Abstract
Abstract
Background
Inspiratory muscle dysfunction, exercise intolerance, dyspnea, and reduced well-being contribute to the burden of chronic obstructive pulmonary disease (COPD). We compared the short-term effects of inspiratory muscle training (IMT), aerobic exercise (AE), combined IMT and AE (IMT
AE
), placebo IMT, and usual care on respiratory, functional, and patient-reported outcomes in women with stable COPD and examined early changes during two weeks after training cessation.
Methods
In this single-center, five-arm, partially blinded randomized controlled trial, 68 women with stable GOLD stage I–II COPD were randomized; 59 completed all assessments and were included in the per-protocol analysis. The four-week intervention was followed by assessments 7 and 14 days after cessation. The prespecified primary outcome was baseline-to-post change in maximal inspiratory pressure (MIP). Secondary outcomes were maximal expiratory pressure (MEP), peak inspiratory flow rate (PIFR), inspiratory volume (IV), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), FEV₁/FVC, 6-min walk test (6MWT) distance, post-exercise Borg dyspnea, and WHO-5 well-being. The primary analysis tested the baseline-to-post group × time interaction for MIP using a 5-group × 2-time mixed-design repeated-measures analysis of variance. Four-time analyses examined secondary and detraining trajectories; additional Welch change-score comparisons were exploratory and unadjusted for multiplicity.
Results
The primary MIP interaction was significant (F(4, 54) = 28.969,
p
Conclusions
Within this sample of women with stable GOLD stage I–II COPD, combined IMT and AE produced the broadest short-term response across respiratory, functional, and patient-reported outcomes. Larger, prospectively registered trials with longer intervention and follow-up periods are needed to confirm these findings.
Trial registration
ClinicalTrials.gov, NCT07604961; first submitted on 17 May 2026 and first posted on 22 May 2026 (retrospectively registered).