High-intensity interval training improves the outcomes of patients with chronic obstructive pulmonary disease: A meta-analysis of randomized controlled trials

Background: Pulmonary exercise is an important part in the treatment of chronic obstructive pulmonary disease (COPD). We aimed to evaluate the effects and safety of high-intensity interval training (HIIT) in patients with COPD, to provide insights to the COPD treatment and care. Methods: Two investigators searched PubMed, Medline, Embase, web of Science, Cochrane library, China Na-tional Knowledge Infrastructure (CNKI), Wanfang, and Weipu databases up to Sept 15, 2022 for randomized controlled trials (RCTs) on the effects and safety of HIIT for COPD patients. RevMan5.3 software was used for statistical analysis. Results: A total of 20 RCTs involving 962 COPD patients were finally included. 514 patients underwent HIIT interventions. Meta-analysis showed that HIIT increased the peak oxygen consumption (SMD = 0.30, 95% CI:0.14-0.46), peak minute ventilation (SMD = 0.26, 95%CI: 0.05-0.47), peak work rate (SMD = 0.34, 95%CI: 0.17-0.51), 6-min walking distance (SMD = 0.39, 95%CI: 0.23-0.55) in COPD patients (all P < 0.05). HIIT improved the quality of life (SMD = 0.30, 95%CI: 0.06-0.54) and reduced the dyspnea (SMD = -0.27, 95%CI: -0.51 similar to-0.03) in COPD patients (all P < 0.05). There were no significant differences in the forced expiratory volume in 1 s/forced vital capacity (SMD = 0.28, 95%CI: -0.01-0.56) and St. George's Respiratory Question-naire score (SMD =-0.35, 95%CI: -0.73-0.03) between HIIT and control group (all P > 0.05). There was no publication bias analyzed by the Egger test and funnel plots (all P > 0.05). Conclusions: HIIT may be beneficial to improve the pulmonary function, exercise capacity and quality of life of patients with COPD, which is worthy of clinical promotion for COPD treatment and care.