Ten weeks of aerobic training does not result in persistent changes in VLDL triglyceride turnover or oxidation in healthy men

Abstract

ObjectiveVery low density lipoprotein triglyceride (VLDL–TG) and free fatty acids (FFA) constitute a substantial proportion of human energy supply both at rest and during exercise. Exercise acutely decreases VLDL–TG concentration, and VLDL–TG clearance is increased after an exercise bout. However, the effects of long-term training are not clear.DesignThe aim was to investigate long-term effects of training by direct assessments of VLDL–TG and palmitate kinetics and oxidation in healthy lean men (n=9) at rest, before and after a 10-week training program, compared with a non-training control group (n=9).MethodsVLDL–TG kinetics were assessed by a primed constant infusion of [1-14C]VLDL–TG, and VLDL–TG oxidation by specific activity (14CO2) in expired air. The metabolic study days were placed 60–72 h after the last exercise bout.ResultsPalmitate kinetics and oxidation were assessed by a 2 h constant infusion of [9,10-3H]palmitate. In the training group (n=9), maximal oxygen uptake increased significantly by ≈20% (P<0.05), and the insulin sensitivity (assessed by the hyperinsulinemic–euglycemic clamp) improved significantly (P<0.05). Despite these metabolic improvements, no changes were observed in VLDL–TG secretion, clearance, or oxidation or in palmitate kinetics.ConclusionWe conclude that 10 weeks of exercise training did not induce changes in VLDL–TG and palmitate kinetics in healthy lean men.