DETERMINATION OF MAXIMAL FAT OXIDATION FOR PRESCRIBING EXERCISE IN SEDENTARY NON-OBESE TYPE 2 DIABETES SUBJECTS

Aim: To determine the exercise intensity that elicits the highest fat oxidation rate in sedentary non-obese subjects with type 2 diabetes. Methods: Eleven sedentary subjects with type 2 diabetes (T2DS) and eleven healthy sedentary subjects (HS), aged 45 to 65 and non-obese, were evaluated to a graded exercise test. Oxygen uptake (VO2) and fat oxidation rate (FAT) were detected. FAT was then plotted as a function of exercise intensity, expressed as percentage of VO2max. We determined the exercise intensity (%VO2max) at which fat oxidation was maximal (FATmax). Results: Absolute FATmax was not significantly different between T2DS and HS (0.51  0.13 vs. 0.56  0.29 g∙min-1). FATmax occurred at 69% of VO2max in T2DS, and at 60% of VO2max in HS. A positive linear correlation between FATmax and VO2max in both groups (r = 0.85; p = 0.0009 in T2DS, and r = 0.77; p = 0.006 in HS) has been found. Discussion: In sedentary non-obese T2DS, FATmax occurs at higher exercise intensity than in HS. This result should be taken into account for the accurate exercise prescription. Moreover, the positive linear correlation between FATmax and VO2max suggests that even in T2D subjects the muscle oxidative capacity might increase in response to training aimed to improve VO2max.