Physical activity and coronary heart disease in men : The Harvard Alumni Health Study

The quantity and intensity of physical activity required for the primary prevention of coronary heart disease (CHD) remain unclear. Therefore, we examined the association of the quantity and intensity of physical activity with CHD risk and the impact of other coronary risk factors. We followed 12 516 middle-aged and older men (mean age 57.7 years, range 39 to 88 years) from 1977 through 1993. Physical activity was assessed at baseline in kilojoules per week (4.2 kJ=1 kcal) from blocks walked, flights climbed, and participation in sports or recreational activities. During follow-up, 2,135 cases of incident CHD, including myocardial infarction, angina pectoris, revascularization, and coronary death, occurred. Compared with men expending /=12,600 kJ/wk had multivariate relative risks of 0.90, 0.81, 0.80, and 0.81, respectively (P: for trend=0.003). When we considered the independent effects of specific physical activity components, only total sports or recreational activities (P: for trend=0.042) and vigorous activities (P: for trend=0.02) were inversely associated with the risk of CHD. These associations did not differ within subgroups of men defined by coronary risk factors. Finally, among men with multiple coronary risk factors, those expending >/=4,200 kJ/wk had reduced CHD risk compared with men expending