Effects of prior moderate exercise on exogenous and endogenous lipid metabolism and plasma factor VII activity

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.