Effectiveness of high-intensity interval training versus moderate-intensity continuous training on endothelial function of arteries in type-2 diabetes patients; a randomized double blind clinical trial

Background: Obesity, characterized with hypertrophy and hyperplasia of adipocytes, is a pro- Background: Considering the importance of exercise intensity in training, the present study aimed to compare the effect of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on endothelial function of arteries in type-2 diabetes patients.Methods: In the present randomized double blind parallel clinical trial, 36 T2D patients were allocated to 3 groups of control (without regular training), MICT, and HIIT. Anthropometric indices, Biochemical evaluation, peak oxygen consumption (VO2peak), resting NOx, and resting ET-1, and insulin resistance index was calculated using homeostatic model assessment (HOMA-IR) method were measured and compared.Results: Both MICT and HIIT reduced haemoglobin A1c [F (2, 33) = 80.2; p < 0.0001], insulin [F (2, 33) = 57.7; p < 0.0001], and HOMA-IR [F (2, 33) = 99.1; p < 0.0001]. However, the effect of HIIT (p = 0.004) was more than MICT (p < 0.001) in reducing the 3 mentioned factors. Both MICT (p < 0.0001) and HIIT (p = 0.0002) led to a significant increase in NOx [F (2, 33) = 57.7; p < 0.0001] in diabetic patients. This increase was significantly higher in HIIT group group (p < 0.0001). In addition, HIIT intervention caused a significant increase in VO2peak compared to control group (p < 0.0001) and MICT group (p < 0.0001) [F (2, 33) = 59.9; p < 0.0001]. ET-1 level was also reduced after training intervention in both MICT (p = 0.02) and HIIT (p = 0.02) groups compared to control group [F (2, 33) = 5.5; p = 0.009]. Conclusion: HIIT can lead to more improvements in endothelial function and controlling diabetes and lipid profile compared to MICT, by causing more increase in aerobic fitness, more decrease in insulin resistance, and more increase in NOx bioactivity.