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

Feng W, Yu WL, Zhao Z, Guo YD, Zhou XJ, Zhai KQ, Liu X, Yan ZW

Question

What are the acute effects of HIIT compared with energy-matched MICT on endothelial function, arterial stiffness, and blood-pressure-related hemodynamics in adults with essential hypertension?

Summary

In 30 adults with essential hypertension, a single treadmill HIIT session and an energy-matched moderate continuous treadmill session were compared in a crossover sequence. The primary endothelial outcome, flow-mediated dilation, did not improve after either session. Moderate continuous exercise produced more favorable acute vascular findings than HIIT, including transient vasodilation and lower brachial-ankle pulse wave velocity lasting to 24 hours, while HIIT produced a larger immediate systolic blood pressure, pulse pressure, and heart rate response.

Methodology

Thirty middle-aged adults with essential hypertension, 16 male and 14 female, with no regular exercise habits in the prior 3 months.
30 participants.
Treadmill running with walking warm-up and cool-down.
Work intervals: 10 x 1 minute at 85-95% HRpeak, approximately 90% VO2peak.
Recovery: 10 x 2 minutes at 60-70% HRpeak.
Intensity: Hard intervals 85-95% HRpeak with Borg RPE target 16-17.
40 minutes including warm-up and cool-down.
Single acute session.
Acute crossover session.
Acute crossover trial comparing one HIIT session with one energy-matched MICT session after a 1-week washout.
Flow-mediated dilation, Brachial-ankle pulse wave velocity, Systolic and diastolic blood pressure, pulse pressure, mean arterial pressure, and Heart rate were tracked.

Outcomes

Flow-mediated dilation

Neither HIIT nor MICT significantly changed FMD, and there were no significant differences between trials.

Time P=0.457; trial P=0.536; time x trial P=0.081.

No clear change

Arterial diameter

MICT increased arterial basal internal diameter at 5 minutes and peak diameter immediately postexercise, while HIIT did not significantly change these measures.

Basal diameter time x trial P=0.028; peak diameter time x trial P=0.019.

Improved

Blood pressure and pulse pressure

Both protocols increased SBP immediately, but MICT reduced SBP by 5 minutes whereas HIIT produced a larger immediate SBP and pulse pressure surge.

SBP time x trial P<0.001; PP time x trial P=0.008.

Mixed

Brachial-ankle pulse wave velocity

MICT reduced baPWV immediately and remained below baseline at 24 hours; HIIT did not significantly change baPWV.

baPWV time x trial P<0.001.

Improved

Ankle-brachial index

ABI did not significantly change after either intervention.

Time P=0.511; trial P=0.413; time x trial P=0.387.

No clear change

Insights

For hypertensive users, HIIT may need more conservative safety framing than moderate continuous exercise because this protocol produced larger immediate SBP, pulse pressure, and HR responses.
A 1-minute hard / 2-minute active recovery treadmill interval structure is reproducible, but its acute vascular results were not favorable relative to MICT in this population.
Moderate continuous exercise may be a better acute option when the goal is immediate vascular stiffness reduction or hemodynamic stabilization.

Limitations

Acute-only study; does not establish chronic training adaptations.
Small clinical sample.
Condition order appears fixed rather than randomized.
High-risk comorbid groups were excluded.
Adherence, enjoyment, and participant experience were not deeply assessed.
Medication discontinuation around testing limits real-world translation.

Safety

Professional medical personnel were present throughout the study to respond to emergencies.
Adverse events during exercise were recorded, but no specific adverse events were reported in the article text.
HIIT produced greater immediate hemodynamic load than MICT in this hypertensive sample.