Demonstration of a relationship between level of physical training and insulin-stimulated glucose utilization in normal humans.

The relationship between level of physical training and in vivo insulin-stimulated glucose utilization was investigated in 33 healthy nonobese subjects. Status of physical training was estimated by maximal oxygen consumption (VO2 max) during graded bicycle ergometry, and insulin action by the insulin clamp technique. Within the study population we defined a significant (r = 0.63, P less than 0.001) correlation between these two variables. This relationship was independent of age and obesity and accounted for over 40% of the variance in insulin-stimulated glucose utilization among these subjects. In addition, significant correlations existed between VO2 max and the plasma glucose (r = -0.35, P less than 0.05) and insulin (r = -0.37, P less than 0.05) responses to an oral glucose load. These results suggest that differences in level of physical training play a regulatory role in control of in vivo insulin action.