Effect of High-Intensity Interval Training on Exercise Capacity, Blood Pressure, and Autonomic Responses in Patients With Hypertension: A Systematic Review and Meta-analysis.

CONTEXT: Despite the well-known positive effects of exercise in hypertensive patients, the best mode of exercise is still under discussion. OBJECTIVE: A systematic review of the literature, synthesizing data on the effects of high-intensity interval training (HIIT) on peak oxygen consumption (VO2 peak), blood pressure (BP), cardiac autonomic modulation, and resting heart rate (HR) in patients with hypertension. DATA SOURCES: MEDLINE (via PubMed), CENTRAL, PEDro database, and SciELO (from the earliest date available to December 31, 2020). STUDY SELECTION: Randomized controlled trials (RCTs) that evaluated the effects of HIIT in hypertensive patients. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: Mean differences (MDs) with a 95% CI were calculated, and heterogeneity was assessed using the I2 test. RESULTS: Nine RCTs encompassing 569 patients met the eligibility criteria and were included in the systematic review. Five trials compared supervised HIIT with moderate-intensity continuous training (MICT) and a control; 1 trial compared HIIT with MICT, and 3 compared HIIT with a control. In comparison with MICT, HIIT improved VO2 peak MD (3.3 mL.kg-1.min-1; 95% CI, 1.4-5.3; N = 130). In comparison with controls, HIIT improved VO2 peak MD (4.4 mL.kg-1.min-1; 95% CI, 2.5-6.2; N = 162). CONCLUSION: Despite the low quality of the evidence, HIIT is superior to MICT in improving VO2 peak in patients with hypertension. HIIT effectively improved VO2 peak, BP, and resting HR when compared with controls. HIIT appears to be safe only when performed in a supervised manner for stage 1 hypertension patients without associated risk factors.