Respiratory Muscle Endurance in Obesity Hypoventilation Syndrome

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.