Effects of inspiratory muscle training on inspiratory muscle strength, and apnoea hypopnoea index, in patients with obstructive sleep apnoea syndrome: A systematic review

Obstructive sleep apnoea (OSA) is a common disorder marked by repetitive occurrence of breathing cessation during sleep due to partial or complete upper airway obstruction. An obstructive airway and the successive asphyxia chronically overload the inspiratory muscles resulting in an increased inspiratory effort.

The present systematic review aimed to examine the effects of inspiratory muscle training (IMT) on inspiratory muscle strength [maximal inspiratory pressure (PImax)], and severity of disease [apnoea hypopnoea index (AHI)] in mild to severe obstructive sleep apnoea syndrome OSAS.

Among 692 articles retrieved from various databases (PubMed, SCOPUS, web of science and Cochrane) 7 articles were found to be eligible for the present review. Randomised controlled trials reporting the effect of IMT in OSA were selected. The quality assessment was conducted using Cochrane risk-of-bias tool for randomized trials.

Total of 658 patients were included in this review diagnosed with OSA, primarily with or without other comorbidities. OSA was clinically diagnosed by polysomnography (PSG) AHI (as mild (5–14.9/hour), moderate (15–29.9/hour) and severe (>30/hour)). The participants mean age was between 40–61 years. participants received IMT as the main intervention with respiratory pressure ranging from 30%-75% of PImax. IMT showed significant improvement in inspiratory muscle strength, and significantly reduced apnoea hypopnoea index.

IMT may be considered as an effective treatment strategy in mild to severe OSA resulting in improved inspiratory muscle strength, and decreasing AHI.