Sedentary Behavior and Inactivity Physiology

Killing you softly and gently

Yannis GuerraEndocrinology DepartmentJohn H. Stroger Jr. Hospital of Cook Countyyannisguerra@yahoo.com@yannisguerra on Twitter

CC www.TheNounProject.com

In this presentation

• Definition of Sedentarism• Distribution of Human Energy Expenditure

– Concept of NEAT (Non Exercise Activity Thermogenesis)

• Inactivity Physiology and Epidemiology– 4 principles

• Solving the problem…or not?

What is to be sedentary?

Is it the: • Baseline exercise amount?

– Minutes/Steps

• Baseline energy used?• Presence or lack of a particular behavior?• Leisure/Work/House based?

What does the literature says?

Seems that we don’t agree.

And these definitions concentrate in the presence/absence of exercise

A more “big picture” approach

A distinct class of behaviors (e.g., sitting, watching TV, driving) characterized by little physical movement and low energy expenditure ( Less/equal to 1.5 METs)

Appl. Physiol. Nutr. Metab. 35: 725–740 (2010)

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Not only the lack of exercise

For a real life example

• 34 years old male, no PMHx

• Fit him with one of these:

– Measures movement with three axis accelerometer.

CC http://www.flickr.com/photos/oskay/1193147290/sizes/o/in/photostream/http://www.flickr.com/photos/terrypaton/4613655114/http://www.flickr.com/photos/zzathras777/2071956401/sizes/o/in/photostream/

Accelerometers are all around us!

For a real life example (cont)

• Choose one very “active day”–11452 steps (5.4 miles)–Exercised 30 minutes

This is the result of the “active day”

And over the long run?

Active Couch Potato

Exerc. Sport Sci. Rev., Vol. 38, No. 3, pp. 105Y113, 2010

Appl. Physiol. Nutr. Metab. 35: 725–740 (2010)

http://www.flickr.com/photos/ptooey/5018659279/

Does it make any difference?

Mayo Clin Proc. • December 2010;85(12):1138-1141

Understanding the Distribution of Energy Expenditure in

Humans

European Journal of CliniCiI Nutrition (1996) 50, 72-92

European Journal of CliniCiI Nutrition (1996) 50, 72-92

Tota

l exe

rcis

e ex

pend

iture

(TEE

) , M

ega

Joul

es

Components

0 Kcal/day

2000 Kcal/day

1000 Kcal/day

Basal Metabolic Rate (BMR)

Activity Thermogenesis

Thermal effect of food

European Journal of ClinicaI Nutrition (1996) 50, 72-92

Weight+Height+Gender Predict 86% of BMR

Basa

l Met

abol

ic R

ate

(BM

R), M

egaJ

oule

s

• Coeficient of Variation (CV) within individual for BMR 3-8%

• Thermal effect of food 10% of TEE– CV 20%

Curr Opin Clin Nutr Metab Care 7:599–605.

Weight+Height+Gender Predict only 7%

Phys

ical

Acti

vity

Lev

el

Returning to the Total Energy Expenditure

0 Kcal/day

2000 Kcal/day

1000 Kcal/day

Basal Metabolic Rate

Activity Thermogenesis

Thermal effect of food

More detailed!

0 Kcal/day

2000 Kcal/day

1000 Kcal/day

Non Exercise Activity Thermogenesis

(NEAT)

Exercise

Which one is more affected by Sedentary

behaviors?Some arguments in favor of NEAT

Circulation. 2007;116:1081-1093

Arterioscler Thromb Vasc Biol 2006;26;729-736

Easy solution, right?Just tell them to exercise more!

I think you’ll find it’s a bit more complicated than that

Ben Goldacre, www.Bad Science.net

Am J Clin Nutr 1995;62:722-9.

• 20 females, BMI 32• 8 weeks of low energy diet

– 500 kcal x 4w– 850 kcal x 4 w

• 2 groups– Exercise 3/w x 90 minutes– No exercise

• Measured Average Daily and Sleeping Metabolic Rates

Am J Clin Nutr 1995;62:722-9.

Non Exercise Activity Thermogenesis

(NEAT)

Exercise

Non Exercise Activity Thermogenesis

(NEAT)

Exercise

What we thought would happen

Non Exercise Activity Thermogenesis

(NEAT)

Exercise

Non Exercise Activity Thermogenesis

(NEAT)

Exercise

What really happened

Revising concepts is NEAT!

• Stable “Exercise” levels• Obesity levels increase• We do “more” with “less”(movement)• NEAT decreases with inactivity.• NEAT decrease may be the main factor in

energy overload

http://xkcd.com/552/

Science 307:584-586

164 min

152 min

Science 283: 212-214

• 16 non obese people, asked not to exercise extra

• 8 weeks of overfeeding– 1000 kcal

Science 283: 212-214

Weight changed from 0.36 kg to 4.23 kg, mainly correlated to activity thermogenesis.

How does this affect our current paradigm of thinking about activity

and weight/metabolic effects?

To decrease NEAT, increase inactivity

Diabetes 56:2655–2667, 2007

• 4 tenets of inactivity physiology– 2 are logical consequences of the argument– 2 are areas where research can prove/disprove

the argument

First

Second

• In cohorts of people who do not exercise– Increased rates of

• DM• CAD• Obesity

Cannot be caused by additional exercise deficiency!

Third

• Cellular and molecular processes of inactivity physiology vs exercise physiology are QUALITATIVELY different from each other

http://xkcd.com/285/

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www.wikipedia.org

Evidence at all levels

Image: Acta ortop. bras. vol.12 no.1 São Paulo Jan./Mar. 2004

What did they do?

• 60 rats. • 12 hours of Hind limb unloading (remember

picture?)then 4 hours of low intensity ambulatory activity.

• Measured gene expression in muscles.• Only used genes that changed more than 1.5x

expression to decrease false positives.

Three types of pattern

Down and up to normal

Up and staying up Up and down to normal

Showing

• 2 types of muscles, that react very differently to both– Exercise– Lack of movement (Sedentarism)

Oh, the Humanity!

Arterioscler Thromb Vasc Biol. 2007;27:2650-2656

Metabolism Clinical and Experimental

Image: Br J Sports Med 2006;40:779-784 doi:10.1136/bjsm.2006.027276

• Australian Diabetes, Obesity and Lifestyle (AusDiab Study)

• 173 patient, underwent OGTT• Accelerometer based

Diabetes Care 30:1384–1389, 2007

Important: Effect even when adjusted for higher intensity activity

Diabetes Care 31:369–371, 2008

• Same population• Relationship of sedentarism and

– Waist circumference• 3.1 cm difference

– Cluster of metabolic risk factors

Evidence for the 3rd tenet

• Changes in RNAm production – Baseline is different than inactivity AND post

inactivity

• Decrease in Lipoprotein lipase production– Difference in between “exercise” muscles and

“posture” muscles

• Metabolic changes – Insulin and glucose levels, OGTT

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What about the 4th tenet?

Times that people spend sitting versus participating in exercise based leisure

time physical activity are different classes of behavior with distinct determinants AND INDEPENDENT RISKS FOR DISEASE

Diabetes 56:2655–2667, 2007

PLoS Med 3(12): e488. doi:10.1371/journal.pmed.0030488

• Cross sectional study of 1921 children,– 9-10 yold and 15-16 yolds

• Accelerometer based activity• Self reported TV viewing• Metabolic risk score• TV viewing was NOT correlated with PA

(r=0.013, p=0.58)

Obes Res. 2005;13:608–614

Epidemiology 1998; 9: 632-35

NEAT

NEA

T

Med. Sci. Sports Exerc., Vol. 41, No. 5, pp. 998–1005, 2009

ExercisersNon Exercisers

Even if you exercise, the effects are still there!

J Am Coll Cardiol 2011;57:292–9

And the beat goes on, and on, and on

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Statistics of direct measurement

No, it’s not Pac-man eating pie

European Heart Journal doi:10.1093/eurheartj/ehq451http://www.bionetics.ca/exercise/mti%20actigraph.htm

JAMA. 2006;296:171-179

Absolute risk

12%

17.6%

24.7%

Evidence for the 4th tenet

• Different effects of sedentary behavior compared to “exercise”

• Metabolic and Mortality effects seen– Through age groups– Through ethnic groups

• Newer objective data seems to support larger self reported data

http://www.flickr.com/photos/knitbunny/753713999/

What can we do about it?

Diabetes Care 31:661–666, 2008

But besides that study…

http://www.flickr.com/photos/cobalt/205542600

But do not despair!

IDLE Breaks Study

• Baker IDI Heart & Diabetes Institute• Effects of acute bout of sitting time in post

prandial Glc/Tg – With and Without Breaks

Unpublished DataGlucose Insulin

Breaking news: New data All are statistically significative!

Hot off the presses

• Treatment group burns 0.18 kcal/min more (17% more) 300 calories/week

• In obese/overweight group, increases to 0.38 kcal/min (32% more) 575 calories/week

Am J Public Health. 2011 Mar 18. [Epub ahead of print]

General Ending Points

We have changed as a species

Int. J. Sports Med 19: 328-35, 1998

Estim

ated

dai

ly e

nerg

y ex

pend

iture

We have changed as a species

http://www.flickr.com/photos/xuxiaohui/15902318/

But not so much

We are failing

http://www.flickr.com/photos/8185675@N07/3902633122/

exercise

But we may be missing something big

Exercise

NEAT inactivity

http://www.flickr.com/photos/tedmurphy/3830352762/

We want to avoid this

And we need to accomplish this!

http://www.flickr.com/photos/31364755@N08/2942780396/in/photostream

Thanks to

David DunstanAssociate Professor Baker IDI Heart & Diabetes Institute

Travis SaundersHealthy Active Living andObesity Research GroupObesity Panacea Blog

Mark E. BendenAssociate ProfessorTexas A&M Health Science CenterSchool of Rural Public Health