Sleep apnea is a common disorder characterized by one or more pauses in breathing during sleep. Breathing pauses can last from a few seconds to a minute or longer. They often occur 5 to 30 times or more an hour. Typically, normal breathing then starts again, sometimes with a loud snort or choking sound. Sleep apnea is usually a chronic (ongoing) condition that disrupts sleep three or more nights each week, causing the sleep to be of poor quality. Sleep apnea is one of the leading causes of excessive daytime sleepiness.
Sleep apnea has three different forms. The first two forms have different mechanisms, whereas the third is a combination of the two other forms.
Obstructive sleep apnea (OSA)
Obstructive sleep apnea is the most common type of sleep apnea. Usually the obstruction is caused by a collapse or blockage of excessive tissue in the airways during sleep. The blockage may cause breathing to be shallow or interrupted. When breathing is attempted, any air that squeezes past the blockage can cause loud snoring. Obstructive sleep apnea happens more often in people who are overweight or have very thick necks.
Central sleep apnea
Central sleep apnea is a less common type of sleep apnea. It occurs when the area of the brain that controls breathing does not send the correct signals to the muscles that move the chest wall. There is no effort to breathe for brief periods of time. Central sleep apnea often occurs with OSA, but it can occur alone. Typically, snoring does not occur with central sleep apnea. One type of central sleep apnea is Cheyne-Stokes respiration. This condition has a specific breathing pattern and is associated with a worse prognosis than other forms of central sleep apnea. Cheyne-Stokes respiration is often seen with congestive heart failure as well as some other chronic conditions.
Complex sleep apnea
This type is a combination of OSA and central sleep apnea.
Signs and Symptoms
One of the most common signs of OSA is loud and chronic (ongoing) snoring. Pauses may occur in the snoring. Choking or gasping may follow the pauses. The snoring usually is loudest when sleeping on the back. Snoring may not happen every night. Over time, the snoring may become more frequent and louder.
Since the snoring or gasping occurs during sleep, the affected person may not know that a problem is present. Often a family member or bed partner will notice the snoring or apneic episodes (short periods when breathing stops).
Another common sign of sleep apnea is fatigue and sleepiness during the day.
Symptoms of sleep apnea may include the following:
- Morning headaches
- Memory, concentration, or learning problems
- Feeling irritable, depressed, or having mood swings or personality changes
- A dry throat in the morning.
- Difficulty staying asleep (insomnia)
In children, sleep apnea can cause hyperactivity, poor school performance, and aggressiveness. Children who have sleep apnea also may have unusual sleeping positions, bedwetting, and may be "mouth breathers" (breathing through the mouth rather than the nose).
During waking hours, throat muscles help keep the airway stiff and open so air can flow into the lungs. During sleep, these muscles are more relaxed. Normally, the relaxed throat muscles do not close the airway and prevent air flow. When OSA is present, the airways can be blocked or narrowed during sleep due to the following:
- The throat muscles and tongue relax more than normal.
- The tongue and tonsils are large compared to the opening into the windpipe.
- The person is overweight. The extra soft fat tissue can thicken the wall of the windpipe. This causes the inside opening to narrow and makes it harder to keep open.
- The shape of one's head and neck (bony structure) may cause a smaller airway size in the mouth and throat area.
- The aging process limits the ability of brain signals to keep the throat muscles stiff during sleep. This makes it more likely that the airway will narrow or collapse.
- Smoking causes inflammation, swelling and narrowing of the upper airway 
Central sleep apnea rarely occurs without serious underlying disease. Since the brain stem controls breathing, any injury to the brain stem may lead to central sleep apnea. Some examples of brain injury include the following:
- Injury to the higher (cervical) spinal cord: radiation, post-surgical complications or stroke.
- Infection (such as poliomyelitis)
- degenerative brain disorders like amyotrophic lateral sclerosis (Lou Gehrig's Disease) or Parkinson's disease
Heart failure may lead to central sleep apnea. This occurs because the breathing is controlled by a message from the brain to the muscles based on the carbon dioxide levels in the blood (when carbon dioxide levels are high, a message is sent to breathe). When the heart does not pump as effectively (as in heart failure), the brain is given an erroneous message about carbon dioxide levels and apnea occurs. The best way to correct the apnea in this case is by treating the heart failure.
Treatment of sleep apnea has several goals:
- Restore regular breathing during sleep
- Relieve symptoms such as loud snoring and daytime sleepiness
Treatment of medical conditions, such as high blood pressure, may also help alleviate sleep apnea.
Lifestyle changes, mouthpieces, breathing devices, and/or surgery are used to treat sleep apnea. Currently, there are no medicines to treat sleep apnea.
Lifestyle changes and/or mouthpieces may be enough to relieve mild sleep apnea. Many approaches have proven effective:
- Avoidance of alcohol and medicines that cause drowsiness because they hinder the ability to keep the throat open during sleep.
- Weight loss; even a small weight loss improves symptoms
- Sleep on the side instead of the back to help keep the throat open. There are special pillows and shirts that prevent sleeping on the back.
- Nose sprays or allergy medications help keep the nasal passages open at night
- Smoking cessation
A mouthpiece, sometimes called an oral appliance, may help some people who have mild sleep apnea. The mouthpiece may also be recommended for snoring without apnea. A dentist or orthodontist can make a custom-fit plastic mouthpiece for treating sleep apnea. An orthodontist specializes in correcting teeth or jaw problems. The mouthpiece adjusts the lower jaw and tongue to help keep the airway open during sleep. These devices may cause a temporary increase in salivation and swallowing.
Continuous positive airway pressure (CPAP)
CPAP is the most common treatment for moderate to severe sleep apnea in adults. A CPAP machine uses a mask that fits over the mouth and nose, or just over the nose. The machine gently blows air into the throat. The air presses on the wall of the airway. The air pressure is adjusted to prevent the airways from becoming narrowed or blocked during sleep.
Treating sleep apnea may help to stop the snoring. The cause of the sleep apnea, however, will remain. The CPAP device should be used even if the snoring stops. Sleep apnea will return if CPAP is stopped or not used correctly.
Some side effects have been associated with CPAP:
- Dry or stuffy nose
- Irritated skin on the face
- Sore eyes
In addition, a improperly adjusted CPAP can cause stomach bloating and discomfort while wearing the mask. Non restrictive, nasal CPAP masks are used in people who are claustrophobic and cannot tolerate the conventional mask.
People who have severe sleep apnea symptoms generally feel much better once they begin treatment with CPAP
Surgery is necessary in some cases of sleep apnea. The type and effectiveness of surgery depend on the cause of the sleep apnea. Some surgical approaches include the following:
- Widening the breathing passages. This usually involves removing, shrinking, or stiffening excess tissue in the mouth and throat or resetting the lower jaw.
- Shrink or stiffen excess tissue in the mouth or throat. Shrinkage is achieved by giving injections into the tissue. To stiffen excess tissue, the doctor makes a small cut in the tissue and inserts a small piece of stiff plastic.
- Removal of the tonsils, which is effective in children.
- In the morbidly obese, bariatric surgery such as Roux-en-Y gastric bypass may be considered to reduce body mass index.
Sleep apnea can often be prevented by lifestyle modifications similar to those used as treatments:
- Avoiding excessive alcohol use
- Quitting smoking
- Making an attempt to lose weight if overweight or obese
Estimates suggest that more than 12 million American adults have OSA. More than half of OSA cases occur in the obese or overweight. Sleep apnea is also more common in the following populations:
- Men: 1 out of 25 middle-aged men and 1 out of 50 middle-aged women have sleep apnea.
- Elderly: At least 1 out of 10 people over the age of 65 has sleep apnea. Women are much more likely to develop sleep apnea after menopause.
- African Americans, Hispanics, and Pacific Islanders
- History of sleep apnea in the family
- People who have small airways in their noses, throats, or mouths
- Small children (often children have enlarged tonsil tissues in the throat)
Other risk factors for sleep apnea include smoking, pressure], and risk factors for sleep apnea include smoking, high blood pressure, stroke, and heart failure.
- Not enough air flows into the lungs when the airway is fully or partly blocked during sleep. This can cause loud snoring and a drop in the blood oxygen levels.
- When the oxygen drops to dangerous levels, it triggers the brain to disturb the sleep. This helps tighten the upper airway muscles and open the windpipe. Normal breathing then starts again, often with a loud snort or choking sound.
- The frequent drops in oxygen level and reduced sleep quality trigger the release of stress hormones. These compounds raise the heart rate and are a major, significant risk factor for high blood pressure, heart attack, stroke, and irregular heart rhythm.
- Stress hormones also raise the risk for, or worsen pre-existing, heart failure.
- Untreated sleep apnea also can lead to changes in how the body uses energy. These changes increase the risk of obesity, abnormal heart rhythm (arrhythmia), and diabetes.
- Finally, the daytime fatigue caused by interrupted sleep increases the chance of having work-related or driving accidents. 
Sleep apnea often goes undiagnosed. Doctors usually cannot detect the condition during routine office visits. Also, there are no blood tests for the condition. Most people who have sleep apnea do not know they have it because it only occurs during sleep. A family member and/or bed partner may first notice the signs.
Doctors diagnose sleep apnea based on the following:
- A medical and family history
- A physical exam
- Results from sleep studies
Medical and family histories
Doctors record sleep habits and daytime fatigue. Sleep diaries are often used to record these habits. Doctors also note snoring frequency and the occurrence of choking or gasping sounds during sleep. Parents of young children often report symptoms to the doctor. Finally, a family history is taken.
The mouth, nose, and throat are examined for extra or large tissues. The tonsils often are enlarged in children with sleep apnea. Many diagnoses in children are based only on a physical exam and medical history. Adults with the condition may have an enlarged uvula or soft palate. The uvula is the tissue that hangs from the middle of the back of the mouth. The soft palate is the roof of the mouth in the back of the throat.
A sleep study is the most accurate test for sleep apnea. It captures what happens with a person's breathing during sleep. A sleep study is often done in a sleep center or sleep lab, which may be part of a hospital. This generally involves an overnight stay.
A polysomnogram, or PSG, is the most common technique used to diagnose sleep apnea. This test records the following:
- Brain activity
- Eye movement and other muscle activity
- Breathing and heart rate
- How much air moves in and out of the lungs during sleep
- The amount of oxygen in the blood
A PSG is painless. Sleep occurs as usual, except for the presence of sensors on the scalp, face, chest, limbs, and finger. The test is performed throughout the night. The test results show the severity of the apnea and directs treatment.
Living With Sleep Apnea
Obstructive sleep apnea can have a very negative impact on quality of life. However, following an effective treatment plan can often improve the living quality of the patient and those around the patient. Treatment can improve sleep and relieve daytime fatigue. It also may prevent high blood pressure, heart disease, and other health problems linked to sleep apnea. Treatment may improve overall health and happiness, as well as quality of sleep (and possibly the family's quality of sleep).
Support from family members
Family members can help a loved one with sleep apnea in many ways:
- Notification of snoring or breathing difficulties during the night
- Help with CPAP
- Emotional support
- ↑ Kashyap, R, Hock, L and Bowman, T. Higher Prevalence of Smoking in Patients Diagnosed as Having Obstructive Sleep Apnea. Sleep Breath. 2001; 5(4): 167-72. Full Text
- ↑ George CF, Smiley A. Sleep apnea & automobile crashes. Sleep. 1999; 22(6):790-5. Abstract
- ↑ Hortsmann S, Hess C, Bessetti C, Gugger M, Mathis J. Sleepiness-Related Accidents in Sleep Apnea Patients. Sleep. 2000; 23(3): 1-7. PDF
- ↑ Noda, A, Yagi, T, Yokota, M, Kayukawa, Y, Ohata, T, Okada. Daytime sleepiness and automobile accidents in patients with obstructive sleep apnea syndrome. Psych Clin Neurosci. 1998; 52(2): 221-222. Full Text
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