1. Impact of Exercise on Obesity Management

2. Topic Outline The Role of Physical Activity in Obesity Management for:
Weight loss
Weight loss maintenance
Prevention of obesity
Reducing general health risks
Mechanisms of Action
Current Recommendations for Physical Activity in Obesity Therapy
Translating Physical Activity Recommendations into Increased Physical Activity in Patients

3. Weight Loss: What Works?
Effect of Physical Activity Without Diet on Body Weight Loss1
Mode
Frequency
Weight Loss
Epstein and Wing
Walk/run
2 - 5x/wk
0.09 kg/wk
Ballor and Kessey
Walk/run/cycle
3 - 4x/wk
0.1 kg/wk
Garrow and Summerbell
Hadjiolva, et al
Various
Daily
(10 hrs/day)
1.8 kg/wk
Lee, et al
Military Training
5x/wk
0.6 kg/wk
1Zachwieja JJ. Endocrinol Metab Clin North Am 1995;25:

4. Physical Activity Usually Does Not Increase Short-Term Diet-Induced Weight Loss
Blonk 1994
Sweeney 1993
-15
-10 -5
Weight Loss (kg) *
Diet only
Diet + exercise
Wadden 1997
Ross 1996
Marks 1995
Ross 1995
Bertram 1990
Each study ranged from 4 to 6 months
*P < 0.05 vs diet-only group
Wing. Med Sci Sports Exerc. 1999;31(suppl):S547.

5. Physical Activity and Weight Loss
Most studies suggest a reasonable amount of physical activity
does not produce weight loss
Exercise alone to 0.1 kg/week
Dose response relationship
does not significantly increase initial weight loss over what is obtained by caloric restriction alone

6. Dr. Steve Blair - Cooper Institute
“Do not judge the impact of physical activity by weight loss”
Dr. Steve Blair - Cooper Institute
September 20, 2004

7. Weight Loss Maintenance: What Works?
Adapted from Pavlou KN, et al. Am J Clin Nutr. 1989;49:

8. Weight Loss Maintenance: What Works?* **
n = 84
n = 102
n = 87
n = 76
n = 80
Jeffery RW et al AJCN 2003;78:684-9.

9. Physical Activity and Weight Loss Maintenance
Data from case studies, correlation studies and randomized control trails have all concluded that high levels of physical activity facilitate maintenance of weight loss long-term

10. Prevention: What Works?
Freshman and Sophomore Women
at the University of Kansas
Donnelly J, Jacobsen D, Hill JO. Archives of Internal Medicine 163: , 2003.

11. Freshman and Sophomore Women at the University of Kansas
225 minutes/week prevented weight gain in women at risk (2.3 kg/16 months)
225 minutes produced a weight loss in men at risk (5.2 kg/16 months)
Women 439 kcal/session (5.4 kcal/kg)
Men 667 kcal/session (6.7 kcal/kg)
Donnelly J, Jacobsen D, Hill JO. Archives of Internal Medicine 163: , 2003.

12. Physical Activity and General Health
Moderate levels of cardiorespiratory fitness substantially reduce mortality risks associated with overweight and obesity
Moderate levels of cardiorespiratory fitness can be developed in 30 minutes of activity at least 5 days per week

13. HERITAGE Family Study * Pre-Training Post-Training
100 90 80 70 60 50 40 30 20 10
High TG Low HDL-C High BP High Glucose High WC Metabolic Syndrome
Pre-Training
Post-Training *
Prevalence of individual risk factors before and after 20 wk of aerobic exercise training in the HERITAGE Family Study among 105 participants with the metabolic syndrome at baseline. *P < 0.05 pre- versus post-training.
Katzmaryck PT, Leon AS, Wilmore JH, et al. Med Sci Sports Exerc, 2003; Vol. 35, No. 10, 1703–1709.

14. Why the difference in impact for physical activity between weight loss and weight loss maintenance?

15. Differences Between Weight Loss and Weight Loss Maintenance
Maintenance of Weight Loss
Time limited
Requires a negative energy balance
Reduced caloric intake is critical
Physical activity not required for success
Common
Life-long
Requires energy balance at a reduced body weight
Physical activity is critical for success
Rare

16. Why Is Physical Activity Critical
Mechanism of Action
Why Is Physical Activity Critical
for Long-Term Success?
Makes it more likely for patients to remain in Energy Balance at a reduced body weight
Why? Possibilities include:
Direct compensation for diet indiscretions
Prevent or attenuate metabolic efficiency associated with weight loss
Improved self-efficacy or mood
Improved satiety/hunger
Allows better “physiological” matching of intake and expenditure to occur

17. Potential Effects of Increasing Physical Activity vs
Potential Effects of Increasing Physical Activity vs. Decreasing Intake on Encouraging Physiological Energy Balance
Obesity Conducive
Environment
Energy Balance
Energy Intake
Physiological
Control Maximized
Activity B A
Intake C
Cognitive
Control Required
Energy Expenditure

18. Physical Activity Recommendations: How Much is Enough?
A Common Patient Misconception
“30 minutes of physical activity every day is all I need to do to manage my weight”

19. How Much is Enough? Current PA Recommendations
Minimal public health recommendations to improve health related outcomes
30 min moderate activity most days of the week (150 minutes/week)
CDC - Centers for Disease Control
ACSM - American College of Sports Medicine
SG - Surgeon General
Maximize weight loss and prevent weight regain
45-60 minutes/day
IOM - Institutes of Medicine
60-90 minutes/day
IASO - International Assoc for Study of Obesity
60 minutes/day (300 minutes/week)
ACSM - American College Sports Medicine
Preventing general weight gain
Unclear

20. Weight Loss Maintenance: How Much is Enough?
Schoeller et al, AJCN 1997;66:551-6.

21. Weight Loss Maintenance: How Much is Enough?
Women in the physically active group gained the least weight after reaching their target for weight loss
Retrospective analysis: Threshold of 11 kcal/kg of body wt/day
80 minutes of moderate intensity activity or minutes of vigorous activity
Supports that body weight is better regulated at a higher energy flux
Schoeller et al, AJCN 1997;66:551-6.

22. Average Energy Expended in Physical Activity in the NWCR
Klem et al, AJCN 1997;66:

23. What About Intensity?
Studies suggest the intensity of physical activity may have limited impact on weight control when total energy expenditure (TEE) is fixed
High levels of energy expenditure (EE) improve weight management
So if vigorous intensity results in greater EE weight loss outcomes will improve
So if moderate intensity results in greater EE weight outcomes will improve
Moderate intensity provides health benefits while presenting low to moderate health risks

24. Planned vs Lifestyle Activity
Planned Activity- completed in a discrete period of time, moderate to high intensity
30 to 60 minutes
Walking, swimming, biking
Lifestyle Activity- completed during everyday tasks
Parking further away, taking stairs, walk to meetings

25. Mean Changes in Body Weight for Lifestyle Activity vs Aerobic Exercise
Anderson et al. JAMA 1999; 281: 337.

26. Long vs Short Bouts
Multiple short bouts are as effective as one long bout and perhaps may facilitate efforts to increase activity
Helps address the barrier of perceived lack of time
Multiple short bouts increase adoption of physical activity during first 6 months
Long-term impact is less clear
Jakicic JM et al. JAMA 1999;282(16):
Jacobsen DJ et al. Int J Sports Med 2003;24:

27. Physical Activity - The “Magic Pill” What Patients Want…
Currently available
Safe, cheap and effective
Increase my “metabolism”
Burn fat as fuel
Allow me to eat more food without gaining weight
Make me “healthier”

28. How to Get Your Overweight Patients to Be More Active

29. How to Get Your Overweight Patients to Be More Active
For many individuals, starting a structured exercise program is not possible
Therefore: Implement small lifestyle changes to increase daily physical activity
Park at end of lot when driving to store
Only have one phone in house so patient has to walk to use it
Find the stairs!
Walk to a co-worker’s office at work instead of calling on the phone
Use elevators only if going up more than 2 floors
Decrease sedentary activity

30. Lifestyle Activity Program
Wear a pedometer every day for a week to determine baseline
Increase steps by 500 steps/day /week
Ultimate goal 10, ,000 steps/day
500 steps = 5 minutes walking moderate
Helps set goals and gives instantaneous feedback
Do all those little changes add up?

31. www: Americaonthemove.org

32. Then What?
After these lifestyle alterations are in place, start on a structured exercise plan
Start slow - perhaps as little as min of activity per day (whatever they enjoy and will continue to do)
Total amount of activity is what counts

33. Conclusions
Physical activity recommendations of 30 minutes most days of the week are based on improving cardiovascular health - a good initial or minimal goal
minutes of physical activity may be what is necessary to prevent regain following a weight loss (long-term goal)
Risk factors associated with Metabolic Syndrome improve with physical activity
How to get patients to do what we know it takes is the real problem
Lifestyle changes and short bouts of activity in sedentary individuals may be the place to start
Gradual increase over years may be necessary
Long-term adherence is the most important goal