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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.
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Clinical Trials

Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans.

NHLBI Research Featured in HBO Documentary Series on Obesity

Hear people talk about their challenges and successes reaching and maintaining a healthy weight on the HBO Documentary Films series, “The Weight of the Nation,” which premiered in May 2012.

The film series spotlights the science behind obesity and how it affects the health of the nation. Watch the series to learn how citizens, groups, and policymakers are working to make a difference in their communities. The films stream free on the HBO Web site.

To learn more about the film series and related public awareness campaign, including how to host a local screening go to

January 27, 2012 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.