Obstructive Sleep Apnea (OSA)

Reviewed by Sheila Tsai, MD
Obstructive sleep apnea is a condition characterized by brief interruptions of breathing during sleep.

People with sleep apnea may have symptoms of: loud, frequent snoring; frequent episodes of apnea (breath holding); or daytime sleepiness.

More than 12 million Americans are estimated to have obstructive sleep apnea (OSA). Because people with sleep apnea don't usually get restful sleep at night, they may be excessively sleepy during the day, which can lead to difficulties at school and work and even to car accidents. Untreated severe OSA is associated with a higher risk for insulin resistance, heart attack, high blood pressure and stroke, and many people with these conditions have undiagnosed OSA. Once OSA is diagnosed, it can be treated, which reduces the risk of diseases that often accompany the syndrome.

Several structures of the nose, mouth and throat can be involved in OSA. The uvula is the piece of tissue that hangs down from the soft palate, at the back of the roof of the mouth. Tonsils are on either side of the throat at the back of the mouth; they are made of lymphoid tissue, part of the body's immune system. The position of the tongue can also affect nighttime breathing. These structures can contribute to OSA by obstructing airflow. Because of greater work to pull in air, the airway collapses due to the strong negative pressure produced by the body's effort to breathe.


Types of Sleep Apnea

There are two types of sleep apnea: obstructive and central.

Obstructive Sleep Apnea (OSA)

OSA is the most common type of sleep apnea. This is caused when the upper airways collapse during sleep, and air cannot flow into or out of one's nose or mouth, although efforts to breathe continue. Breathing stops for several seconds to over a minute, and levels of blood oxygen may drop during these episodes. Each episode can cause brief awakenings, although the person may not be aware of these brief awakenings.


Central sleep apnea (CSA)

CSA is a much less common condition, and occurs when the brain does not send the appropriate signals to the breathing muscles for respiration. Since some people with central sleep apnea have other medical conditions such as congestive heart failure or stroke, treating those conditions may improve the central sleep apnea, too.

Some people have a mix of both obstructive and central sleep apnea.

Continuous positive airway pressure, or CPAP, may help people with obstructive or central sleep apnea. Some people with central sleep apnea may require bi-level positive pressure therapy (BPAP or BiPAP) or more advanced PAP therapies.

Acetazolamide may be prescribed for some people with central sleep apnea. Acetazolamide is normally prescribed for epilepsy, glaucoma and altitude sickness, but some studies have found that it decreases the apnea episodes in central sleep apnea if taken at bedtime.


What is Obstructive Sleep Apnea (OSA) in Adults?

Obstructive sleep apnea is a problem that affects breathing while sleeping. If OSA goes untreated, it can cause serious health problems to develop.

During sleep, OSA blocks air (obstruction) from flowing normally into the lungs and causes people to stop breathing for short periods of time when asleep. This block in airflow is caused by the collapse of the soft tissues in the back of the throat and tongue during sleep. Certain factors tend to worsen obstructive sleep apnea, such as sleeping on one’s back, weight gain and alcohol.

OSA is common in men, women after menopause, people over the age of 65 and occasionally in children, particularly kids who snore. People who are overweight, have large tonsils or adenoids, have jaw problems or with a family history of OSA are at increased risk of developing OSA.

To learn more about symptoms, dangers and treatment view the patient information from the American Thoracic Society’s Patient Information series on .


National Jewish Health experts provided information on this topic for use on the website.


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