It is not clear why obesity hypoventilation syndrome affects some obese people and not others. Extra fat in your neck or chest or over your stomach can make it difficult to breathe deeply and produce hormones that affect your body's breathing patterns. You may also have a problem with the way your brain controls your breathing. Most people with obesity hypoventilation syndrome also have sleep apnea.

You can help prevent this condition by maintaining a healthy weight. If you have been diagnosed with obesity, your doctor can screen you for obese hypoventilation syndrome by measuring the oxygen or carbon dioxide levels in your blood.

If you have obesity hypoventilation syndrome, you may feel sluggish or sleepy during the day, have a headache or be breathless. You or a loved one may find that you often snore, choke or gasp for breath, or have trouble breathing at night. Your symptoms may get worse over time. Complications of obesity hypoventilation syndrome include pulmonary hypertension; right heart failure, also known as cor pulmonale; and secondary erythrocytosis.

To diagnose obesity hypoventilation syndrome, your doctor will perform a physical exam to measure your weight and height, calculate your body mass index (BMI), and measure your waist and neck circumference. Your doctor may perform other tests, such as lung function tests, sleep tests, a chest X-ray, or an arterial blood gas or serum bicarbonate test. Other blood tests can help rule out other causes or can be used to plan your treatment. You can be diagnosed in the hospital if you have breathing problems and go to the emergency room with respiratory failure. You may be diagnosed based on tests routinely done before surgery.

If you are diagnosed with obesity hypoventilation syndrome, your doctor may recommend healthy lifestyle changes, such as aiming for a healthy weight and being physically active. You may also need a CPAP (continuous positive airway pressure) machine or other breathing device to keep your airways open and increase oxygen levels in the blood. Other treatments may include weight loss surgery, medications, or a tracheostomy.

To avoid complications, use your CPAP machine as instructed and proceed with healthy lifestyle changes recommended by your doctor. Tell your doctor about any new signs and symptoms, such as swelling around your ankles, chest pain, dizziness, or wheezing. Talk to your doctor if you are flying or need surgery, as these situations can increase your risk of serious complications.