Improvements in glucose tolerance in obese males with abnormal glucose tolerance following 10 days of aerobic exercise

BACKGROUND: Aerobic exercise training has been shown to produce beneficial changes in glucose tolerance and insulin sensitivity in obese individuals if performed at high enough intensities and/or durations. We examined the effects of a moderate intensity, short-term exercise training protocol on glucose tolerance in obese males with glucose intolerance. METHODS: Fourteen abdominally obese, sedentary males with normal glucose tolerance (NGT; n = 7) and abnormal glucose tolerance (AGT; n = 7) completed 40 min of exercise bouts for 10 consecutive days at approximately 75% of age-predicted maximum heart rate. Fasting glucose and insulin levels, and glucose tolerance and insulin response to glucose were measured before and after the training period. RESULTS: Participants did not experience significant mass loss during the 10-day investigation. Individuals in the AGT group experienced significant (P < 0.05) improvement in glucose tolerance [glucose area: 1,763.67 (255.98) mmol L(-1) x 120 min(-1) vs. 1,682.98 (266.91) mmol L(-1) x 120 min(-1)] and fasting insulin levels [44.57 (7.58) microU mL(-1) vs. 36.14 (3.97) microU mL(-1)] as a result of training. Significant (P < 0.05) reductions in fasting glucose concentrations [5.82 (0.19) mmol L(-1) vs. 5.42 (0.18) mmol L(-1)] and a decrease in fasting insulin concentrations [44.71 (9.39) microU mL(-1) vs. 35.0 (7.15) microU mL(-1); P = 0.064] were observed in the NGT group following the training period. CONCLUSIONS: The data suggest that moderate, short-term exercise without concomitant mass loss is effective in improving glucose tolerance and insulin response to a glucose load in obese males with abnormal glucose tolerance.