Mihaela Tanasescu, MD; Michael F. Leitzmann, MD; Eric B. Rimm, ScD; Walter C. Willett, MD; Meir J. Stampfer, MD; Frank B. Hu, MD
Context: Studies have shown an inverse relationship between exercise and risk of coronary heart disease (CHD), but data on type and intensity are sparse.
Objective: To assess the amount, type, and intensity of physical activity in relation to risk of CHD among men.
Design, Setting, and Participants: A cohort of 44 452 US men enrolled in the Health Professionals’ Follow-up Study, followed up at 2-year intervals from 1986 through January 31, 1998, to assess potential CHD risk factors, identify newly diagnosed cases of CHD, and assess levels of leisure-time physical activity.
Main Outcome Measure: Incident nonfatal myocardial infarction or fatal CHD occurring during the follow-up period.
Results: During 475 755 person-years, we documented 1700 new cases of CHD. Total physical activity, running, weight training, and rowing were each inversely associated with risk of CHD. The RRs (95% confidence intervals [CIs]) corresponding to quintiles of metabolic equivalent tasks (METs) for total physical activity adjusted for age, smoking, and other cardiovascular risk factors were 1.0, 0.90 (0.78-1.04), 0.87 (0.75-1.00), 0.83 (0.71-0.96), and 0.70 (0.59-0.82) (P<.001 for trend). Men who ran for an hour or more per week had a 42% risk reduction (RR, 0.58; 95% CI, 0.44-0.77) compared with men who did not run (P<.001 for trend). Men who trained with weights for 30 minutes or more per week had a 23% risk reduction (RR, 0.77; 95% CI, 0.61-0.98) compared with men who did not train with weights (P = .03 for trend). Rowing for 1 hour or more per week was associated with an 18% risk reduction (RR, 0.82; 05% CI, 0.68-0.99). Average exercise intensity was associated with reduced CHD risk independent of the total volume of physical activity. The RRs (95% CIs) corresponding to moderate (4-6 METs) and high (6-12 METs) activity intensities were 0.94 (0.83-1.04) and 0.83 (0.72-0.97) compared with low activity intensity (<4 METs) (P = .02 for trend). A half-hour per day or more of brisk walking was associated with an 18% risk reduction (RR, 0.82; 95% CI, 0.67-1.00). Walking pace was associated with reduced CHD risk independent of the number of walking hours.
Conclusions: Total physical activity, running, weight training, and walking were each associated with reduced CHD risk. Average exercise intensity was associated with reduced risk independent of the number of MET-hours spent in physical activity.