title: A single 1-h bout of evening exercise increases basal FFA flux without affecting VLDL-triglyceride and VLDL-apolipoprotein B-100 kinetics in untrained lean men.
abstract: Our group (Magkos F, Wright DC, Patterson BW, Mohammed BS, Mittendorfer B, Am J Physiol Endocrinol Metab 290: E355-E362, 2006) has recently demonstrated that a single, prolonged bout of moderate-intensity cycling (2 h at 60% of peak oxygen consumption) in the evening increases basal whole-body free fatty acid (FFA) flux and fat oxidation, decreases hepatic VLDL-apolipoprotein B-100 (apoB-100) secretion, and enhances removal efficiency of VLDL-triglyceride (TG) from the circulation the following day in untrained, healthy, lean men. In the present study, we investigated the effect of a single, shorter-duration bout of the same exercise (1 h cycling at 60% of peak oxygen consumption) on basal FFA, VLDL-TG, and VLDL-apoB-100 kinetics in seven untrained, healthy, lean men by using stable isotope-labeled tracer techniques. Basal FFA rate of appearance in plasma and plasma FFA concentration were approximately 55% greater (P < 0.05) the morning after exercise than rest, whereas resting metabolic rate and whole-body substrate oxidation rates were not different after rest and exercise. Exercise had no effect on plasma VLDL-TG and VLDL-apoB-100 concentrations, hepatic VLDL-TG and VLDL-apoB-100 secretion rates, and VLDL-TG and VLDL-apoB-100 plasma clearance rates (all P > 0.05). We conclude that in untrained, healthy, lean men 1) the exercise-induced changes in basal whole-body fat oxidation, VLDL-TG, and VLDL-apoB-100 metabolism during the late phase of recovery from exercise are related to the duration of the exercise bout; 2) single sessions of typical recreational activities appear to have little effect on basal, fasting plasma TG homeostasis; and 3) there is a dissociation between systemic FFA availability and VLDL-TG and VLDL-apoB-100 secretion by the liver.
authors.affiliation: Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Faidon
authors.initials: F
authors.lastname: Magkos
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Patterson
authors.forename: B Selma
authors.initials: BS
authors.lastname: Mohammed
authors.forename: Bettina
authors.initials: B
authors.lastname: Mittendorfer
mesh_terms: D000328:Adult; D053299:Apolipoprotein B-100 / Q000097:blood*; D002940:Circadian Rhythm; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008079:Lipoproteins, VLDL / Q000097:blood*; D008297:Male; D009994:Osmolar Concentration; D010101:Oxygen Consumption; D013851:Thinness / Q000097:blood*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
chemical_list: D053299:Apolipoprotein B-100; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030106:very low density lipoprotein triglyceride