
T2-T3
CTP
0.51
0.89
0.57
0.26
0.97
0.60
0.13
0.47
0.26
0.48
0.21
P
T1-T2
HY/CTP
0.15
0.09
0.21
0.90
0.41
0.07
0.41
0.66
0.51
0.24
0.90
P
T2-T3
HY/CTP
Table 2: Results after hatha yoga (HY) or conventional training program (CTP) in patients with COPD or Asthma. Mean (or median) differences over time
(CIs and p-values) between time (T) intervals (T1=baseline, T2=after 12-week intervention, T3=follow-up 6 months after ending the intervention) was
calculated (positive results shows increased value). For DD-index, CRQ, EQ-5D median values (with range within parenthesis) and CI are shown. P=p-value.
T3; n=15 in both groups
YOGA AND FUNCTIONAL CAPACITY
SpO2 rest
0.39
0.71
RMSSD
breathing
0.50
pNN50%
bpm
0.08
6MWD (m)
(cm H2O)
PEmax
0.11
-0.11; 0.07
-0.11; 0.12
0.44
FEV1 (L)
(cm H2O)
-0-02
0.01
0.37
T2-T3
T1-T2
(g x t)
CTP; n=17
HY
HY
P**
HY; n=19
Table 2: Results after hatha yoga (HY) or conventional training program (CTP) in patients with COPD or Asthma. Mean (or median) differences over time
(CIs and p-values) between time (T) intervals (T1=baseline, T2=after 12-week intervention, T3=follow-up 6 months after ending the intervention) was
calculated (positive results shows increased value). For DD-index, CRQ, EQ-5D median values (with range within parenthesis) and CI are shown. P=p-value.
T3; n=15 in both groups
YOGA AND FUNCTIONAL CAPACITY
0.69
0.37
0.95
0.90
0.97
0.04
0.71
0.72
0.25
0.47
0.47
P
T1-T3
HY/CTP
0.69
0.37
0.95
0.90
0.97
0.04
0.71
0.72
0.25
0.47
0.47
P
T1-T3
HY/CTP
23
23
Fatigue
0.73
0.64
-5 (-30-25)
-15.1; 3.4
Q (-20-5)
-4.1; 10.1
Q (-5-10)
-0.52; 0.21
3 (-25-40)
-0.25 (-1.25-1.0)
0.34
0.01*
0.13
0.95
0.18
0.05*
0.15
0.31
0.07
0.09
0.20
0.80
Q (-5-15)
-3.9; 18.2
5 (-30-57)
0.28; 1.31
0.5 (-1.0-2.5)
0.17; 0.99
0.57 (-0.71-2.57)
0.15; 1.12
0.75 (-1-2.5)
0.04; 1.05
0.45 (-1.80-2.65)
-2.38; 2.32
-0.03
-0.46; 1.63
Q (-20-0)
-29.0; 0.0
-5 (-79-10)
-0.72; 0.18
0.00 (-1.75-1.0)
-0.39; 0.39
0.00 (-1.29-1.0)
-0.53; 0.28
-0.13 (-1.75-1.5)
-0.13; 0.43
0.18 (-1.0-1.0)
-3.07; 0.17
-1.45
-0.56; 0.76
0.22
0.01*
0.01*
0.02*
0.01*
0.98
0.03*
0.43
1.00
0.28
0.17
0.06
0.60
0.53
0.16
0.08
0.20
0.19
0.50
0.98
0.12
0.33
0.07
0.21
Fatigue
0.73
0.64
-5 (-30-25)
-15.1; 3.4
Q (-20-5)
-4.1; 10.1
Q (-5-10)
-0.52; 0.21
3 (-25-40)
-0.25 (-1.25-1.0)
0.34
0.01*
0.13
0.95
0.18
0.05*
0.15
0.31
0.07
0.09
0.20
0.80
Q (-5-15)
-3.9; 18.2
5 (-30-57)
0.28; 1.31
0.5 (-1.0-2.5)
0.17; 0.99
0.57 (-0.71-2.57)
0.15; 1.12
0.75 (-1-2.5)
0.04; 1.05
0.45 (-1.80-2.65)
-2.38; 2.32
-0.03
-0.46; 1.63
Q (-20-0)
-29.0; 0.0
-5 (-79-10)
-0.72; 0.18
0.00 (-1.75-1.0)
-0.39; 0.39
0.00 (-1.29-1.0)
-0.53; 0.28
-0.13 (-1.75-1.5)
-0.13; 0.43
0.18 (-1.0-1.0)
-3.07; 0.17
-1.45
-0.56; 0.76
0.22
0.01*
0.01*
0.02*
0.01*
0.98
0.03*
0.43
1.00
0.28
0.17
0.06
0.60
0.53
0.16
0.08
0.20
0.19
0.50
0.98
0.12
0.33
0.07
0.21
second; FEV=forced expiratory volume; FVC=forced vital capacity; CRQ= chronic respiratory questionnaire (median/range/CI); DD-index=perceived exertion using BorgCR 10-scale at the end of 6MWD divided by feet x 1000; PI max=maximal inspiratory pressure; PEmax=maximal expiratory pressure; SpO2=oxygen saturation; HR=heart rate;
NN50 count (time domain unit)=Number of pairs of adjacent NN intervals differing by more than 50 ms in the 5 min recording; pNN50% =NN50 count divided by the total
number of all NN intervals; RMSSD=the square root of the mean of the sum of the squares of differences between adjacent NN intervals; EQ-5D/VAS=self-reported health,
median/ranges and inter quartile ranges (Q). FEV1/FVC ratio is calculated on Liter values. ANOVA, t-tests or Wilcoxon rank-sum tests were computed to analyze differences
at baseline (T1), 12 weeks (T2) and follow-up 6 months (T3) within and between groups (depending on skewness). Last observation carried forward was not performed
therefore in T3 n=15 in both HY and CTP groups
*p<0.05; P**=interaction (group x time) ANOVA; P=p-value; L=liter; m=meters; 6MWD=distance during 6 minutes walking; FEV1=forced expiratory volume in one
(VAS)
EQ-5D
(CRQ)
Mastery
0.22; 0.89
-0.74; 0.00
-0.07; 0.48
Emotional
0.5 (-0.5-1.75)
-0.57 (-1.14-1.0)
0.14 (-1.0-1.0)
(CRQ)
(CRQ)
-0.72; 0.07
-0.37; 0.45
0.02
-0.38 (-1.75-1.25)
0.00 (-1.50-1.75)
0.04
(CRQ)
Dysphnea
-0.51; 0.27
-2.14; 2.72
-3.98; 0.15
-0.20 (-1.20-1.80)
0.29
-1.17; 0.99
-1.98
0.20; 1.80
-0.09; 0.54
0.22
0.32
0.30 (-1.05-1.40)
rate (f)
Respiratory
(%)
YOGA AND FUNCTIONAL CAPACITY
second; FEV=forced expiratory volume; FVC=forced vital capacity; CRQ= chronic respiratory questionnaire (median/range/CI); DD-index=perceived exertion using BorgCR 10-scale at the end of 6MWD divided by feet x 1000; PI max=maximal inspiratory pressure; PEmax=maximal expiratory pressure; SpO2=oxygen saturation; HR=heart rate;
NN50 count (time domain unit)=Number of pairs of adjacent NN intervals differing by more than 50 ms in the 5 min recording; pNN50% =NN50 count divided by the total
number of all NN intervals; RMSSD=the square root of the mean of the sum of the squares of differences between adjacent NN intervals; EQ-5D/VAS=self-reported health,
median/ranges and inter quartile ranges (Q). FEV1/FVC ratio is calculated on Liter values. ANOVA, t-tests or Wilcoxon rank-sum tests were computed to analyze differences
at baseline (T1), 12 weeks (T2) and follow-up 6 months (T3) within and between groups (depending on skewness). Last observation carried forward was not performed
therefore in T3 n=15 in both HY and CTP groups
*p<0.05; P**=interaction (group x time) ANOVA; P=p-value; L=liter; m=meters; 6MWD=distance during 6 minutes walking; FEV1=forced expiratory volume in one
(VAS)
EQ-5D
(CRQ)
Mastery
0.22; 0.89
-0.74; 0.00
-0.07; 0.48
Emotional
0.5 (-0.5-1.75)
-0.57 (-1.14-1.0)
0.14 (-1.0-1.0)
(CRQ)
(CRQ)
-0.72; 0.07
-0.37; 0.45
0.02
-0.38 (-1.75-1.25)
0.00 (-1.50-1.75)
0.04
(CRQ)
Dysphnea
-0.51; 0.27
-2.14; 2.72
-3.98; 0.15
-0.09; 0.54
0.29
-1.17; 0.99
-1.98
0.20; 1.80
-0.20 (-1.20-1.80)
0.22
0.32
0.30 (-1.05-1.40)
rate (f)
Respiratory
(%)
YOGA AND FUNCTIONAL CAPACITY
0.63
0.79
0.01
0.07
0.11
0.89
0.63
0.79
0.01
0.07
0.11
0.89
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
Table 3: Number of participants (HY=hatha yoga; CTP=conventional training program) and
% of participants in each group (HY, CTP) with minimal clinically significant improvement
(MCID) in Chronic Respiratory Questionnaire (CRQ) (>=0.5) at different time intervals.
HY
HY
HY
CTP
CTP
CTP
CRQT1→T2
T2→T3
T1→T3
T1→T2
T2→T3 T1→T3
domains
(n=19)
(n=19)
(n=16)
(n=17)
(n=17)
(n=14)
6 (32%)
3 (16%)
6 (38%)
8 (47%)
3 (18%) 7 (50%)
Dysphnea
5 (26%)
3 (16%)
3 (19%)
11 (65%) 2 (12%) 9 (64%)
Fatigue
7 (37%)
2 (11%)
2 (13%)
9 (53%)
4 (24%) 6 (43%)
Emotional
12 (63%)
3 (16%)
7 (44%)
10 (59%)
1 (6%)
5 (36%)
Mastery
Note: Time; T1=baseline; T2=after 12-week intervention; T3=6-months after ending the
intervention. MCID in CRQ
Table 3: Number of participants (HY=hatha yoga; CTP=conventional training program) and
% of participants in each group (HY, CTP) with minimal clinically significant improvement
(MCID) in Chronic Respiratory Questionnaire (CRQ) (>=0.5) at different time intervals.
HY
HY
HY
CTP
CTP
CTP
CRQT1→T2
T2→T3
T1→T3
T1→T2
T2→T3 T1→T3
domains
(n=19)
(n=19)
(n=16)
(n=17)
(n=17)
(n=14)
6 (32%)
3 (16%)
6 (38%)
8 (47%)
3 (18%) 7 (50%)
Dysphnea
5 (26%)
3 (16%)
3 (19%)
11 (65%) 2 (12%) 9 (64%)
Fatigue
7 (37%)
2 (11%)
2 (13%)
9 (53%)
4 (24%) 6 (43%)
Emotional
12 (63%)
3 (16%)
7 (44%)
10 (59%)
1 (6%)
5 (36%)
Mastery
Note: Time; T1=baseline; T2=after 12-week intervention; T3=6-months after ending the
intervention. MCID in CRQ
24
24
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
References:
References:
1. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease:
a systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
2. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and
meta-analysis. Ann Allergy Asthma Immunol 2014.
3. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy
for the diagnosis, management, and prevention of chronic obstructive pulmonary
disease: GOLD executive summary. American journal of respiratory and critical care
medicine 2013;187(4):347-65.
4. Carlsson AC, Wandell P, Osby U, Zarrinkoub R, Wettermark B, Ljunggren G. High
prevalence of diagnosis of diabetes, depression, anxiety, hypertension, asthma and
COPD in the total population of Stockholm, Sweden - a challenge for public health.
BMC Public Health 2013;13:670.
5. Danielsson P, Olafsdottir IS, Benediktsdottir B, Gislason T, Janson C. The prevalence of
chronic obstructive pulmonary disease in Uppsala, Sweden--the Burden of Obstructive
Lung Disease (BOLD) study: cross-sectional population-based study. Clin Respir J
2012;6(2):120-7.
6. Hagstad S, Backman H, Bjerg A, Ekerljung L, Ye X, Hedman L, et al. Prevalence and risk
factors of COPD among never-smokers in two areas of Sweden - Occupational
exposure to gas, dust or fumes is an important risk factor. Respir Med
2015;109(11):1439-45.
7. Spruit MA, Singh SJ, Garvey C, ZuWallack R, Nici L, Rochester C, et al. An official
American Thoracic Society/European Respiratory Society statement: key concepts and
advances in pulmonary rehabilitation. American journal of respiratory and critical
care medicine 2013;188(8):e13-64.
8. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of
controlled breathing exercises and respiratory muscle training in people with chronic
obstructive pulmonary disease: results from evaluating the quality of evidence in
systematic reviews. BMC Pulm Med 2014;14:184.
9. Incorvaia C, Russo A, Foresi A, Berra D, Elia R, Passalacqua G, et al. Effects of pulmonary
rehabilitation on lung function in chronic obstructive pulmonary disease: the FIRST
study. Eur J Phys Rehabil Med 2014;50(4):419-26.
10. Greulich T, Koczulla AR, Nell C, Kehr K, Vogelmeier CF, Stojanovic D, et al. Effect of a
Three-Week Inpatient Rehabilitation Program on 544 Consecutive Patients with Very
Severe COPD: A Retrospective Analysis. Respiration 2015;90(4):287-92.
11. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A
systematic review of associations of yoga style and conclusions in randomized yoga
trials. Complementary therapies in medicine 2016.
12. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga
Self-Efficacy Scale (YSES). BMC complementary and alternative medicine
2016;16(1):3.
13. Wang F, Eun-Kyoung Lee O, Feng F, Vitiello MV, Wang W, Benson H, et al. The effect
of meditative movement on sleep quality: A systematic review. Sleep Med Rev
2015;30:43-52.
14. Lorenc AB, Wang Y, Madge SL, Hu X, Mian AM, Robinson N. Meditative movement for
respiratory function: a systematic review. Respiratory care 2014;59(3):427-40.
1. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease:
a systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
2. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and
meta-analysis. Ann Allergy Asthma Immunol 2014.
3. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy
for the diagnosis, management, and prevention of chronic obstructive pulmonary
disease: GOLD executive summary. American journal of respiratory and critical care
medicine 2013;187(4):347-65.
4. Carlsson AC, Wandell P, Osby U, Zarrinkoub R, Wettermark B, Ljunggren G. High
prevalence of diagnosis of diabetes, depression, anxiety, hypertension, asthma and
COPD in the total population of Stockholm, Sweden - a challenge for public health.
BMC Public Health 2013;13:670.
5. Danielsson P, Olafsdottir IS, Benediktsdottir B, Gislason T, Janson C. The prevalence of
chronic obstructive pulmonary disease in Uppsala, Sweden--the Burden of Obstructive
Lung Disease (BOLD) study: cross-sectional population-based study. Clin Respir J
2012;6(2):120-7.
6. Hagstad S, Backman H, Bjerg A, Ekerljung L, Ye X, Hedman L, et al. Prevalence and risk
factors of COPD among never-smokers in two areas of Sweden - Occupational
exposure to gas, dust or fumes is an important risk factor. Respir Med
2015;109(11):1439-45.
7. Spruit MA, Singh SJ, Garvey C, ZuWallack R, Nici L, Rochester C, et al. An official
American Thoracic Society/European Respiratory Society statement: key concepts and
advances in pulmonary rehabilitation. American journal of respiratory and critical
care medicine 2013;188(8):e13-64.
8. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of
controlled breathing exercises and respiratory muscle training in people with chronic
obstructive pulmonary disease: results from evaluating the quality of evidence in
systematic reviews. BMC Pulm Med 2014;14:184.
9. Incorvaia C, Russo A, Foresi A, Berra D, Elia R, Passalacqua G, et al. Effects of pulmonary
rehabilitation on lung function in chronic obstructive pulmonary disease: the FIRST
study. Eur J Phys Rehabil Med 2014;50(4):419-26.
10. Greulich T, Koczulla AR, Nell C, Kehr K, Vogelmeier CF, Stojanovic D, et al. Effect of a
Three-Week Inpatient Rehabilitation Program on 544 Consecutive Patients with Very
Severe COPD: A Retrospective Analysis. Respiration 2015;90(4):287-92.
11. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A
systematic review of associations of yoga style and conclusions in randomized yoga
trials. Complementary therapies in medicine 2016.
12. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga
Self-Efficacy Scale (YSES). BMC complementary and alternative medicine
2016;16(1):3.
13. Wang F, Eun-Kyoung Lee O, Feng F, Vitiello MV, Wang W, Benson H, et al. The effect
of meditative movement on sleep quality: A systematic review. Sleep Med Rev
2015;30:43-52.
14. Lorenc AB, Wang Y, Madge SL, Hu X, Mian AM, Robinson N. Meditative movement for
respiratory function: a systematic review. Respiratory care 2014;59(3):427-40.
25
25
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
15. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and
cardiopulmonary function: a literature review. Journal of alternative and
complementary medicine 2002;8(6):797-812.
16. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma.
Cochrane Database Syst Rev 2016;4:CD010346.
17. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients
with chronic obstructive pulmonary disease: a systematic review and meta-analysis. J
Thorac Dis 2014;6(6):795-802.
18. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases
dyspnea-related distress and improves functional performance in people with chronic
obstructive pulmonary disease: a pilot study. Journal of alternative and
complementary medicine 2009;15(3):225-34.
19. Holland AE, Hill CJ, Jones AY, McDonald CF. Breathing exercises for chronic
obstructive pulmonary disease. Cochrane Database Syst Rev 2012;10:CD008250.
20. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary
function in healthy individuals: a literature review. Journal of alternative and
complementary medicine 2013;19(3):185-90.
21. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects
of Iyengar yoga practice on the health-related quality of life of patients with chronic
respiratory diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
22. Chu P, Gotink RA, Yeh GY, Goldie SJ, Hunink MM. The effectiveness of yoga in
modifying risk factors for cardiovascular disease and metabolic syndrome: A
systematic review and meta-analysis of randomized controlled trials. European
journal of preventive cardiology 2016;23(3):291-307.
23. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A, Dobos G. Effects of yoga on
cardiovascular disease risk factors: a systematic review and meta-analysis. Int J
Cardiol 2014;173(2):170-83.
24. Ward L, Stebbings S, Cherkin D, Baxter GD. Yoga for Functional Ability, Pain and
Psychosocial Outcomes in Musculoskeletal Conditions: A Systematic Review and
Meta-Analysis. Musculoskeletal Care 2013;11(4):203-17.
25. Pascoe MC, Bauer IE. A systematic review of randomised control trials on the effects of
yoga on stress measures and mood. Journal of Psychiatric Research 2015;68:270-82.
26. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of
yoga breathing in patients with chronic obstructive pulmonary disease: a pilot study. J
Cardiopulm Rehabil Prev 2009;29(2):133-7.
27. Watz H, Pitta F, Rochester CL, Garcia-Aymerich J, ZuWallack R, Troosters T, et al. An
official European Respiratory Society statement on physical activity in COPD. The
European respiratory journal 2014;44(6):1521-37.
28. Sheel AW, Foster GE, Romer LM. Exercise and its impact on dyspnea. Curr Opin
Pharmacol 2011;11(3):195-203.
29. Goldberg R, Hillberg R, Reinecker L, Goldstein R. Evaluation of patients with severe
pulmonary disease before and after pulmonary rehabilitation. Disabil Rehabil
2004;26(11):641-8.
30. Young P, Dewse M, Fergusson W, Kolbe J. Improvements in outcomes for chronic
obstructive pulmonary disease (COPD) attributable to a hospital-based respiratory
rehabilitation programme. Aust N Z J Med 1999;29(1):59-65.
31. ATS/ERS Statement on respiratory muscle testing. American journal of respiratory and
critical care medicine 2002;166(4):518-624.
32. Mancia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, et al. 2007
Guidelines for the management of arterial hypertension: The Task Force for the
15. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and
cardiopulmonary function: a literature review. Journal of alternative and
complementary medicine 2002;8(6):797-812.
16. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma.
Cochrane Database Syst Rev 2016;4:CD010346.
17. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients
with chronic obstructive pulmonary disease: a systematic review and meta-analysis. J
Thorac Dis 2014;6(6):795-802.
18. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases
dyspnea-related distress and improves functional performance in people with chronic
obstructive pulmonary disease: a pilot study. Journal of alternative and
complementary medicine 2009;15(3):225-34.
19. Holland AE, Hill CJ, Jones AY, McDonald CF. Breathing exercises for chronic
obstructive pulmonary disease. Cochrane Database Syst Rev 2012;10:CD008250.
20. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary
function in healthy individuals: a literature review. Journal of alternative and
complementary medicine 2013;19(3):185-90.
21. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects
of Iyengar yoga practice on the health-related quality of life of patients with chronic
respiratory diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
22. Chu P, Gotink RA, Yeh GY, Goldie SJ, Hunink MM. The effectiveness of yoga in
modifying risk factors for cardiovascular disease and metabolic syndrome: A
systematic review and meta-analysis of randomized controlled trials. European
journal of preventive cardiology 2016;23(3):291-307.
23. Cramer H, Lauche R, Haller H, Steckhan N, Michalsen A, Dobos G. Effects of yoga on
cardiovascular disease risk factors: a systematic review and meta-analysis. Int J
Cardiol 2014;173(2):170-83.
24. Ward L, Stebbings S, Cherkin D, Baxter GD. Yoga for Functional Ability, Pain and
Psychosocial Outcomes in Musculoskeletal Conditions: A Systematic Review and
Meta-Analysis. Musculoskeletal Care 2013;11(4):203-17.
25. Pascoe MC, Bauer IE. A systematic review of randomised control trials on the effects of
yoga on stress measures and mood. Journal of Psychiatric Research 2015;68:270-82.
26. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of
yoga breathing in patients with chronic obstructive pulmonary disease: a pilot study. J
Cardiopulm Rehabil Prev 2009;29(2):133-7.
27. Watz H, Pitta F, Rochester CL, Garcia-Aymerich J, ZuWallack R, Troosters T, et al. An
official European Respiratory Society statement on physical activity in COPD. The
European respiratory journal 2014;44(6):1521-37.
28. Sheel AW, Foster GE, Romer LM. Exercise and its impact on dyspnea. Curr Opin
Pharmacol 2011;11(3):195-203.
29. Goldberg R, Hillberg R, Reinecker L, Goldstein R. Evaluation of patients with severe
pulmonary disease before and after pulmonary rehabilitation. Disabil Rehabil
2004;26(11):641-8.
30. Young P, Dewse M, Fergusson W, Kolbe J. Improvements in outcomes for chronic
obstructive pulmonary disease (COPD) attributable to a hospital-based respiratory
rehabilitation programme. Aust N Z J Med 1999;29(1):59-65.
31. ATS/ERS Statement on respiratory muscle testing. American journal of respiratory and
critical care medicine 2002;166(4):518-624.
32. Mancia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, et al. 2007
Guidelines for the management of arterial hypertension: The Task Force for the
26
26
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
Management of Arterial Hypertension of the European Society of Hypertension (ESH)
and of the European Society of Cardiology (ESC). Eur Heart J 2007;28(12):1462-536.
33. Viskoper R, Shapira I, Priluck R, Mindlin R, Chornia L, Laszt A, et al. Nonpharmacologic
treatment of resistant hypertensives by device-guided slow breathing exercises. Am J
Hypertens 2003;16(6):484-7.
34. Kingsley M, Lewis MJ, Marson R. Comparison of polar 810 s and an ambulatory ECG
system for RR interval measurement during progressive exercise. International
journal of sports medicine 2005;26(01):39-44.
35. Heart rate variability. Standards of measurement, physiological interpretation, and clinical
use. Task Force of the European Society of Cardiology and the North American
Society of Pacing and Electrophysiology. Eur Heart J 1996;17(3):354-81.
36. Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality
of life for clinical trials in chronic lung disease. Thorax 1987;42(10):773-8.
37. Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann
Med 2001;33(5):337-43.
38. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al.
Standardisation of spirometry. The European respiratory journal 2005;26(2):319-38.
39. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc
1982;14(5):377-81.
40. Borg G. Ratings of perceived exertion and heart rates during short-term cycle exercise and
their use in a new cycling strength test. Int J Sports Med 1982;3(3):153-8.
41. Chhabra SK, Gupta AK, Khuma MZ. Evaluation of three scales of dyspnea in chronic
obstructive pulmonary disease. Ann Thorac Med 2009;4(3):128-32.
42. Puhan MA, Chandra D, Mosenifar Z, Ries A, Make B, Hansel NN, et al. The minimal
important difference of exercise tests in severe COPD. The European respiratory
journal 2011;37(4):784-90.
43. Redelmeier DA, Bayoumi AM, Goldstein RS, Guyatt GH. Interpreting small differences
in functional status: the Six Minute Walk test in chronic lung disease patients.
American journal of respiratory and critical care medicine 1997;155(4):1278-82.
44. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory
changes and intensity of exercise. Evidence-based complementary and alternative
medicine : eCAM 2011;2011:241294.
45. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in
chronic obstructive pulmonary disease. American journal of therapeutics
2012;19(2):96-100.
46. Courtney R, van Dixhoorn J, Greenwood KM, Anthonissen EL. Medically unexplained
dyspnea: partly moderated by dysfunctional (thoracic dominant) breathing pattern. J
Asthma 2011;48(3):259-65.
47. Courtney R, Greenwood KM, Cohen M. Relationships between measures of dysfunctional
breathing in a population with concerns about their breathing. Journal of bodywork
and movement therapies 2011;15(1):24-34.
48. Bezerra LA, de Melo HF, Garay AP, Reis VM, Aidar FJ, Bodas AR, et al. Do 12-week
yoga program influence respiratory function of elderly women? J Hum Kinet
2014;43:177-84.
49. Jones M, Harvey A, Marston L, O'Connell NE. Breathing exercises for dysfunctional
breathing/hyperventilation syndrome in adults. Cochrane Database Syst Rev
2013;5:CD009041.
50. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic
meditation and supine rest. Appl Psychophysiol Biofeedback 2010;35(2):135-40.
Management of Arterial Hypertension of the European Society of Hypertension (ESH)
and of the European Society of Cardiology (ESC). Eur Heart J 2007;28(12):1462-536.
33. Viskoper R, Shapira I, Priluck R, Mindlin R, Chornia L, Laszt A, et al. Nonpharmacologic
treatment of resistant hypertensives by device-guided slow breathing exercises. Am J
Hypertens 2003;16(6):484-7.
34. Kingsley M, Lewis MJ, Marson R. Comparison of polar 810 s and an ambulatory ECG
system for RR interval measurement during progressive exercise. International
journal of sports medicine 2005;26(01):39-44.
35. Heart rate variability. Standards of measurement, physiological interpretation, and clinical
use. Task Force of the European Society of Cardiology and the North American
Society of Pacing and Electrophysiology. Eur Heart J 1996;17(3):354-81.
36. Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality
of life for clinical trials in chronic lung disease. Thorax 1987;42(10):773-8.
37. Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann
Med 2001;33(5):337-43.
38. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al.
Standardisation of spirometry. The European respiratory journal 2005;26(2):319-38.
39. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc
1982;14(5):377-81.
40. Borg G. Ratings of perceived exertion and heart rates during short-term cycle exercise and
their use in a new cycling strength test. Int J Sports Med 1982;3(3):153-8.
41. Chhabra SK, Gupta AK, Khuma MZ. Evaluation of three scales of dyspnea in chronic
obstructive pulmonary disease. Ann Thorac Med 2009;4(3):128-32.
42. Puhan MA, Chandra D, Mosenifar Z, Ries A, Make B, Hansel NN, et al. The minimal
important difference of exercise tests in severe COPD. The European respiratory
journal 2011;37(4):784-90.
43. Redelmeier DA, Bayoumi AM, Goldstein RS, Guyatt GH. Interpreting small differences
in functional status: the Six Minute Walk test in chronic lung disease patients.
American journal of respiratory and critical care medicine 1997;155(4):1278-82.
44. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory
changes and intensity of exercise. Evidence-based complementary and alternative
medicine : eCAM 2011;2011:241294.
45. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in
chronic obstructive pulmonary disease. American journal of therapeutics
2012;19(2):96-100.
46. Courtney R, van Dixhoorn J, Greenwood KM, Anthonissen EL. Medically unexplained
dyspnea: partly moderated by dysfunctional (thoracic dominant) breathing pattern. J
Asthma 2011;48(3):259-65.
47. Courtney R, Greenwood KM, Cohen M. Relationships between measures of dysfunctional
breathing in a population with concerns about their breathing. Journal of bodywork
and movement therapies 2011;15(1):24-34.
48. Bezerra LA, de Melo HF, Garay AP, Reis VM, Aidar FJ, Bodas AR, et al. Do 12-week
yoga program influence respiratory function of elderly women? J Hum Kinet
2014;43:177-84.
49. Jones M, Harvey A, Marston L, O'Connell NE. Breathing exercises for dysfunctional
breathing/hyperventilation syndrome in adults. Cochrane Database Syst Rev
2013;5:CD009041.
50. Patra S, Telles S. Heart rate variability during sleep following the practice of cyclic
meditation and supine rest. Appl Psychophysiol Biofeedback 2010;35(2):135-40.
27
27
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
51. Mueck-Weymann M, Janshoff G, Mueck H. Stretching increases heart rate variability in
healthy athletes complaining about limited muscular flexibility. Clinical Autonomic
Research 2004;14(1):15-18.
52. Papp ME, Lindfors P, Storck N, Wandell PE. Increased heart rate variability but no effect
on blood pressure from 8 weeks of hatha yoga - a pilot study. BMC Res Notes
2013;6:59.
53. Cahalin LP, Braga M, Matsuo Y, Hernandez ED. Efficacy of diaphragmatic breathing in
persons with chronic obstructive pulmonary disease: a review of the literature. J
Cardiopulm Rehabil 2002;22(1):7-21.
54. Courtney R. The functions of breathing and its dysfunctions and their relationship to
breathing therapy. International Journal of Osteopathic Medicine 2009;12(3):78-85.
55. Rocha T, Souza H, Brandao DC, Rattes C, Ribeiro L, Campos SL, et al. The Manual
Diaphragm Release Technique improves diaphragmatic mobility, inspiratory capacity
and exercise capacity in people with chronic obstructive pulmonary disease: a
randomised trial. J Physiother 2015;61(4):182-9.
56. Passino C, Beutler E, Beltrami FG, Boutellier U, Spengler CM. Effect of Regular Yoga
Practice on Respiratory Regulation and Exercise Performance. Plos One
2016;11(4):e0153159.
57. Gupta SS, Sawane MV. A comparative study of the effects of yoga and swimming on
pulmonary functions in sedentary subjects. International journal of yoga
2012;5(2):128.
58. Hancox RJ, Gray AR, Sears MR, Poulton R. Systemic inflammation and lung function: A
longitudinal analysis. Respiratory Medicine 2016;111:54-59.
59. Fagevik Olsén M, Lannefors L, Westerdahl E. Positive expiratory pressure – Common
clinical applications and physiological effects. Respiratory Medicine 2015;109(3):297307.
60. Donohue JF. Minimal clinically important differences in COPD lung function. COPD
2005;2(1):111-24.
61. Wahlstrom M, Rydell Karlsson M, Medin J, Frykman V. Effects of yoga in patients with
paroxysmal atrial fibrillation - a randomized controlled study. Eur J Cardiovasc Nurs
2016.
62. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease:
A Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
51. Mueck-Weymann M, Janshoff G, Mueck H. Stretching increases heart rate variability in
healthy athletes complaining about limited muscular flexibility. Clinical Autonomic
Research 2004;14(1):15-18.
52. Papp ME, Lindfors P, Storck N, Wandell PE. Increased heart rate variability but no effect
on blood pressure from 8 weeks of hatha yoga - a pilot study. BMC Res Notes
2013;6:59.
53. Cahalin LP, Braga M, Matsuo Y, Hernandez ED. Efficacy of diaphragmatic breathing in
persons with chronic obstructive pulmonary disease: a review of the literature. J
Cardiopulm Rehabil 2002;22(1):7-21.
54. Courtney R. The functions of breathing and its dysfunctions and their relationship to
breathing therapy. International Journal of Osteopathic Medicine 2009;12(3):78-85.
55. Rocha T, Souza H, Brandao DC, Rattes C, Ribeiro L, Campos SL, et al. The Manual
Diaphragm Release Technique improves diaphragmatic mobility, inspiratory capacity
and exercise capacity in people with chronic obstructive pulmonary disease: a
randomised trial. J Physiother 2015;61(4):182-9.
56. Passino C, Beutler E, Beltrami FG, Boutellier U, Spengler CM. Effect of Regular Yoga
Practice on Respiratory Regulation and Exercise Performance. Plos One
2016;11(4):e0153159.
57. Gupta SS, Sawane MV. A comparative study of the effects of yoga and swimming on
pulmonary functions in sedentary subjects. International journal of yoga
2012;5(2):128.
58. Hancox RJ, Gray AR, Sears MR, Poulton R. Systemic inflammation and lung function: A
longitudinal analysis. Respiratory Medicine 2016;111:54-59.
59. Fagevik Olsén M, Lannefors L, Westerdahl E. Positive expiratory pressure – Common
clinical applications and physiological effects. Respiratory Medicine 2015;109(3):297307.
60. Donohue JF. Minimal clinically important differences in COPD lung function. COPD
2005;2(1):111-24.
61. Wahlstrom M, Rydell Karlsson M, Medin J, Frykman V. Effects of yoga in patients with
paroxysmal atrial fibrillation - a randomized controlled study. Eur J Cardiovasc Nurs
2016.
62. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease:
A Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
28
28
YOGA AND FUNCTIONAL CAPACITY
YOGA AND FUNCTIONAL CAPACITY
29
29
IV
IV
Experiences of yoga
Experiences of yoga
Title: Experiences of hatha yogic exercises among patients with obstructive
Title: Experiences of hatha yogic exercises among patients with obstructive
pulmonary disease- a qualitative study
pulmonary disease- a qualitative study
Authors:
Authors:
Marian E Papp1*; Maria Henriques3; Gabriele Biguet2; Per E Wändell1; Malin Nygren-
Marian E Papp1*; Maria Henriques3; Gabriele Biguet2; Per E Wändell1; Malin Nygren-
Bonnier2,4
Bonnier2,4
Correspondence to: Marian Papp, Department of Neurobiology Care Sciences and Society,
Correspondence to: Marian Papp, Department of Neurobiology Care Sciences and Society,
Division of family medicine, Karolinska Institutet, Alfred Nobels alle 23, SE-141 83,
Division of family medicine, Karolinska Institutet, Alfred Nobels alle 23, SE-141 83,
Stockholm, Sweden; phone; + 46706946553, e-mail: [email protected];
Stockholm, Sweden; phone; + 46706946553, e-mail: [email protected];
[email protected]
[email protected]
Author affiliations:
Author affiliations:
1
1
Department of Neurobiology Care Sciences and Society, Division of family medicine,
Department of Neurobiology Care Sciences and Society, Division of family medicine,
Karolinska Institutet, Stockholm, Sweden
Karolinska Institutet, Stockholm, Sweden
2
2
Department of Neurobiology Care Sciences and Society, Division of Physiotherapy,
Department of Neurobiology Care Sciences and Society, Division of Physiotherapy,
Karolinska Institutet, Stockholm, Sweden
Karolinska Institutet, Stockholm, Sweden
3
Haninge Rehab, Handens Vardcentral, Box 550, SE-136 45 Haninge, Sweden
3
Haninge Rehab, Handens Vardcentral, Box 550, SE-136 45 Haninge, Sweden
4
Functional Area Occupational therapy & Physiotherapy, Allied Health Professionals
4
Functional Area Occupational therapy & Physiotherapy, Allied Health Professionals
Function, Karolinska University Hospital, SE-141 86, Stockholm, Sweden
Function, Karolinska University Hospital, SE-141 86, Stockholm, Sweden
Author contributions: MP and MH performed the literature search, MP and MNB designed
Author contributions: MP and MH performed the literature search, MP and MNB designed
the study, MP, MH and MNB performed the study with data collection. MP, MNB and MH,
the study, MP, MH and MNB performed the study with data collection. MP, MNB and MH,
GB analyzed the data. MP wrote the manuscript assisted by MNB, PW and GB. All authors
GB analyzed the data. MP wrote the manuscript assisted by MNB, PW and GB. All authors
read and approved the final version of the manuscript.
read and approved the final version of the manuscript.
1
1
Experiences of yoga
Experiences of yoga
Experiences of hatha yogic exercises among patients with obstructive
pulmonary disease- a qualitative study
Experiences of hatha yogic exercises among patients with obstructive
pulmonary disease- a qualitative study
Purpose: Obstructive pulmonary diseases can involve dyspnea and deconditioning. Hatha
Purpose: Obstructive pulmonary diseases can involve dyspnea and deconditioning. Hatha
yogic exercises are a form psychophysical attention-based activity. Research of experiences
yogic exercises are a form psychophysical attention-based activity. Research of experiences
after participating in an adapted hatha yoga (YE) intervention remains limited. The aim of the
after participating in an adapted hatha yoga (YE) intervention remains limited. The aim of the
present study was to explore the experiences of patients with obstructive pulmonary disorders
present study was to explore the experiences of patients with obstructive pulmonary disorders
participating in a 12-week hatha yoga intervention (YE). Method: Fifteen patients (10 women
participating in a 12-week hatha yoga intervention (YE). Method: Fifteen patients (10 women
and 5 men, median age = 61, range: 44–76 y) who had participated in a YE were interviewed
and 5 men, median age = 61, range: 44–76 y) who had participated in a YE were interviewed
after the intervention. Interview data were analyzed using qualitative content analysis.
after the intervention. Interview data were analyzed using qualitative content analysis.
Results: Three main categories emerged: “A new focus and awareness”, “To gain new
Results: Three main categories emerged: “A new focus and awareness”, “To gain new
knowledge by practice” and “To experience how one can influence the own situation”. The
knowledge by practice” and “To experience how one can influence the own situation”. The
overall theme “From limitation to opportunity – to develop awareness and control over one’s
overall theme “From limitation to opportunity – to develop awareness and control over one’s
breathing” illustrates a learning process on different levels. The participants perceived
breathing” illustrates a learning process on different levels. The participants perceived
improved physical symptoms and breathing technique, greater energy/stamina and body
improved physical symptoms and breathing technique, greater energy/stamina and body
awareness along with a new sense of control over their breathing in different situations.
awareness along with a new sense of control over their breathing in different situations.
Conclusions: Patients with obstructive pulmonary disease can strengthen their self-awareness
Conclusions: Patients with obstructive pulmonary disease can strengthen their self-awareness
and improve control and new ways of breathing after practicing YE, which may provide an
and improve control and new ways of breathing after practicing YE, which may provide an
efficient tool to control disease symptoms.
efficient tool to control disease symptoms.
Registration number: NCT02233114
Registration number: NCT02233114
Abbreviations: YE- yogic exercises based on hatha yoga; CTP - individualized program of
Abbreviations: YE- yogic exercises based on hatha yoga; CTP - individualized program of
strength and endurance training based on physiotherapy; FEV1= forced expiratory volume in
strength and endurance training based on physiotherapy; FEV1= forced expiratory volume in
one second; FVC=forced vital capacity; COPD= Pulmonary disease, chronic obstructive
one second; FVC=forced vital capacity; COPD= Pulmonary disease, chronic obstructive
Keywords: Breathing Exercises; Mind-body therapies; Pulmonary Disease, Chronic
Keywords: Breathing Exercises; Mind-body therapies; Pulmonary Disease, Chronic
Obstructive; Dyspnea
Obstructive; Dyspnea
2
2
Experiences of yoga
Experiences of yoga
Implications for rehabilitation
Implications for rehabilitation


Patients with obstructive pulmonary disease can strengthen awareness and improve
control of breathing through yogic exercise (YE) practice.

control of breathing through yogic exercise (YE) practice.
Yogic exercises can help individuals to discover new ways of breathing and to control

dyspnea.

Yogic exercises can help individuals to discover new ways of breathing and to control
dyspnea.
Yogic exercises provide an efficient tool for strengthening self-efficacy to control and

master the obstructive pulmonary disease.

Patients with obstructive pulmonary disease can strengthen awareness and improve
Yogic exercises provide an efficient tool for strengthening self-efficacy to control and
master the obstructive pulmonary disease.
The mechanism of change and the active tool in YE seems to involve the simultaneous

The mechanism of change and the active tool in YE seems to involve the simultaneous
awareness and focus of body, breath and mind and the consistent practice. The power
awareness and focus of body, breath and mind and the consistent practice. The power
of practice has to be highlighted for the patient group.
of practice has to be highlighted for the patient group.
Introduction
Introduction
Chronic Obstructive Pulmonary Disease (COPD) and obstructive asthma has a prevalence of
8-10 % worldwide.
1-3
Chronic Obstructive Pulmonary Disease (COPD) and obstructive asthma has a prevalence of
8-10 % worldwide. 1-3 Prevalence of COPD and asthma in all health care forms in Stockholm
Prevalence of COPD and asthma in all health care forms in Stockholm
County (according to registered diagnoses in electronic patient records) is estimated at 1.8%
County (according to registered diagnoses in electronic patient records) is estimated at 1.8%
4
and 5.9%, respectively. Symptoms of COPD include breathlessness (dyspnea), excessive
and 5.9%, respectively. 4 Symptoms of COPD include breathlessness (dyspnea), excessive
sputum production, coughing and exacerbations with a persistent airflow limitation and it is a
sputum production, coughing and exacerbations with a persistent airflow limitation and it is a
3
chronic inflammation in the lung tissue with structural changes. Asthma is a chronic
chronic inflammation in the lung tissue with structural changes. 3 Asthma is a chronic
inflammation with episodes of broncho-obstruction and symptoms include smooth muscle
inflammation with episodes of broncho-obstruction and symptoms include smooth muscle
contractions of genetic or environmental cause.
contractions of genetic or environmental cause.
For patients with COPD, treatment that decreases dyspnea and fatigue are both pharmacologic
For patients with COPD, treatment that decreases dyspnea and fatigue are both pharmacologic
3
and non-pharmacologic. The pharmacologic treatments are more efficient for asthma
and non-pharmacologic. 3 The pharmacologic treatments are more efficient for asthma
patients and often reverse their obstructive symptoms. Patients with decreased lung function
patients and often reverse their obstructive symptoms. Patients with decreased lung function
often have low physical capacity and physical function meaning that physical activity and
often have low physical capacity and physical function meaning that physical activity and
rehabilitation may be avoided due to fear of dyspnea. Thus, any pharmacologic treatment is
rehabilitation may be avoided due to fear of dyspnea. Thus, any pharmacologic treatment is
often supplemented by pulmonary rehabilitation. This is performed at 2-3 times a week in a
often supplemented by pulmonary rehabilitation. This is performed at 2-3 times a week in a
form of physical activity and is equally important for both diseases to optimize physical
form of physical activity and is equally important for both diseases to optimize physical
5
function, prevent muscle dysfunction, decrease symptoms and quality of life. Although there
function, prevent muscle dysfunction, decrease symptoms and quality of life. 5 Although there
is a consensus that patients with obstructive pulmonary disease benefit from rehabilitation,
is a consensus that patients with obstructive pulmonary disease benefit from rehabilitation,
relatively few patients attend to pulmonary hospital-based rehabilitation programs in
relatively few patients attend to pulmonary hospital-based rehabilitation programs in
6
Sweden. A reason may involve practical barriers and worries of not being able to manage the
Sweden.6 A reason may involve practical barriers and worries of not being able to manage the
exercises. 7 Physical hatha yogic exercises has been shown to increase physical function and
exercises. 7 Physical hatha yogic exercises has been shown to increase physical function and
3
3
Experiences of yoga
Experiences of yoga
quality of life 8-10 and may thus constitute an alternative form of rehabilitation for patients not
quality of life 8-10 and may thus constitute an alternative form of rehabilitation for patients not
preferring conventional treatments (e.g., using devices and gyms).
preferring conventional treatments (e.g., using devices and gyms).
Yogic exercises based on Hatha yoga are the most used yoga-style in the West. 11 It aims to
Yogic exercises based on Hatha yoga are the most used yoga-style in the West. 11 It aims to
use body, breath and mind simultaneously. Body, breath and mind are the three main tools of
use body, breath and mind simultaneously. Body, breath and mind are the three main tools of
yogic practice and differ from other “mainstream” physical activity methods. Hatha yoga is a
yogic practice and differ from other “mainstream” physical activity methods. Hatha yoga is a
form of psychophysical activity
12
form of psychophysical activity 12 but also a more intensive and modern style of yoga as well
but also a more intensive and modern style of yoga as well
as a type of moving meditation. 13 It is reported to be a contemplative practice and grounded
as a type of moving meditation. 13 It is reported to be a contemplative practice and grounded
with embodiment and movement and involves cultivating the interoceptive, proprioceptive
with embodiment and movement and involves cultivating the interoceptive, proprioceptive
and kinesthetic awareness.
14
and kinesthetic awareness. 14 Hatha yoga has been reported to improve breathing technique,
Hatha yoga has been reported to improve breathing technique,
chest expansion, lung function, body posture 9 15 16, health-related quality of life and to
chest expansion, lung function, body posture 9 15 16, health-related quality of life and to
decrease respiratory complaints. 2 8 17 18
decrease respiratory complaints. 2 8 17 18
Yoga programs have been suggested as a useful addition to formal rehabilitation programs 19
Yoga programs have been suggested as a useful addition to formal rehabilitation programs 19
and as a safe complementary alternative to other breathing exercises for asthma patients.2
and as a safe complementary alternative to other breathing exercises for asthma patients.2
When assessing the effect of treatment measures, biomarkers of lung function and lung
When assessing the effect of treatment measures, biomarkers of lung function and lung
specific or generic health questionnaires are often used. However, it is difficult to cover all
specific or generic health questionnaires are often used. However, it is difficult to cover all
relevant aspects of the effects of a treatment with quantitative methods, which means that it is
relevant aspects of the effects of a treatment with quantitative methods, which means that it is
of value to complement such evaluations with qualitative data. Qualitative research methods
of value to complement such evaluations with qualitative data. Qualitative research methods
aim to explore beliefs, attitudes and experiences during and after an intervention. This is of
aim to explore beliefs, attitudes and experiences during and after an intervention. This is of
particular importance since yoga is multifaceted and uses body, breath and mind
particular importance since yoga is multifaceted and uses body, breath and mind
simultaneously and involves the mindfulness (observation) part and thus differs from other
simultaneously and involves the mindfulness (observation) part and thus differs from other
conventional physical activity treatments. Previous studies on experiences of yoga report
conventional physical activity treatments. Previous studies on experiences of yoga report
However, studies
increased body awareness, less pain and increased health control. 20-22 However, studies
exploring authentic experiences of physical hatha yogic exercises (YE) in patients with
exploring authentic experiences of physical hatha yogic exercises (YE) in patients with
obstructive lung diseases are lacking. The aim of the present study was to describe the
obstructive lung diseases are lacking. The aim of the present study was to describe the
experiences and beliefs of a newly developed multifaceted hatha yoga program (YE) among
experiences and beliefs of a newly developed multifaceted hatha yoga program (YE) among
patients with obstructive respiratory disorders.
patients with obstructive respiratory disorders.
increased body awareness, less pain and increased health control.
20-22
4
4
Experiences of yoga
Experiences of yoga
Methods
Methods
Study-design: Inductive qualitative content analysis method analysing both manifest and
Study-design: Inductive qualitative content analysis method analysing both manifest and
latent content based on individual interviews with participants attending hatha yoga (YE)
latent content based on individual interviews with participants attending hatha yoga (YE)
twice a week for 12 weeks (1 h. each occasion).
23
twice a week for 12 weeks (1 h. each occasion). 23
Participants
Participants
The participants were recruited from a larger RCT study24 including a hatha yogic and a
The participants were recruited from a larger RCT study24 including a hatha yogic and a
conventional treatment (individually adjusted strength and endurance exercise). Participants
conventional treatment (individually adjusted strength and endurance exercise). Participants
enlisted in the RCT study were recruited from the Stockholm county area via medical doctors,
enlisted in the RCT study were recruited from the Stockholm county area via medical doctors,
nurses, physiotherapists, and via bulletin boards, social media and email-lists from academic
nurses, physiotherapists, and via bulletin boards, social media and email-lists from academic
primary care centres and personal invitation letters. In total 127 responded with 40 were
primary care centres and personal invitation letters. In total 127 responded with 40 were
eligible and randomized into yoga or conventional treatment. There were 4 drop-outs (there
eligible and randomized into yoga or conventional treatment. There were 4 drop-outs (there
24
were 19 in yoga group in the original RCT trial ) due to the following reasons; immune
were 19 in yoga group in the original RCT trial24) due to the following reasons; immune
disease, exacerbations, broken ankle and started another intervention program. The majority
disease, exacerbations, broken ankle and started another intervention program. The majority
of the participants had no prior experience of yoga. Regarding medication, all participants
of the participants had no prior experience of yoga. Regarding medication, all participants
used pulmonary inhaler treatments including corticosteroids, either short and/or long acting
used pulmonary inhaler treatments including corticosteroids, either short and/or long acting
β2-adrenergic drugs. Some took statins, anticoagulants, blood pressure medication and anti-
β2-adrenergic drugs. Some took statins, anticoagulants, blood pressure medication and anti-
arrhythmic medication. Two participants had both asthma and COPD (Table 1). Adherence to
arrhythmic medication. Two participants had both asthma and COPD (Table 1). Adherence to
yoga practice was median 20 (6-24) out of a total of 24 classes.
yoga practice was median 20 (6-24) out of a total of 24 classes.
All participants of the yoga group, including eight with COPD and seven with asthma, were
All participants of the yoga group, including eight with COPD and seven with asthma, were
invited and agreed to participate in an interview study (10 women, 5 men median age 61,
invited and agreed to participate in an interview study (10 women, 5 men median age 61,
range 44-76). Inclusion criteria were; age 35-85 years with diagnosed (according to electronic
range 44-76). Inclusion criteria were; age 35-85 years with diagnosed (according to electronic
patient records) obstructive pulmonary disease as COPD with mild to severe obstructions with
patient records) obstructive pulmonary disease as COPD with mild to severe obstructions with
GOLD 1-3, FEV1/FVC < 0.70 or diagnosed asthma with FEV1 and FEV1% of predicted
GOLD 1-3, FEV1/FVC < 0.70 or diagnosed asthma with FEV1 and FEV1% of predicted
respiratory function of; 30% ≤ FEV1 ≤ 90%, (FVC=forced vital capacity).
respiratory function of; 30% ≤ FEV1 ≤ 90%, (FVC=forced vital capacity).
Exclusion criteria included severe neurological, orthopedic or rheumatologic injuries or
Exclusion criteria included severe neurological, orthopedic or rheumatologic injuries or
diseases; inability to walk less than 200 meters; severe lung diseases and lung function;
diseases; inability to walk less than 200 meters; severe lung diseases and lung function;
decreased mobility and chronic diseases that can affect performance; surgery within 6
decreased mobility and chronic diseases that can affect performance; surgery within 6
months; severe mental disease diagnosis (incl. medication affecting attention); heart infarction
months; severe mental disease diagnosis (incl. medication affecting attention); heart infarction
within the last 12 months and medication change during the last 6 weeks.
within the last 12 months and medication change during the last 6 weeks.
The study was approved by the Regional Ethical Review Board in Stockholm (Ref. No.:
The study was approved by the Regional Ethical Review Board in Stockholm (Ref. No.:
2011/248-31/1). The eligible participants signed informed consent forms and were informed
2011/248-31/1). The eligible participants signed informed consent forms and were informed
5
5
Experiences of yoga
Experiences of yoga
of participation being voluntary and that participation could be cancelled at any time, without
of participation being voluntary and that participation could be cancelled at any time, without
specifying any reason.
specifying any reason.
Table 1: Participant characteristics
Table 1: Participant characteristics
Participant No. Age group Gender Diagnosis
Years since
Participant No. Age group Gender Diagnosis
diagnosis
1
70-75
M
COPD
2
60-65
W
3
40-45
4
Years since
diagnosis
33
1
70-75
M
COPD
COPD/Asthma 2
2
60-65
W
COPD/Asthma 2
W
Asthma
3
40-45
W
Asthma
55-60
W
COPD/Asthma 2
4
55-60
W
COPD/Asthma 2
5
45-50
W
Asthma
5
5
45-50
W
Asthma
5
6
55-60
M
Asthma
26
6
55-60
M
Asthma
26
7
55-60
M
Asthma
8
7
55-60
M
Asthma
8
8
75-80
W
COPD
7
8
75-80
W
COPD
7
9
75-80
W
COPD
5
9
75-80
W
COPD
5
10
70-75
W
COPD
11
10
70-75
W
COPD
11
11
55-60
W
Asthma
6
11
55-60
W
Asthma
6
12
60-65
W
Asthma
-
12
60-65
W
Asthma
-
13
70-75
M
COPD
5
13
70-75
M
COPD
5
14
60-65
M
Asthma
56
14
60-65
M
Asthma
56
15
60-65
W
COPD
-
15
60-65
W
COPD
-
43
33
43
Note: Age is presented in 5 years spans for confidentiality M=male; W=female;
Note: Age is presented in 5 years spans for confidentiality M=male; W=female;
COPD=Chronic Obstructive Pulmonary Disease.
COPD=Chronic Obstructive Pulmonary Disease.
6
6
Experiences of yoga
Experiences of yoga
Data collection procedures
Data collection procedures
Face to face, semi-structured interviews were conducted (in Swedish) and took place at the
Face to face, semi-structured interviews were conducted (in Swedish) and took place at the
hospital and lasted approx. 20-45 minutes. The interview guide was developed by the research
hospital and lasted approx. 20-45 minutes. The interview guide was developed by the research
group (two physiotherapists with experiences of patients with obstructive lung diseases and
group (two physiotherapists with experiences of patients with obstructive lung diseases and
rehabilitation, MNB and MH, and one physiotherapist with experience of qualitative methods,
rehabilitation, MNB and MH, and one physiotherapist with experience of qualitative methods,
GB, and the first author experienced in public health and yoga, MP) and consisted of open-
GB, and the first author experienced in public health and yoga, MP) and consisted of open-
ended and broad questions concerning the participants’ experiences during and after the YE.
ended and broad questions concerning the participants’ experiences during and after the YE.
Expectations, challenges in everyday life regarding the YE and daily life were included
Expectations, challenges in everyday life regarding the YE and daily life were included
(Table 2). To deepen the discussion and to get a wide range of descriptions, verbal prompts
(Table 2). To deepen the discussion and to get a wide range of descriptions, verbal prompts
and follow-up questions on each topic were used, as well as concluding remarks in the closing
and follow-up questions on each topic were used, as well as concluding remarks in the closing
part of the interview. Two pilot interviews were made to test the interview guide, however no
part of the interview. Two pilot interviews were made to test the interview guide, however no
changes were needed.
changes were needed.
The interviews were performed by a physiotherapist (MH) not involved in the RCT study or
The interviews were performed by a physiotherapist (MH) not involved in the RCT study or
the yoga classes and with no knowledge about the structure of the yoga program. Moreover,
the yoga classes and with no knowledge about the structure of the yoga program. Moreover,
the interviewer did not meet any of the participants before the interview. The interviews were
the interviewer did not meet any of the participants before the interview. The interviews were
audio recorded with a digital Dictaphone (Olympus Digital Voice recorder VN-8500PC) and
audio recorded with a digital Dictaphone (Olympus Digital Voice recorder VN-8500PC) and
transcribed verbatim by MH and first author. Both were familiar with the transcription
transcribed verbatim by MH and first author. Both were familiar with the transcription
process. The interviews were numbered and the interview transcripts were anonymized.
process. The interviews were numbered and the interview transcripts were anonymized.
Table 2: Interview guide used in the semi-structured interviews
Table 2: Interview guide used in the semi-structured interviews








Expectations
Do you remember what it was that convinced you to start practicing YE? Did you
have any expectations (goals) with YE?
Experience of YE
What have YE meant to you? What was the most important thing with YE?
Experiences of YE in the beginning and towards the end of the intervention. What
have you learned?
Was there anything in particular that was challenging? Can you describe a situation
during YE when you were assisted or got no help at all?
How did you feel practicing YE in a group?
How did you experience the role of the teacher during the YE classes?
Advice
What advice would you like to give to someone else with obstructive pulmonary
disorder who wants to start practicing YE?
What advice would you give a physiotherapist regarding this intervention?








7
Expectations
Do you remember what it was that convinced you to start practicing YE? Did you
have any expectations (goals) with YE?
Experience of YE
What have YE meant to you? What was the most important thing with YE?
Experiences of YE in the beginning and towards the end of the intervention. What
have you learned?
Was there anything in particular that was challenging? Can you describe a situation
during YE when you were assisted or got no help at all?
How did you feel practicing YE in a group?
How did you experience the role of the teacher during the YE classes?
Advice
What advice would you like to give to someone else with obstructive pulmonary
disorder who wants to start practicing YE?
What advice would you give a physiotherapist regarding this intervention?
7
Experiences of yoga
Experiences of yoga
Data analysis
Data analysis
The transcribed interviews were analysed using inductive qualitative content analysis
The transcribed interviews were analysed using inductive qualitative content analysis
23
focusing on both latent and manifest content . The manifest analysis examines raw and
focusing on both latent and manifest content 23. The manifest analysis examines raw and
unchanged data directly from the text whereas the latent content identifies the underlying
unchanged data directly from the text whereas the latent content identifies the underlying
meaning of the text. The following steps were used in the analysis in accordance with the
meaning of the text. The following steps were used in the analysis in accordance with the
description of Graneheim and Lundman.
23
description of Graneheim and Lundman. 23 The first step consisted of reading the interview
The first step consisted of reading the interview
transcripts to get a general idea of the content. Then meaning units were formed, i.e. parts of
transcripts to get a general idea of the content. Then meaning units were formed, i.e. parts of
the original text that is closely associated with the research question were extracted and
the original text that is closely associated with the research question were extracted and
condensed. This was done independently by MH and the first author MP and then compared
condensed. This was done independently by MH and the first author MP and then compared
and discussed until reaching consensus about the meaning units. The analysis proceeded with
and discussed until reaching consensus about the meaning units. The analysis proceeded with
abstracting the condensed meaning units and labeling these with a code, which represented a
abstracting the condensed meaning units and labeling these with a code, which represented a
description close to the text. The text was then reread several times and compared to the codes
description close to the text. The text was then reread several times and compared to the codes
so no information was lost from the body of text. The codes were sorted into groups
so no information was lost from the body of text. The codes were sorted into groups
representing a higher level of abstraction, and further divided into subcategories and
representing a higher level of abstraction, and further divided into subcategories and
categories while comparing similarities and differences in codes, and code groups (Table 3).
categories while comparing similarities and differences in codes, and code groups (Table 3).
This process involved the close collaboration between MH and the first author. Both
This process involved the close collaboration between MH and the first author. Both
categories and sub-categories were considered expressions of the manifest content of the text
categories and sub-categories were considered expressions of the manifest content of the text
and examined to be mutually exclusive. Finally, an overall theme was developed to link the
and examined to be mutually exclusive. Finally, an overall theme was developed to link the
underlying meaning between the emerging categories. This sentence described the latent
underlying meaning between the emerging categories. This sentence described the latent
content of the text which has to be interpreted. 23
content of the text which has to be interpreted. 23
8
8
Experiences of yoga
Experiences of yoga
Table 3: Examples from the analysis process
Table 3: Examples from the analysis process
Meaning unit
Condensed
meaning unit
Code
Subcategories
after a couple of times I was able to get
into that mood very quickly, when you
filter out all unecessary things, you don’t
bring along any thoughts about different
things, instead I could easily focus on
being there, in that moment and I
thought that was a positive effect
after a couple of Focus on
times I was able the
to filter out all moment
unecessary
things, and
easily focus on
being there,
which I thought
of as something
positive
in the beginning, when we started this
breathing training, then I often started
coughing and sometimes I felt that I was
hyperventilating and yes, but then when
you have found the pace, that is your
own pace and work on it, well I felt that
this makes a difference, that is when the
Yoga gave me something more than it
did in the beginning
It was only
To focus To focus
when I found
on oneself on oneself
my own pace in
the breathing
training that I
felt the
difference that
the yoga made
and it gave
something back
Categories
A new
focus and
awareness
Meaning unit
Condensed
meaning unit
Code
Subcategories
after a couple of times I was able to get
into that mood very quickly, when you
filter out all unecessary things, you don’t
bring along any thoughts about different
things, instead I could easily focus on
being there, in that moment and I
thought that was a positive effect
after a couple of Focus on
times I was able the
to filter out all moment
unecessary
things, and
easily focus on
being there,
which I thought
of as something
positive
in the beginning, when we started this
breathing training, then I often started
coughing and sometimes I felt that I was
hyperventilating and yes, but then when
you have found the pace, that is your
own pace and work on it, well I felt that
this makes a difference, that is when the
Yoga gave me something more than it
did in the beginning
It was only
To focus To focus
when I found
on oneself on oneself
my own pace in
the breathing
training that I
felt the
difference that
the yoga made
and it gave
something back
Categories
A new
focus and
awareness
During the analysis steps credibility of preliminary findings and the process of reflexivity
During the analysis steps credibility of preliminary findings and the process of reflexivity
were addressed in the whole research group by carefully following up on the whole analysis
were addressed in the whole research group by carefully following up on the whole analysis
process and categorization. Divergent views concerning the categorization were discussed
process and categorization. Divergent views concerning the categorization were discussed
until consensus was reached.
25 26
until consensus was reached. 25 26
Quotations chosen from all interviews to illustrate the present findings were assigned with a
Quotations chosen from all interviews to illustrate the present findings were assigned with a
number for each participant. Quotes have been translated from Swedish into English.
number for each participant. Quotes have been translated from Swedish into English.
Yoga intervention
Yoga intervention
The yoga classes were held at the Karolinska University hospital with 1-2 yoga teachers and
The yoga classes were held at the Karolinska University hospital with 1-2 yoga teachers and
in a light and well-ventilated room without music. No talking, except for questions to the
in a light and well-ventilated room without music. No talking, except for questions to the
teacher, was allowed during the yoga class.
teacher, was allowed during the yoga class.
The participants were sitting quietly on chairs with general yogic breathing instructions using
The participants were sitting quietly on chairs with general yogic breathing instructions using
the complete yogic breath technique. Standing (upright half-moon, triangle, side angle pose)
the complete yogic breath technique. Standing (upright half-moon, triangle, side angle pose)
sitting and twisting poses were used and breathing control and awareness was emphasized
sitting and twisting poses were used and breathing control and awareness was emphasized
throughout the classes. Sitting and supine poses (cat and cow, bridge, universal pose) and
throughout the classes. Sitting and supine poses (cat and cow, bridge, universal pose) and
classical breathing exercises (kapalabhati, bhastrika, nadi shodhana, bhramari) were taught.
classical breathing exercises (kapalabhati, bhastrika, nadi shodhana, bhramari) were taught.
9
9
Experiences of yoga
Experiences of yoga
Props including blocks, chairs and blankets were used to increase safety and individual
Props including blocks, chairs and blankets were used to increase safety and individual
adaptation for each patient. The class included 35 min asanas, 20 min of breathing exercises
adaptation for each patient. The class included 35 min asanas, 20 min of breathing exercises
with 5-10 minutes of relaxation. Home exercises were recommended and the participants
with 5-10 minutes of relaxation. Home exercises were recommended and the participants
received a DVD with a 55-min program.
received a DVD with a 55-min program.
Results
Results
The analysis resulted in an overall theme, 3 categories and 7 sub categories (Table 4).
The analysis resulted in an overall theme, 3 categories and 7 sub categories (Table 4).
Table 4: Overview of the findings
Table 4: Overview of the findings
Overall theme
Overall theme
From limitation to opportunity – to develop awareness and control over
one’s breathing
From limitation to opportunity – to develop awareness and control over
one’s breathing
Categories
Categories
A new focus and
awareness
To gain new
A new focus and
awareness
To experience how one
knowledge by practice can influence the own
To gain new
To experience how one
knowledge by practice can influence the own
situation
situation
Subcategories
Subcategories
To focus on oneself
To feel safe and be
guided
To be able to control
the breathing
To focus on oneself
To feel safe and be
guided
To be able to control
the breathing
To be aware of
breathing and to
discover
Learning by doing
To be able to manage
To be aware of
breathing and to
discover
Learning by doing
To be able to manage
stress and achieve
stress and achieve
balance
balance
To have more stamina
To have more stamina
and to master
and to master
challenges
challenges
10
10
Experiences of yoga
Experiences of yoga
From limitation to opportunity – to develop awareness and control over one’s breathing
From limitation to opportunity – to develop awareness and control over one’s breathing
The overall theme revealed that the participants developed a greater awareness of their
The overall theme revealed that the participants developed a greater awareness of their
breathing and this initiated a learning process and a feeling of being in more control over the
breathing and this initiated a learning process and a feeling of being in more control over the
breathing and in daily life situations. This process of learning can be described as a shift
breathing and in daily life situations. This process of learning can be described as a shift
“from limitations to opportunity”.
“from limitations to opportunity”.
The analysis shows clearly that having an obstructive lung disease was experienced as a
The analysis shows clearly that having an obstructive lung disease was experienced as a
limitation. Symptoms directly associated with the lung disease reported included dyspnea
limitation. Symptoms directly associated with the lung disease reported included dyspnea
with physical exertion, low coping and energy, cough, phlegm, stress and sleep disturbances.
with physical exertion, low coping and energy, cough, phlegm, stress and sleep disturbances.
Taking part in the YE challenged the participants breathing and physical exertion, however it
Taking part in the YE challenged the participants breathing and physical exertion, however it
also confronted them with the fact that there are possibilities to control and master the
also confronted them with the fact that there are possibilities to control and master the
breathing. Realizing that they had this new control over their breathing, the patients perceived
breathing. Realizing that they had this new control over their breathing, the patients perceived
that they were able to control stress but also control different situations in daily life as well as
that they were able to control stress but also control different situations in daily life as well as
to have control during physical exercise. To be able to control and manage the dyspnea,
to have control during physical exercise. To be able to control and manage the dyspnea,
especially during exercise, and knowing that it is not dangerous was a positive experience and
especially during exercise, and knowing that it is not dangerous was a positive experience and
involved feeling safe and secure.
involved feeling safe and secure.
”I actually think that if I feel the asthma, so instead of taking a quick Ventolin (medication), it
”I actually think that if I feel the asthma, so instead of taking a quick Ventolin (medication), it
is possible to do a breathing exercise and it works. It is not that I have stopped taking my
is possible to do a breathing exercise and it works. It is not that I have stopped taking my
meds but instead feel that perhaps I should but instead I do these breathing exercises and it
meds but instead feel that perhaps I should but instead I do these breathing exercises and it
becomes better.” (Interview No. 6)
becomes better.” (Interview No. 6)
“… I got a much better understanding of the breathing that you can actually
“… I got a much better understanding of the breathing that you can actually
breathe in different ways not just in and out,.. that you can actually control the
breathe in different ways not just in and out,.. that you can actually control the
breathing a lot and that has helped me a lot during physical activity .…
breathing a lot and that has helped me a lot during physical activity .…
Interview No. 7
Interview No. 7
“From limitation to opportunity” reflects a learning process on different levels. The YE
“From limitation to opportunity” reflects a learning process on different levels. The YE
increased self-knowledge and body-awareness in a new way. Specifically this included
increased self-knowledge and body-awareness in a new way. Specifically this included
learning new breathing exercises that could be used in daily life. New insights were
learning new breathing exercises that could be used in daily life. New insights were
established through the realization that it was possible to control the breathing, which had
established through the realization that it was possible to control the breathing, which had
previously been experienced only as a limitation.
previously been experienced only as a limitation.
“this is helpful, but maybe not in a physical way, like ok, now my lungs are 10 per cent better,
“this is helpful, but maybe not in a physical way, like ok, now my lungs are 10 per cent better,
it is not in that or rather….you know and you think more about how you are breathing and
it is not in that or rather….you know and you think more about how you are breathing and
from your own conditions and resources make it more optimal.” Interview No. 14
from your own conditions and resources make it more optimal.” Interview No. 14
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11
Experiences of yoga
Experiences of yoga
A new focus and awareness
A new focus and awareness
In this category the participants described YE as an opportunity to focus and to be aware of
In this category the participants described YE as an opportunity to focus and to be aware of
their breathing in a new way. Both the focus and awareness of the breathing was experienced
their breathing in a new way. Both the focus and awareness of the breathing was experienced
as an important part of the YE and seemed necessary for developing new insights about ways
as an important part of the YE and seemed necessary for developing new insights about ways
of breathing.
of breathing.
To focus on oneself
To focus on oneself
The importance of being fully focused during YE helped the participants to perform the
The importance of being fully focused during YE helped the participants to perform the
exercises at their own pace and to synchronize the movements with the breathing. To focus
exercises at their own pace and to synchronize the movements with the breathing. To focus
was described as being present in the moment and concentrating on the body, breathing and
was described as being present in the moment and concentrating on the body, breathing and
the exercises. Self-focus on the breathing was also described as a way of relaxing, with a joy
the exercises. Self-focus on the breathing was also described as a way of relaxing, with a joy
of setting aside time for oneself and ones’ needs. The participants pointed out the importance
of setting aside time for oneself and ones’ needs. The participants pointed out the importance
of being fully aware of their own body during the YE.
of being fully aware of their own body during the YE.
”after a few times I was able to get into that mood very quickly, when you filter out all
”after a few times I was able to get into that mood very quickly, when you filter out all
unnecessary things, you don’t bring along any thoughts about different things…instead I
unnecessary things, you don’t bring along any thoughts about different things…instead I
could easily focus on being there, in that moment and I thought that was a positive effect”
could easily focus on being there, in that moment and I thought that was a positive effect”
Interview No. 14
Interview No. 14
“I think that this, that I get to relax, to shut everything out and to be selfish and only think of
“I think that this, that I get to relax, to shut everything out and to be selfish and only think of
me…” Interview No. 13
me…” Interview No. 13
The participants were surprised of the effect of being together with others in a group and at
The participants were surprised of the effect of being together with others in a group and at
the same time being able to focus strongly on themselves. To be fully absorbed and focused
the same time being able to focus strongly on themselves. To be fully absorbed and focused
on the breathing, but also losing track of time was reported by the participants. They were
on the breathing, but also losing track of time was reported by the participants. They were
amazed of not being disturbed by the others in the group during the YE, not even when they
amazed of not being disturbed by the others in the group during the YE, not even when they
received individual guidance. The calm yoga teacher seemed to create a positive atmosphere,
received individual guidance. The calm yoga teacher seemed to create a positive atmosphere,
making it possible for the participants to continue focusing on their own practice. This created
making it possible for the participants to continue focusing on their own practice. This created
a positive experience of YE in a group situation.
a positive experience of YE in a group situation.
“In the beginning when you did the exercises and so, ouch, oh, oh and you noticed that it
“In the beginning when you did the exercises and so, ouch, oh, oh and you noticed that it
really took an hour but lately it’s been like, what, did one hour just pass? Where did it go? It
really took an hour but lately it’s been like, what, did one hour just pass? Where did it go? It
becomes totally different, like no, we can’t have finished…” Interview No. 11
becomes totally different, like no, we can’t have finished…” Interview No. 11
12
12
Experiences of yoga
Experiences of yoga
To be aware of breathing and to discover
To be aware of breathing and to discover
Discovering different ways of breathing resulted in participants reflecting over their breathing
Discovering different ways of breathing resulted in participants reflecting over their breathing
thus becoming more aware of their breathing patterns. For example they were surprised over
thus becoming more aware of their breathing patterns. For example they were surprised over
the fact that single breathing exercise could have powerful effects. The participants also
the fact that single breathing exercise could have powerful effects. The participants also
mentioned their thoughts around different bodily processes influencing each other. Other
mentioned their thoughts around different bodily processes influencing each other. Other
discoveries involved participants increasing their awareness of how different body positions
discoveries involved participants increasing their awareness of how different body positions
can change the depth of breathing, how nasal breathing felt gentle for the breathing passages
can change the depth of breathing, how nasal breathing felt gentle for the breathing passages
and regarding the importance of the exhalation but also that breathing was easier with relaxed
and regarding the importance of the exhalation but also that breathing was easier with relaxed
muscles.
muscles.
”Well…yes, the more you hear people say, that this can cure both this and that and widen,
”Well…yes, the more you hear people say, that this can cure both this and that and widen,
you perhaps think that the body needs more attention and that everything goes together and
you perhaps think that the body needs more attention and that everything goes together and
that breathing is important. And that you can do a lot, suddenly when you start breathing in
that breathing is important. And that you can do a lot, suddenly when you start breathing in
one way you start freezing and in another way you start sweating and it is amazing what you
one way you start freezing and in another way you start sweating and it is amazing what you
can do to the body” Interview No. 5
can do to the body” Interview No. 5
”I think some exercises have been really good, that is you immediately feel that they open up
”I think some exercises have been really good, that is you immediately feel that they open up
the airways and that you get a lot of oxygen during these exercises and so that was a great
the airways and that you get a lot of oxygen during these exercises and so that was a great
surprise, that you get that feeling in just one exercise” Interview No. 3
surprise, that you get that feeling in just one exercise” Interview No. 3
The participants described how they became more aware of the short and shallow breathing
The participants described how they became more aware of the short and shallow breathing
they had before the intervention and mentioned that they consciously started to breathe more
they had before the intervention and mentioned that they consciously started to breathe more
deeply and efficiently by using the diaphragm. They also experienced an increased awareness
deeply and efficiently by using the diaphragm. They also experienced an increased awareness
of symptoms such as nasal congestion and phlegm in the respiratory tract. This increased
of symptoms such as nasal congestion and phlegm in the respiratory tract. This increased
body-awareness and breath-awareness and respiratory symptoms were helpful in consultations
body-awareness and breath-awareness and respiratory symptoms were helpful in consultations
with their doctors regarding medication. The YE home training created another possibility for
with their doctors regarding medication. The YE home training created another possibility for
reflection and increased awareness.
reflection and increased awareness.
”At least I think that you get an…in yoga they use to talk about body control or body
”At least I think that you get an…in yoga they use to talk about body control or body
awareness, but that you…well I feel that in these exercises, I’ve been able to breathe through
awareness, but that you…well I feel that in these exercises, I’ve been able to breathe through
my nose (laughs) or how it feels in the chest and feel that, no now it is phlegm and perhaps I
my nose (laughs) or how it feels in the chest and feel that, no now it is phlegm and perhaps I
haven’t felt it so early on before so it’s body awareness or something” Interview No. 3
haven’t felt it so early on before so it’s body awareness or something” Interview No. 3
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Experiences of yoga
Experiences of yoga
To gain new knowledge by practice
To gain new knowledge by practice
This category revealed that actively participating in YE involved conquering new knowledge
This category revealed that actively participating in YE involved conquering new knowledge
about the body and breath by doing the exercises that is “learning by doing”. Even those with
about the body and breath by doing the exercises that is “learning by doing”. Even those with
some previous experience of yoga, mentioned that participating in YE deepened their
some previous experience of yoga, mentioned that participating in YE deepened their
knowledge about breathing techniques and how to use the techniques in daily life.
knowledge about breathing techniques and how to use the techniques in daily life.
Specifically, the YE was experienced as an opportunity to anchor the new knowledge through
Specifically, the YE was experienced as an opportunity to anchor the new knowledge through
the hands-on trying and practising.
the hands-on trying and practising.
To feel safe and be guided
To feel safe and be guided
The yoga teacher’s guidance was experienced as important, not only due to participants
The yoga teacher’s guidance was experienced as important, not only due to participants
getting feedback on correct techniques and body positions but also getting feedback on the
getting feedback on correct techniques and body positions but also getting feedback on the
power of practicing and how to adjust the poses to individual needs. The teacher feedback
power of practicing and how to adjust the poses to individual needs. The teacher feedback
seemed important for feeling safe and secure and gave everyone the same attention.
seemed important for feeling safe and secure and gave everyone the same attention.
”When you feel totally dizzy then she says that you can feel very dizzy, like this and you do. So
”When you feel totally dizzy then she says that you can feel very dizzy, like this and you do. So
you don’t think that you faint and that you have problems. So she has been really clear and all
you don’t think that you faint and that you have problems. So she has been really clear and all
have felt safe…” Interview No. 5
have felt safe…” Interview No. 5
It was reported that group training was experienced as joyful with a positive atmosphere
It was reported that group training was experienced as joyful with a positive atmosphere
giving opportunities to share experiences and challenges.
giving opportunities to share experiences and challenges.
”It gives a sense of belonging to a group. You get to know (each other) and you have similar
”It gives a sense of belonging to a group. You get to know (each other) and you have similar
preconditions to work with but then we have different bodies and I often find it easier to work
preconditions to work with but then we have different bodies and I often find it easier to work
in a group because you push each other more” Interview No. 1
in a group because you push each other more” Interview No. 1
”I have never experienced it as a group…perhaps I am against doing things in a group but
the yoga is like you are so focused on…you are in your own world…so I think of the yoga as
something positive…not like other activities when you are in a big group” Interview No. 10
”I have never experienced it as a group…perhaps I am against doing things in a group but
the yoga is like you are so focused on…you are in your own world…so I think of the yoga as
something positive…not like other activities when you are in a big group” Interview No. 10
Learning by doing
Learning by doing
While doing the exercises the participants mentioned instantly feeling the effects of the
While doing the exercises the participants mentioned instantly feeling the effects of the
different breathing techniques. The metronome was described as an efficient feedback
different breathing techniques. The metronome was described as an efficient feedback
instrument and helpful for observing the breathing and to feel the different qualities of the
instrument and helpful for observing the breathing and to feel the different qualities of the
breathing as the length of the different breath-phases. This helped the participants to more
breathing as the length of the different breath-phases. This helped the participants to more
strongly perceive the breathing and was reported to induce a deeper and calmer breath. Also,
strongly perceive the breathing and was reported to induce a deeper and calmer breath. Also,
by using the diaphragmatic breathing, the patients perceived an improvement of the depth of
by using the diaphragmatic breathing, the patients perceived an improvement of the depth of
breathing both during the classes and during the intervention period.
breathing both during the classes and during the intervention period.
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Experiences of yoga
Experiences of yoga
“When you were to exhale then you could exhale for twice as long…” Interview No. 1
“When you were to exhale then you could exhale for twice as long…” Interview No. 1
”I feel I learned these exercises, I will continue with these…I got this control and harmony
”I feel I learned these exercises, I will continue with these…I got this control and harmony
and balance thing, and now I have it. I understand how to master it…I did, I didn’t do that
and balance thing, and now I have it. I understand how to master it…I did, I didn’t do that
when I started. I will take this to my heart …” Interview No. 14
when I started. I will take this to my heart …” Interview No. 14
”it probably took like four five six times before you, because in the beginning then I think,
when you haven’t done this before, I haven’t at least, and you rushed, you did things too
quickly and when you do yoga, that I’ve understood, it has to be slow with slow movements”
Interview No. 7
”it probably took like four five six times before you, because in the beginning then I think,
when you haven’t done this before, I haven’t at least, and you rushed, you did things too
quickly and when you do yoga, that I’ve understood, it has to be slow with slow movements”
Interview No. 7
The YE involved a learning process, reflected in the participants expressing how they learned
The YE involved a learning process, reflected in the participants expressing how they learned
to work at their own level with them feeling stronger throughout the intervention as well as
to work at their own level with them feeling stronger throughout the intervention as well as
feeling more relaxed as they could practise the poses better as the intervention proceeded. In
feeling more relaxed as they could practise the poses better as the intervention proceeded. In
the beginning of the intervention difficulties to perform the exercises properly were described
the beginning of the intervention difficulties to perform the exercises properly were described
but also synchronizing the movements with the breath. Feelings of insecurity could also
but also synchronizing the movements with the breath. Feelings of insecurity could also
surface when not understanding clearly the aims of some of the breathing exercises. Home
surface when not understanding clearly the aims of some of the breathing exercises. Home
training exercises was difficult and depended on many factors including practical reasons and
training exercises was difficult and depended on many factors including practical reasons and
confusion about how to perform the movements. The regular practise of YE was perceived as
confusion about how to perform the movements. The regular practise of YE was perceived as
an important factor for improvements to occur. Some participants reported that they were
an important factor for improvements to occur. Some participants reported that they were
unsure of whether to proceed with the intervention in the beginning but after a few weeks they
unsure of whether to proceed with the intervention in the beginning but after a few weeks they
decided to continue. The YE got more challenging throughout the intervention and this
decided to continue. The YE got more challenging throughout the intervention and this
increased the participants’ motivation and joy since they were able to manage the exercises.
increased the participants’ motivation and joy since they were able to manage the exercises.
” Yes, every time it improves… Every time you get stronger, in the beginning you couldn’t
” Yes, every time it improves… Every time you get stronger, in the beginning you couldn’t
relax, in the beginning you get tense and don’t want to relax but then, eventually you learn
relax, in the beginning you get tense and don’t want to relax but then, eventually you learn
and feel that you can do it” Interview No. 12
and feel that you can do it” Interview No. 12
To experience how one can influence the own situation
To experience how one can influence the own situation
This category revealed that participating in YE created opportunities to self-control symptoms
This category revealed that participating in YE created opportunities to self-control symptoms
related to the lung disease but also in daily life situations. The participants reported that they
related to the lung disease but also in daily life situations. The participants reported that they
were able to control the breathing and stress voluntarily, thus achieving feelings of harmony
were able to control the breathing and stress voluntarily, thus achieving feelings of harmony
and balance. They also experienced increased energy, improved stamina, coping and feelings
and balance. They also experienced increased energy, improved stamina, coping and feelings
of safety and security while doing the YE and other physical activities.
of safety and security while doing the YE and other physical activities.
15
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Experiences of yoga
Experiences of yoga
To be able to control the breathing
To be able to control the breathing
Participants reported that they started to use many of the poses and breathing techniques in
Participants reported that they started to use many of the poses and breathing techniques in
everyday life for example, diaphragmatic breathing, using active exhalations (using the
everyday life for example, diaphragmatic breathing, using active exhalations (using the
abdominals) and different restorative resting positions. Voluntary breath-control, which was
abdominals) and different restorative resting positions. Voluntary breath-control, which was
achieved through the different breathing techniques, was reported to minimize breathlessness,
achieved through the different breathing techniques, was reported to minimize breathlessness,
dyspnea, coughing and cramp in the respiratory tract. Other things the participants noticed
dyspnea, coughing and cramp in the respiratory tract. Other things the participants noticed
were the increased efficiency and power of the breathing muscles and they learned how to
were the increased efficiency and power of the breathing muscles and they learned how to
prevent chest breathing. The increased self-efficacy created feelings of safety and less panic
prevent chest breathing. The increased self-efficacy created feelings of safety and less panic
during dyspnea.
during dyspnea.
”This bit shows how important the breathing is and how, it is not only about breathing up
”This bit shows how important the breathing is and how, it is not only about breathing up
here (pointing at upper chest), I think I have been breathing up here, like this (breaths
here (pointing at upper chest), I think I have been breathing up here, like this (breaths
quickly, shallow panting) all my life, instead the breathing should go (pointing down at
quickly, shallow panting) all my life, instead the breathing should go (pointing down at
stomach) and you open up the lungs” Interview No. 10
stomach) and you open up the lungs” Interview No. 10
”I have learnt that you should bend forwards if you get these breathing problems so I know
”I have learnt that you should bend forwards if you get these breathing problems so I know
that I can use that tool so to speak if I get this cramp” Interview No. 8
that I can use that tool so to speak if I get this cramp” Interview No. 8
The participants experienced less phlegm, cough, allergic complaints and several reported that
The participants experienced less phlegm, cough, allergic complaints and several reported that
they reduced their asthma medications during the intervention. They also reported improved
they reduced their asthma medications during the intervention. They also reported improved
sleep quality.
sleep quality.
To be able to manage stress and achieve balance
To be able to manage stress and achieve balance
The participants reported that performing YE reduced their stress and improved relaxation.
The participants reported that performing YE reduced their stress and improved relaxation.
Here, the instructor’s calm state contributed to the relaxation. Some participants felt calm
Here, the instructor’s calm state contributed to the relaxation. Some participants felt calm
already before the yoga class but during the class they too reported developing a gradually
already before the yoga class but during the class they too reported developing a gradually
deeper relaxation. After the classes feelings of well-being, balance and being satisfied with
deeper relaxation. After the classes feelings of well-being, balance and being satisfied with
oneself was experienced. To be able to participate in training that had previously been
oneself was experienced. To be able to participate in training that had previously been
associated with discouragement of symptom impairments was described to create feelings of
associated with discouragement of symptom impairments was described to create feelings of
relief.
relief.
”oh it was, what should I say, really relaxing. So you wouldn’t want to be without it. You
”oh it was, what should I say, really relaxing. So you wouldn’t want to be without it. You
almost rushed to get here (laughs) to get this calm nice moment, this hour, since you felt calm
almost rushed to get here (laughs) to get this calm nice moment, this hour, since you felt calm
and balanced afterwards” Interview No. 11
and balanced afterwards” Interview No. 11
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Experiences of yoga
Experiences of yoga
The home training involved developing feelings of being able to reduce stress and was
The home training involved developing feelings of being able to reduce stress and was
experienced as a form of self-control. Coping with stress and to be able to unwind and induce
experienced as a form of self-control. Coping with stress and to be able to unwind and induce
calmness was described as very important:
calmness was described as very important:
”it feels very good that you can lay down and it is like meditating, almost the same thing, you
”it feels very good that you can lay down and it is like meditating, almost the same thing, you
are totally calm and the whole body, I think you can use this all life so to speak so that you
are totally calm and the whole body, I think you can use this all life so to speak so that you
can relax during stressful situations and not get stressed but instead try to calm down”
can relax during stressful situations and not get stressed but instead try to calm down”
Interview No. 8
Interview No. 8
To have more stamina and to master challenges
To have more stamina and to master challenges
Increased stamina was experienced as a strong experience after YE, with participants
Increased stamina was experienced as a strong experience after YE, with participants
perceiving that they were able to run faster and longer, to maintain walking speed with their
perceiving that they were able to run faster and longer, to maintain walking speed with their
spouses, something that had been impossible before, and to be able to cope with daily
spouses, something that had been impossible before, and to be able to cope with daily
activities. In general participants reported mastering activities that they previously thought
activities. In general participants reported mastering activities that they previously thought
were impossible to deal with. They also reported experiencing a faster recovery after physical
were impossible to deal with. They also reported experiencing a faster recovery after physical
exertion. All these effects were considered by the participants to relate to a more efficient
exertion. All these effects were considered by the participants to relate to a more efficient
breathing technique.
breathing technique.
”I have realized that I can cope with situations in a different way. I can do more now, can
”I have realized that I can cope with situations in a different way. I can do more now, can
and have the strength to do more, I realize that I can walk longer without having to rest”
and have the strength to do more, I realize that I can walk longer without having to rest”
Interview No. 13
Interview No. 13
More energy was described as a tendency to get things done. It was described as a feeling of
More energy was described as a tendency to get things done. It was described as a feeling of
joy and euphoria that improved coping and stamina that could be self-controlled. During the
joy and euphoria that improved coping and stamina that could be self-controlled. During the
intervention generally improved physical well-being, improved strength, balance,
intervention generally improved physical well-being, improved strength, balance,
coordination and flexibility were mentioned as perceived physical benefits after YE. Some
coordination and flexibility were mentioned as perceived physical benefits after YE. Some
also mentioned less pain and improved urinary bladder control.
also mentioned less pain and improved urinary bladder control.
”…and then I have realized that after, afterwards, you can get completely euphoric. I jump
”…and then I have realized that after, afterwards, you can get completely euphoric. I jump
home and feel ready to do all those things that I felt…oh…how will I manage…before
home and feel ready to do all those things that I felt…oh…how will I manage…before
stepping into the class” Interview No. 5
stepping into the class” Interview No. 5
” it affected the whole, not just the breathing. When you breathe well, it becomes a good
” it affected the whole, not just the breathing. When you breathe well, it becomes a good
feeling throughout the body, it all goes together in some way” Interview No. 11
feeling throughout the body, it all goes together in some way” Interview No. 11
The obstacles and challenges with the YE were something that the participants seemed to
The obstacles and challenges with the YE were something that the participants seemed to
conquer. Specifically, they reported that the YE was physically challenging, they (really) got
conquer. Specifically, they reported that the YE was physically challenging, they (really) got
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Experiences of yoga
Experiences of yoga
the opportunity to stretch their bodies, becoming tired after exerting themselves both during
the opportunity to stretch their bodies, becoming tired after exerting themselves both during
and after class. A common observation was that individual adaptations to their own needs
and after class. A common observation was that individual adaptations to their own needs
were necessary for some of the poses. Uneasiness including tiredness and pain usually
were necessary for some of the poses. Uneasiness including tiredness and pain usually
decreased gradually during the intervention.
decreased gradually during the intervention.
”I did not manage to lay down, the strength in the muscles did not last as long as it was
”I did not manage to lay down, the strength in the muscles did not last as long as it was
supposed to... Is it called the Tiger when you stand on all fours and stretch your legs and
supposed to... Is it called the Tiger when you stand on all fours and stretch your legs and
arms diagonally? I did not manage to do it all that long, my muscles ran out of power”
arms diagonally? I did not manage to do it all that long, my muscles ran out of power”
Interview No. 13)
Interview No. 13)
” sometimes I was really tired. Even though I thought the exercises were quite simple and not
” sometimes I was really tired. Even though I thought the exercises were quite simple and not
so exhausting one at a time, but I was still quite drained afterwards” Interview No. 3
so exhausting one at a time, but I was still quite drained afterwards” Interview No. 3
Discussion
Discussion
This is one of the first qualitative studies exploring experience of patients with obstructive
This is one of the first qualitative studies exploring experience of patients with obstructive
respiratory disorders participating in a newly developed hatha yoga program with YE. As
respiratory disorders participating in a newly developed hatha yoga program with YE. As
effects often are measured only by quantitative methods, this is an important contribution to
effects often are measured only by quantitative methods, this is an important contribution to
the understanding of the subjective effects of yoga on treatment on respiratory diseases.
the understanding of the subjective effects of yoga on treatment on respiratory diseases.
The main findings of the analysis revealed that the participants discovered new ways of
The main findings of the analysis revealed that the participants discovered new ways of
controlling and using their breath as a way to counteract symptoms related to obstructive
controlling and using their breath as a way to counteract symptoms related to obstructive
pulmonary disease, such as breathlessness, dyspnea and coughing. The participants also
pulmonary disease, such as breathlessness, dyspnea and coughing. The participants also
reported that practising YE by “learning by doing” was helpful to become more focused
reported that practising YE by “learning by doing” was helpful to become more focused
which lead to a calmer and deeper breathing with an increasing body awareness but also
which lead to a calmer and deeper breathing with an increasing body awareness but also
increasing in energy and stamina. This is an important complement to the traditionally
increasing in energy and stamina. This is an important complement to the traditionally
measured effects on biomarkers of lung function, and results of health questionnaires. To
measured effects on biomarkers of lung function, and results of health questionnaires. To
strengthen the patient’s own ability to master the disease in the everyday practice is often
strengthen the patient’s own ability to master the disease in the everyday practice is often
referred to as empowerment, and the contribution of yoga to do this in respiratory diseases is a
referred to as empowerment, and the contribution of yoga to do this in respiratory diseases is a
new and important finding. Improved awareness of the breathing together with improved
new and important finding. Improved awareness of the breathing together with improved
breathing techniques was experienced as an important learning opportunity as well as
breathing techniques was experienced as an important learning opportunity as well as
increased perceived control over their health. This becomes evident in the three categories in
increased perceived control over their health. This becomes evident in the three categories in
the present study (Table 4).
the present study (Table 4).
These three categories can be related to the three main tools and active ingredients of YE;
These three categories can be related to the three main tools and active ingredients of YE;
1.Body, 2.Breath, 3.Mind. These three tools are unique in involving the individual fully while
1.Body, 2.Breath, 3.Mind. These three tools are unique in involving the individual fully while
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Experiences of yoga
Experiences of yoga
practicing yoga as compared to usual treatments in health-care. Especially, the focused
practicing yoga as compared to usual treatments in health-care. Especially, the focused
attention and “listening” aspect of yoga brings a new dimension to patients with chronic
attention and “listening” aspect of yoga brings a new dimension to patients with chronic
illnesses as compared to other conventional physical activities. This means that the individual
illnesses as compared to other conventional physical activities. This means that the individual
is involved in the practise in a more focused way.
12 27
is involved in the practise in a more focused way. 12 27
These three yogic tools fit to the overall theme emerged in the present study “From limitation
These three yogic tools fit to the overall theme emerged in the present study “From limitation
to opportunity - to develop awareness and control over one’s breathing”.
to opportunity - to develop awareness and control over one’s breathing”.
According to Bandura 28, self-efficacy is the most important predictor of behaviour change. In
According to Bandura 28, self-efficacy is the most important predictor of behaviour change. In
general this means that the individual takes more responsibility of self-controlling symptoms.
general this means that the individual takes more responsibility of self-controlling symptoms.
In this study, it was done through the help of the yogic tools and especially the breathing part.
In this study, it was done through the help of the yogic tools and especially the breathing part.
as increased self-
The importance of reinforcing patients’ confidence in their own abilities 21 as increased self-
efficacy is an important outcome and goal with YE and has been clearly verbalized from the
efficacy is an important outcome and goal with YE and has been clearly verbalized from the
participants in this study. This was reported in the category “To experience how one can
participants in this study. This was reported in the category “To experience how one can
The importance of reinforcing patients’ confidence in their own abilities
21
influence the own situation”. Using an evaluated yogic self-efficacy scale
29
influence the own situation”. Using an evaluated yogic self-efficacy scale 29 would be
would be
valuable for further studies to measure the efficiency of yogic interventions in terms of
valuable for further studies to measure the efficiency of yogic interventions in terms of
obstacles and maintaining yogic practise as health behaviour.
obstacles and maintaining yogic practise as health behaviour.
The power of continuous practice i.e. “learning by doing” increased body awareness and
The power of continuous practice i.e. “learning by doing” increased body awareness and
control over health and was in the present study mainly described in the category “To gain
control over health and was in the present study mainly described in the category “To gain
new knowledge by practice”. This is in line with previous qualitative studies on yoga using a
new knowledge by practice”. This is in line with previous qualitative studies on yoga using a
somewhat similar structure such as the one used in the present study and reporting effects as
somewhat similar structure such as the one used in the present study and reporting effects as
increased body awareness, less pain and increased health control despite these studies
increased body awareness, less pain and increased health control despite these studies
including pain-,
20 21
and cancer patients.
22
including pain-, 20 21 and cancer patients. 22
Other qualitative studies report that increased awareness is the active ingredient of YE needed
for improvements to occur
20 21
Other qualitative studies report that increased awareness is the active ingredient of YE needed
for improvements to occur 20 21, especially for patients with pain and obstructive pulmonary
, especially for patients with pain and obstructive pulmonary
diseases. 17 This suggests that the attention part of yoga is an important tool for this patient
diseases. 17 This suggests that the attention part of yoga is an important tool for this patient
group. This is in line with Cramer et al., 20 who mention that body awareness is the key
group. This is in line with Cramer et al., 20 who mention that body awareness is the key
mechanism of yogic training and that it is important to recognize changes in habitual patterns
mechanism of yogic training and that it is important to recognize changes in habitual patterns
of posture and muscle tension in patients with chronic non-specific neck pain.
of posture and muscle tension in patients with chronic non-specific neck pain.
The style of YE in the present intervention involved more active and challenging postures
The style of YE in the present intervention involved more active and challenging postures
similar to other forms of physical activity (using vigorous standing poses). The patients
similar to other forms of physical activity (using vigorous standing poses). The patients
participating in the present study reported increased stamina and energy, which can perhaps
participating in the present study reported increased stamina and energy, which can perhaps
be explained by the dynamic parts of the program.
be explained by the dynamic parts of the program.
19
19
Experiences of yoga
Experiences of yoga
Quantitative data (Epub ahead) from the group investigated here revealed that functional
Quantitative data (Epub ahead) from the group investigated here revealed that functional
capacity, measured with the 6 minute-walk test, increased significantly after YE (12 weeks).
capacity, measured with the 6 minute-walk test, increased significantly after YE (12 weeks).
This finding is in line with our qualitative results with participants reporting improved energy
This finding is in line with our qualitative results with participants reporting improved energy
and stamina and also follows other studies for lung disease patients.
29
and stamina and also follows other studies for lung disease patients. 2 9 The mechanism for
The mechanism for
increased functional capacity in the quantitative study with the same patients as are
interviewed here may involve a more efficient breathing pattern and having more energy.
increased functional capacity in the quantitative study with the same patients as are
30
interviewed here may involve a more efficient breathing pattern and having more energy. 30
For example one participant reported increased ability to walk longer distances without
For example one participant reported increased ability to walk longer distances without
stopping.
stopping.
Patients with obstructive diseases reduce their physical activity levels (already at GOLD II)
and rehabilitation is an important factor to prevent deconditioning and disease progression.
Patients with obstructive diseases reduce their physical activity levels (already at GOLD II)
31
and rehabilitation is an important factor to prevent deconditioning and disease progression. 31
Rehabilitation helping patients to self-manage their symptoms and quality of life needs to be
Rehabilitation helping patients to self-manage their symptoms and quality of life needs to be
emphasized for this patient group. Also it has to be emphasized that maintenance of health
emphasized for this patient group. Also it has to be emphasized that maintenance of health
through physical activity is important.
32
A recent Cochrane review reports that yoga probably
through physical activity is important. 32 A recent Cochrane review reports that yoga probably
improves quality of life and asthma symptoms to some extent without serious adverse events
improves quality of life and asthma symptoms to some extent without serious adverse events
33
33
and it has been suggested to serve as an alternative rehabilitation choice for patients with
19
and it has been suggested to serve as an alternative rehabilitation choice for patients with
obstructive lung diseases. Moreover asthma symptoms, quality of life, exercise capacity and
obstructive lung diseases.19 Moreover asthma symptoms, quality of life, exercise capacity and
bronchial hyper reactivity has been reported to improve in asthmatics after physical training 34
bronchial hyper reactivity has been reported to improve in asthmatics after physical training 34
and can be used as a tool to control the disease. In line with reported effects, patients with
and can be used as a tool to control the disease. In line with reported effects, patients with
asthma in the present study reported less use of bronchodilators and less breathlessness as
asthma in the present study reported less use of bronchodilators and less breathlessness as
well as an increased mastery of dyspnea after YE, which is reported in the category “To
well as an increased mastery of dyspnea after YE, which is reported in the category “To
experience how one can influence the own situation”.
experience how one can influence the own situation”.
Using breathing exercises (pranayama) improves breathing technique 18 and is one of the
Using breathing exercises (pranayama) improves breathing technique 18 and is one of the
important yogic tools to increase awareness which the patients in the present study
important yogic tools to increase awareness which the patients in the present study
experienced. This was reported in category “To experience how one can influence one’s own
experienced. This was reported in category “To experience how one can influence one’s own
situation”. Other yogic interventions
35
using only breathing exercises (3 weeks and 15 hours
situation”. Other yogic interventions 35 using only breathing exercises (3 weeks and 15 hours
in total) showed significant improvements on sleep with yoga when compared to usual care.
in total) showed significant improvements on sleep with yoga when compared to usual care.
This indicates that short interventions can have powerful and non-pharmacological effects. In
This indicates that short interventions can have powerful and non-pharmacological effects. In
the present study difficulties and challenges in performing the movements and synchronizing
the present study difficulties and challenges in performing the movements and synchronizing
the breath with movements were reported in the beginning, but after 5-6 times they reported
the breath with movements were reported in the beginning, but after 5-6 times they reported
that it became easier.
that it became easier.
Social interactions before and after YE in the present study may have strengthened the
Social interactions before and after YE in the present study may have strengthened the
experiences and effects of YE even though no conversation were encouraged during the
experiences and effects of YE even though no conversation were encouraged during the
20
20
Experiences of yoga
Experiences of yoga
classes. Being in a group setting with a common goal may have created a positive social
classes. Being in a group setting with a common goal may have created a positive social
atmosphere 17 and may have increased the participants personal empowerment 22 as well as
atmosphere 17 and may have increased the participants personal empowerment 22 as well as
added to their awareness of the self and the physical body. This importance of a positive
added to their awareness of the self and the physical body. This importance of a positive
atmosphere is reported in the category: To focus and be aware in a new way.
atmosphere is reported in the category: To focus and be aware in a new way.
The category “To experience how one can influence one’s own situation” and the overall
The category “To experience how one can influence one’s own situation” and the overall
theme to go from limitation to opportunity can be described as a form of improvement in
theme to go from limitation to opportunity can be described as a form of improvement in
quality of life since the patients were able to master their symptoms themselves.
quality of life since the patients were able to master their symptoms themselves.
Others have mentioned improved quality of life (CRQ-fatigue), breathing capacity but also
Others have mentioned improved quality of life (CRQ-fatigue), breathing capacity but also
improvements in anxiety, pain and energy in reporting experiences as; "increased tidal
improvements in anxiety, pain and energy in reporting experiences as; "increased tidal
volume with slowing expiration", "I have an overall feeling of well-being" and "excellent
volume with slowing expiration", "I have an overall feeling of well-being" and "excellent
amount of energy".
17
amount of energy". 17
Measuring quality of life with CRQ-scale mastery increased significantly in the RCT-trial24
Measuring quality of life with CRQ-scale mastery increased significantly in the RCT-trial24
showing that objective and subjective data mirror each other in the present intervention.
showing that objective and subjective data mirror each other in the present intervention.
Methodological considerations
Methodological considerations
An important strength of the present study was that all the participants engaged in the YE
An important strength of the present study was that all the participants engaged in the YE
intervention accepted to be interviewed. This together with the variation of participants,
intervention accepted to be interviewed. This together with the variation of participants,
regarding gender, age and different levels of obstructive lung diseases provided a broad view
regarding gender, age and different levels of obstructive lung diseases provided a broad view
of YE experiences and thus strengthens the transfer of the findings to a wider sample.
of YE experiences and thus strengthens the transfer of the findings to a wider sample.
Credibility in data collection and analysis was assured by close cooperation within the
Credibility in data collection and analysis was assured by close cooperation within the
research group with good competency in using content analyses, yoga teacher experiences and
research group with good competency in using content analyses, yoga teacher experiences and
clinical experiences of working with obstructive pulmonary disorders as well as the
clinical experiences of working with obstructive pulmonary disorders as well as the
interviews being performed by an independent interviewer not involved in the intervention.
interviews being performed by an independent interviewer not involved in the intervention.
The interview guide was developed by the research group and two test interviews were
The interview guide was developed by the research group and two test interviews were
performed in order to strengthen the interview technique. Further, the interviews were
performed in order to strengthen the interview technique. Further, the interviews were
performed directly after the intervention while the participants had their experiences fresh in
performed directly after the intervention while the participants had their experiences fresh in
24
mind and the YE program was described in detail elsewhere .
mind and the YE program was described in detail elsewhere24.
The limitations involve excluding GOLD grade four COPD patients due to the characteristics
The limitations involve excluding GOLD grade four COPD patients due to the characteristics
of the YE. Thus transfer of our findings to patients with severe obstruction is not fully
of the YE. Thus transfer of our findings to patients with severe obstruction is not fully
possible. Three participants with more severe illness and one younger woman also dropped
possible. Three participants with more severe illness and one younger woman also dropped
out which may be due to the intensity of the program and personal reasons. Moreover, the
out which may be due to the intensity of the program and personal reasons. Moreover, the
recruitment process and the participants’ preferences and expectations for treatment
recruitment process and the participants’ preferences and expectations for treatment
assignment and positive outcomes should be considered as a limitation. However, the
assignment and positive outcomes should be considered as a limitation. However, the
21
21
Experiences of yoga
Experiences of yoga
information to participants was clear regarding the fact that the study involved two different
information to participants was clear regarding the fact that the study involved two different
conditions with eligible participants being randomized into yoga or conventional treatment.
conditions with eligible participants being randomized into yoga or conventional treatment.
Regarding the YE program insecurity appeared when the aim of some breathing exercises was
Regarding the YE program insecurity appeared when the aim of some breathing exercises was
not clearly understood. To improve program design, future interventions should introduce
not clearly understood. To improve program design, future interventions should introduce
fewer exercises in the beginning. As for the home training program, difficulties were
fewer exercises in the beginning. As for the home training program, difficulties were
experienced due to participants being unsure of how to perform the movements. This suggests
experienced due to participants being unsure of how to perform the movements. This suggests
that future home training programs should be very clearly designed.
that future home training programs should be very clearly designed.
Conclusions
Conclusions
Patients with obstructive pulmonary disease experienced improved awareness and control of
Patients with obstructive pulmonary disease experienced improved awareness and control of
breathing with YE. The power of practicing YE, i.e. learning by doing was emphasized and
breathing with YE. The power of practicing YE, i.e. learning by doing was emphasized and
seemed central for facilitating self-awareness and new ways of breathing. Moreover
seemed central for facilitating self-awareness and new ways of breathing. Moreover
controlling symptoms and breathlessness through YE practice can serve as an efficient tool
controlling symptoms and breathlessness through YE practice can serve as an efficient tool
for strengthening self-efficacy of the obstructive pulmonary disease. The recognition of yoga
for strengthening self-efficacy of the obstructive pulmonary disease. The recognition of yoga
as a treatment of COPD and asthma in medical practice, and its contribution to the
as a treatment of COPD and asthma in medical practice, and its contribution to the
empowerment of patients in their everyday practice is an important new finding.
empowerment of patients in their everyday practice is an important new finding.
Acknowledgements: Thanks to all patients who volunteered participation. Thanks to
Acknowledgements: Thanks to all patients who volunteered participation. Thanks to
Professor Petra Lindfors for language editing and valuable feedback on the manuscript.
Professor Petra Lindfors for language editing and valuable feedback on the manuscript.
Declarations of interest: We conformed to the Helsinki Declaration concerning human rights
Declarations of interest: We conformed to the Helsinki Declaration concerning human rights
and informed consent, and followed correct procedures concerning treatment of humans.
and informed consent, and followed correct procedures concerning treatment of humans.
Marian Papp, Malin Nygren-Bonnier, Gabriele Biguet, Per Wändell and Maria Henriques
Marian Papp, Malin Nygren-Bonnier, Gabriele Biguet, Per Wändell and Maria Henriques
declare that they have no conflict of interest.
declare that they have no conflict of interest.
Funding: None
Funding: None
Congresses: None
Congresses: None
All data are stored at Department of Neurobiology Care Sciences and Society, Division of
Family Medicine, Karolinska Institutet
All data are stored at Department of Neurobiology Care Sciences and Society, Division of
Family Medicine, Karolinska Institutet
22
22
Experiences of yoga
Experiences of yoga
References:
References:
1. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease: a
systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
2. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014.
3. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2013;187(4):347-65.
4. Carlsson AC, Wandell P, Osby U, Zarrinkoub R, Wettermark B, Ljunggren G. High prevalence of
diagnosis of diabetes, depression, anxiety, hypertension, asthma and COPD in the total
population of Stockholm, Sweden - a challenge for public health. BMC Public Health
2013;13:670.
5. Osadnik CR, Rodrigues FMM, Camillo CA, Loeckx M, Janssens W, Dooms C, et al. Principles of
Rehabilitation and Reactivation. Respiration 2015;89(1):2-11.
6. Wadell K, Janaudis Ferreira T, Arne M, Lisspers K, Stallberg B, Emtner M. Hospital-based pulmonary
rehabilitation in patients with COPD in Sweden--a national survey. Respir Med
2013;107(8):1195-200.
7. Fischer MJ, Scharloo M, Abbink JJ, Thijs-Van A, Rudolphus A, Snoei L, et al. Participation and dropout in pulmonary rehabilitation: a qualitative analysis of the patient's perspective. Clin
Rehabil 2007;21(3):212-21.
8. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in chronic
obstructive pulmonary disease. American journal of therapeutics 2012;19(2):96-100.
9. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients with chronic
obstructive pulmonary disease: a systematic review and meta-analysis. J Thorac Dis
2014;6(6):795-802.
10. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases dyspnearelated distress and improves functional performance in people with chronic obstructive
pulmonary disease: a pilot study. Journal of alternative and complementary medicine
2009;15(3):225-34.
11. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A systematic
review of associations of yoga style and conclusions in randomized yoga trials.
Complementary therapies in medicine 2016.
12. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and cardiopulmonary
function: a literature review. Journal of alternative and complementary medicine
2002;8(6):797-812.
13. Shelov DV, Suchday S, Friedberg JP. A pilot study measuring the impact of yoga on the trait of
mindfulness. Behav Cogn Psychother 2009;37(5):595-8.
14. Schmalzl L, Crane-Godreau MA, Payne P. Movement-based embodied contemplative practices:
definitions and paradigms. Front Hum Neurosci 2014;8:205.
15. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of yoga
breathing in patients with chronic obstructive pulmonary disease: a pilot study. J Cardiopulm
Rehabil Prev 2009;29(2):133-7.
16. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary function in
healthy individuals: a literature review. Journal of alternative and complementary medicine
2013;19(3):185-90.
17. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects of Iyengar
yoga practice on the health-related quality of life of patients with chronic respiratory
diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
1. Farver-Vestergaard I, Jacobsen D, Zachariae R. Efficacy of psychosocial interventions on
psychological and physical health outcomes in chronic obstructive pulmonary disease: a
systematic review and meta-analysis. Psychother Psychosom 2015;84(1):37-50.
2. Cramer H, Posadzki P, Dobos G, Langhorst J. Yoga for asthma: a systematic review and metaanalysis. Ann Allergy Asthma Immunol 2014.
3. Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy for the
diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD
executive summary. American journal of respiratory and critical care medicine
2013;187(4):347-65.
4. Carlsson AC, Wandell P, Osby U, Zarrinkoub R, Wettermark B, Ljunggren G. High prevalence of
diagnosis of diabetes, depression, anxiety, hypertension, asthma and COPD in the total
population of Stockholm, Sweden - a challenge for public health. BMC Public Health
2013;13:670.
5. Osadnik CR, Rodrigues FMM, Camillo CA, Loeckx M, Janssens W, Dooms C, et al. Principles of
Rehabilitation and Reactivation. Respiration 2015;89(1):2-11.
6. Wadell K, Janaudis Ferreira T, Arne M, Lisspers K, Stallberg B, Emtner M. Hospital-based pulmonary
rehabilitation in patients with COPD in Sweden--a national survey. Respir Med
2013;107(8):1195-200.
7. Fischer MJ, Scharloo M, Abbink JJ, Thijs-Van A, Rudolphus A, Snoei L, et al. Participation and dropout in pulmonary rehabilitation: a qualitative analysis of the patient's perspective. Clin
Rehabil 2007;21(3):212-21.
8. Fulambarker A, Farooki B, Kheir F, Copur AS, Srinivasan L, Schultz S. Effect of yoga in chronic
obstructive pulmonary disease. American journal of therapeutics 2012;19(2):96-100.
9. Liu XC, Pan L, Hu Q, Dong WP, Yan JH, Dong L. Effects of yoga training in patients with chronic
obstructive pulmonary disease: a systematic review and meta-analysis. J Thorac Dis
2014;6(6):795-802.
10. Donesky-Cuenco D, Nguyen HQ, Paul S, Carrieri-Kohlman V. Yoga therapy decreases dyspnearelated distress and improves functional performance in people with chronic obstructive
pulmonary disease: a pilot study. Journal of alternative and complementary medicine
2009;15(3):225-34.
11. Cramer H, Lauche R, Langhorst J, Dobos G. Is one yoga style better than another? A systematic
review of associations of yoga style and conclusions in randomized yoga trials.
Complementary therapies in medicine 2016.
12. Raub JA. Psychophysiologic effects of Hatha Yoga on musculoskeletal and cardiopulmonary
function: a literature review. Journal of alternative and complementary medicine
2002;8(6):797-812.
13. Shelov DV, Suchday S, Friedberg JP. A pilot study measuring the impact of yoga on the trait of
mindfulness. Behav Cogn Psychother 2009;37(5):595-8.
14. Schmalzl L, Crane-Godreau MA, Payne P. Movement-based embodied contemplative practices:
definitions and paradigms. Front Hum Neurosci 2014;8:205.
15. Pomidori L, Campigotto F, Amatya TM, Bernardi L, Cogo A. Efficacy and tolerability of yoga
breathing in patients with chronic obstructive pulmonary disease: a pilot study. J Cardiopulm
Rehabil Prev 2009;29(2):133-7.
16. Abel AN, Lloyd LK, Williams JS. The effects of regular yoga practice on pulmonary function in
healthy individuals: a literature review. Journal of alternative and complementary medicine
2013;19(3):185-90.
17. Santana MJ, J SP, Mirus J, Loadman M, Lien DC, Feeny D. An assessment of the effects of Iyengar
yoga practice on the health-related quality of life of patients with chronic respiratory
diseases: a pilot study. Can Respir J 2013;20(2):e17-23.
23
23
Experiences of yoga
Experiences of yoga
18. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of controlled
breathing exercises and respiratory muscle training in people with chronic obstructive
pulmonary disease: results from evaluating the quality of evidence in systematic reviews.
BMC Pulm Med 2014;14:184.
19. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease: A
Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
20. Cramer H, Lauche R, Haller H, Langhorst J, Dobos G, Berger B. "I'm more in balance": a qualitative
study of yoga for patients with chronic neck pain. Journal of alternative and complementary
medicine 2013;19(6):536-42.
21. Keosaian JE, Lemaster CM, Dresner D, Godersky ME, Paris R, Sherman KJ, et al. "We're all in this
together": A qualitative study of predominantly low income minority participants in a yoga
trial for chronic low back pain. Complementary therapies in medicine 2016;24:34-9.
22. McCall M, Thorne S, Ward A, Heneghan C. Yoga in adult cancer: an exploratory, qualitative
analysis of the patient experience. BMC complementary and alternative medicine 2015;15(1).
23. Graneheim UH, Lundman B. Qualitative content analysis in nursing research: concepts,
procedures and measures to achieve trustworthiness. Nurse Educ Today 2004;24(2):105-12.
24. Papp M, Lindfors P, Wandell P, Nygren-Bonnier M. Effects of yogic exercises on functional
capacity, lung function and quality of life in participants with obstructive pulmonary disease:
a randomized controlled study. Eur J Phys Rehabil Med. 2016 Nov 10. [Epub ahead of print],
PMID: 27830924
18. Borge CR, Hagen KB, Mengshoel AM, Omenaas E, Moum T, Wahl AK. Effects of controlled
breathing exercises and respiratory muscle training in people with chronic obstructive
pulmonary disease: results from evaluating the quality of evidence in systematic reviews.
BMC Pulm Med 2014;14:184.
19. Desveaux L, Lee A, Goldstein R, Brooks D. Yoga in the Management of Chronic Disease: A
Systematic Review and Meta-analysis. Med Care 2015;53(7):653-61.
20. Cramer H, Lauche R, Haller H, Langhorst J, Dobos G, Berger B. "I'm more in balance": a qualitative
study of yoga for patients with chronic neck pain. Journal of alternative and complementary
medicine 2013;19(6):536-42.
21. Keosaian JE, Lemaster CM, Dresner D, Godersky ME, Paris R, Sherman KJ, et al. "We're all in this
together": A qualitative study of predominantly low income minority participants in a yoga
trial for chronic low back pain. Complementary therapies in medicine 2016;24:34-9.
22. McCall M, Thorne S, Ward A, Heneghan C. Yoga in adult cancer: an exploratory, qualitative
analysis of the patient experience. BMC complementary and alternative medicine 2015;15(1).
23. Graneheim UH, Lundman B. Qualitative content analysis in nursing research: concepts,
procedures and measures to achieve trustworthiness. Nurse Educ Today 2004;24(2):105-12.
24. Papp M, Lindfors P, Wandell P, Nygren-Bonnier M. Effects of yogic exercises on functional
capacity, lung function and quality of life in participants with obstructive pulmonary disease:
a randomized controlled study. Eur J Phys Rehabil Med. 2016 Nov 10. [Epub ahead of print],
PMID: 27830924
25. Elo S, Kyngäs H. The qualitative content analysis process. Journal of Advanced Nursing
2008;62(1):107-15.
26. Elo S, Kaariainen M, Kanste O, Polkki T, Utriainen K, Kyngas H. Qualitative Content Analysis: A
Focus on Trustworthiness. SAGE Open 2014;4(1).
27. Selman L, McDermott K, Donesky D, Citron T, Howie-Esquivel J. Appropriateness and acceptability
of a Tele-Yoga intervention for people with heart failure and chronic obstructive pulmonary
disease: qualitative findings from a controlled pilot study. BMC complementary and
alternative medicine 2015;15:21.
28. Bandura A. Health Promotion by Social Cognitive Means. Health Education & Behavior
2004;31(2):143-64.
29. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga SelfEfficacy Scale (YSES). BMC complementary and alternative medicine 2016;16(1):3.
30. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes and
intensity of exercise. Evidence-based complementary and alternative medicine : eCAM
2011;2011:241294.
31. Troosters T, Sciurba F, Battaglia S, Langer D, Valluri SR, Martino L, et al. Physical inactivity in
patients with COPD, a controlled multi-center pilot-study. Respir Med 2010;104(7):1005-11.
32. Gysels MH, Higginson IJ. Self-management for breathlessness in COPD: the role of pulmonary
rehabilitation. Chron Respir Dis 2009;6(3):133-40.
33. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma. Cochrane Database
Syst Rev 2016;4:CD010346.
34. Eichenberger PA, Diener SN, Kofmehl R, Spengler CM. Effects of Exercise Training on Airway
Hyperreactivity in Asthma: A Systematic Review and Meta-Analysis. Sports Medicine
2013;43(11):1157-70.
35. Sendhilkumar R, Gupta A, Nagarathna R, Taly AB. “Effect of pranayama and meditation as an addon therapy in rehabilitation of patients with Guillain-Barré syndrome—a randomized control
pilot study”. Disability and Rehabilitation 2012;35(1):57-62.
25. Elo S, Kyngäs H. The qualitative content analysis process. Journal of Advanced Nursing
2008;62(1):107-15.
26. Elo S, Kaariainen M, Kanste O, Polkki T, Utriainen K, Kyngas H. Qualitative Content Analysis: A
Focus on Trustworthiness. SAGE Open 2014;4(1).
27. Selman L, McDermott K, Donesky D, Citron T, Howie-Esquivel J. Appropriateness and acceptability
of a Tele-Yoga intervention for people with heart failure and chronic obstructive pulmonary
disease: qualitative findings from a controlled pilot study. BMC complementary and
alternative medicine 2015;15:21.
28. Bandura A. Health Promotion by Social Cognitive Means. Health Education & Behavior
2004;31(2):143-64.
29. Birdee GS, Sohl SJ, Wallston K. Development and Psychometric Properties of the Yoga SelfEfficacy Scale (YSES). BMC complementary and alternative medicine 2016;16(1):3.
30. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy expenditure, respiratory changes and
intensity of exercise. Evidence-based complementary and alternative medicine : eCAM
2011;2011:241294.
31. Troosters T, Sciurba F, Battaglia S, Langer D, Valluri SR, Martino L, et al. Physical inactivity in
patients with COPD, a controlled multi-center pilot-study. Respir Med 2010;104(7):1005-11.
32. Gysels MH, Higginson IJ. Self-management for breathlessness in COPD: the role of pulmonary
rehabilitation. Chron Respir Dis 2009;6(3):133-40.
33. Yang ZY, Zhong HB, Mao C, Yuan JQ, Huang YF, Wu XY, et al. Yoga for asthma. Cochrane Database
Syst Rev 2016;4:CD010346.
34. Eichenberger PA, Diener SN, Kofmehl R, Spengler CM. Effects of Exercise Training on Airway
Hyperreactivity in Asthma: A Systematic Review and Meta-Analysis. Sports Medicine
2013;43(11):1157-70.
35. Sendhilkumar R, Gupta A, Nagarathna R, Taly AB. “Effect of pranayama and meditation as an addon therapy in rehabilitation of patients with Guillain-Barré syndrome—a randomized control
pilot study”. Disability and Rehabilitation 2012;35(1):57-62.
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Experiences of yoga
Experiences of yoga
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Thesis for doctoral degree (Ph.D.)
2017
Hatha yogic exercises for physical function in
healthy individuals and patients with obstructive
respiratory disorders
Hatha yogic exercises for physical function in healthy individuals and patients
with obstructive respiratory disorders
Marian E Papp
Marian E Papp