A person with sleep apnea stops breathing during their sleep. There are three forms of sleep apnea: central, obstructive, and complex. The most common of these is obstructive sleep apnea (OSA).

Various studies have estimated that between 4% and 50% of the population have OSA. The prevalence of sleep apnea in any given study depends on the definition that the researchers use, as well as the age, sex, and weight of the participants and any underlying health conditions. A 2015 review of 11 studies found an average prevalence of 22% in males and 17% in females.

Knowing about the different types of sleep apnea can help a person identify the cause of their symptoms and seek the right medical care.

Research has linked sleep apnea to inflammation in the body, which increases the risk of various conditions, such as type 2 diabetes, high blood pressure, heart attack, and stroke. Keep reading to learn more.

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The most common form of sleep apnea is OSA. It occurs when there is a functional obstruction in the mouth and throat. For example, when the tongue falls against the soft palate during sleep, and the soft palate and uvula then fall against the throat, it makes breathing more difficult, or even impossible in some cases.

OSA can lead to snoring as the tongue and soft palate rattle. It can also cause a person to wake up feeling as though they cannot breathe. With OSA, the lungs work normally, and the body still tries to breathe, but it is not possible to get enough air in through the upper airway.

OSA becomes more common with age and is more prevalent in males, people with excess body weight, pregnant people, and people who sleep on their back. Some symptoms include:

  • waking during sleep or feeling very tired when awake
  • waking from sleep feeling panicked
  • snoring or gasping for air during sleep
  • frequent headaches
  • awaking with a dry mouth
  • feeling confused or unable to concentrate at work or school


Treating this form of sleep apnea requires fixing the obstruction that blocks the airway. Sometimes, simply changing sleep position is sufficient. Other people find that losing weight, quitting smoking, or becoming more physically active can reduce the symptoms.

Some medical treatments that may help include:

  • Continuous positive airway pressure (CPAP): A CPAP machine continuously blows air into the throat via a mask worn over the nose (or the nose and mouth), keeping the airway open. It helps a person breathe during sleep by “stenting” the upper airway open with pressurized air.
  • Surgery: Surgery can address structural issues in the mouth and upper airway by removing excess tissue or reshaping the airway.
  • Oral appliances: Certain appliances can help keep the airway open by preventing the tongue from falling back against the soft palate.
  • Medications: Some medications can help with daytime sleepiness if it persists after adequate treatment, but they do not address the underlying sleep apnea. For example, the Food and Drug Administration (FDA) have approved the drug modafinil for people who experience excessive sleepiness despite using a CPAP machine.

Learn more about OSA here.

Central sleep apnea also inhibits breathing at night, but it does not occur due to upper airway obstruction. Instead, the cause is neurological.

Unlike with OSA, the body does not try to breathe in central sleep apnea, so there is no snoring. Instead, because the brain and nervous system do not consistently send a signal to breathe, the person stops breathing.

Some people have no symptoms, but others may notice:

  • insomnia
  • waking up short of breath or feeling panicky
  • daytime sleepiness or trouble concentrating

Some potential causes include:

  • drugs, especially sedating drugs such as opiates
  • sleeping at high altitudes
  • congestive heart failure

However, central sleep apnea can sometimes be idiopathic, which means that doctors cannot identify an underlying disease.

Sometimes central sleep apnea occurs in a pattern called Cheyne-Stokes breathing, a kind of breathing that causes a person to alternate between hyperventilating and not breathing at all. This type of central sleep apnea can occur with congestive heart failure.


It is important to address the underlying cause of central sleep apnea, as this may resolve the apnea. However, it will not always cure the condition.

CPAP machines may improve central sleep apnea, but specialized positive airway pressure modes may be necessary in some cases. Bilevel positive airway pressure or adaptive servo-ventilation can be helpful. These devices deliver breaths when a person stops breathing.

Learn more about central sleep apnea here.

Having one type of sleep apnea does not necessarily mean that a person cannot have another.

Complex sleep apnea syndrome is a type of sleep apnea that combines OSA and central sleep apnea. Sometimes, complex sleep apnea syndrome is obvious in an initial sleep study. Other times, it becomes apparent after the apnea does not resolve with a typical CPAP machine or other traditional OSA treatments.

The symptoms are similar to those of OSA and include:

  • brief wakings from sleep
  • daytime fatigue
  • confusion on getting up
  • headaches or dry mouth
  • insomnia or poor quality sleep

A 2006 retrospective review of 223 people with sleep apnea symptoms found that 15% had complex sleep apnea syndrome, 84% had OSA, and just 0.4% had central sleep apnea.


The treatment for complex sleep apnea syndrome may involve a combination of interventions, including treatment for any underlying conditions and the use of CPAP or other positive airway pressure modes.

Sleep apnea can affect a person’s quality of life, and it is a risk factor for many potentially lethal illnesses.

The right treatment can help a person get a good night’s rest and may reduce the risk of chronic health problems.

People who feel tired during the day or wake frequently at night can ask a doctor about undergoing a sleep study.