Portal de Periódicos da CAPES

Effects of Exercise Training on Glucose Homeostasis

2005; American Diabetes Association; Volume: 28; Issue: 1 Linguagem: Inglês

10.2337/diacare.28.1.108

1935-5548

Normand G. Boulé, S. John Weisnagel, Timo A. Lakka, Angelo Tremblay, Richard N. Bergman, Tuomo Rankinen, Arthur S. Leon, James S. Skinner, Jack H. Wilmore, D. C. Rao, Claude Bouchard,

Adipose Tissue and Metabolism

OBJECTIVE—To determine the effect of a 20-week endurance training program in healthy, previously sedentary participants on measures derived from an intravenous glucose tolerance test (IVGTT). RESEARCH DESIGN AND METHODS—An IVGTT was performed before and after a standardized training program in 316 women and 280 men (173 blacks and 423 whites). Participants exercised on cycle ergometers 3 days per week for 60 sessions. The exercise intensity was progressively increased from 55% Vo2max for 30 min per session to 75% Vo2max for 50 min per session. RESULTS—Mean insulin sensitivity increased by 10% (P < 0.001) following the intervention, but the variability in the changes was high. Men had larger improvements than women (P = 0.02). Improvements in fasting insulin were transitory, disappearing 72 h after the last bout of exercise. There were also significant mean increases in the glucose disappearance index (3%, P = 0.02) and in glucose effectiveness (11%, P < 0.001), measures of glucose tolerance and of the capacity of glucose to mediate its own disposal, respectively. The acute insulin response to glucose, a measure of insulin secretion, increased by 7% in the quartile with the lowest baseline glucose tolerance and decreased by 14% in the quartile with the highest baseline glucose tolerance (P < 0.001). The glucose area below fasting levels during the IVGTT was reduced by 7% (P = 0.02). CONCLUSIONS—Although the effects of structured regular exercise were highly variable, there were improvements in virtually all IVGTT-derived variables. In the absence of substantial weight loss, regular exercise is required for sustained improvements in glucose homeostasis.