Effect of exercise on glucose metabolism in postmenopausal women

A cross-sectional study was conducted to examine the effect of treadmill and muscle resistance training on glucose tolerance and insulin levels in a group of 25 normal-weight, naturally menopausal women. Subjects trained 20 minutes three times per week for at least 6 months to 70% to 85% of maximum heart rate on a treadmill, or to maximum effort for all major muscle groups on Nautilus equipment. A nonexercising age-height-weight--matched group was monitored as a control. All three groups were of above-average fitness for age as measured by aerobic capacity during initial testing. The treadmill group significantly increased its maximal oxygen uptake over the training period. Glucose tolerance and insulin response, measured as areas under the curve after a 75 gm oral glucose load, were improved in both exercise groups compared with controls, with more marked improvement in the treadmill group. The only difference achieving statistical significance was the insulin levels 30 minutes or less after glucose ingestion, representing the first phase of insulin release. Long-term exercise training that increases aerobic power thus maintains normoglycemia with lower insulin values than in otherwise physically fit postmenopausal women.