The influence of exercise on postprandial triacylglycerol metabolism.

Trained people exhibit low plasma concentrations of triacylglcyeride (TAG) in both fasted and postprandial states. This mainly reflects enhanced uptake of TAG into skeletal muscle, via enhanced activity of lipoprotein lipase, the rate-limiting step in TAG removal. Endurance athletes possess a large, well-vascularised muscle mass and this may contribute through the increased availability of endothelial binding sites for LPL. However, each session of exercise stimulates a delayed increase in LPL activity so that prior exercise enhances uptake into muscle. Intramuscular TAG is one source of energy for muscular contraction so this may serve to replenish muscle nutrient stores which have been diminished by exercise. Regular, frequent aerobic exercise may oppose the atherogenic disturbances to lipoprotein metabolism evident during the postprandial period. It may also, by favouring the disposition of dietary fatty acids in muscle, improve the matching of fat oxidation to fat intake and hence help with maintenance of a desirable level of body fatness.