Title

Effects of chromium supplementation on glycogen synthesis after high-intensity exercise

Document Type

Journal Article

Publisher

Lippincott Williams and Wilkins

Faculty

Computing, Health and Science

School

Exercise, Biomedical and Health Science, Centre for Alzheimer's Disease

RAS ID

4277

Comments

This article was originally published as: Volek, J. S., Silvestre, R., Kirwan, J. P., Sharman, M. J., Judelson, D. A., Spiering, B. A., ... & Kraemer, W. J. (2006). Effects of chromium supplementation on glycogen synthesis after high-intensity exercise. Medicine and science in sports and exercise, 38(12), 2102. Original available here

Abstract

Purpose: Chromium enhances insulin signaling and insulin-mediated glucose uptake in cultured cells. We investigated the effect of chromium on glycogen synthesis and insulin signaling in humans. Methods: Sixteen overweight men (BMI = 31.1 +/- 3.0 kg.m) were randomly assigned to supplement with 600 microg.d chromium as picolinate (Cr; N = 8) or a placebo (Pl; N = 8). After 4 wk of supplementation, subjects performed a supramaximal bout of cycling exercise to deplete muscle glycogen, which was followed by high-glycemic carbohydrate feedings for the next 24 h. Muscle biopsies were obtained at rest, immediately after exercise, and 2 and 24 h after exercise. Results: Elevations in glucose and insulin during recovery were not different, but the lactate response was significantly higher in Cr. There was a significant depletion in glycogen immediately after exercise, an increase at 2 h, and a further increase above rest at 24 h (P < 0.05). The rate of glycogen synthesis during the 2 h after exercise was not different between groups (Cr: 25.8 +/- 8.0 and Pl: 17.1 +/- 4.7 mmol.kg.h). Glycogen synthase activity was significantly increased immediately after exercise in both groups. Muscle phosphatidylinositol 3-kinase (PI 3-kinase) activity decreased immediately after exercise and increased at 2 h (P < 0.05), with a trend for a lower PI 3-kinase response in Cr (P = 0.08). Conclusions: Chromium supplementation did not augment glycogen synthesis during recovery from high-intensity exercise and high-carbohydrate feeding, although there was a trend for lower PI 3-kinase activity.

DOI

10.1249/01.mss.0000235353.09061.54

 

Link to publisher version (DOI)

10.1249/01.mss.0000235353.09061.54