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

Am J Physiol Endocrinol Metab. 2001 Jun;280(6):E982-93. doi: 10.1152/ajpendo.2001.280.6.E982.


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 same oral supplement (10 g protein, 8 g carbohydrate, 3 g fat) being administered either immediately (EARLY) or 3 h (LATE) after 60 min of moderate-intensity exercise. Leg blood flow and circulating concentrations of glucose, amino acids, and insulin were similar for EARLY and LATE. Leg glucose uptake and whole body glucose utilization (D-[6,6-2H(2)]glucose) were stimulated threefold and 44%, respectively, for EARLY vs. LATE. Although essential and nonessential amino acids were taken up by the leg in EARLY, they were released in LATE. Although proteolysis was unaffected, leg (L-[ring-2H(5)]phenylalanine) and whole body (L-[1-13C]leucine) protein synthesis were elevated threefold and 12%, respectively, for EARLY vs. LATE, resulting in a net gain of leg and whole body protein. Therefore, similar to carbohydrate homeostasis, EARLY postexercise ingestion of a nutrient supplement enhances accretion of whole body and leg protein, suggesting a common mechanism of exercise-induced insulin action.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amino Acids / blood
  • Amino Acids / pharmacokinetics
  • Blood Glucose
  • Dietary Carbohydrates / pharmacokinetics
  • Dietary Proteins / pharmacokinetics*
  • Eating / physiology*
  • Energy Metabolism / physiology
  • Female
  • Glucose / pharmacokinetics*
  • Glycerol / blood
  • Homeostasis / physiology*
  • Humans
  • Insulin / blood
  • Leg
  • Male
  • Muscle Proteins / metabolism
  • Muscle, Skeletal / metabolism
  • Nutritional Requirements
  • Physical Exertion / physiology*
  • Time Factors


  • Amino Acids
  • Blood Glucose
  • Dietary Carbohydrates
  • Dietary Proteins
  • Insulin
  • Muscle Proteins
  • Glucose
  • Glycerol