Effects of High-Intensity Interval Training Versus Moderate-Intensity Continuous Training On Blood Pressure in Adults with Pre- to Established Hypertension: A Systematic Review and Meta-Analysis of Randomized Trials.

Background: Aerobic exercise reduces blood pressure (BP), but it is unknown whether a high-intensity training approach can elicit a greater BP reduction in populations with elevated BP. This systematic review compared the efficacy of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) for reducing BP in adults with pre- to established hypertension.

Methods: Five electronic databases (MEDLINE, EMBASE, CENTRAL, PEDro, and SPORTDiscus) were searched for randomized trials comparing the chronic effects of HIIT versus MICT on BP in individuals with resting systolic BP ≥ 130 mmHg and/or diastolic BP ≥ 85 mmHg and/or under antihypertensive medication. Random-effects modelling was used to compare changes from pre- to post-intervention in resting and ambulatory BP between HIIT and MICT. Changes from pre- to post-intervention in maximal oxygen uptake ([Formula: see text]O) between HIIT and MICT were also meta-analyzed. Data were reported as weighted mean difference (MD) and 95% confidence interval (CI).

Results: Ambulatory BP was excluded from the meta-analysis due to the limited number of studies (two studies). Comparing changes from pre- to post-intervention, no differences in resting systolic BP (MD - 0.22 mmHg [CI 95%, - 5.36 to 4.92], p = 0.93, I = 53%) and diastolic BP (MD - 0.38 mmHg [CI 95%, - 3.31 to 2.54], p = 0.74, I = 0%) were found between HIIT and MICT (seven studies; 164 participants). HIIT improved [Formula: see text]O to a greater magnitude than MICT (MD 2.13 ml/kg/min [CI 95%, 1.00 to 3.27], p < 0.01, I = 41%) with similar completion rates of the intervention and attendance at the exercise training sessions (nine studies; 245 participants). Limited data were available to compare the incidence of adverse events between HIIT and MICT.

Conclusion: HIIT and MICT provided comparable reductions in resting BP in adults with pre- to established hypertension. HIIT was associated with greater improvements in [Formula: see text]O when compared to MICT. Future randomized trials should investigate the efficacy of HIIT versus MICT for reducing ambulatory BP in adults with pre- to established hypertension.

Registration: PROSPERO registration (2016: CRD42016041885).