Changes in serum lipids, lipoproteins, and heparin releasable lipolytic enzymes during moderate physical training in man: a longitudinal study.

Serum lipids, postheparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activity, and furthermore adipose tissue LPL activity were studied in 20 middle-aged men undergoing a moderate training program of 15-wk. These same parameters were also measured in 7 nontraining control subjects. The training caused a significant (P less than 0.001) increase in physical fitness, and also considerable changes in serum lipid levels and lipolytic enzymes activities. In the trainers, serum HDL cholesterol increased by about 7% (P less than 0.01 and HDL/total cholesterol ratio by 11% (P less than 0.001). Decreases were observed in serum total (P less than 0.10 and LDL (P less than 0.05) cholesterol levels and in insulin values (P less than 0.05). No changes in these parameters occurred in the reference group. Postheparin plasma and adipose tissue LPL activity increased by 33% (P less than 0.001) and 56%, respectively, in the trainers. Postheparin plasma HL activity remained essentially the same in both groups, although a trend towards decreased values was seen in the trainers. On the other hand, postheparin plasma HL activity correlated negatively with serum HDL cholesterol levels both before and after the training period. The present results suggest that even with a moderate training program, beneficial effects on serum lipids in middle-aged men can be accomplished. There is also reason to believe that these changes are, at least in part, mediated by changes in the activities of lipolytic enzymes involved in lipoprotein metabolism, namely LPP and HL.