Obesity hypoventilation syndrome (OHS) is a condition in some obese people in which poor breathing leads to lower oxygen and higher carbon dioxide levels in the blood.
The exact cause of OHS is not known. Doctors believe OHS results from a defect in the brain's control over breathing and excess weight (due to obesity) against the chest wall. This makes it hard for a person to breathe deeply and quickly enough. As a result, the blood has too much carbon dioxide and not enough oxygen.
The main symptoms of OHS are due to lack of sleep and include:
Piper AJ, Grunstein RR. Obesity hypoventilation syndrome: mechanisms and management. Am J Respir Crit Care Med. 2011;183:292-298.
Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.