Effects of a moderate exercise session on postprandial lipoproteins, apolipoproteins and lipoprotein remnants in middle-aged men

Prior moderate exercise reduces postprandial triglyceride concentrations. Its effects on the concentrations, compositions and potential atherogenicity of lipoprotein subfractions were investigated in the present study. Twenty normoglycaemic middle-aged men each underwent two fat tolerance tests (blood taken fasting and for 8 h after a meal containing 80 g fat and 70 g carbohydrate). On the afternoon before one test, subjects performed a 90-min treadmill walk (exercise); no exercise was performed before the control test. Prior exercise significantly reduced postprandial concentrations of chylomicrons (Sf >400) by 28.6% (absolute reduction 14.6 mg dl^-1), of large VLDL₁ (Sf 60-400) by 34.4% (39.7 mg dl^-1) and of small VLDL₂ (Sf 20-60) by 23.0% (9.6 mg dl^-1). Over 95% of VLDL₁ and VLDL₂ comprised apolipoprotein (apo) B100-containing particles. Exercise also reduced postprandial remnant-like lipoprotein cholesterol (by 35%) and triglyceride concentrations (by 29%). Postprandial apo CIII/apo B and apo E/apo B ratios in VLDL₁ were lower following exercise. Postprandial cholesteryl ester/triglyceride ratios were lower in VLDL₁ and VLDL₂ and higher in HDL ₂ following exercise. These data suggest that the effect of prior moderate exercise on VLDL₁ is quantitatively greater than its effect on chylomicrons and that, in addition to reducing lipoprotein concentrations, exercise induces compositional changes to lipoprotein species which are likely to influence their metabolism and atherogenicity.