Lipoprotein subfraction changes after continuous or intermittent exercise training.
PURPOSE: This study compared total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) and their respective subfractions after completing 4 wk of either intermittent (INT-EX) or continuous (CON-EX) aerobic exercise training (TRAIN). METHODS: Untrained males (N = 7) and females (N = 11) completed 4 wk of TRAIN of supervised treadmill jogging occurring 5 d.wk(-1) for 30 min per session at 60% VO2max (75% HRmax). CON-EX was a single 30-min bout. INT-EX consisted of three 10-min bouts separated by 20 min of seated rest. Pre- and post-TRAIN fasting plasma samples were collected after subjects had followed 48 h of activity restriction and a 24-h repeated diet including a 12-h dietary fast. Postprandial lipemia was measured for 8 h following a standardized high-fat meal. RESULTS: Fasting triglycerides and very LDL-C were not affected by TRAIN, and TRAIN did not change postprandial area under the curve or peak in either group. With groups combined, TRAIN significantly decreased TC, total LDL-C, and the TC:HDL ratio, and increased HDL-C subfraction 2 and LDL mean particle size. Total intermediate-density lipoprotein cholesterol remained unchanged at post-TRAIN, and was not different between groups. CONCLUSIONS: To prevent dyslipidemia, our findings suggest that persons who are normolipidemic can improve the lipoprotein profile equally with CON-EX and INT-EX by lowered TC through the sum of changes in LDL-C subfractions, increased mean LDL particle size, and increased HDL-C subfraction 2 concentration.