EFFECT OF EXERCISE TIMING ON LIPOPROTEIN LIPASE ACTIVITY IN PATIENTS WITH HYPERTRIGLY CERIDEMIA

Abstract

An acute exercise bout causes elevation of lipoprotein lipase activity (LPLA). The purpose of this study was to investigate the time course of acute exercise induced LPLA in patients with hypertriglyceridemia. Subjects were 10 sedentary normolipidemic males (NTG) (fasting plasma triglyceride (TG) = 127 ± 13 mg/dl, age = 37 ± 2y, VO2max = 36 ± 2ml/kg/min, body fat = 22 ± 2%) and 6 hyperlipidemic males (HTG) (fasting TG = 267 ± 35mg/dl, age = 41 ± 3y, VO2max = 28 ± 2ml/kg/ml, body fat = 23 ± 2%). Each subject performed a control trial (no exercise), and 4 exercise trials. In the exercise trials, a subject jogged on a treadmill at 60% of his VO2max for 1h. One heparinized blood sample was taken at baseline (control trial), and 4h, 8h, 12h and 24h after an exercise session, each time point taken in a separate day for LPLA determination. The results showed that LPLA in HTG group did not differ (p > 0.05) from NTG group at baseline (4.3 ± 0.8 μmol free fatty acid/ml/h vs 3.8 ± 0.6), and 4h (2.5 ± 0.3 vs 3.9 ± 0.7), 8h (3.4 ± 0.9 vs 4.1 ± 0.7), 12h (3.6 ± 0.5 vs 4.9 ± 1.1) and 24h (5.2 ± 0.8 vs 5.5 ± 0.9) after exercise although there was a trend for lower LPLA in HTG Group in the exercise trials. When the LPLA data from the two groups were combined, LPLA at 24h after exercise was significantly (p < 0.05) higher than baseline, or 4h, 8h, 12h after exercise. There were significant differences (p < 0.05) in TG between HTG and NTG groups across all time periods (baseline: 267 ± 35mg/dl vs 127 ± 13, 4h: 299 ± 32 vs 157 ± 16, 8h: 264 ± 31 vs 154 ± 14, 12h: 295 ± 61 vs 150 ± 17, 24h: 230 ± 39 vs 133 ± 12). Plasma epinephrine concentrations in HTG group did not differ from NTG group both prior and immediately after exercise (prior exercise: 44 ± 4.8 pg/ml vs 49 ± 4.8; after exercise: 66 ± 3.8 vs 62 ± 4.6). Plasma insulin levels prior to exercise were higher (p < 0.05) in HTG than NTG group (13.4 ± 2.0 μU/ml vs 9.8 ± 1.2), and this difference disappeared immediately after exercise (9.0 ± 1.2 vs 11.1 ± 2.1). These results suggest that LPLA is still increasing 24h after an acute aerobic exercise and the patterns of the exercise induced LPLA time course are similar in HTG and NTG groups.