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Sleep Apnea - Central and Obstructive Sleep Apnea

Last Updated: Mar 1, 2019


Sleep apnea is a disorder in which a person repeatedly stops breathing during sleep. This disorder is characterized by episodes of shallow breathing or long pauses (apneic events).

cross section of throat and upper airway

Sleep apnea commonly occurs in both children and adults. The condition affects both men and women, but it is much more prevalent in men.

Types of Sleep aAnea

  1. Obstructive sleep apnea is the most common type of sleep apnea. The problem occurs when muscles of the throat relax during sleep. Such relaxation allows the soft tissues in the back of the throat (soft palate and uvula) to collapse and block airflow into the lungs. Loud snoring occurs as air moves in the narrowed passageway. There are shallow breaths, long pauses, and choking sensations. Episodes of sleep apnea decrease the blood oxygen level, triggering the brain to urgently jolt the person awake and open the airway. The brain immediately falls back to sleep and the cycle of sleep apnea starts over again. Many individuals experience numerous disruptive cycles of sleep apnea an hour.
  2. Central sleep apnea is a rarer form of sleep apnea, caused by a disorder in the part of the brain that controls breathing. This condition may also be triggered by medications that affect the brain functions.


Overweight or obese people are more likely to develop obstructive sleep apnea because of an increased amount of fat in the airway tissues. In children, sleep apnea is often associated with enlarged tonsils and adenoids.

Risk factors for obstructive sleep apnea include:

  • Male gender
  • Obese thick neck
  • Abnormal jaw or facial features
  • Narrowed airway
  • Enlarged tongue
  • Enlarged tonsils
  • Enlarged uvula
  • Advanced age
  • Smoking.

In central sleep apnea, the brain malfunctions and fails to properly maintain breathing. This disorder can be caused by heart failure or stroke. Central sleep apnea is more prevalent in people over age 60.


Individuals with sleep apnea are typically unaware of their condition and have no recall of the apneic episodes occurring while they are asleep. Family members or bed partners observe loud snoring, repeated apneic events, choking, and gasping during sleep. Sleeping on the back exacerbates these episodes compared to sleeping on the side.

People with sleep apnea experience numerous sleep interruptions all night long. This problem deprives their bodies of deep restorative sleep, causing numerous daytime symptoms.

The following symptoms are frequently associated with sleep apnea:

  • Loud snoring
  • Breathing that starts and stops during sleep
  • Fatigue
  • Daytime sleepiness
  • Falling asleep at work or while driving
  • Irritability and mood swings
  • Memory problems
  • Difficulty concentrating
  • Dry mouth
  • Morning headache.

Complications Resulting from Untreated Sleep Apnea

Over time, the frequent drops in blood oxygen level and poor sleep quality cause harmful increases in stress hormones and serious complications may occur, including:


The diagnosis is easily missed because people with the condition are asleep when the problem is occurring. Since not everyone who snores has sleep apnea, a complete medical evaluation is required. The physical examination of a person with obstructive sleep apnea may reveal an enlargement of the tongue, tonsils, or uvula. Often further testing is required to confirm the diagnosis.

Sleep study

During a sleep study, sensors are applied to monitor a person’s breathing, vital signs, and oxygen level during sleep. This test, known as polysomnography, is usually performed overnight in a special sleep center.


  • Weight loss removes a prominent cause of obstructive sleep apnea.
  • Avoid smoking.
  • Avoid alcohol.
  • Avoid sedative medications.
  • Special pillows or devices promote sleeping on the side instead of the back.
  • A mouthpiece can help to keep the airway open.
  • A continuous positive airway pressure (CPAP) mask is a device placed over the mouth and nose (or just the nose). It blows air into the throat. The increased air pressure in the throat keeps the airway open during sleep.
  • Surgery can remove the excess tissue that is narrowing the airway.
  • Surgery can also reposition the jaw.


Maintaining normal body weight is a very important factor in decreasing the risk for obstructive sleep apnea. Other lifestyle choices, such as quitting smoking and avoiding excess alcohol, are also beneficial.


  • What Is Sleep Apnea? National Heart, Lung, and Blood Institute website. Accessed March 19, 2015.
  • Sleep Apnea. Johns Hopkins Medicine website.,P01301/. Accessed March 19, 2015.
  • Sleep Apnea. Mayo Clinic website. Accessed March 19, 2015.

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Tina Shahian, PhD

Tina is a writer for Innerbody Research, where she has written a large body of informative guides about health conditions.


A communication specialist in life science and biotech subjects, Tina’s successful career is rooted in her ability to convey complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. Tina Shahian’s Linkedin profile.


In her spare time, Tina enjoys drawing science-related cartoons.