Improvement of Glucose Homeostasis After Exercise Training in Non-insulin-dependent Diabetes

Six obese patients with recent-onset, non-insulin-dependent diabetes underwent assessment of glucose tolerance, insulin secretory capacity, and insulin-induced glucose disposal before and after 6–10 wk of intensive aerobic training while maintaining body weight. Fasting plasma glucose declined in every subject (average = −33 mg/dl), and oral glucose tolerance (3 h integrated plasma glucose) improved in five of the six (average = −74 mg × 3 h/dl) after training. Individual improvement in control of plasma glucose was directly proportional to degree of hyperglycemia before training and correlated well with an observed improvement in the early (30-min) plasma insulin response to oral glucose (all six subjects). The response of insulin action to training was highly variable; although the observed increase in average insulin-induced glucose disposal rate (M) during the euglycemic clamp did not reach statistical significance in our small cohort, the relative change in M was directly related to reduction in fasting insulin levels after training. Our results show that regular endurance exercise is effective in improving glucose homeostasis and may serve as an adjunct to other modes of treatment in recent-onset, non-insulin-dependent diabetic individuals.