Effect of intensive endurance training on lipoprotein profiles in young and older men

Although there are considerable data concerning the effects of endurance exercise training (ET) on plasma lipoproteins, the results have been quite inconsistent. The observed variability of response may be related to the age, sex, adiposity, or diet of the subjects tested, or to the type and intensity of the exercise intervention. Furthermore, there is relatively little such data in older individuals. Therefore, in the present study, we investigated the effects of intensive ET on lipoprotein profiles in healthy young (n = 12; 28.2 ± 2.4 years) and older (n = 15; 67.5 ± 5.8 years) men. Unlike subjects in most similar studies, our subjects were weight-stabilized on a constant-composition diet for 21 days prior to determination of the lipoprotein profile before and after the ET program. At baseline, the two groups were not significantly different with respect to any individual component of their lipoprotein profiles, relative weight, or percent body fat, but the older men had a more central distribution of fat by both waist to hip ratio (WHR) and computed tomography (CT). Maximal aerobic power, expressed per kilogram of body weight (V̇ O 2 max), was 33% lower ( P < .001) in the older men at baseline. Following the 6-month, walk/jog/bike ET program (5 d/wk), both the young (+18%, P < .001) and the older (+22%, P < .001) men increased their V̇ O 2 max. This was associated with small, but significant, decrements in weight, percent body fat, and WHR only in the older men. The only ET-induced change observed in the lipoprotein profile in the young was a 14% increase in total high-density lipoprotein cholesterol (HDL-C, 40.8 ± 8.1 v 46.3 < 8.0 mg/dL, P = .01). In the older men, ET was associated with a similar 15% increment in HDL-C (38.0 ± 7.2 v 43.6 ± 8.9 mg/dL, P < .001), and a 63% increase in the HDL 2-C subfraction (7.1 ± 3.9 v 11.6 ± 6.4 mg/dL, P < .001). A 21% decrease in plasma triglyceride concentration ( P = .02) and a 13% decrease in the ratio of low-density lipoprotein cholesterol (LDL-C) to HDL-C ( P = .01) were also noted only in the older subjects. None of the changes in the lipoprotein profile were significantly correlated to changes in V̇ O 2 max, body composition, or fat distribution in either group. We conclude that potentially important improvements in the lipoprotein profiles, specifically in HDL-C levels, are found following an intensive ET program, in both healthy young and older men.