Effects of Inspiratory Muscle Training in People with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

This study aimed to investigate the effects of inspiratory muscle training (IMT) on inspiratory muscle strength, dyspnea, and quality of life (QOL) in COPD patients. A comprehensive search was undertaken on the Web of Science, Scopus, Embase, Cochrane, and PubMed databases, encompassing data published up to 31 March 2024. A meta-analysis was subsequently conducted to quantify the standardized mean difference (SMD) and 95% confidence interval (CI) for the effects of IMT in COPD patients. Sixteen studies met the inclusion criteria. IMT significantly improved inspiratory muscle strength (SMD, 0.86, p < 0.00001), dyspnea (SMD = -0.50, p < 0.00001), and QOL (SMD = 0.48, p = 0.0006). Subgroup analysis showed that <60% maximal inspiratory muscle pressure (PImax) IMT (inspiratory muscle strength, SMD = 1.22, p = 0.005; dyspnea, SMD = -0.92, p < 0.0001), IMT conducted for <= 20 min (inspiratory muscle strength, SMD = 0.97, p = 0.008; dyspnea, SMD = -0.63, p = 0.007; QOL, SMD = 1.66, p = 0.007), and IMT conducted >3 times per week (inspiratory muscle strength, SMD = 1.06, p < 0.00001; dyspnea, SMD = -0.54, p < 0.00001; QOL, SMD = 0.48, p = 0.0009) had greater effects. This meta-analysis provides clinicians with evidence supporting the recommendation that COPD patients engage in IMT at <60% PImax for more than 3 times per week, with each session lasting no more than 20 min, to improve inspiratory muscle strength, dyspnea, and QOL.