Weekly mileage and heart disease risk factors

Physical activity appears to reduce the risk of heart disease in men. Current physical activity guidelines emphasize the benefits of moderate amounts of moderately intense activity. Such activities expend 3 to 6 times more calories than sitting at rest.

Vigorously intense activity on the other hand, such as running, expends over six times as many calories as sitting at rest. To better understand the health effects of vigorous exercise, we examined the dose-response relationships between reported distance ran per week and heart disease risk factors in 8,290 men who participated in the National Runners' Health Study. The risk factors were obtained from medical records provided by the runners' physicians.

The graph to the right shows how high-density lipoprotein (HDL)-cholesterol is related to reported weekly distance ran. The height of the bar represents the average HDL-cholesterol level of men who had been grouped by their distance ran per week. The men's HDL-cholesterol concentrations increased significantly
in association with each 10 mile increment in running distance between 0 and 49 miles ran per week.
HDL-C
Plasma HDL-cholesterol at levels of 60 mg/dL or more has been recognized by the National Cholesterol Education Program as providing some protection from heart attacks. In fact, it is sufficiently protective to eliminate the detrimental affects of one risk factor (e.g., diabetes, hypertension, cigarette smoking, family history of premature heart disease, or being male over 45 years old). Compared to running under 10 miles per week, running over 40 miles per week was associated with a 2.5-fold increase in the