Resistance-based interval exercise acutely improves endothelial function in type 2 diabetes

Abstract

Different modes of exercise, disease, and training status can modify endothelial shear stress and result in distinct effects on endothelial function. To date, no study has examined the influence of type 2 diabetes (T2D) and training status on the acute endothelial response to different modes of interval exercise (INT). We examined the effect of a single session of resistance- and cardio-based INT compared with a time-matched control on endothelial function in 12 age-matched T2D participants, 12 untrained, and 11 trained adults (aged 56 ± 7 yr). Flow-mediated dilation (%FMD) of the brachial artery was assessed at baseline and immediately, 1, and 2 h after an acute bout of cardio interval (C-INT), resistance interval (R-INT), and seated control (CTL); these interventions were randomized and separated by >2 days. C-INT involved seven 1-min cycling intervals at 85% of peak power with 1-min recovery between. R-INT involved the same pattern of seven 1-min intervals using leg resistance exercises. Endothelial function (%FMD) was improved after R-INT in all groups (Condition × Time interaction, P < 0.01), an effect that was most robust in T2D where %FMD was higher immediately (+4.0 ± 2.8%), 1 h (+2.5 ± 2.5%), and 2 h (+1.9 ± 1.9%) after R-INT compared with CTL (P < 0.01 for all). C-INT improved %FMD in T2D at 1-h postexercise (+1.6 ± 2.2%, P = 0.03) compared with CTL. In conclusion, R-INT acutely improves endothelial function throughout the 2-h postexercise period in T2D patients. The long-term impact of resistance exercise performed in an interval pattern is warranted.

Keywords: HIIT; blood flow; blood pressure; flow-mediated dilation; high-intensity interval exercise; high-intensity interval training; strength training; vascular function.

Fig. 1.

Schematic illustrating the timeline of the experimental trials, including a figure illustrating the cardio-based (C-INT) and resistance-based (R-INT) interval exercise protocols, which were performed in a random order with a sitting-control condition (CTL). Flow-mediated dilation (FMD) and blood pressure (BP) were measured before (Pre), immediately (0), 1, and 2 h after each experimental trial. HR, heart rate.

Fig. 2.

Flow-mediated dilation (%FMD), absolute FMD (mm), and shear rate area under the curve (SRAUC) before, immediately, 1, and 2 h (mean ± SD) after control (CTL), resistance interval exercise (R-INT), and cardio interval exercise C-INT in type 2 diabetes (T2D: A, D, and G), age-matched untrained normoglycemic (UN-NG: B, E, and H), and highly trained normoglycemic (TR-NG: C, F, and I) participants. *P < 0.05, compared with CTL.

Fig. 3.

Baseline mean (lines), antegrade, and retrograde shear rate (s⁻¹; bars) before, immediately, 1, and 2 h after control (CTL), C-INT, and R-INT for T2D (A), UN-NG (B), and TR-NG (C) participants. *P < 0.05, compared with CTL.

Fig. 4.

Mean arterial blood pressure (MAP) and vascular conductance before, immediately, 1, and 2 h after CTL, C-INT, and R-INT in T2D (A and D), age-matched UN-NG (B and E), and TR-NG (C and F) participants. *P < 0.05, compared with CTL.