Postprandial fatty acid trafficking in obese women after either endurance or resistance exercise

Abstract

We investigated effects of two exercise modalities on postprandial triglyceride (TG) and free fatty acid (FFA) metabolism. Sedentary, obese women were studied on 3 occasions in randomized order: Endurance exercise for 60 min at 65% VO2peak (E), ~60 min high‐intensity resistance exercise (R), and a sedentary control (C). A liquid mixed meal (48% CHO, 36% Fat, 16% Protein) containing [U‐13C]palmitate was consumed 30 min after exercise and subjects were studied over 7 hours. Content and isotopic enrichment of plasma TG and FFA were measured by mass spectrometry. Labeled fatty acids were inferred to be of exogenous (dietary) origin and unlabeled inferred to be endogenous. Total and endogenous plasma TG content were significantly reduced in both E and R compared to C (P < 0.05) with no effect of exercise on circulating exogenous TG content. Exogenous plasma FFA content was significantly increased following both E and R compared with C (P < 0.05), while total and endogenous FFA were elevated only in E (P < 0.05) compared with C. The results reflect integration of TG and FFA metabolism following E and R exercise. The present results indicate that R and E may be equally effective in reducing plasma TG level, and this reduction in postprandial lipemia is not achieved by enhanced clearance of dietary fat, but rather is achieved by reduced circulating abundance of endogenously produced TG.Funding: Busch Biomedical Foundation