Relationship of distance run per week to coronary heart disease risk factors in 8283 male runners. The National Runners' Health Study.

BACKGROUND Official guidelines from the Centers for Disease Control and Prevention and the American College of Sports Medicine state that every adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week. OBJECTIVE To examine the dose-response relationship between coronary heart disease (CHD) risk factors and vigorous exercise above the recommended minimum levels to assess whether further benefits accrue. METHODS Physician-supplied medical data were compared with reported distance run in a national cross-sectional survey of 8283 male recreational runners. RESULTS Compared with runners who ran less than 16 km (10 miles) per week, long-distance runners (> or = 80 km/wk) showed an 85% reduced prevalence of high-density lipoprotein cholesterol levels that were clinically low (< 0.9 mmol/L [< 35 mg/dL]), a 2.5-fold increased prevalence of clinically defined high levels of high-density lipoprotein cholesterol (ie, > or = 1.55 mmol/L [> or = 60 mg/dL], the level thought to be protective against CHD), a nearly 50% reduction in hypertension, and more than a 50% reduction in the use of medications to lower blood pressure and plasma cholesterol levels. Estimated age-adjusted 10-year CHD risk was 30% lower in runners who averaged more than 64 km/wk than in those who averaged less than 16 km/wk (42 vs 61 events per 1000 men). Each 16-km incremental increase in weekly distance run up to 64 to 79 km/wk was associated with significant increases in high-density lipoprotein cholesterol levels and significant decreases in adiposity, triglyceride levels, the ratio of total cholesterol to high-density lipoprotein cholesterol level, and estimated CHD risk. CONCLUSIONS Our data (1) suggest that substantial health benefits occur at exercise levels that exceed current minimum guidelines and (2) do not exhibit a point of diminishing return to the health benefits of running at any distance less than 80 km/wk.