Acute increase in lipoprotein lipase following prolonged exercise.

We investigated the acute effects of prolonged exercise on lipoprotein metabolism. Serum lipid and lipoprotein concentrations and plasma postheparin lipolytic activity were measured in ten well-trained men (ages 21 to 39) the day before and after a 42 km foot race. LDL cholesterol decreased by 10% (113 +/- 31 to 103 +/- 32 mg/dL, P less than 0.01) and total HDL-cholesterol levels increased by 9% (65 +/- 18 to 71 +/- 19 mg/dL, P less than 0.01) the day after the race. No changes in the concentration of apolipoprotein A-I or A-II occurred. Triglyceride levels decreased by 39% (95 +/- 38 to 58 +/- 23 mg/dL, P less than 0.001). Two days after the race, total HDL cholesterol (74 +/- 21 mg/dL, P less than 0.05) and the HDL2 subfraction (37 +/- 19 mg/dL, P less than 0.05) remained significantly elevated compared to pre-race values. Most dramatically, the level of lipoprotein lipase activity measured in postheparin plasma nearly doubled after the race, demonstrating that vigorous exercise acutely increases this enzyme activity. The increase in lipoprotein lipase activity probably mediated the fall in serum triglycerides after exercise and may also account for the increase in HDL cholesterol.