Occurrence of Diabetic Type of Plasma Ffa and Glycerol Responses to Physical Exercise in Prediabetic Subjects

The mobilization of glycerol and free fatty acids (FFA) from fat stores during physical exercise has been studied in 6 patients with insulin‐dependent diabetes, 3 with diabetes in clinical remission, 10 with prediabetes and in 11 healthy control subjects. They were all submitted to the same relative exercise test calculated as about 60% of the maximal capacity. All subjects with manifest diabetes, 4 of the prediabetics and one of the diabetics in remission, but none of the controls, demonstrated exaggerated increases in plasma glycerol and FFA during the exercise test. There were no consistent differences between the groups as regards the changes in glucose, insulin and growth hormone (GH) in plasma during exercise. The findings of elevated plasma glycerol and FFA could not be attributed to subnormal increase in the lactate levels during exercise. A possible explanation of the increased lipolytic response might be that in certain prediabetics the diminished insulin response to hyperglycemia results in decreased antilipolytic capacity of adipose tissue. The increased lipid mobilization in some of the prediabetics seems to add another feature to this phase of diabetes.