Moderate exercise, postprandial lipaemia and triacylglycerol clearance

Background Moderate intensity exercise reduces postprandial triacylglycerol (TG) concentrations. We tested whether this reflects increased TG clearance. Materials and methods Eight normotriglyceridaemic men, aged 48.3 +/- 7.3 years (mean +/- SD), performed two oral fat tolerance tests (blood samples taken in the fasted state and for six hours after a high-fat meal containing 1.00 g fat, 0.97 g carbohydrate, 58 kJ energy kg(-1) fat-free body mass) and two intravenous fat tolerance tests (blood samples in the fasted state and after a bolus injection of Intralipid, 0.1 g fat kg(-1) body mass). The afternoon before one oral and one intravenous test, subjects walked briskly for 90 min; no exercise was performed before the control tests. Results Prior exercise reduced fasting TG concentration similarly in the oral (16 +/- 7 %) (mean +/- SEM) and intravenous (18 +/- 7 %) tests, and reduced postprandial TG concentrations in the oral test by 18 +/- 6 % (all P < 0.05). However, prior exercise did not increase Intralipid clearance (disappearance curve slopes: control, 4.69 +/- 0.49 % min(-1); exercise, 4.85 +/- 0.40 % min(-1)). Conclusions These data suggest that mechanisms other than increased TG clearance mediate the lower postprandial TG concentrations seen after moderate exercise.