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 < 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 < 0.05) and insulin (r = −0.37, P < 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.