CIinical Science and Molecular Medicine (1975) 48, 171s-174s.
Yoga and biofeedback in the management
of ‘stress’ in hypertensive patients
C. PATEL
Croydon, Surrey
Summary
1. Psychophysical relaxation exercises based on
yogic principles and reinforced by biofeedback
instruments were used for behaviour modification
in sixteen hypertensive subjects.
2. Preliminary studies indicated that their pressor
response to emotional and physical stimuli became
less exaggerated and less protracted compared with
controls.
Key words: behaviour therapy, biofeedback,
emotional stress, environmental stress, hypertension,
operant conditioning, pressor response, psychophysiological exercises, Yoga.
Introduction
Physical and emotional stimuli are effective in
modifying blood pressure in man. Pressor responses
to various stimuli are exaggerated and protracted in
hypertensive patients (Brod, Fencl, Heji & Jirka,
1959; Brod, 1960, 1963, 1970; Shapiro, 1961;
Sokolow, Werdegar, Perloff, Cowan & Brenenstuhl,
1970; Amery, Julius, Whitlock & Conway, 1967;
Sannerstedt, 1966; Wolf, Pfeiffer, Riply, Winter &
Wolf, 1948). The true pressure load on the left
ventricle and vessel walls is neither the resting pressure nor the occasional peak of pressure in response
to a mental or emotional stress but the integrated
average pressure over longer periods. Anti-hypertensivedrugs taken in adequate amounts lower the resting
pressures but there is no evidence that they prevent
the pressure rises associated with intermittent
excitatory discharges provoked by events in daily
life. As Smirk (1967) has pointed out, the physiologically induced peaks of increased pressure in
response to emotions are added to a high base-line
pressure and the two together carry the final height
of the pressure to degrees which contribute to the
hypertensive cardiovascular disease. As the subjects
get older, various organs begin to deteriorate under
the onslaught of the transient pressure elevations.
Intensive emotional disturbances are known to
precede complications like the malignant phase of
hypertension (Reiser, Rosenman & Ferris, 195 I ) ,
congestive heart failure (Chambers & Reiser, 1953),
or myocardial infarction (Russek, 1967). Cardiovascular complications may be precipitated by
emotional tension (Reiser rt a/., 1951; Chambers &
Reiser, 1953). The advantages of any therapy that
could reduce the magnitude or duration of these
pressure rises are obvious. Significant reduction in
blood pressure from relaxation exercises, with or
without biofeedback, have been reported previously
(Datey, Deshmukh, Dalvi & Vinekar, 1969; Patel,
1973; Patel & Datey, 1974a, b; Shapiro, Tursky &
Schwartz, 1971 ; Benson, Rosner & Marzetta, 1974;
Elder & Rinz, 1973; Deabler, Fidel, Dillenkoffer &
Elder, 1973). Although no long-term follow-up
results have yet been published one group has been
followed up for 1 year now with very satisfactory
maintenance of reduction of blood pressure (unpublished work).
This communication presents the results of a
preliminary investigation to see if the regular practice
of such an exercise could alter the pressor response
to ‘stress’.
Patients
Thirty-two patients, twenty-one females and eleven
males, between the ages of 34 and 75 years (average
age 5 8 5 ) , with essential hypertension of known
duration from 6 months to 13 years (average = 5.7
years) were randomly divided into a treatment group
Correspondence: Dr Chandra Patel, 1 I Upfield, Croydon,
Surrey.
171s
C . Patel
172s
and a control group. Fourteen patients in the
treatment group and fifteen in the control group
were receiving anti-hypertensive drugs.
Methods
The patients were given two ‘stress’ tests: an exercise
test’ and a ‘cold pressor test’ at the beginning, and
repeated after 6 weeks.
Base-line blood pressure was first obtained after a
20 rnin rest in the supine position. The exercise test
consisted of climbing a 9 inch step twenty-five times.
I n the cold pressor test, the patient was alerted 60s
in advance about the test to be performed; the
left hand was then immersed in water at 4°C for 80 s.
Blood pressure was taken during the alert, at the
end of each test and every 5 min until it returned to
the original value or up to a maximum of 40 min.
All the measurements were taken by a trained
nurse using a mercury sphygmomanometer. The
maximum rise in systolic and diastolic pressures as
well as the time taken for ‘recovery’ in each case
were recorded. Differences in the above measurement
obtained during the repetition of the tests were
compared within the groups as well as between the
groups by Student’s t-test.
In the 6 weeks’ between-tests period, all patients
attended the clinic twice weekly. The patients in the
treatment group were given 30 min of training in
relaxation and meditation based on yogic principles.
This training was reinforced, with biofeedback
instruments giving auditory signals relating to
galvanic skin resistance, electromyographic activity
and alpha waves in the electroencephalograph.
TABLE
1. Changes in blood pressure (B.P.) and recorery times for the exercise test and
cold pressor test in treated and untreated groiips of patients
For details of tests and treatment see the Methods section. Pre. = first tcst; Post. =
test repeated after 6 weeks. N.S. = Not significant.
Systolic B.P.
Max. rise
(mmHg)
-_
Exercise test
Treatment group
( n = 16)
Pre.
Post.
Diff.
P
Control group
( n = 16)
Pre.
Post
Diff.
P
Treatment vs.
control group
difference
Cold pressor test
Treatment group
( n = 16)
t
=
P
=
Pre.
Post.
Diff.
P
Control group
( n = 16)
Treatment vs.
control group
difference
18.43
8.75
9.68
9.25
4.12
5.13
13.12
6.25
6.87
<0.005
<0.05
< 0.05
29.62
26.87
2.75
N.S.
18.13
17.20
0.93
N.S.
3.8 1
7.3 I
3.50
N.S.
5.62
13.62
8.00
N.S.
0.9725
=
P
=
2.6216
2.6493
3.9868
N.S.
< 0.02
< 0.02
<0.001
19.31
10.75
8.56
< 0.025
18.12
5.62
12.50
7.3 I
2.19
5.12
< 0.005
< 0.005
12.8 I
4.69
8.12
< 0.025
14.37
17.50
-3.12
N.S.
6.06
14.56
- 8.5
N.S.
4.68
13.75
- 9.07
N.S.
N.S.
t
Recovery
time
(rnin)
27.43
18.8 I
8.62
<0.025
- 11.50
P
Max. rise
(mmHg)
-
22.31
33.81
Pre.
Post.
Diff.
Recovery
time
(rnin)
Diastolic B.P.
3.2581
io.01
3.41 65
< 0.01
4.8049
< 0~001
3.572
< 0.01
Yoga and stress in hypertension
(For details of principle and procedures see Kamiya,
Barber, Dicava, Miller, Shapiro & Stoya, 1971;
Shapiro, Barber, Dicara, Kamiya, Miller & Stoyva,
1973.)
Patients were asked to practise relaxation and
meditation at home twice daily for 20 min. They
were also asked to make frequent checks of their
tension and quick relaxation several times a day.
Red traffic lights, ringing telephones and other
personal situations served as signals to perform
quick relaxation lasting 30 s to 3 min.
Results
During the alert preceding the cold pressor test the
blood pressure rose in most patients. The changes
were of small magnitude and were not statistically
analysed. Other results are given in Table 1.
In the treatment group there was a significant
reduction in the ‘pressure rises’ as well as in recovery
time (P<O.O5). Mere repetition of the tests did not
influence these indications of ‘stress’, as is shown by
the results in the control group; some measurements
increased. When the differences between the groups
were compared by unpaired t-tests, all measurements
except the systolic pressure rise after exercise showed
significant improvement in the treated group
(P < 0.02).
Discussion
The mean response to ‘stress’ became less exaggerated and less protracted in the group whose
behaviour was modified as a result of training in the
psychophysical exercise. Assuming that systolic
elevation primarily indicates increase in cardiac
output and that during exercise most of the increase
would be in proportion to the metabolic demand,
one could not expect a great deal of reduction in the
systolic rise due to relaxation training except for the
rise that could possibly be due to emotional aspects
of the exercise (Wolf, Carbon, Shepard & Wolf,
1955). However, the mechanism of systolic elevation
probably differs in different age groups and it is
impossible to make any simple deduction (Amery
et al., 1967). Two to three patients in the treatment
group during pre-treatment tests and two to three
patients in the control group during pre- as well as
post-control tests failed to recover or reach the
original level of blood pressure in the designated
173s
time. However, when the tests were repeated after
the relaxation training, every patient recovered.
There are several deficiencies in the data. It is
known that circulatory readjustment starts as soon
as the event is over. A continuous automatic
measurement of blood pressure during and after the
test would be more suitable. Since the measurements
are intermittent, the calculated recovery time is
only approximate. Most of the patients were on
anti-hypertensive drugs, which might have altered the
response. However, since we are concerned with the
change in response rather than the actual response,
the data are in this respect still valid.
It is difficult to know what situations will produce
‘stress’ response in our highly complex environment,
in which psychological and socio-economic patterns
are changing at an accelerated pace. Continuous
understanding of the relationship of environmental
‘stress’ to cardiovascular pathology and effective
ways of coping with ‘stress’ could lead us to new
preventive and therapeutic approaches. Results of
this preliminary investigation clearly justify further
research,
Acknowledgments
This study was supported by a Research Grant from
the South West Thames Regional Health Authority.
I thank Professor K. Datey, Emeritus Professor of
Cardiology, K.E.M. Hospital, Bombay, for his
advice on the design of the experiment. I also thank
Professor T. Pilkington of St George’s Hospital for
his helpful suggestions and advice in writing this
paper.
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