Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis

Although the importance of postexercise nutrient ingestion timing has been investigated for glycogen metabolism, little is known about similar effects for protein dynamics. Each subject (n = 10) was studied twice, with the sa me oral supplement (10 g protein, 8 g carbohydrate, 3 g fat) being administ ered either immediately (EARLY) or 3 h (LATE) after 60 min of moderate-inte nsity exercise. Leg blood flow and circulating concentrations of glucose, a mino acids, and insulin were similar for EARLY and LATE. Leg glucose uptake and whole body glucose utilization (D-[6,6-H-2(2)]glucose) were stimulated threefold and 44%, respectively, for EARLY vs. LATE. Although essential an d nonessential amino acids were taken up by the leg in EARLY, they were rel eased in LATE. Although proteolysis was unaffected, leg (L-[ring-H-2(5)] ph enylalanine) and whole body (L-[1-C-13]leucine) protein synthesis were elev ated threefold and 12%, respectively, for EARLY vs. LATE, resulting in a ne t gain of leg and whole body protein. Therefore, similar to carbohydrate ho meostasis, EARLY postexercise ingestion of a nutrient supplement enhances a ccretion of whole body and leg protein, suggesting a common mechanism of ex ercise-induced insulin action.