Jmr. Gill et al., Effects of prior moderate exercise on exogenous and endogenous lipid metabolism and plasma factor VII activity, CLIN SCI, 100(5), 2001, pp. 517-527
Moderate exercise reduces postprandial triacylglycerol concentrations, whic
h are a risk marker for coronary heart disease. The present study sought to
determine the qualitative nature of exercise-induced changes in lipid meta
bolism and their association (if any) with changes in factor VII activation
. Eleven normotriglyceridaemic men, aged 51.7 +/- 6.1 years (mean +/- S.D.)
, participated in two oral fat tolerance tests after different pre-conditio
ns: control (no exercise), and exercise (90 min of brisk walking the day be
fore). Venous blood samples were obtained in the fasted state and for 8 h a
fter ingestion of a high-fat meal (1.32 g of fat, 1.36 g of carbohydrate, 0
.30 g of protein and 10 mg of [1,1,1-C-13] tripalmitin kg(-1) body mass). P
rior exercise reduced postprandial plasma triacylglycerol concentrations by
25 +/- 3% (mean +/- S.E.M.), with lower concentrations in the Svedberg flo
tation rate (Sf) 20-400 (very-low-density lipoprotein) fraction accounting
for 79 +/- 10% of this reduction. There was no effect on plasma factor VII
coagulant activity or on the concentration of the active form of factor Vil
a. Prior exercise increased postprandial serum 3-hydroxybutyrate and plasma
fatty acid concentrations, decreased serum postprandial insulin concentrat
ions and increased exogenous (8 h C-13 breath excretion of 15.1 +/- 0.9% of
ingested dose compared with 1 1.9 +/- 0.8%; P = 0.00001) and endogenous po
stprandial fat oxidation. These data raise the possibility that reduced hep
atic secretion of very-low-density lipoprotein plays a role in the attenuat
ion of plasma triacylglycerol concentrations seen after exercise, although
it is possible that increased triacylglycerol clearance also contributes to
this effect.