Muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion

J Appl Physiol (1985). 1988 Apr;64(4):1480-5. doi: 10.1152/jappl.1988.64.4.1480.


The time of ingestion of a carbohydrate supplement on muscle glycogen storage postexercise was examined. Twelve male cyclists exercised continuously for 70 min on a cycle ergometer at 68% VO2max, interrupted by six 2-min intervals at 88% VO2max, on two separate occasions. A 25% carbohydrate solution (2 g/kg body wt) was ingested immediately postexercise (P-EX) or 2 h postexercise (2P-EX). Muscle biopsies were taken from the vastus lateralis at 0, 2, and 4 h postexercise. Blood samples were obtained from an antecubital vein before and during exercise and at specific times after exercise. Muscle glycogen immediately postexercise was not significantly different for the P-EX and 2P-EX treatments. During the first 2 h postexercise, the rate of muscle glycogen storage was 7.7 mumol.g wet wt-1.h-1 for the P-EX treatment, but only 2.5 mumol.g wet wt-1.h-1 for the 2P-EX treatment. During the second 2 h of recovery, the rate of glycogen storage slowed to 4.3 mumol.g wet wt-1.h-1 during treatment P-EX but increased to 4.1 mumol.g wet wt-1.h-1 during treatment 2P-EX. This rate, however, was still 45% slower (P less than 0.05) than that for the P-EX treatment during the first 2 h of recovery. This slower rate of glycogen storage occurred despite significantly elevated plasma glucose and insulin levels. The results suggest that delaying the ingestion of a carbohydrate supplement post-exercise will result in a reduced rate of muscle glycogen storage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Dietary Carbohydrates*
  • Fatty Acids, Nonesterified / blood
  • Glycogen / biosynthesis*
  • Glycogen Synthase / metabolism
  • Humans
  • Insulin / blood
  • Kinetics
  • Male
  • Muscles / metabolism*
  • Physical Exertion*
  • Time Factors


  • Blood Glucose
  • Dietary Carbohydrates
  • Fatty Acids, Nonesterified
  • Insulin
  • Glycogen
  • Glycogen Synthase