EFFECTS OF EXERCISE WITH VARYING ENERGY-EXPENDITURE ON HIGH-DENSITY LIPOPROTEIN-CHOLESTEROL

To investigate the effect of varying energy expenditure on acute high- density lipoprotein-cholesterol (HDL-C) changes, 12 healthy endurance- trained men completed three- counterbalanced running trials at differe nt energy expenditures: trial 1, 1690.3 (24.4) kJ [mean (SD)]; trial 2 , 2529.1 (24.0) kJ; trial 3, 3384.3 (36.6) kJ, with exercise intensity at 75% of maximal oxygen consumption. For each trial, blood samples w ere collected at 24 h pre-exercise (24 h Pre), immediately post-exerci se, Ih post-exercise, 6 h post-exercise (6 h PE), and 24 h post-exerci se (34 h PE), Plasma samples were analyzed for HDL-C, HDL(2)-C and HDL (3)-C subfractions, and triglycerides (TG). In addition, postheparin p lasma samples were analyzed at 24 h Pre, 6 h PE and 24 h PE for lipopr otein lipase activity (LPLA) and hepatic triglyceride lipase activity. All samples were corrected for plasma volume changes and compared to 23 h Pre (baseline). When trials were combined, an increase (P < 0.05) in HDL(3)-C. An increase (P < 0.05) in LPLA and decrease (P<0.05) in TG at 24 h PE is suggested to be responsible for the increase in HDL(3 )-C. In conclusion, no difference in HDL-C was observed among trials. However, when trials were combined, an increase in HDL-C was observed, suggesting that an energy expenditure of no greater than 3384 kJ is n eeded to promote favorable changes in HDL-C.