Obesity Hypoventilation Syndrome: Causes, Symptoms, and Treatment

Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.

What kind of doctor treats Obesity Hypoventilation Syndrome?

A pulmonologist, a doctor who treats lung and breathing problems, often leads care for obesity hypoventilation syndrome. A sleep medicine doctor, who treats sleep problems, may also help. A sleep study is one of the tests used to help diagnose OHS. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.

What is obesity hypoventilation syndrome?

Obesity hypoventilation syndrome (OHS) is a breathing disorder that affects some people with obesity. It is also called Pickwickian syndrome.

You breathe out carbon dioxide, a waste gas made when your body breaks down food for energy. With OHS, your blood has too much carbon dioxide and too little oxygen. Without treatment, it can cause serious and even life-threatening health problems.

Symptoms

Many symptoms come from poor sleep and low oxygen. Common symptoms include:

  • Poor sleep quality and daytime sleepiness.
  • Extreme tiredness.
  • Headaches.
  • Dizziness.
  • Shortness of breath or feeling tired after little effort.
  • Depression.

You or a loved one may notice loud snoring, choking, gasping, or trouble breathing at night. Symptoms may get worse over time. Most people with OHS also have sleep apnea.

A physical exam may show a bluish color in the lips, fingers, toes, or skin. It may also show swollen legs or feet, which can be a sign of right-sided heart failure.

Causes and who gets it

The exact cause of OHS is not known. Doctors believe it comes from a problem with how the brain controls breathing. Extra weight on the chest wall also makes deep breaths harder.

Having overweight or obesity raises your risk. Extra fat on your neck, chest, or belly can make it hard to breathe deeply. No one knows why OHS affects some people with obesity and not others.

How doctors diagnose it

People with OHS have obesity, meaning a body mass index (BMI) of 30 or greater. A provider will do a physical exam. They will measure your weight and height and work out your BMI. They will also measure your waist and neck.

Tests that help diagnose OHS include:

  • Arterial blood gas, a blood test that checks oxygen and carbon dioxide.
  • A chest x-ray or CT scan to look for other possible causes.
  • Lung function tests.
  • A sleep study, also called polysomnography.
  • An echocardiogram, which is an ultrasound of the heart.

Providers can tell OHS from obstructive sleep apnea because a person with OHS has a high carbon dioxide level in the blood when awake.

Treatment

Treatment involves breathing help from special machines. You wear a CPAP or BiPAP machine as a mask over your nose or nose and mouth, mainly for sleep. These machines use air pressure to keep your airway open. For severe cases, breathing help can be given through an opening in the neck called a tracheostomy.

Oxygen therapy by itself is not a treatment for OHS. Treatment can be started in the hospital or as an outpatient.

Weight loss can reverse OHS, although it is often difficult to achieve. Your provider may recommend healthy lifestyle changes, such as getting to and keeping a healthy weight and being physically active. Other treatments may include weight-loss surgery or medicines. If you are prescribed a CPAP machine, use it as instructed.

When to see a doctor

Contact your provider if you are very tired during the day or have other symptoms that suggest OHS. Untreated, OHS can lead to serious heart and blood vessel problems, severe disability, or death.

Tell your provider about new symptoms, such as swelling around your ankles, lightheadedness, or wheezing. Talk to your provider before flying or having surgery. These can raise your risk for serious problems.

Call 911 or go to the emergency room if you have trouble breathing, chest pain or discomfort lasting two minutes or more, fainting, or a sudden change in mental state, such as confusion or being very hard to wake up.

How a direct primary care or concierge doctor fits in

A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A doctor like this can review your symptoms and arrange tests. They can also coordinate care with a lung or sleep specialist and help with long-term follow-up.

Common questions

What is another name for obesity hypoventilation syndrome?

Obesity hypoventilation syndrome is also called Pickwickian syndrome. It is a breathing disorder that affects some people who have obesity.

Can obesity hypoventilation syndrome be reversed?

Weight loss can reverse OHS, although it is often difficult to achieve. Breathing machines used at night can also help treat it.

How is obesity hypoventilation syndrome different from sleep apnea?

Providers can tell OHS from obstructive sleep apnea because a person with OHS has a high carbon dioxide level in the blood when awake. Most people with OHS also have sleep apnea.

Is oxygen alone a treatment for obesity hypoventilation syndrome?

No, oxygen therapy by itself is not a treatment for OHS. Treatment involves breathing help from machines, such as CPAP or BiPAP.

Is obesity hypoventilation syndrome serious?

Yes, it can be serious without treatment. Untreated, OHS can lead to serious heart and blood vessel problems, severe disability, or death.

Sources

  1. MedlinePlus - Obesity hypoventilation syndrome (OHS)
  2. National Heart, Lung, and Blood Institute - Obesity Hypoventilation Syndrome

Medical Disclaimer

This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.