Background Moderate intensity exercise reduces postprandial triacylglycerol
(TG) concentrations. We tested whether this reflects increased TG clearanc
e.
Materials and methods Eight normotriglyceridaemic men, aged 48.3 +/- 7.3 ye
ars (mean +/- SD), performed two oral fat tolerance tests (blood samples ta
ken 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) an
d two intravenous fat tolerance tests (blood samples in the fasted state an
d after a bolus injection of Intralipid, 0.1 g fat kg(-1) body mass). The a
fternoon 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 or
al (16 +/- 7 %) (mean +/- SEM) and intravenous (18 +/- 7 %) tests, and redu
ced postprandial TG concentrations in the oral test by 18 +/- 6 % (all P <
0.05). However, prior exercise did not increase Intralipid clearance (disap
pearance 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 clea
rance mediate the lower postprandial TG concentrations seen after moderate
exercise.