Presentation on theme: "Impact of Exercise on Obesity Management. Topic Outline The Role of Physical Activity in Obesity Management for: –Weight loss –Weight loss maintenance."— Presentation transcript:
Impact of Exercise on Obesity Management
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
Weight Loss: What Works? 1 Zachwieja JJ. Endocrinol Metab Clin North Am 1995;25: Effect of Physical Activity Without Diet on Body Weight Loss 1 ModeFrequencyWeight Loss Epstein and WingWalk/run2 - 5x/wk0.09 kg/wk Ballor and KesseyWalk/run/cycle3 - 4x/wk0.1 kg/wk Garrow and SummerbellWalk/run/cycle3 - 4x/wk0.1 kg/wk Hadjiolva, et alVarious Daily (10 hrs/day) 1.8 kg/wk Lee, et alMilitary Training5x/wk0.6 kg/wk
Physical Activity Usually Does Not Increase Short-Term Diet-Induced Weight Loss Wing. Med Sci Sports Exerc. 1999;31(suppl):S547. Each study ranged from 4 to 6 months *P < 0.05 vs diet-only group Blonk 1994 Sweeney Weight Loss (kg) * Diet only Diet + exercise Wadden 1997 Ross 1996 Marks 1995 Ross 1995 Bertram 1990
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
Do not judge the impact of physical activity by weight loss Dr. Steve Blair - Cooper Institute September 20, 2004
Weight Loss Maintenance: What Works? Adapted from Pavlou KN, et al. Am J Clin Nutr. 1989;49:
Weight Loss Maintenance: What Works? Jeffery RW et al AJCN 2003;78: * ** n = 84 n = 102 n = 87 n = 76 n = 80 n = 87
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
Prevention: What Works? Donnelly J, Jacobsen D, Hill JO. Archives of Internal Medicine 163: , Freshman and Sophomore Women at the University of Kansas
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.
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
HERITAGE Family Study Katzmaryck PT, Leon AS, Wilmore JH, et al. Med Sci Sports Exerc, 2003; Vol. 35, No. 10, 1703–1709. 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 High TG Low HDL-C High BP High Glucose High WC Metabolic Syndrome Pre-TrainingPost-Training * * * *
Why the difference in impact for physical activity between weight loss and weight loss maintenance?
Differences Between Weight Loss and Weight Loss Maintenance Weight LossMaintenance 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
Mechanism of Action 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 Why Is Physical Activity Critical for Long-Term Success?
Physiological Control Maximized Energy Intake Energy Expenditure Obesity Conducive Environment Cognitive Control Required Activity Intake A B C Energy Balance Potential Effects of Increasing Physical Activity vs. Decreasing Intake on Encouraging Physiological Energy Balance
Physical Activity Recommendations: How Much is Enough? 30 minutes of physical activity every day is all I need to do to manage my weight A Common Patient Misconception
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
Weight Loss Maintenance: How Much is Enough? Schoeller et al, AJCN 1997;66:551-6.
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 35 minutes of vigorous activity Supports that body weight is better regulated at a higher energy flux Schoeller et al, AJCN 1997;66: Weight Loss Maintenance: How Much is Enough?
Average Energy Expended in Physical Activity in the NWCR Klem et al, AJCN 1997;66:
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
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
Mean Changes in Body Weight for Lifestyle Activity vs Aerobic Exercise Anderson et al. JAMA 1999; 281: 337.
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:
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
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-workers office at work instead of calling on the phone –Use elevators only if going up more than 2 floors Decrease sedentary activity How to Get Your Overweight Patients to Be More Active
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?
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
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