Effect of exercise conditioning on plasma high density lipoproteins and other lipoproteins.

Epidemiologic studies have demonstrated an inverse correlation between HDL-cholesterol and the incidence of coronary artery disease. Although physically active individuals tend to have higher HDL levels than their sedentary peers, they also have lower body weights. It has yet to be shown that physical activity by itself can raise HDL when other variables such as body weight are maintained constant. We examined the effect of a 6-week exercise conditioning program on 10 young normal subjects who were maintained on a constant composition, iso-weight diet. A training effect was documented by an increase in maximum oxygen consumption from 44 to 49 ml/min/kg and by a fall in heart rate at submaximal exercise from 120 to 109 beats/min. Total plasma cholesterol levels decreased significantly from 156 to 140 mg/dl. However, there was no significant change in plasma triglyceride, VLDL, LDL or HDL-cholesterol levels, although all these values decreased. Thus, under the conditions of this study in which diet and weight were controlled, exercise conditioning did not elevate HDL-cholesterol levels. HDL levels have been shown to be inversely related to body weight. These data are consistent with the concept that exercise conditioning may affect HDL via alterations in body weight.