The impact of two different aerobic exercise intensities on cardiometabolic parameters in type 2 diabetic patients: A randomized trial

Background: Regular exercise significantly reduces cardiovascular risk and helps prevent primary and secondary cardiac events. However, the mechanisms through which exercise affects cardiovascular health remain unclear. This study investigates the acute effects of high-intensity interval training (HIIT) versus moderate-intensity continuous exercise (MOD) on endothelial function and glycemic control in patients with type 2 diabetes (T2D). Objectives: The study aimed to compare the acute effects of a single session of HIIT and MOD on endothelial function, hemodynamic parameters, and blood glucose levels in T2D patients. Design: This was a randomized controlled trial (RCT). Setting: Conducted at the Laboratory of Cardiopulmonary Rehabilitation. Participants: Fifty-seven sedentary patients with type 2 diabetes (39 women and 18 men) participated in the study. Methods: Participants were randomly assigned to either HIIT (10 sprints of 30 s at 85-100% of maximum heart rate, with 1-min active pauses) or MOD (continuous exercise at 60-70% of maximum heart rate for 30 min). Brachial artery flow-mediated dilation (%FMD) and blood glucose levels were measured before and immediately after the sessions. Results: HIIT significantly increased %FMD (9.3 +/- 5.3% vs 20.05 +/- 9.3%, p < 0.01) and reduced glucose levels (189 [106-335] mg/dL vs 149 [70-448] mg/dL, p < 0.01). Although MOD also showed positive responses, HIIT yielded more pronounced improvements in endothelial function. Conclusion: HIIT is more effective for cardiovascular protection than MOD, although both exercises improve glycemic control in T2D patients. Higher %FMD is associated with better physical capacity and heart rate recovery, indicating a favorable prognosis.