Effect of the Low or High Volume of High- Intensity Interval Training Protocols on the Leptin and Lipid Profile in Men with Type 2 Diabetes

Introduction: Sport activity leads to metabolic and physiological adaptations, which may have a beneficial role for diabetic patients. The purpose of this study was to compare the effects of low volume and high volume high-intensity interval training (HIIT) on serum leptin and some of the lipid profiles of type 2 diabetic men. Methods: In this randomized clinical trial, 30 males with type 2 diabetes mellitus were divided into three groups of 10, including low volume and high volume HIIT and control groups. The low volume groups underwent intensive training for up to two minutes and a high volume group up to six minutes for 8 weeks. Blood lipid profile indicators were measured before and 48 hours after the last exercise session. By using SPSS version 25, the paired t-test, ANOVA, ANCOVA and LSD as a post hoc test were used to analyze the data. For all analysis α=0.05 was considered as the level of statistical significance. Results: There was a significant difference before and after 8 weeks of lowvolume HIIT training at triglyceride (p = 0.049). However, there was no significant difference in serum leptin, cholesterol, LDL-C, and HDL-C in men with type 2 diabetes (p>0.05). ANCOVA only found a differences between groups on BMI (F2, 26 = 3.61, p = 0.041). Also, the post hoc in two by two comparisons of HDL showed that there was a significant difference between high volume HIIT and control groups (p = 0.021) and low volume and control group (p = 0.011). The HDL-C levels in HIIT training groups increased significantly compared to controls. Discussion: Considering other proven adaptations of HIIT training on triglyceride, HDL and improving glycemic indexes is a useful and safe training for type 2 diabetic patients. Therefore, needing a very short time for this training, metabolic, functional and physiological adaptations of HIIT training, along with other exercises are recommended to improve the condition and reduce the risk of cardiovascular disease and complications of type 2 diabetes.