Acute effects of high-intensity interval exercise and moderate-intensity continuous training on arterial stiffness and endothelial function in hypertension: A crossover trial

Hypertension contributes to endothelial dysfunction and arterial stiffness, elevating cardiovascular disease risk. While moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) have demonstrated long-term benefits for these vascular conditions, their acute effects on hypertensive patients are unclear. Thirty participants with essential hypertension completed a baseline testing session, followed by a HIIT session (10 × 1 min at 90% VO_2peak) and then a MICT session of equal energy (32 min at 65% VO_2peak) after a 1-week washout (no exercise). Measurements were taken at baseline, immediately postexercise, 5 min post-exercise, and 24 h post-exercise. The primary outcome was flow-mediated dilation (FMD), with secondary outcomes including the arterial basal internal diameter, peak diameter, systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR), wall shear stress, brachial‒ankle pulse wave velocity (baPWV), and the ankle‒brachial index (ABI). A total of 30 hypertensive participants (16 males, 14 females; mean age 54 ± 4 years) were included. Significant intervention-specific effects were observed: MICT acutely increased both the arterial basal diameter (4.58 to 4.84 mm, P = 0.036) and peak diameter (4.77 to 5.05 mm, P = 0.025), whereas HIIT induced no significant changes. HIIT provoked a greater immediate increase in SBP (159 ± 9 vs 156 ± 9 mmHg; P < 0.001) and increased PP (64 to 70 mmHg, P < 0.001) than did MICT, in contrast to the reduction in MICT in the PP after 5 min. The immediate postexercise HR increase was significantly greater after HIIT than after MICT (105 ± 9 bpm vs. 101 ± 9 bpm; P < 0.001). BaPWV decreased after MICT (17.56 to 15.75 m/s, P < 0.001) but remained unchanged after HIIT (P > 0.05). No differential effects were found for wall shear stress, FMD or ABI (P > 0.05) between HIIT and MICT. Both types of exercise led to an immediate increase in SBP postexercise, but MICT decreased at 5 min. MICT was more effective in reducing arterial stiffness and improving vasodilation, with its impact on arterial stiffness lasting up to 24 h. The acute reduction in vascular stiffness following MICT may prioritize its use for hypertensive patients requiring immediate hemodynamic stabilization.