Physical fitness, insulin secretion, and glucose tolerance in healthy males and mild type-2 diabetes.

The nature of the relation between physical fitness and glucose homeostasis was evaluated in two studies: (A) a cross-sectional study on 108 middle-aged non-diabetic men; (B) a five-month training program involving nine males with non-insulin-dependent (type 2) diabetes. It was found that the level of physical fitness was positively related to glucose tolerance, and that this relation was largely independent of body weight and basal insulin secretion. Furthermore, the training program for the diabetics resulted in improved glucose tolerance without change in either body weight or glucose-induced insulin secretion. It is concluded that glucose balance is significantly influenced by the physical fitness level, which is likely to be an important element in the pathogenesis of type 2 diabetes as well as in the treatment of that disease.