Effects of physical activity on insulin action and glucose tolerance in obesity.

The purpose of this paper is to examine the effect of physical activity on glucose tolerance in relation to obesity. We reviewed current literature, with particular emphasis on randomized clinical trials, to prepare an evidence-based evaluation of the effects of physical activity on glucose intolerance in obesity. This literature review indicates that physical activity has favorable effects on reducing insulin resistance in obesity and among patients with type 2 diabetes mellitus. Improvement in glucose tolerance is less consistently observed and is related to intensity of exercise, collateral changes in adiposity, the interval between exercise and testing of glucose tolerance, and the baseline severity of glucose intolerance. A review of currently published clinical trial data supports the conclusion that physical activity can reduce insulin resistance and improve glucose intolerance in obesity.