High-intensity interval training improves specific functional and muscle outcomes in patients with COPDHigh intensity training shows specific benefits for COPD patients

BACKGROUND: Chronic Obstructive Pulmonary Disease(COPD) leads to reduced exercise capacity, lung function, and muscle dysfunction, highlighting the need for effective rehabilitation. Exercise is a key component of COPD management. PURPOSE: This study aims to compare the effectiveness of high-intensity interval training (HIIT) and Moderate-Intensity Continuous Training (MICT) on functional capacity, pulmonary function, and muscle performance in individuals with COPD. METHODS: Eight electronic databases were systematically searched from inception to August 2025. Data extraction and quality assessment were independently performed by two reviewers. Methodological quality was assessed using the PEDro scale and the JBI Critical Appraisal Checklist. The risk of bias was evaluated using the Cochrane Collaboration's Tool and the ROBINS-I tool. RESULTS: Twelve studies with 401 participants were included. Seven of the included studies involved patients with GOLD stage III (severe COPD), and five involved patients with GOLD stage II (moderate COPD). HIIT did not demonstrate a statistically significant superiority over MICT in improving lung function parameters ( > .05). The combined mean difference for FEV was 6.84 (95% CI: -1.59 to 15.28;  = .11) and the mean difference for FEV/FVC was 1.15 (95% CI: -8.98 to 11.28;  = .82). In terms of functional capacity, MICT showed superiority for VOpeak (MD =  -41.79 mL/min, 95% CI [-74.77, -8.81],  = .01; I = 39%,  = .12), while HIIT significantly improved 6MWT performance (MD = 14.63 m, 95% CI [1.00, 28.25],  = .04; I = 33%,  = .22); no significant difference was observed for 12MWT (MD =  -55.00 m, 95% CI [-147.40, 37.40],  = .24). In terms of muscle function, HIIT provided greater benefits than MICT, including improvements in respiratory pressure, quadriceps endurance, handgrip strength, and muscle fiber composition. CONCLUSION: HIIT is superior to MICT in improving selected functional capacity outcomes and muscle function in COPD patients, and shows comparable effects to MICT in other functional measures. HIIT is a viable alternative training method; further research is needed to determine optimal protocols to maximize its benefits.