This study has been designed to investigate, in five non-insulin-dependent diabetic patients, the influence of physical training (1 h a day, 7 days a wk for 6 wk, at 50-60% maximum oxygen uptake) on blood glucose control, glucose tolerance, insulin secretion, and insulin action. Physical training resulted in a significant improvement in blood glucose control, glucose tolerance, and insulin action. These results suggest that short-term intense physical training ameliorates the main metabolic derangements of non-insulin-dependent diabetes mellitus.