Effect of High-intensity Interval Training on Endothelial Function in Type 2 Diabetic Females

Background: Flow-mediated dilation (FMD) is a noninvasive approach to examine endothelial function. Objectives: The purpose of this study was to investigate the effect of 12 weeks of high-intensity interval training (HIIT) on FMD and circulating levels of adropin and nitric oxide (NO) in females with type 2 diabetes. Methods: Thirty females with type 2 diabetes were randomly assigned into two equal groups of HIIT and control. The exercise program consisted of three sessions a week for 12 weeks. Each training session included 4 × 4-minute running intervals at 85 - 95% of maximal heart rate (HRmax) with 3-minute active recoveries at 50 - 60% of HRmax. Circulating levels of adropin, NO, glucose, HbA1c, insulin, HOMA-IR, as well as lipid profile, and body composition parameters were measured before and after the intervention. Results: A significant increase of FMD% was observed after the intervention in the HIIT group (P = 0.001). In addition, the circulation levels of adropin and NO enhanced as a result of HIIT (P = 0.012 and P < 0.001, respectively). There were also significant positive effects on the levels of lipid profile (except for HDL), FBS, and HbA1c; as well as on the insulin resistance and the body composition variables. There were no significant changes in the control group except an increase in the total cholesterol levels (P < 0.01). Conclusions: The results showed that 12 weeks of the HIIT program could improve the endothelial function, glucose-related indices, lipid profile, and body composition variables in females with type 2 diabetes.