Learn About Obesity Hypoventilation Syndrome (OHS)
Obesity hypoventilation syndrome (OHS) causes poor breathing in some people with obesity. It leads to lower oxygen and higher carbon dioxide levels in the blood.
Pickwickian syndrome
The exact cause of OHS is not known. It is believed that OHS results from a defect in the brain's control over breathing. Excess weight against the chest wall also makes it harder for the muscles to draw in a deep breath and to breathe quickly enough. This worsens the brain's breathing control. As a result, the blood contains too much carbon dioxide and not enough oxygen.
Over time, the kidneys help the body compensate for the carbon dioxide that builds up.
The main symptoms of OHS are due to lack of sleep and include:
- Poor sleep quality
- Sleep apnea
- Daytime sleepiness
- Depression
- Headaches
- Tiredness
Symptoms of low blood oxygen level (chronic hypoxia) and high carbon dioxide can occur. Symptoms include shortness of breath or feeling tired after little effort.
Treatment involves breathing assistance using special machines (mechanical ventilation). Options include:
- Noninvasive mechanical ventilation such as continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) through a mask that fits tightly over the nose or nose and mouth (mainly for sleep)
- Breathing help through an opening in the neck (tracheostomy) for severe cases
Oxygen therapy, by itself, is not a treatment for obesity hypoventilation syndrome. Treatment is started in the hospital or as an outpatient.
Other treatments are aimed at weight loss, which can reverse OHS, although it is often difficult to achieve.
Nicholas Hart practices in London, United Kingdom. Mr. Hart is rated as an Elite expert by MediFind in the treatment of Obesity Hypoventilation Syndrome (OHS). His top areas of expertise are Obesity Hypoventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease (COPD), Obstructive Sleep Apnea, Gastrostomy, and Colostomy.
Rush University Medical Group
Babak Mokhlesi is a Pulmonary Medicine specialist and a Sleep Medicine provider in Chicago, Illinois. Dr. Mokhlesi is rated as an Elite provider by MediFind in the treatment of Obesity Hypoventilation Syndrome (OHS). His top areas of expertise are Obstructive Sleep Apnea, Obesity Hypoventilation Syndrome (OHS), Excessive Daytime Sleepiness, Central Sleep Apnea, and Adenoidectomy. Dr. Mokhlesi is currently accepting new patients.
Amanda Piper practices in Camperdown, Australia. Ms. Piper is rated as an Elite expert by MediFind in the treatment of Obesity Hypoventilation Syndrome (OHS). Her top areas of expertise are Obesity Hypoventilation Syndrome (OHS), Obstructive Sleep Apnea, Obesity, and Cystic Fibrosis.
Untreated, OHS can lead to serious heart and blood vessel problems, severe disability, or death.
OHS complications related to a lack of sleep may include:
- Depression, agitation, irritability
- Increased risk for accidents or mistakes at work
- Problems with intimacy and sex
OHS can also cause heart problems, such as:
- High blood pressure (hypertension)
- Right-sided heart failure (cor pulmonale)
- High blood pressure in the lungs (pulmonary hypertension)
Contact your provider if you are very tired during the day or have any other symptoms that suggest OHS.
Maintain a healthy weight. Use your CPAP or BiPAP treatment as your provider prescribed.
Introduction: Obesity Hypoventilation Syndrome (OHS) is defined as the coexistence of obesity (BMI ≥ 30 kg/m²), daytime hypercapnia (PaCO₂ \> 45 mmHg) in the absence of other causes of hypoventilation, and sleep-disordered breathing. OHS represents the most severe form of obesity-related respiratory failure and leads to serious consequences such as increased mortality rates, chronic heart failure, pulmonary hyp...
Summary: Research is being conducted into chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), asthma, interstitial lung disease, and bronchiectasis. The investigation specifically focuses on sleep-disordered breathing (SDB) in individuals with chronic respiratory disease. SDB encompasses a range of conditions, the most common of which is obstructive sleep apnoea. In obstru...
Published Date: July 25, 2025
Published By: David A. Kaufman, MD, Director of Clinical Innovation and Education, Medical Critical Care, NYU Langone Medical Center, Tisch Hospital, NYU School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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Mokhlesi B, Masa JF, Brozek JL, et al. Evaluation and management of obesity hypoventilation syndrome. An official American Thoracic Society clinical practice guideline. Am J Respir Crit Care Med. 2019;200(3):e6-e24. PMID: 31368798 pubmed.ncbi.nlm.nih.gov/31368798/.
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