Short-Term Expiratory Muscle Strength Training Attenuates Sleep Apnea and Improves Sleep Quality in Patients with Obstructive Sleep Apnea

Abstract This study investigated the effects of 5 weeks of expiratory muscle strength training (EMST) on sleep apnea, sleep quality, and respiratory muscle strength in patients with different levels of obstructive sleep apnea (OSA). Twenty-five outpatients who received a diagnosis of OSA participated in the study and were assigned to either the EMST group (n = 13) or control group (CTRL, n = 12). The training intensity for the EMST group was 75% of the maximum static expiratory (PE max ) score (5 days/week). The PE max , apnea–hypoapnea index (AHI), Epworth Sleepiness Scale (ESS), and Pittsburgh Sleep Quality Index (PSQI) scores were evaluated before and after the treatment. EMST improved the scores for AHI (−40%), PE max (+68%), and PSQI (−28%) and reduced the PSQI scores of the moderate OSA subgroup but not the mild OSA subgroup. The percent changes (Δ%) in the AHI and PE max scores of participants with OSA were negatively correlated. We demonstrated that EMST effectively improved sleep apnea, sleep quality, and expiratory muscle strength in participants with OSA. Participants with moderate OSA exhibited greater improvement than did those with mild OSA, and the improvement in PE max scores was correlated with a decrease in sleep apnea.