Potentiation of the thermic effect of insulin by exercise: differences between lean, obese, and noninsulin-dependent...

We studied the effects of prior high-intensity cycle exercise (85% VO2 max) on total energy expenditure (EE) and the thermic effect of insulin (TEI) in normal controls and in obese insulin-resistant and noninsulin-dependent diabetic (NIDDM) subjects. Normal controls, but not obese or NIDDM subjects, showed a significant increase (3-7%) in total EE 12-16 h after exercise (p less than 0.05). Prior exercise increased lipid and decreased glucose oxidation in all groups. During low-dose insulin infusion (40 mU X M2 X min), prior exercise potentiated TEI in control and NIDDM subjects (p less than 0.05), whereas obese subjects showed no response. During high-dose insulin infusion (400 mU X M2 X min), TEI was similar in NIDDM and control subjects but was significantly less in the obese group. In this study, we found a positive correlation between TEI and insulin-stimulated rates of glucose disposal (r = 0.91, p less than 0.001). The predicted cost of glucose storage accounted for 42% of TEI.