The Role of Physical Activity The Role of Physical Activity in Obesity Therapyin Obesity Therapy

Benefits of Regular Physical Activity in Benefits of Regular Physical Activity in Obese PersonsObese Persons Decreases loss of fat-free

mass associated with weight loss

Improves maintenance of weight loss

Improves cardiovascular and metabolic health, independent of weight loss

0

5

10

15

20

25

30

35

Physical Activity Helps Preserve Fat-Free Physical Activity Helps Preserve Fat-Free Mass During Weight LossMass During Weight Loss

Diet Only

Loss

of F

at-F

ree

Mas

s(%

Tot

al W

eigh

t Los

s)

Ballor and Poehlman. Int J Obes Relat Metab Disord 1994;18:35.

Diet PlusPhysical Activity

Men

Women

*P<0.05

0

1

Energy Expenditure of Physical ActivityEnergy Expenditure of Physical ActivityE

nerg

y E

xpen

ditu

re (

kcal

/h)

Adapted from: Alpers. Undergraduate Teaching Project. Nutrition: energy and protein. American Gastroenterological Association, 1978.

All out competitive sports

Running 10 mph

Running 6 mphClimbing stairs

Sexual intercourseGardening

Walking 4 mphBicycling

Walking 2 mphChewing gum (11 kcal/h)

400

600

1000

200

800

1200

-7.0 -5.0 -3.0 -1.0 1.0

Physical Activity Alone Results in Physical Activity Alone Results in Minimal Weight LossMinimal Weight Loss

Wing. Med Sci Sports Exerc 1999;31(suppl):S547.

*P<0.05 vs control group

Duration of each study ranged from 4 to 12 months.

Stefanick 1998

Stefanick 1998a

Anderssen 1995

Hammer 1989

Verity 1989

Rönnemaa 1988

Wood 1988

Wood 1983

Weight loss (kg)

Control Group

Exercise Group

**

**

Effect of 16-month Supervised Aerobic Exercise on Effect of 16-month Supervised Aerobic Exercise on Body Weight in Overweight and Obese Young AdultsBody Weight in Overweight and Obese Young Adults

Donnelly et al.Arch Intern Med 2003;163:1343

*p<0.05 vs control

-6

-3

0

3

6

Wei

ght C

hang

e (k

g)

Men Women

*

Control

Exercise

*

-15 -10 -5 0

Physical Activity Usually Does Not Increase Physical Activity Usually Does Not Increase Short-Term Diet-Induced Weight LossShort-Term Diet-Induced Weight Loss

*P<0.05 vs diet-only group.

Wadden 1997

Ross 1996

Marks 1995

Ross 1995

Blonk 1994

Sweeney 1993

Bertram 1990

Weight loss (kg) Diet Only

Diet + Exercise

*

Wing RR. Med Sci Sports Exerc. 1999;31(suppl):S547-S552.

Each study ranged from 4 to 6 months.

0

20

40

60

80

100

Relationship Between Physical Activity Relationship Between Physical Activity and Maintenance of Weight Lossand Maintenance of Weight Loss

Not Maintained

Sub

ject

s E

xerc

isin

g (%

)

P<0.001

Kayman et al. Am J Clin Nutr 1990;52:800.

Weight Loss PatternMaintained

-16-14-12-10-8-6-4-20

Considerable Physical Activity is Considerable Physical Activity is Necessary for Weight Loss Necessary for Weight Loss MaintenanceMaintenance

Jakicic et al. JAMA 1999;282:1554.

Cha

nge

in W

eigh

t (kg

)

Time (months)0 6 12 18

Weekly Biweekly Monthly

Concomitant Behavior Therapy

*P<0.05

<150 min/wk<150 min/wk

>150 min/wk>150 min/wk

>200 min/wk>200 min/wk

-12

-10

-8

-6

-4

-2

0

Effect of Low-Activity (1000 kcal/wk) and Effect of Low-Activity (1000 kcal/wk) and High-Activity (2500 kcal/wk) on Body WeightHigh-Activity (2500 kcal/wk) on Body Weight

0

Months

Wei

ght C

hang

e (k

g)

6 12 18

Jeffery et al. Am J Clin Nutr 2003;78:684-689.

PP < 0.05 < 0.05

Behavior therapy+ Low activity

Behavior therapy+ High activity

0

20

40

60

80

100

Compliance is Greater with Home-Based Compliance is Greater with Home-Based versus Group-Based Activityversus Group-Based Activity

1

Ses

sion

s C

ompl

eted

(%

)

Perri et al. J Consult Clin Psychol 1997;65:278.

* P<0.05 group-based vs home-based.

Month2 3 4 5 6 7 8 9 10 11 12

Home-basedGroup-based

***

***

-14

-12

-10

-8

-6

-4

-2

0

Effect of Group-Based vs Home-Based Effect of Group-Based vs Home-Based Physical Activity on Body WeightPhysical Activity on Body Weight

Wei

ght C

hang

e (k

g)

Time (months)

0 3 6 9

Perri et al. J Consult Clin Psychol 1997;65:278.

12 15

Group-based

Home-based

*P<0.05

170

180

190

200

210

220

230

Effect of Long vs Short Bouts of Exercise on Effect of Long vs Short Bouts of Exercise on Total Amount of Activity and Weight LossTotal Amount of Activity and Weight Loss

Long bout = one 40-min session.Short bout = four 10-min sessions.

Act

ivity

(m

in/w

k)

LongBouts

ShortBouts

LongBouts

ShortBouts

10

8

6

4

2

0

Weight Loss (kg)

P=0.08 P=0.07

Jakicic et al. J Obes Relat Metab Disord 1995;19:893.

-10

-8

-6

-4

-2

0

Weight Maintenance Can Be Achieved with Weight Maintenance Can Be Achieved with Either Programmed or Lifestyle ActivityEither Programmed or Lifestyle Activity

Wei

ght C

hang

e (k

g)

Time (months)

Diet + programmed activity

Diet + lifestyle activity

P=0.06

Andersen et al. JAMA 1999;281:335.

0 8 36 52 6816 28 44 60

TreatmentTreatmentPhasePhase Maintenance PhaseMaintenance Phase

-25

-20

-15

-10

-5

0

Effect of Decreasing Sedentary Activities vs Effect of Decreasing Sedentary Activities vs Increasing Physical Activities on Body Weight in Increasing Physical Activities on Body Weight in Children 6-12 Years OldChildren 6-12 Years Old

0Time (months)

Decreased Sedentary Activity

Cha

nge

in P

erce

nt O

verw

eigh

t

Increased Physical Activity

Epstein et al. Health Psychol 1995;14:109.

4 8 12

-7

-6

-5

-4

-3

-2

-1

0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Decreasing Television Viewing Leads to Decreasing Television Viewing Leads to improved Body Mass Index in Childrenimproved Body Mass Index in Children

6-monthintervention

Robinson JAMA 1999;282:1561.

Control

Change in BMI (kg/m2)

6-monthintervention

Control

Change in TV viewing (h/wk)

P=0.002

P<0.001

012345678

Fatness, Fitness and Cardiovascular Fatness, Fitness and Cardiovascular Disease MortalityDisease Mortality

Lean<16.7%

Rel

ativ

e R

isk

of C

VD

Mor

talit

y

Body Fat Category (% Weight as Fat)Lee et al. Am J Clin Nutr 1999;69:373.

Normal16.7%-24.9%

Obese>25%

Aerobically fit

Unfit

Guidelines for Increasing Guidelines for Increasing Physical ActivityPhysical Activity Assessment

1) Medical and psychological readiness

2) Physical limitations

3) Current activities

4) Barriers to activity

Develop physical activity plan Start activity slowly and gradually increase planned aerobic

activity to 200 min/wk Enhance compliance

– Programmed vs lifestyle activity

– At-home vs onsite activity

– Multiple short bouts vs single long bout of activity