Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity [body mass index (BMI) ≥30 kg/m2], chronic daytime hypercapnia (PaCO2 >45 mm Hg), and sleep-apnea in the absence of other known causes of hypercapnia. Respiratory system compliance decreases and resistance increases in OHS. This causes increase in work of breathing and oxygen cost of breathing, which may result in respiratory muscle fatigue. Increase in respiratory workload and increase in resistance to respiration is expected to decrease in respiratory muscle endurance (RME) in subjects with OHS.

In the literature, studies evaluating RME in subjects with OHS are limited. No study has been found to evaluate RME using the incremental load test in subjects with OHS. Accordingly, it was aimed to evaluate and compare respiratory muscle endurance in subjects with OHS and a control group, and to determine factors associated with respiratory muscle endurance.

Inclusion Criteria:

• Diagnosed with OHS
• Obese subjects (30 < body mass index < 40 kg/m2) with low risk of obstructive sleep apnea (STOP-BANG score < 3)

Exclusion Criteria:

• Severe respiratory disease
• Subjects with orthopeadic and/or neurologic disorders that could limit exercise tests

All subjects who had polysomnography performed in the sleep laboratory and were diagnosed with OHS were screened.

Age and sex-matched obese subjects (30 < body mass index < 40 kg/m2) with low risk of obstructive sleep apnea (STOP-BANG score < 3) included in the study as the control group.