Exercise as Medicine Instructor of Medicine Department of Medicine Division of Sports Medicine...

Exercise as MedicineInstructor of MedicineDepartment of MedicineDivision 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

2000

Obesity Trends* Among U.S. AdultsBRFSS, 1990, 2000, 2010

(*BMI 30, or about 30 lbs. overweight for 5’4” person)

2010

1990

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

(*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person)

No Data <10% 10%–14%

Obesity Trends* Among U.S. AdultsBRFSS, 1985


No Data <10% 10%–14%



No Data <10% 10%–14%



No Data <10% 10%–14%



No Data <10% 10%–14%



No Data <10% 10%–14%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19%



No Data <10% 10%–14% 15%–19% ≥20%



No Data <10% 10%–14% 15%–19% ≥20%



No Data <10% 10%–14% 15%–19% ≥20%



No Data <10% 10%–14% 15%–19% ≥20%



No Data <10% 10%–14% 15%–19% 20%–24% ≥25%



No Data <10% 10%–14% 15%–19% 20%–24% ≥25%



No Data <10% 10%–14% 15%–19% 20%–24% ≥25%



No Data <10% 10%–14% 15%–19% 20%–24% ≥25%



No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%



No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%



No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%



No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%



No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%



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


• 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


• 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


• May prevent and improve depression and anxiety

• May increase energy levels and decrease fatigue

How to Improve Muscular Fitness

• Free weights, machines with stacked weights or pneumatic resistance, resistance bands

Improving Muscular Fitness

• Emphasize dynamic exercises involving concentric (shortening) and eccentric (lengthening) muscle actions that recruit multiple muscle groups Target major muscle groups -- chest, shoulders,

back, hips, legs, trunk an arms Train opposing muscle groups (antagonists)

• Quads/hamstrings, abdominals/lumbar extensors


• Sets: 2-4 sets of resistance exercises per muscle group

• Rest Duration: intervals of 2-3 min of rest most effective for achieving increases in muscle strength and hypertrophy


• Selected resistance should permit completion of 8-12 reps per set Number needed to induce fatigue but not

exhaustion• Recommend 2-3 times per week of weight training,

rest period of 48-72 hours between sessions


• Risk of accidental falls and resulting bone fractures more closely related to decline in muscular power rather than strength

• Resistance training for older persons should emphasize development of power Completing 3 sets of 8-12 reps at very light to

moderate intensity effectively increases strength and power and improves balance in older persons

Benefits of Flexibility Exercise

• No consistent link has been shown between regular flexibility exercise and reduction of musculotendinous injuries, prevention of low back pain or DOMS

• Increased flexibility can improve posture and balance• Joint ROM improves transiently after flexibility

exercise, chronically after about 3-4 weeks of regular stretching at a frequency of at least 2-3 times per week May improve in as few as 10 sessions with intensive

program


• Holding stretch for 10-30 sec at the point of tightness or slight discomfort enhances joint ROM

• Repeat each flexibility exercise 2-4 times Enhancement of joint ROM

occurs during 3-12 weeks, at least 2-3 days per week


• Target major muscle-tendon units of shoulder girdle, chest, neck, trunk, lower back, hips, posterior and anterior legs and ankles recommended

• Most effective when muscle temp is elevated

Maintaining Beneficial Effects of Exercise

• Many physiological changes occur as soon as 1-2 weeks after cessation of exercise training

• Studies on trained athletes Decreasing volume, frequency and/or intensity of exercise

has little or modest influence on VO2max over periods of several months


• Williams et al (2006): 6000 runners followed for 7.4 years Magnitude of increase in abdominal adiposity associated

with reduction in training was dose-dependent More exercise required to improve cardiorespiratory

fitness and cardiometabolic health than is required to maintain these these improvements

Williams PT et al. Obesity (Silver Spring).2006.


• Resistance training-induced improvements in muscle strength and power reverse quickly with complete cessation of exercise Neuromuscular and functional changes seem to be

maintained for longer period• Intensity is important component of maintaining the effects

of resistance training


• Improvements in joint ROM reverse within 4-8 weeks of cessation of stretching exercise Variable responses among muscle-tendon groups

Prescribing Exercise


• Emphasize individual choice, preference and enjoyment in prescription -- can achieve current recommendations in many ways

• Previous exercise experience -- may respond better to vigorous exercise

• Previously inactive -- may be better-suited for moderate intensity exercise

Enhancing Adherence

• Mode of exercise (aerobic vs. resistance, walking vs. running) has very minimal to no effect on adherence to exercise

• Supervision by experienced exercise leader can enhance adherence

Enhancing Adherence

• Clarify individual’s motives to exercise• Create short-term, realistic goals• Start low, go slow• Provide written exercise prescription• Frequent follow up, activity log• Consider referral to PT to get started

Enhancing Adherence

• Community-based interventions

• Programs incorporating brief advice

• Use of pedometers, telecommunications and group support

• Desire for strength, feelings of empowerment, previous exercise experience may increase adoption of and adherence to resistance training among older adults

Enhancing Adherence

• Limited evidence suggests pleasant affective responses to exercise may enhance future exercise behavior More negative affect reported when exercising

above ventilatory threshold Exercise environments with engaging distractions

may ameliorate affective experience and increase adherence


• Pedometers: popular and effective for promoting physical activity and modest weight loss Provide inexact index of exercise volume Quality of steps can often not be determined (speed,

grade, duration)


• Goal of 10,000 steps often cited, but even fewer steps can meet current exercise recommendations

• Meta-analysis of pedometer use -- increase in 2000 steps per day in participants in RCT who had elevated BP Associated with modest decrease in SBP (~4mmHg)

independent of BMI changes• Best to use both steps per minute plus currently

recommended durations of exercise 100 steps/min is rough approximation of moderate-

intensity exercise

Bravata DM et al. JAMA. 2007.Kang M et al. Res Q Exerc Sport.2009.

Risks of Exercise

• Risk of CHD and musculoskeletal complications increase transiently during strenuous physical activity compared with risk at other times

• Musculoskeletal injury is most common exercise-related complication

• Type and intensity of exercise seem to be more important factors in incidence of injury

• Volume of exercise is less important factor in incidence of injury

Risks of Exercise

• Rhabdomyolysis associated with exercise is uncommon, but serious Disorder resulting from damage to skeletal muscle that can

cause acute kidney failure, cardiac arrhythmias and death Risk is increased in both experienced and novice exercisers

who undertake unaccustomed eccentric exercise, particularly under hot ambient conditions

Risks of Exercise

• Heart attack, sudden cardiac death Can be triggered by unaccustomed vigorous physical

exertion• Few data support the role of routine diagnostic exercise

testing as an effective method for reducing the risk of exercise-related CHD events

Exercise Testing

• No randomized controlled trial that shows that asymptomatic people with a positive exercise treadmill test (ETT) have fewer heart attacks or receive better medical management than those without screening ETT

ACSM Exercise Treadmill Testing

Low Risk Men < 45 yrs, women < 55 yrs and no more than 1 CAD risk factor

No ETT

Moderate Risk Men >/= 45 yrs, women >/= 55 or at least 2 CAD risk factors

ETT for vigorous exercise

High Risk Any signs, symptoms or h/o CV, pulmonary or metabolic disease

ETT for moderate or vigorous exercise

Special Populations

• Hypertension: exercise is great way to control blood pressure Resistance training: lower weight, high reps (avoid

valsalva) Beta blockers -- decrease HR and therefore exercise

capacity BB + diuretics may increase risk for heat illness in

hot and humid conditions

Special Populations

• Arthritis: Modify type of activity to low impact

• Aquatic, cycling, walking Start low, go slow Perform functional activities daily

• Climb stairs• Sit to stand exercises

Special Populations

• Diabetes: exercise is great way to control blood sugar Must have good blood sugar control before starting

exercise regimen Exercise with partner or under supervision Be aware of symptoms of hypoglycemia Post-exercise hypoglycemia can last 48 hrs after

exercise• Monitor plasma glucose levels• Eat carbohydrates as needed

Special Populations

• Other Considerations for Diabetics: Retinopathy: high arterial pressures can cause retinal

detachment; if severe, avoid SBP > 170 Peripheral neuropathy: may have balance and gait

abnormalities Autonomic neuropathy: use RPE to monitor intensity

Summary

• Obesity and sedentary lifestyle on the rise across the US• ACSM/AHA Recommendations: 30 minutes of moderate

exercise daily, at least 5 days per week• Physical and psychological benefits to exercise• Cardio, resistance training and flexibility exercises all have

health benefits• Prescribing exercise: pedometers, reasonable goal-setting,

social support• Risks of exercise: ETT only in specific settings, MSK injuries

most common

References

• Asikainen TM, Miilunpalo S, Oja P, et al. Randomised, controlled walking trials in postmenopausal women: the minimum dose to improve aerobic fitness? Br J Sports Med. 2002;36(3):189-94.

• Bigaard J, Fredericksen K, Tjonneland A, et al. Waist circumference and body composition in relation to all-cause mortality in middle-aged men and women. Int J Obes. 2005;29(7):778-84.

• Bravata DM, Smith-Spangler C, Sundaram V, et al. Using pedometers to increase physical activity and improve health: a systematic review. JAMA. 2007;298(19):2296-304.

• Butcher LR, Thomas A, Backx K, Roberts A, Webb R, Morris K. Low-intensity exercise exerts beneficial effects o plasma lipids via PPAR. Med Sci Sports Exerc. 2002;4(1):19-27.

• Carroll TJ, Herbert RD, Munn J, Lee M, Gandevia SC. Contralateral effects of unilateral strength training: evidence and possible mechanisms. J Appl Physiol. 2006;101(5):1514-22.

• Church TS, Earnest CP, Skinner JS, Blair SN. Effects of different doses of physical activity on cardiorespiratory fitness among sedentary, overweight or obese postmenopausal women with elevated blood pressure: a randomized controlled trial. JAMA. 2007;297(19):2081-91.

• De Vos NJ, Singh NA, Ross DA, Stavrinos TM, Orr R, Fiatarone Singh MA. Optimal load for increasing muscle power during explosive resistance training in older adults. J Gerontol A Biol Sci Med Sci. 2005;60(5):638-47.

• DiPietro L, Dziura J, Yeckel CW, Neufer PD. Exercise and improved insulin sensitivity in older women: evidence of the enduring benefits of higher intensity training. J Appl Physiol. 2006;100(1):142-9.

• Fatouros IG, Kambas A, Katrabasas I, et al. Strength training and detraining effects on muscular strength anaerobic power and mobility of inactive older men are intensity dependent. Br J Sports Med. 2005;39(10):776-80.

• Haskell WL, Lee IM, Pate RR, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc. 2007;39(8):1423-34.

• Healy GN, Dustan DW, Salmon J, et al. Breaks in sedentary time: beneficial associations with metabolic risk. Diabetes Care. 2008;31(4):661-6.

References

• Heitmann BL, Erikson H, Ellisinger BM, Mikkelsen KL, Larsson B. Mortality associated with body fat, fat-free mass and body mass index among 60-year-old Swedish men -- a 22-year follow-up. The study of men born in 1913. Int J obes Relat Metab Disord. 2000;24(1):33-7.

• Hewett TE, Myer GD, Ford KR. Reducing knee and anterior cruciate ligament injuries among female athletes: a systematic review of neuromuscular training interventions. J Knee Surg. 2005;18(1)82-8.

• Kang M, Marshall SJ, Barreira TV, Lee JO. Effect of pedometer-based physical activity interventions: a meta-analysis. Res Q Exerc Sport. 2009;80(3):41-52.

• Kohrt WM, Bloomfield SA, Little KS, Nelson ME, Yingling VR, American College of Sports Medicine. Position Stand: physical activity and bone health. Med Sci Sports Exerc. 2004;36(11):1985-96.

• Lee IM, Sesso HD, Paffenbarger RS Jr. Physical activity and coronary heart disease risk in men: does the duration of exercise episodes predict risk? Circulariton. 2000;102(9):981-6.

• Lind E, Ekkekakis P, Vazou S. The affective impact of exercise intensity that slightly exceeds the preferred level: ‘pain’ for no additional ‘gain’. J Health Psychol. 2008;13(4):464-8.

• Maimoun L, Sultan C. Effects of physical activity on bone remodeling. Metabolism. [Epub ahead of print}. 2010 [cited 2010 Mar 30]

• Marshall SJ, Levy SS, Tudor-Locke CE, et al. Translating physical activity recommendations into a pedometer-based step goal: 3000 steps in 30 minutes. Am J Prev Med. 2009;36(5):410-5.

• Meyer T, Auracher M, Heeg K, Urhausen A, Kindermann W. Does cumulating endurance training at the weekends impair training effectiveness? Eur J Cardiovasc Prev Rehabil. 2006;13(4):578-84.

• Nybo L, Sundstrup E, Jakobsen MD, et al. High-intensity training versus traditional exercise interventions for promoting health. Med Sci Sports Exerc. 2010;42(10):1951-8.

• Orr R, de Vos NJ, Singh NA, Ross DA, Stavrinos TM, Fiatarone-Singh MA. Power training improves balance in healthy older adults. J Gerontol A Biol Sci Med Sci. 2006;61(1):78-85.

• Owen N, Healy GN, Matthews CE, Dunstan DW. Too much sitting: the population health science of sedentary behavior. Exerc Sport Sci Rev. 2010;38(3):105-13.

References

• Richardson CR, Newton TL, Abraham JJ, Sen A, Jimbo M, Swartz AM. A meta-analysis of pedometer-based walking interventions and weight loss. Ann Fam Med. 2008;6(1):69-77.

• Seguin RA, Economos CD, Palombo R, Hyatt R, Kuder J, Nelson ME. Strength training and older women: a cross-sectional study examining factors related to exercise adherence. J Aging Phys Act. 2010;18(2):201-18.

• Suominen H. Muscle training for bone strength. Aging Clin Exp Res. 2006;18(2):85-93.• Swain DP. Moderate or vigorous intensity exercise: which is better for improving aerobic fitness? Prev Cardiol.

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• Warren TY, Barry V, Hooker SP, Sui X, Church TS, Blair SN. Sedentary behaviors increase risk of cardiovascular disease mortality in men. Med Sci Sports Exerc. 2010;42(5):879-85.

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Exercise as Medicine Instructor of Medicine Department of Medicine Division of Sports Medicine...

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