Effects of High-Intensity Interval Training on Cardiorespiratory Fitness in Patients with Stroke: A Meta-Analysis

BACKGROUND: Stroke survivors typically exhibit impaired cardiorespiratory fitness (CRF) and walking ability, which hinder their recovery and independence. High-intensity interval training (HIIT) has been proposed as a time-efficient strategy, but its efficacy and safety remain limited. METHODS: We conducted a systematic review and meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. MEDLINE, EMBASE, Web of Science, and Cochrane CENTRAL were searched (January 2025?July 2025) for randomized controlled trials (RCTs) comparing HIIT with low- to moderate-intensity training or conventional rehabilitation in stroke survivors. The primary outcomes were CRF and walking ability, and subgroup analyses were conducted for patient characteristics and intervention dose. RESULTS: Eleven randomized controlled trials (551 participants) of moderate-to-high quality were included. Compared with conventional rehabilitation, HIIT significantly improved CRF (MD 3.12 mL/kg/min; 95% CI 2.15?4.09; I2 = 85%) and walking ability (MD 0.11 m/s; 95% CI 0.03?0.19; I2 = 77%); these values exceeded clinically meaningful thresholds. Subgroup analyses indicated greater improvements in CRF among middle-aged participants (? 60 years; MD 4.18 mL/kg/min), and the benefits were consistent across stroke severity and chronicity. Although intervention times exceeding 20 minutes provided additional gains, no significant differences were observed in terms of intervention frequency or program length. CONCLUSIONS: Compared with conventional rehabilitation, HIIT improves cardiorespiratory fitness and walking ability in stroke survivors, thus identifying this approach as an effective and time-efficient strategy.