High‐Intensity Interval Training and Moderate‐Intensity Continuous Training Improve Endothelial Function Similarly in Adults with Type 2 Diabetes

Abstract

Endothelial function is a predictor of cardiovascular disease, the leading cause of death in adults with type 2 diabetes. Aerobic exercise training may preserve or improve endothelial function; however, the optimal exercise prescription remains uncertain. Recently, there has been increasing interest in high‐intensity interval training (HIIT) vs. moderate‐intensity continuous training (MICT). These protocols are most commonly performed on the treadmill which may limit implementation in patients who have lower limb limitations or balance issues. We sought to compare the effect of non‐weight‐bearing all‐extremity HIIT vs. MICT on endothelial function in adults with type 2 diabetes. Forty‐nine sedentary men and postmenopausal women with type 2 diabetes aged 46 to 78 yrs (mean±SE: 63±1 yrs), free of cardiovascular disease, were randomized to HIIT (n=18), MICT (n=16), or non‐exercise control (CONT; n=15). HIIT (4×4‐min intervals at 90% of peak heart rate (HRpeak) interspersed by 3 min recovery bouts at 70% HRpeak) and isocaloric MICT (32 min at 70% of HRpeak) were performed on an Airdyne® all‐extremity ergometer 4 days/week under supervision. Including warm‐up and cool‐down, the total exercise duration per session was 40 min for HIIT and 47 min for MICT. Endothelial function in response to reactive hyperemia was assessed non‐invasively by brachial artery flow‐mediated dilation (FMD) via ultrasonography. Following the 8‐week intervention, FMD increased similarly in HIIT (pre‐ vs. post‐intervention: 3.17±0.62 vs. 4.03±0.71%, P=0.01) and MICT (3.54±0.63 vs. 4.39±0.61%; P=0.02 and P>0.99 for HIIT vs. MICT) while it did not change in CONT (4.02±0.46 vs. 3.74±0.51%, P=0.4). The improvement in FMD was not confounded by changes in brachial baseline diameter, hyperemic shear rate, or systolic and diastolic blood pressure (P≥0.3). In conclusion, all‐extremity HIIT and MICT similarly improve endothelial function in adults with type 2 diabetes which suggests that all‐extremity MICT is an effective alternative for those who are unable or unwilling to engage in all‐extremity HIIT.Support or Funding InformationThis work was supported by National Institute of Aging grant AG050203 to DDC.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.