Key result
Moderate-intensity continuous training acutely increases peripheral arterial stiffness by ~0.35 m/s vs HIIT.
Why the study?
The acute effects of high-intensity interval training versus moderate-intensity continuous training on central and peripheral arterial stiffness and vascular reactivity in healthy adults were compared.
Does high-intensity interval training (HIIT) compared to moderate-intensity continuous training (MICT) differentially affect acute central and peripheral arterial stiffness and vascular reactivity in healthy young adults?
RCT (n=16)
Randomized crossover
No
Does high-intensity interval training (HIIT) compared to moderate-intensity continuous training (MICT) differentially affect acute central and peripheral arterial stiffness and vascular reactivity in healthy young adults?
Mean Difference: 0.35
Absolute Event Rate: 0.35% vs -0.09%
p-value: p=0.024
Moderate-intensity continuous training acutely increases peripheral arterial stiffness compared to high-intensity interval training, highlighting segment-specific vascular responses to different exercise intensities.
Acute vascular responses to HIIT versus MICT in healthy adults remain inconclusive; hypothesis-generating for clinical populations.
Purpose To assess and compare the acute effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on central and peripheral arterial stiffness, as well as endothelial and microvascular reactivity in healthy, physically active adults. Methods Sixteen healthy young adults (8 M/8F; age: 24 ± 3 yrs) completed a randomized crossover trial consisting of two cycling exercise protocols: HIIT (4 × 4 min at 100–105% respiratory compensation point (RCP) power) and MICT (30 min at 65% RCP power). Arterial stiffness was assessed via carotid-femoral pulse wave velocity (cfPWV) and brachial-radial pulse wave velocity (brPWV). Flow-mediated slowing (FMS) and microvascular reactivity following a vascular occlusion test were used for determination of vascular reactivity. All measurements were taken within 5–15 min following exercise cessation. Results A significant time-by-condition interaction was observed for brPWV (F = 7.08, p = 0.024), revealing a significant increase following MICT whereas no significant change was observed following HIIT (MD = 0.35 m/s). There were no interactions regarding cfPWV, although a trend towards increased cfPWV following both conditions was observed (F = 3.42, p = 0.086), as well as mean arterial pressure (F = 4.03, p = 0.063). No significant changes were observed for FMS or microvascular reactivity. Conclusion These findings demonstrate a differential acute vascular response to exercise intensity. MICT elicited a significant increase in brPWV following MICT, while no change was observed following HIIT. Central arterial stiffness response does not seem to be mediated by exercise intensity. These distinct, segment-specific responses highlight the importance of assessing both central and peripheral vascular compartments when evaluating the acute impact of aerobic exercise. Trial registration number (clinical trials) NCT07048509.
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Iskra et al. (2026) conducted an RCT in Healthy, physically active adults (n=16). Moderate-intensity continuous training (MICT) vs. High-intensity interval training (HIIT) was evaluated on Brachial-radial pulse wave velocity (brPWV) (MD 0.35, p=0.024). Moderate-intensity continuous training elicited a significant acute increase in peripheral arterial stiffness (brPWV mean difference 0.35 m/s) compared to high-intensity interval training.
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