What causes Obesity Hypoventilation Syndrome ?
Obesity hypoventilation syndrome (OHS) is a breathing disorder that affects some obese people. Why these people develop OHS isn't fully known. Researchers think that several factors may work together to cause OHS. These factors include:
                
A respiratory (RES-pih-rah-tor-e) system that has to work harder than normal and perhaps differently because of excess body weight. (The respiratory system is a group of organs and tissues, including the lungs, that helps you breathe.)
                
A slow response by the body to fix the problem of too much carbon dioxide and too little oxygen in the blood.
                
The presence of sleep apnea, usually obstructive sleep apnea.