Effect of exercise training on plasma high-density lipoprotein cholesterol level at constant weight.

Previous investigations have demonstrated an increase of plasma high-density lipoprotein cholesterol (HDL-Chol) and a decrease in the ratio of low density lipoprotein (LDL)-Chol/HDL-Chol (Atherogenic Index; AI) as a result of exercise training. The question of whether elevation of HDL-Chol was a consequence of weight reduction or physical training itself was unsolved. The present study was designed to prevent the weight reduction that is associated with exercise training. Five healthy and mildly active male volunteers, aged 28-31 years, participated in a 4-week training programme. They ran on a treadmill at 140-160 m/min at 0% grade for 50 min, 5 times a week, equivalent to an energy expenditure of 9 kcal/kg body weight/day. Subjects maintained their body weights by increasing calorie intake to match increased energy expenditure. No changes were observed in mean body weight, skinfold thickness, basal metabolism, and maximal oxygen uptake after the training programme. The HDL-Chol level increased from 54 to 73 mg/dl (P less than 0.05), and the reduction of AI was 30.8% (P less than 0.05) in response to the exercise training. However, the exercise training did not induce changes in plasma total cholesterol and triglyceride (TG) levels. The results of this experiment suggested that moderate physical training itself can be a potent factor for the regulation of HDL-Chol level and improvement of the AI in the absence of alterations in body weight.