Effect of a Single Session of Acute Aerobic Exercise on the Activities of High Density Lipoprotein Enzymes

High Density Lipoprotein (HDL) is considered to be an anti-atherogenic molecule and its beneficial function is driven by a number of enzymes such as LCAT (Lecithin Cholesterol Acyl Transferase), PON1 (Paraoxonase 1), PAF-AH (Platelet-Activating Factor Acetyl Hydrolase) and CETP (Cholesteryl Ester Transfer Protein). Low HDL-C level is the most prevalent dyslipidemia seen in India and exercise is one reliable way to improve its levels. While acute exercise is known to increase HDL-C levels, not much is known about its effects on HDL functions. This study was aimed at assessing the effect of a single bout of acute aerobic exercise on key HDL functions. Ten healthy adult male volunteers (20-35 years) were made to exercise at 65-80% VO₂ max to expend 200 Kcal using a modified Bruce protocol. Plasma samples were collected at different time points (before exercise, 15 min, 1 hour, 2 hours, 4 hours, 24 hours, 48 hours post-exercise) for analysis of HDL anti-inflammatory function and its related enzyme activities. Friedman ANOVA followed by post-hoc Wilcoxon matched pair test, showed that PON1 activity increased immediately but reached significance 48 hours post-exercise (Z=-2.666, p=0.008). CETP and LCAT activities were decreased significantly at the 4^th hour post-exercise and continued to be low even up to 48 hours (Z=-2.666, p=0.008), whereas HDL-C levels, MPO activity and HDL-II did not vary significantly at different time points. Enhanced activity of the antioxidant enzyme PON1, in combination with decreased activities of pro-atherogenic enzymes CETP and LCAT suggest that even a single bout of acute exercise could be effective in eliciting athero-protective changes in HDL function independent of HDL-C levels.