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

Abstract

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.

Figure 1

Percentage of men with clinically defined low high-density lipoprotein (HDL) cholesterol levels {<0.91 mmol/L (<35 mg/dL), considered at risk of coronary heart disease} and high HDL cholesterol levels {≥1.55 mmol/L (≥60 mg/dL), considered protective for coronary heart disease [22]} in 7059 white, nonvegetarian, nonsmoking runners who were without a history of heart disease or cancer and who were not using medications that might affect lipoprotein levels.

Figure 2

Percentage of hyperlipidemic men (top; low-density lipoprotein [LDL] cholesterol level ≥4.14 mmol/L [≥160 mg/dL] or taking cholesterol-lowering medication) and hypertensive men (bottom; systolic blood pressure > 140 or diastolic blood pressure >90 mm Hg or taking medication for blood pressure control) in 8054 white, non vegetarian, nonsmoking runners who were without a history of heart disease or cancer. (Untreated hypertension may be overestimated because it is based on readings from a single clinic visit.) These analyses cannot distinguish between an effect of medication use on running level and an effect of running level on medication use.

Figure 3

Ten-year risk of coronary heart disease (CHD) (estimated by the equation derived from the Framingham Study [21] and age adjusted) in 7059 white, nonvegetarian, nonsmoking runners who were without a history of heart disease or cancer and who were not using medications that might affect lipoprotein levels.