Effects of inspiratory muscle training on inspiratory muscle strength and exercise tolerance in patients with COPD: a meta-analysis and systematic review

Objective To systematically evaluate the effects of inspiratory muscle training (IMT) on inspiratory muscle strength, exercise tolerance, and dyspnea in patients with COPD, including both stable and post-AECOPD rehabilitation-phase participants, and to explore the moderating role of comparator type on treatment efficacy. Methods Following PRISMA 2020 guidelines, we systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Scopus from inception to March 1, 2026. Randomized controlled trials (RCTs) involving adults with stable COPD were included. The primary outcomes were PImax, 6MWD, and dyspnea (SMD). A random-effects model was used to pool effect sizes, and subgroup analyses, sensitivity analyses, and meta-regression were performed. Results Thirteen RCTs ( n = 1,170) were included. IMT significantly improved PImax (SMD = 1.23, 95%CI 0.12–2.34, p = 0.034, I 2 = 90.9%) and 6MWD (SMD = 0.43, 95%CI 0.09–0.77, p = 0.018, I 2 = 70.6%). The improvement in 6MWD reached statistical significance only in the sham-controlled subgroup (SMD = 0.51, p = 0.046), whereas no additional benefit was observed in the “IMT added to pulmonary rehabilitation (PR)” subgroup (SMD = −0.05, p = 0.875). Dyspnea showed a favorable trend that did not reach statistical significance (SMD = 0.33, 95%CI −0.11–0.77, p = 0.129), and no significant improvement was found in FEV₁ (MD = 0.14 L, 95%CI −0.17–0.44, p = 0.190). Meta-regression suggested that comparator type explained approximately 37.8% of the heterogeneity in 6MWD ( p = 0.062). Conclusion IMT can significantly enhance inspiratory muscle strength and improve exercise tolerance, but its incremental benefit is highly dependent on the comparator type. The effect is more evident in non-pulmonary rehabilitation control settings, whereas additional benefit is limited in patients who have already undergone comprehensive pulmonary rehabilitation. IMT is more suitable for stable COPD patients who cannot tolerate standard pulmonary rehabilitation. Future high-quality, longer-term head-to-head studies are needed to determine the optimal strategies for different training modalities. Systematic review registration https://doi.org/10.37766/inplasy2026.5.0046 , identifier (INPLASY202650046).