Effects of inspiratory muscle training in adults with obesity and obstructive sleep apnea: a systematic review

To systematize and critically analyze scientific evidence on the effects of inspiratory muscle training (IMT) in adults with obesity and obstructive sleep apnea (OSA), focusing on outcomes related to OSA severity, respiratory muscle strength, respiratory function, cardiovascular parameters, sleep quality, and excessive daytime sleepiness. A systematic literature review was performed, in accordance with PRISMA 2020 guidelines. Searches were conducted in November 2025, across six databases (PubMed, Cochrane Library, SciELO, Scopus, Web of Science, and Embase). The review was registered in PROSPERO (CRD420251057891). Included studies were randomized controlled trials that evaluated the effects of IMT in adults with obesity and OSA. Six studies were identified that investigated IMT in individuals with OSA and with an average body mass index BMI ≥ 30 kg/m². The primary outcomes assessed included the effects of IMT on maximal inspiratory pressure (MIP), the apnea-hypopnea index (AHI), cardiovascular parameters, excessive daytime sleepiness (EDS), sleep quality, neck and waist circumference, and functional capacity. The studies provided favorable evidence suggesting the use of IMT to improve these parameters, although some results showed inconsistencies. Although IMT is a low-cost, feasible, and home-based intervention, the current evidence is insufficient to support its recommendation as a standard therapeutic approach. Further high-quality randomized controlled trials with clearly defined obesity-based inclusion criteria and adequate follow-up are required to establish the effectiveness and clinical role of IMT as an adjunctive, non-pharmacological therapy in adults with obesity and OSA.