Exercise acutely increases high density lipoprotein-cholesterol and lipoprotein lipase activity in trained and untrained men

We studied the effects of a single exercise session on lipid and lipoprotein concentrations and on postheparin plasma lipoprotein lipase (LPLA) and hepatic triglyceride hydrolase activities (HTGLA) in 11 trained (T) and ten untrained (UT) men. Subjects exercised on a bicycle ergometer at 80% of their maximal heart rate for one (UT) or two hours (T). Blood samples were drawn 24 hours before and at ten minutes and 24, 48, and 72 hours after exercise. Values were analyzed before and after adjustment for estimated changes in plasma volume (PV). High density lipoprotein cholesterol (HDL-C) increased 2 ± 4 mg/dL in T (P < 0.05) and 1 ± 2 mg/dL in UT subjects beginning 48 hours after exercise. This increase was magnified by adjusting for the 5% to 8% postexercise expansion of PV. The increase in HDL in the T subjects was produced by increases in the HDL₂-C subfraction (+3 ± 4 mg/dL, P < 0.05) whereas HDL₃ increased in the UT men (+2 ± 3 mg/dL, P < 0.05). LPLA did not change in either subject group when estimated PV changes were ignored but increased 11% (P < 0.05) at 24 hours after exercise when PV was considered. HTGLA was 11% below baseline in the UT men 24 to 72 hours after exercise (P < 0.05) but showed no change in either subject group after adjustment for PV. These results demonstrate that exercise acutely increases HDL levels by raising the HDL₂ subfraction in T and the HDL₃ subfraction in UT men. Exercise also acutely increases LPLA, but changes in lipase activities may be obscured by concomitant changes in PV. The magnitude of acute changes in lipid, lipoprotein, and lipase values were insufficient to account for the larger differences in these parameters generally noted between T and UT subjects.