Short-term effects of exercise on plasma very low density lipoproteins (VLDL) and fatty acids

Purpose: In the fasted state the lipid fuels for muscle metabolism are free fatty acids (FFA) released either from intramuscular triglycerides (TG), p lasma albumin, or TG in circulating very low density lipoproteins (VLDL). T he purposes of this study were. to determine the influence of acute exercis e of moderate intensity on 1) plasma total concentration of TG and VLDL com ponents, 2) the plasma concentration and distribution of individual albumin -bound long-chain FFA, and 3) lipid peroxidation as measured by thiobarbitu ric acid reactive substances (TBARS). Methods: Eight healthy male subjects each participated in one exercise (EX) and one rest (RE) experiment. In EX the subjects exercised for 90 min at 58 +/- 5% (mean +/- SD) of maximal O-2 uptake on a cycle ergometer followed by 4.5 h bedrest. RE followed the sam e protocol, but without exercise. Results: In EX there was no immediate cha nge in VLDL concentration during the exercise. After exercise there was a d ecrease in VLDL, VLDL-TG, -cholesterol, -protein and -phospholipids compare d with those after RE. There was no change in percentage composition of VLD L as result of exercise. Total plasma FFA concentration increased appreciab ly during exercise and remained elevated for several hours postexercise. Th ere was no correlation between the change in FFA concentration and VLDL-TG. There was a:significant positive correlation between the exercise-related increments in the various long-chain FFA, but the effect varied so that the relative abundance of oleic acid increased and that of stearic and arachid onic acid decreased during exercise. Plasma TBARS concentration increased d uring the day in both experiments. Conclusion: The results indicate that th ere is a delay in the effect of an exercise bout on plasma VLDL and confirm that exercise affects various FFA in plasma differentially.