Sitting too much is not the same as
exercising too little
Travis Saunders, CSEP-CEP, PhD (c)
Who am I?
• PhD Candidate in Human Kinetics at the Children’s
Hospital of Eastern Ontario Research Institute and the
University of Ottawa
• Studying the impact of acute and chronic sedentary
behaviour on chronic disease risk in children and youth
• Also a CSEP-CEP, and a proud New Brunswicker
Learning Outcomes
At the end of this session, you will be able to:
1. Describe what sedentary behaviour is
2. Distinguish between sedentary and non-sedentary
behaviours
3. Identify the general association between sedentary
behaviour and chronic disease
What is sedentary behaviour?
Image: http://www.worldislandinfo.com/
How does it differ from physical
activity?
Image: http://www.worldislandinfo.com/
What is Sedentary Behaviour?
Any waking activity with an energy expenditure ≤ 1.5 METs
Sedentary
0
1
Light PA
Vigorous
PA
Moderate PA
2
3
4
5
Metabolic Equivalents
6
7
Spot the sedentary behaviours
Image: http://www.flickr.com/photos/deltamike/
Spot the sedentary behaviours
Image: http://www.flickr.com/photos/anantablamichhane
Spot the sedentary behaviours
http://www.denverpost.com/portlet/article/html/imageDisplay.jsp?contentItemRelationshipId=3947489
Spot the sedentary behaviours
Image: http://www.flickr.com/photos/kylemay
Spot the sedentary behaviours
Image: http://i-love-cartoons.us
Spot the sedentary behaviours
Spot the sedentary behaviours
Image: http://www.flickr.com/photos/oksidor
What is Sedentary Behaviour?
Any waking activity with an energy expenditure ≤ 1.5 METs
Sedentary
0
1
Light PA
Vigorous
PA
Moderate PA
2
3
4
5
Metabolic Equivalents
6
7
Who is Physically Active?
A person meeting Canada’s Physical Activity Guidelines = Active
A person not meeting the Guidelines = Inactive
Can an active person also
be very sedentary?
Sedentary Behaviour
Both Sedentary & Active?
Sedentary & Inactive
Sedentary & Active
Inactive,
Not Sedentary
Active,
Not Sedentary
Physical Activity
Both Sedentary & Active?
From Dunstan et al. 2010 (Touch Briefings)
Active, Sedentary, or Both?
Adult woman
•
•
•
•
Cashier at grocery store
Takes public transit to work
Doesn’t like going to the gym
Watches 1 half-hour show before bed
Not Active,
Not Sedentary
Active, Sedentary, or Both?
Adult man
•
•
•
•
•
•
45 minute run every morning
Drives to work
Works a desk job
Drives home
Eats frozen dinner
Watches TV until falling asleep
How Sedentary Are We?
How Sedentary Are Canadian Adults?
Sedentary
Light PA
Moderate PA
Vigorous PA
9.5 Hours
Colley et al. 2011 (Health Reports)
How Sedentary Are Canadian Kids?
Sedentary
Light PA
Moderate PA
Vigorous PA
8.5 Hours
Colley et al. 2011 (Health Reports)
How Sedentary Are Canadian Kids?
• Canadian children and Youth
average 6 hours/day of
screen time on weekdays
• Over 7 hours per day on
weekends.
Questions?
Why should we care about
chronic sedentary behaviour?
Question
If a person is physically active, does it
matter how much time they spend sitting?
• What would be a problem of sitting too much?
• Are there any problems related to sitting too little?
Morris Bus Study: Active or Not Sedentary?
Morris JN, Heady JA, Raffle PAB, Roberts CG, Parks JN. Coronary heart disease
and physical activity of work. Lancet 1953;ii:1053–57; 1111–20.
Image: http://www.flickr.com/photos/3336
Morris Bus Study: Active or Not Sedentary?
Hamilton et al, 2007 (Diabetes)
What is Sedentary Behaviour?
Sedentary
0
1
Light PA
Vigorous
PA
Moderate PA
2
3
4
5
Metabolic Equivalents
6
7
Sedentary Time and Risk of Death
1.8
1.6
Risk of Death
1.4
1.2
1
0.8
11%
0.6
36%
54%
0.4
0.2
0
25%
50%
75%
% Time Spent Sitting
100%
Katzmarzyk et al., 2009. MSSE. 41(5): 998-1005.
Sedentary Time and Risk of Death
Deaths per 10,000 person-years
180
Active
160
Inactive
p<0.001
140
120
p=0.008
100
80
60
40
20
0
<25%
50%
25%
75%
Time Spent Sitting (%)
>75%
Katzmarzyk et al, 2009 (MSSE)
Sedentary Behaviour and CVD
Risk of Cardiovascular Events
(Hazard Ratios)
2.5
2
1.5
1
98%
110%
0.5
0
<2 hours/day
2-4 hours/day
Screen Time
>4 hours/day
Stamatakis, 2011 (J Am Coll Cardiol)
Sedentary Behaviour and Mortality
Systematic Review:
…there is strong evidence for a relationship
between sedentary behavior and mortality from
all causes and from CVD, but no evidence for
the relationship between sedentary behavior and
mortality from cancer.
Proper, 2011 (Am J Preventive Med)
Sedentary Behaviour and Mortality
Life Table Analysis:
Compared
…TV viewing
with
time
persons
may be
who
associated
watch nowith
TV, athose
loss
of life
who
that
spend
is comparable
a lifetime average
to other of
major
6 h/day
chronic
disease
watching
riskTV
factors
can expect
such astophysical
live 4.8 inactivity
years less.
and obesity.
On average, every single hour of TV viewed after
the age of 25 reduces the viewer's life expectancy
by 21.8 minutes.
Veerman, 2011 (British J Sports Med)
Sedentary Behaviour and Mortality
=
Regardless of physical activity
Sedentary Behaviour and Chronic Disease
Systematic Review:
…In general, consistent fındings exist with
respect to engaging in high levels of sedentary
behavior and increased risk for diabetes and
site-specifıc cancers; including ovarian, colon,
and endometrial cancer
Thorp, 2011 (Am J Preventive Med)
Sedentary Behaviour and Chronic Disease
Systematic Review:
…elevated
of sedentary
behavior
were consistently
Based on levels
the fındings,
there is
a reasonable
level of
associated
with weight
gain sedentary
evidence to conclude
associations
between
in both
and
in women.
these
behavior
and men
health
outcomes
areImportantly,
not mediated
by time
associations remained
following
further adjustment
spent in physical
activity
for physical activity.
Thorp, 2011 (Am J Preventive Med)
Sedentary Behaviour in Children
Systematic Review:
During childhood and/or adolescence, engagement in
sedentary behavior was consistently shown to predict
obesity and increased BMI in adulthood. These
relationships were independent of BMI during
childhood/adolescence and time spent in physical
activity
Thorp, 2011 (Am J Preventive Med)
Sedentary Behaviour in Children
Systematic Review:
232 studies including 983,840 participants met inclusion
criteria and were included in the review.
Watching TV for more than 2 hours per day was
associated with unfavourable body composition,
decreased fitness, lowered scores for self-esteem and
pro-social behaviour and decreased academic
achievement.
Tremblay, 2011 (Int j Beh Nutr and Phys Act)
Sedentary Behaviour in Children
9
Prevalence of MetS (%)
8
7
6
5
4
3
2
1
0
≤1
2
3
Screen Time(Hours/day)
4
≥5
Mark et al, 2008 (JPH)
Less Sedentary Behaviour = Less Body Weight
Epstein, 2008 (Arch Intern Med)
Less Sedentary Behaviour = Less Body Weight
Epstein, 2008 (Arch Intern Med)
Less Sedentary Behaviour = Less Body Weight
No change in physical activity levels
Epstein, 2008 (Arch Intern Med)
Sedentary Behaviour in Children
Systematic Review:
Meta-analysis was completed for randomized
controlled studies that aimed to reduce sedentary time
and reported change in body mass index (BMI) as their
primary outcome. In this regard, a meta-analysis
revealed an overall significant effect …indicating an
overall decrease in mean BMI associated with the
interventions
Tremblay, 2011 (Int j Beh Nutr and Phys Act)
Questions?
Does it matter how you
accumulate sedentary behaviour?
Breaks In Sedentary Time
Dunstan et al, 2010 (Touch Briefings)
Benefits of Breaks in Sedentary Time
Independent of total sedentary time and moderateto-vigorous intensity activity time, increased breaks
in sedentary time were beneficially associated with
waist circumference, BMI, triglycerides, and 2-h
plasma glucose.
Healy, 2008 (Diabetes)
Questions?
90 second stretch break
Why should we care about acute
sedentary behaviour?
5 Days of Bed Rest = Reduced Metabolic Health
Hamburg, 2007 (ATVB)
5 Days of Bed Rest = Reduced Metabolic Health
60
% Increase
50
40
30
20
10
0
Fasting Insulin
Insulin Resistance
Triglycerides
Hamburg, 2007 (ATVB)
Impact of 1 Day of Sitting
14 Healthy Adults
2 Conditions
1. Standing for an entire day
2. Sitting for an entire day
Stephens, 2011 (Metabolism)
1 Day of Sitting = Reduced Insulin Sensitivity
39% Reduction
Whole-body
insulin action
1 Day Standing
1 Day Sitting
Stephens, 2011 (Metabolism)
My thesis
Does 1 day of sitting increase cardiometabolic
risk in healthy children and youth aged 10-14?
1 Hour of Video Games=Increased Food Intake
Net surplus of 163 kcal
Chaput, 2011 (Am J Clin Nutr)
Mental Work = Increased Food Intake
Caloric Intake (kcals)
1200
+ 200 Calories
1000
800
600
400
200
0
Sitting Quietly
Reading-Writing
Test Questions
Chaput, 2008 (Psychosomatic Medicine)
What are the physiological mechanisms
behind sedentary behaviour?
Physiological Mechanisms – Lipoprotein Lipase
Hamilton, 2007 (Diabetes)
Physiological Mechanisms – GLUT4
Megeney, 1993 (Am J Phys – Endo & Metab)
Physiological Mechanisms – GLUT4
Megeney, 1993 (Am J Phys – Endo & Metab)
Ways to Reduce Sedentary
Behaviour
Is Sitting Required, Or Simply the Default?
vs
Is Sitting Required, Or Simply the Default?
vs
Is Sitting Required, Or Simply the Default?
vs
http://www.denverpost.com/portlet/article/html/imageDisplay.jsp?contentItemRelationshipId=3947489
Is Sitting Required, Or Simply the Default?
$25!
Is Sitting Required, Or Simply the Default?
Findings:
Time Sitting Reduced by 90 Minutes/day
Steps/day Increased by 2700 steps
Waist Circumference Reduced by 5cm
John, 2011 (J Phys Act & Health)
Is Sitting Required, Or Simply the Default?
Drive Medical Pedal Exerciser
$23 on Amazon.com
Ways to reduce screen time
• Watch specific shows - avoid channel surfing
• Shut off email on evenings and weekends
• Set screen time limits for kids
• Some software options may help
www.csep.ca/guidelines
Take Breaks
• During commercial breaks
• Drink lots of water
• Software may help here as well
Assessing Sedentary Behaviour
Unfortunately, no great tools at the moment
• Accelerometers are ideal, but costly (~$500/each)
• Self-report questionnaires have lots of error, but are
very affordable (e.g. IPAQ)
• Software may be useful here as well
Remember…
It’s not about standing all the time, it’s about sitting less
Learning outcomes revisited
1. Sedentary behaviour is any behaviour with a low
energy expenditure (≤ 1.5 METs)
2. Sedentary behaviours and non-sedentary behaviours
are distinguished by their level of energy expenditure
3. In general, people who sit more die sooner
Conclusions
1. Sedentary behaviour is an important and extremely
prevalent risk factor for chronic disease in both
children and adults
2. Sedentary time can be reduced using relatively
simple and inexpensive interventions
3. Reductions in sedentary time are likely to result in
reduced risk for multiple chronic diseases
Sedentary Behaviour Research Network
www.sedentarybehaviour.org
Obesity Panacea
www.blogs.plos.org/obesitypanacea
Healthy Active Living & Obesity Research at CHEO
www. Haloresearch.ca
Thanks!
[email protected]