How Much Exercise Is Necessary to Prevent CV Disease? Thomas G. Allison, PhD, MPH Mayo Clinic, Rochester, MN, USA

Exercise Prevention of CHD Amount of exercise? Exercise intensity? Type of exercise?

The relationship between exercise or physical fitness and CHD is curvilinear – CHD risk = f(1/x)

Benefits of Exercise Increase with Age (and Risk)

CHD Risk Factor Trends in US Risk factors declining since 1980 Smoking LDL cholesterol Risk factors increasing since 1980 Obesity Diabetes/IFG Low HDL cholesterol High triglycerides Sedentary lifestyle Not strongly associated with exercise/physical activity Strongly associated with exercise/physical activity

Physical Activity and All-cause Mortality In Iowa Women Prospective cohort study of 40,417 women Aged years at baseline Followed 7 years Physical activity assessed by mailed questionnaire Kushi et al, JAMA 1997;277:

All-cause Mortality In Iowa Women Related to Moderate and Vigorous Activity

CHD and Exercise in Women Women’s Health Initiative Observational Study 73,743 women reporting amount and intensity of exercise, including walking, and amount of time sitting –age years –no baseline CHD or cancer –followed from through August 27, 2000 Manson et al, NEJM 2002;347:

Age-Adjusted Rate of CV Events According to Quintiles of Total Physical Activity (1000 kcal/week  16.7 MET-hours/week)

CHD and Exercise in Men Health Professionals Follow-up Study 44,452 male health professionals Baseline age years Excluding baseline CHD and cancer Biennial questionnaire reporting amount and type of physical activity Followed 1986 to January 31, 1998 Tanasescu et al, JAMA 2002;288:

Rate of New CHD According to Quintiles of Total Physical Activity (2000 kcal/week  33.3 MET-hours/week)

Types of Exercise Significant reductions in risk seen with –total physical activity –running –jogging –walking –rowing –weight training > 30 minutes per week

CHD and Exercise Intensity New analysis of Harvard Alumni Study 7337 men reporting amount and absolute and relative exercise intensity –average age 66 years –no baseline CHD or cancer –followed from 1988 to 1995 –CHD = angina pectoris, MI, PTCA, CABG, CHD death Lee et al, Circ 2003;107:

Exercise Classification Amount of exercise: [< 1000] vs [ ] vs [  2500 kcal/week] Absolute intensity of exercise: [ 6 METs] Relative intensity of exercise (based on 10-point Borg Scale): [Weak or less (0-2)] vs [Moderate (3)] vs [Somewhat Strong (4)] vs [Strong or greater (5+)]

0Nothing at all 0.5Very, very weak 1Very weak 2Weak 3Moderate 4Somewhat strong 5 Strong 6 7Very strong Very, very strong Maximal

Results Age-adjusted relative risk of CHD (n = 551) by ascending categories of exercise amount, absolute intensity, and relative intensity

How Does CV Fitness Contribute to Risk Stratification? FAC Group (% predicted) FRS Group >110% % 70-89%50-69%<50% < 5% % – 14.9% – 19.9% ≥ 20% Al Badarin FJ, Kopecky SL, Allison TG. JACC 2009 Mar; 53(10 Suppl 1):A258. (Abstract) 8-Year All-Cause Mortality

Recommendations Start with a level of exercise appropriate to the baseline fitness and activity level of the patient Progressively advance the exercise prescription until risk factors are optimally controlled … or limits of tolerance are reached

Recommendations Amount of exercise To “get on the flat tail” of the CHD:exercise curve, it appears that one or more of the following are needed: – “vigorous” exercise at least 2-4 times per week –at least 2000 kcal/week in leisure-time physical activity –exercise capacity of 10 METs for men or 9 METs for women

Recommendations Exercise intensity Relative exercise intensity of 4 (“somewhat strong”) on the 10-point Borg scale –probably on the older 6-20 Borg scale Type of exercise Running, jogging, walking, rowing, weight training have all been validated

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