Skip Navigation LinksHome > March 2006 - Volume 38 - Issue 3 > Exercise-Induced Changes in Insulin Action and Glycogen Meta...
Medicine & Science in Sports & Exercise:
doi: 10.1249/01.mss.0000191417.48710.11
CLINICAL SCIENCES: Clinically Relevant

Exercise-Induced Changes in Insulin Action and Glycogen Metabolism in Elderly Adults

COKER, ROBERT H.1; HAYS, NICHOLAS P.1; WILLIAMS, RICK H.1; BROWN, AMY D.1; FREELING, SCOTT A.1; KORTEBEIN, PATRICK M.1; SULLIVAN, DENNIS H.2; STARLING, RAYMOND D.3; EVANS, WILLIAM J.1,2

Collapse Box

Abstract

Purpose: Although data suggest that physical activity is associated with decreased insulin resistance, recommendations for exercise training are not specific for age or level of obesity. Therefore, we examined the influence of moderate-intensity (50% of V̇O2max) exercise training (MI) versus high-intensity (75% of V̇O2max) exercise training (HI) on insulin-stimulated glucose disposal (ISGD) in elderly individuals.

Methods: Following medical examinations, 21 overweight (body mass index = 29 ± 1 kg·m−2) elderly (74 ± 1 yr) subjects were randomized to 1) HI, 2) MI, or a 3) nonexercising control group. Subjects enrolled in HI or MI completed a 12-wk exercise training regimen designed to expend 1000 kcal·wk−1. ISGD was assessed using a hyperinsulinemic, euglycemic clamp pre- and postintervention. ISGD was corrected for hepatic glucose production (glucose Ra) using a constant rate infusion of [6,6-2H2]glucose and determined during the last 30 min of the clamp by subtracting glucose Ra from the exogenous glucose infusion rate. Nonoxidative glucose disposal was calculated using indirect calorimetry. Body composition testing was completed using dual energy x-ray absorptiometry.

Results: ISGD increased by approximately 20% with HI (Δ of 1.4 ± 0.5 mg·kg−1 FFM·min−1). However, ISGD did not change (Δ of −0.4 ± 0.1 mg·kg−1 FFM·min−1) with MI and was not different (Δ of −0.2 ± 0.1 mg·kg−1 FFM·min−1) in the control group. Nonoxidative glucose disposal increased with HI (Δ of 1.4 ± 0.5 mg·kg−1 FFM·min−1), but there was no change in nonoxidative glucose disposal with MI or in the control group. No change in body weight or percentage of body fat was observed in any group.

Conclusion: In weight-stable subjects, MI resulted in no change in ISGD, and the improvement in ISGD with HI was completely reliant on improvements in nonoxidative glucose disposal.

©2006The American College of Sports Medicine

Login

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.

Connect With Us