Exercise Training and the Apolipoprotein A-I to HDL-Cholesterol Ratio

Abstract

Plasma concentration of apolipoprotein A-I (apoA-I), the major apoprotein of high-density lipoprotein (HDL), has been shown to be lower in patients with coronary obstructive disease than in patients without disease. Regular endurance-exercise training results in increased HDL-cholesterol (HDL-C) concentration, but its effects on apoA-I are uncertain. The purpose of the present study was to compare plasma apoA-I and HDL-C concentrations in three groups of healthy, nonsmoking middle-aged men (range, 31–54 yr) with three distinctly different patterns of habitual exercise: sedentary (N = 15), low exercise (N = 8, ran an average of 11 miles/wk), and high exercise (N = 8, ran an average of 37 miles/wk). Dietary composition (percent kilocalories from carbohydrates, fats, protein, and alcohol consumption) was similar for all groups. The high-exercise group had significantly higher maximal oxygen uptake (VO2max), lower body fatness, and higher HDL-C levels than the other groups. Apolipoprotein A-I concentration was not different for the three groups and was not significantly correlated with VO2max, miles run per week, dietary fat intake, or body fatness. However, the ratio of apoA-I to HDL-C (apoA-I/HDL-C) was significantly lower in the high-exercise group (2.7 \Pm 0.2 [mean \Pm SEM]) than in the sedentary group (4.3 \Pm 0.3). We conclude that regular exercise training in healthy middle-aged men is not associated with an increased plasma apoA-I concentration, but is associated with a lower apoA-I/HDL-C. This suggests the possibility of an increased ability of apoA-I to bind cholesterol into the HDL particle in exercise-trained subjects.