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 × 120 min−1 vs. 1,682.98 (266.91) mmol L−1 × 120 min−1] and fasting insulin levels [44.57 (7.58) μU mL−1 vs. 36.14 (3.97) μU 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) μU mL−1 vs. 35.0 (7.15) μU 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.