Exercise a s Medicine

Exercise as Medicine Instructor of Medicine Department of Medicine Division of Sports Medicine Northwestern University Feinberg School of Medicine

Exercise as Medicine • The Scope of the Problem • Health Benefits of Physical Activity and Exercise • Benefits of Weight Training and Muscular Fitness • How to Improve Muscular Fitness • Benefits of Flexibility Exercise • Maintaining Effects of Exercise • Prescribing Exercise • Risks of Exercise

Risk Factors for Heart Disease • Family History • Cigarette Smoking • Hypertension • Diabetes/Impaired Fasting Glucose • Obesity • Sedentary Lifestyle

Prevalence of Sedentary Time

Obesity Trends* Among U.S. AdultsBRFSS,1990, 2000, 2010 (*BMI 30, or about 30 lbs. overweight for 5’4” person) 2000 1990 2010 No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. AdultsBRFSS,1985 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. AdultsBRFSS,1991 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. AdultsBRFSS,1997 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20%

Obesity Trends* Among U.S. AdultsBRFSS,2001 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. AdultsBRFSS,2005 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Exercise Recommendations • ACSM/AHA Guidelines: • At least 150 minutes per week of moderate exercise or 75 minutes per week of vigorous exercise • 30 minutes per day, 5 times per week • Perform activities that maintain or increase muscular strength and endurance a minimum of 2 days each week Garber et al. ACSM Postion Stand on Exercise. 2011.

Physical Benefits of Exercise • Decreased risk of CHD, stroke, type 2 Diabetes Mellitus, colon and breast cancers • Lowers blood pressure, improves cholesterol profile, CRP, increases insulin sensitivity • Preserves bone mass and reduces risk of falling • All-cause mortality is delayed by regularly engaging in physical activity Garber et al. ACSM Postion Stand on Exercise. 2011.

Psychological Benefits of Exercise • Prevents/improves mild to moderate depressive disorders and anxiety • Lowers risk of cognitive decline and dementia

Exercise Intensity • Important determinant of physiological responses to exercise training • DiPietro et al (2006): significant improvement in glucose utilization in sedentary older men and women who engaged in vigorous (80% VO2max) exercise • Not in those who performed moderate (65% VO2max) exercise DiPietro et al. J Appl Physiol. 2006.

Intensity Threshold • Threshold of exercise intensity varies depending on fitness level • Higher intensity threshold for trained individuals vs. untrained individuals to improve VO2 max • Little evidence for intensity threshold for changes in HDL, LDL or TG, BP, glucose intolerance or insulin resistance Butcher LR et al. Med Sci Sports Exerc. 2002.

Intensity Threshold • Several studies suggest exercise intensity does not influence magnitude of loss of body weight or fat stores • Subjects who walked at self-selected pace with fixed volume (10,000 steps/day x 3 days/wk) • Improved cholesterol profiles and expression of genes involved in reverse lipid transport • No accompanying changes in body weight and total body fat Butcher LR et al. Med Sci Sports Exerc. 2002. Butcher et al. Med Sci Sports Exerc. 2008.

Patterns of Exercise • Discontinuous Exercise • Weekend Warrior • Interval Training • Sedentary Behavior

Discontinuous Exercise • Moderate-intensity physical activity may be accumulated in bouts of 10 or more min each to attain goal of at least 30 min daily • Effectiveness of long vs. short bouts of exercise for improving body composition, cholesterol or mental health inconclusive • Volume of energy expended rather than the duration of exercise that is important

Weekend Warrior • This pattern of exercise was associated with lower rates of premature mortality compared with being sedentary in a study of men without CV risk

Interval Training • Short term (< 3 mos) has resulted in similar or greater improvements in cardiorespiratory fitness and cardiometabolic biomarkers compared to single-intensity exercise • Lipoproteins, glucose, IL-6, and TNF alpha, muscle fatty acid transport

Interval Training • Study of healthy untrained men: • Interval running exercise more effective than sustained running of similar total duration in improving cardiorespiratory fitness and blood glucose concentrations • Less effective in improving resting HR, body composition and total cholesterol/HDL ratio

Sedentary Behavior • Associated with elevated risk of CHD mortality, depression, increased waist circumference, elevated BP, depressed lipoprotein lipase activity and worsened chronic disease biomarkers • Glucose, insulin, lipoproteins • Detrimental even among individuals who meet current physical activity recommendations

Sedentary Behavior • Amount of time spent in activities such as TV watching and sitting at a desk should be assessed • When sedentariness is broken up by short bouts of physical activity or standing, attenuation of adverse biological effects

Effect of Exercise on Cardiometabolic Risk Factors • Improvement in high blood pressure, glucose tolerance, insulin resistance, dyslipidemia and inflammatory markers • Benefits of exercise on cardiometabolic risk factors are acute (hours to days) and chronic • Regular exercise participation on most days of the week is important

Exercise + Diet Modification • Exercise without dietary modification has modest effect on short-term weight loss • Favorable changes in visceral abdominal fat, total body fat and biomarkers can occur even without weight reduction • Weight loss enhances these improvements

Dose Response • Church et al. (2007) evaluated effect of varying exercise volumes at fixed intensity (50% VO2max) • Sedentary, overweight or obese postmenopausal women randomized to exercise volumes of 50%, 100% or 150% of recommended weekly energy expenditure • Dose-response effect across 3 volumes observed • Initial level of fitness may affect the training responses to a set volume of exercise Church TS et al. JAMA. 2007.

Benefits of Weight Training and Muscular Fitness • Higher levels of muscular strength are associated with significantly better cardiometabolic risk factor profiles, lower risk of all-cause mortality, fewer CVD events, lower risk of developing functional limitations and nonfatal disease

Benefits of Weight Training and Muscular Fitness • Limited data on dose-response characteristics between muscular fitness and health outcomes or existence of threshold for benefit • Muscular fitness can lead to improvements in body composition, blood glucose levels, insulin sensitivity and blood pressure in persons with pre hypertension and stage I hypertension

Benefits of Weight Training and Muscular Fitness • Resistance training may be effective to prevent and treat “metabolic syndrome” • Increases bone mass and bone strength of specific bones stressed • Prevents, slows or even reverses the loss of bone mass in people with osteoporosis • Muscle weakness is a risk factor for development of osteoarthritis • Resistance training may reduce chance of developing MSK disorders

Exercise a s Medicine