What Is Sleep Apnea?

What Is Sleep Apnea?
Sleep apnea is a common condition in which your breathing stops and restarts many times while you sleep. This can prevent your body from getting enough oxygen. You may want to talk to your healthcare provider about sleep apnea if someone tells you that you snore or gasp during sleep, or if you experience other symptoms of poor-quality sleep, such as excessive daytime sleepiness.
There are two types of sleep apnea.
  • Obstructive sleep apnea happens when your upper airway becomes blocked many times while you sleep, reducing or completely stopping airflow. This is the most common type of sleep apnea. Anything that could narrow your airway such as obesity, large tonsils, or changes in your hormone levels can increase your risk for obstructive sleep apnea.
  • Central sleep apnea happens when your brain does not send the signals needed to breathe. Health conditions that affect how your brain controls your airway and chest muscles can cause central sleep apnea.
To diagnose sleep apnea, your provider may have you do a sleep study. Breathing devices such as continuous positive air pressure (CPAP) machines and lifestyle changes are common sleep apnea treatments. If these treatments do not work, surgery may be recommended to correct the problem that is causing your sleep apnea. If your sleep apnea is not diagnosed or treated, you may not get enough good quality sleep. This can lead to trouble concentrating, making decisions, remembering things, or controlling your behavior. Sleep apnea is also linked to serious health problems.


Your partner may alert you to some of the symptoms of sleep apnea, such as:
  • Breathing that starts and stops during sleep
  • Frequent loud snoring
  • Gasping for air during sleep
You may also notice the following symptoms yourself:
  • Daytime sleepiness and tiredness, which can lead to problems learning, focusing, and reacting
  • Dry mouth or headaches
  • Sexual dysfunction or decreased libido
  • Waking up often during the night to urinate
Children who have sleep apnea may be overactive and may experience bedwetting, worsening asthma, and trouble paying attention in school.
Talk to your healthcare provider about your symptoms. You may need a sleep study to help diagnose the condition.


Your healthcare provider will ask you about your symptomsrisk factors, and whether you have a family history of sleep apnea. You may need a sleep study to help diagnose sleep apnea.

Sleep study

Your healthcare provider will ask you to see a sleep specialist or go to a center for a sleep study. Sleep studies can help diagnose which type of sleep apnea you have and how serious it is.

Sleep diary

Sleep diary thumbnailA sleep diary can help you keep track of how long and how well you sleep, and how sleepy you feel during the day. These details can help your healthcare provider diagnose your condition.
See a sample sleep diary.

Ruling out other medical conditions

Your provider may order other tests to help rule out other medical conditions that can cause sleep apnea.
  • Blood tests check the levels of certain hormones to check for endocrine disorders that could contribute to sleep apnea. thyroid hormonestests can rule out hypothyroidism. Growth hormone tests can rule out acromegaly. Total testosterone and dehydroepiandrosterone sulphate (DHEAS) tests can help rule out polycystic ovary syndrome (PCOS).
  • Pelvic ultrasounds examine the ovaries and help detect cysts. This can rule out PCOS.
Your provider will also want to know whether you are using medicines, such as opioids, that could affect your sleep or cause breathing symptoms of sleep apnea. They may want to know whether you have traveled recently to altitudes greater than 6,000 feet, because these low-oxygen environments can cause symptoms of sleep apnea for a few weeks after traveling.

Causes and Risk Factors

What causes sleep apnea?

Central sleep apnea is caused by problems with the way your brain controls your breathing while you sleep.

Obstructive sleep apnea is caused by conditions that block airflow through your upper airways during sleep. For example, your tongue may fall backward and block your airway.

Your age, family history, lifestyle habits, other medical conditions, and some features of your body can raise your risk of sleep apnea. Healthy lifestyle changes can help lower your risk.

What raises the risk of obstructive sleep apnea?

Many conditions can cause sleep apnea. Some factors, such as unhealthy lifestyle habits, can be changed. Other factors, such as age, family history, race and ethnicity, and sex, cannot be changed.
  • Age: Sleep apnea can occur at any age, but your risk increases as you get older. As you age, fatty tissue can build up in your neck and the tongue and raise your risk of sleep apnea.
  • Endocrine disorders, or changes in your hormone levels: Your hormone levels can affect the size and shape of your face, tongue, and airway. People who have low levels of thyroid hormones or high levels of insulin or growth hormone have a higher risk of sleep apnea.
  • Family history and genetics: Sleep apnea can be inherited. Your genes help determine the size and shape of your skull, face, and upper airway. Also, your genes can raise your risk of other health conditions that can lead to sleep apnea, such as cleft lip and cleft palateexternal link and Down syndrome.
  • Heart or kidney failure: These conditions can cause fluid to build up in your neck, which can block your upper airway.
  • Large tonsils and a thick neck: These features may cause sleep apnea because they narrow your upper airway. Also, having a large tongue and your tongue’s position in your mouth can make it easier for your tongue to block your airway while you sleep.
  • Lifestyle habits: Drinking alcohol and smoking can raise your risk of sleep apnea. Alcohol can make the muscles of your mouth and throat relax, which may close your upper airway. Smoking can cause inflammation in your upper airway, which affects breathing.
  • Obesity: This condition is a common cause of sleep apnea. People with this condition can have increased fat deposits in their necks that can block the upper airway. Maintaining a healthy weight can help prevent or treat sleep apnea caused by obesity.
  • Sex: Sleep apnea is more common in men than in women. Men are more likely to have serious sleep apnea and to get sleep apnea at a younger age than women.

What raises the risk of central sleep apnea?

  • Age: As you get older, normal changes in how your brain controls breathing during sleep may raise your risk of sleep apnea.
  • Family history and genetics: Your genes can affect how your brain controls your breathing during sleep. Genetic conditions such as congenital central hypoventilation syndrome can raise your risk.
  • Lifestyle habits: Drinking alcohol and smoking can affect how your brain controls sleep or the muscles involved in breathing.
  • Opioid use: Opioid use disorder or long-term use of prescribed opioid-based pain medicines can cause problems with how your brain controls sleep.
  • Health conditions: Some conditions that affect how your brain controls your airway and chest muscles can raise your risk. These include heart failurestrokeamyotrophic lateral sclerosis (ALS), and myasthenia gravis. Also, your hormone levels can affect how your brain controls your breathing.
  • Premature birth: Babies born before 37 weeks of pregnancy have a higher risk of breathing problems during sleep. In most cases, the risk gets lower as the baby gets older.

Research for your health

NHLBI research found that sleep apnea may raise the risk of high blood pressure, diabetes, heart disease, and stroke. Our current research will help develop new and improved treatments for sleep apnea to help prevent these complications.

Can you prevent sleep apnea?

You may be able to prevent obstructive sleep apnea by making healthy lifestyle changes, such a eating a heart-healthy dietaiming for a healthy weightquitting smoking, and limiting alcohol intake. Your healthcare provider also may ask you to sleep on your side and to adopt healthy sleep habits such as getting the recommended amount of sleep.


If a sleep study shows that you have sleep apnea, your healthcare provider may talk to you about making lifelong heart-healthy lifestyle changes. You may also need breathing or oral devices or surgery to help keep your airways open while you sleep.

Healthy lifestyle changes

Healthy lifestyle changes
To help treat your sleep apnea, you may need to adopt lifelong healthy lifestyle changes. These include getting regular physical activity, maintaining healthy sleeping habits and a healthy weight, limiting alcohol, and quitting smoking. Your provider also may ask you to sleep on your side and not on your back. This helps keep your airway open while you sleep.

Breathing devices

A breathing device, such as a CPAP machine, is the most common treatment for sleep apnea. A CPAP machine provides constant air pressure in your throat to keep the airway open when you breathe in.
Breathing devices work best when you also make healthy lifestyle changes. Side effects of CPAP treatment may include:
  • Congestion
  • Dry eyes
  • Dry mouth
  • Nosebleeds
  • Runny nose
If you experience stomach discomfort or bloating, you should stop using your CPAP machine and contact your healthcare provider.
Depending on the type of sleep apnea you have, you may need another type of breathing device such as an auto-adjusting positive airway pressure (APAP) machine or a bilevel positive airway pressure (BPAP) machine. Living With Sleep Apnea has information about how to take care of your breathing device.

Oral devices

Oral devices, also called oral appliances, are custom-fit devices that you typically wear in your mouth while you sleep. There are two types of oral devices that work differently to open the upper airway while you sleep. Some hybrid devices have features of both types.
  • Mandibular repositioning mouthpieces are devices that cover the upper and lower teeth and hold the jaw in a position that prevents it from blocking the upper airway.
  • Tongue retaining devices are mouthpieces that hold the tongue in a forward position to prevent it from blocking the upper airway.
A new type of oral device was recently approved by the FDAexternal link for use while awake. The device delivers electrical muscle stimulation through a removable mouthpiece that sits around the tongue. You wear the mouthpiece once a day for 20 minutes at a time, for 6 weeks. The device stimulates the tongue muscle while awake to help prevent the tongue from collapsing backward and blocking the airway during sleep.

If you have sleep apnea, your provider may prescribe an oral device if you do not want to use CPAP or cannot tolerate CPAP. They will recommend that you visit a dentist who will custom make an appliance for you, make sure that it is comfortable, and teach you how to use it to get the best results.

Therapy for your mouth and facial muscles

Exercises for your mouth and facial muscles, also called orofacial therapy, may help treat sleep apnea in children and adults. This therapy helps improve the position of your tongue and strengthens the muscles that control your lips, tongue, upper airway, and face.

Surgical procedures

You may need surgery if other treatments do not work for you. Possible surgical procedures include:
  • Adenotonsillectomy to remove your tonsils and adenoids
  • Surgery to place an implant that monitors your breathing patterns and helps control certain muscles that open your airways during sleep
  • Surgery to remove some soft tissue from your mouth and throat, which helps make your upper airway bigger
  • Maxillary or jaw advancement surgery to move your upper jaw (maxilla) and lower jaw (mandible) forward, which helps make your upper airway bigger

Living With

If you have been diagnosed with sleep apnea, you will need to schedule regular check-ups to make sure that your treatment is working and whether you have any complications. You may need to repeat your sleep study to monitor your symptoms while using your treatment, especially if you gain or lose a lot of weight. You may also need treatment for other health conditions that caused your sleep apnea or can make it worse.

How sleep apnea affects your health

Undiagnosed or untreated sleep apnea prevents you from getting enough rest, which can cause problems concentrating, remembering things, making decisions, or controlling your behavior, as well as dementia in older adults. In children, sleep apnea can lead to problems with learning and memory, known as learning disabilities. The daytime sleepiness and fatigue that results from sleep apnea can also impact your child’s behavior and their desire to be physically active.
Sleep apnea affects many parts of your body. It can cause low oxygen levels in your body during sleep and can prevent you from getting enough good quality sleep. Also, it takes a lot of effort for you to restart breathing many times during sleep, and this can damage your organs and blood vessels. These factors may raise your risk of the following conditions:

Using and caring for your breathing device

It is important that you properly use and care for your breathing device.
  • Be patient as you learn to use your breathing device. It may take time to adjust to breathing with the help of a CPAP machine.
  • Use your breathing device for all sleep, including naps. If you are traveling, be sure to bring your breathing device with you.
  • Talk to your healthcare provider if the mask of your breathing device is not comfortable, if your mask is not staying on or fitting well, or if it leaks air. Also, tell your provider if you are having difficulty falling or staying asleep, if you wake up with dry mouth, or if you have a stuffy or runny nose. Your provider may ask you to try different masks or nasal pillows, or to adjust the machine’s pressure timing and settings.
  • Clean your mask and wash your face before you put on your mask. This can help make a better seal between the mask and your skin. You may need to try a different breathing device that has a humidifier chamber or provides bi-level or auto-adjusting pressure settings.
  • Know how to set up and properly clean all parts of your machine. Be sure to refill prescriptions on time for all of the device’s parts that need to be replaced regularly, including the tubes, masks, and air filters.
Your healthcare provider, and possibly your insurance provider, may ask to check the data card from your breathing device. This card shows how often you use your device and whether the device is working properly.

Using and caring for your oral device

Using and caring for your oral device

If you are using an oral device, you may need to see your dentist after 6 months and then every year. Your dentist will check whether your device is working correctly and whether it needs to be adjusted or replaced.

Ask your dentist how to properly care for your oral device. If it does not fit right or your symptoms do not improve, let your dentist know. It is common to feel some discomfort after a device is adjusted until your mouth and facial muscles get used to the new fit.

Information to help you stay safe

Sleep apnea can raise your risks of complications if you are having surgery and it can affect how well you drive.
  • If you need medicine to make you sleep during surgery or pain medicine after surgery, tell your healthcare provider that you have sleep apnea. Your provider may have to take extra steps to make sure that your airway stays open during the surgery and that your pain medicine doesn’t make it harder for your airway to stay open.
  • Untreated sleep apnea can make you sleepy during the day and can make it difficult for you to pay attention and make decisions while you drive. This can cause road accidents. Pay attention to your symptoms and do not drive if you feel very tired or sleepy.

Sleep Apnea and Women

Women may be more at risk for sleep apnea during pregnancy, or during and after menopause, because of hormone changes. Hormone problems in women who have polycystic ovarian syndrome (PCOS) may also raise the risk of sleep apnea.

Sleep apnea symptoms in women

Sleep apnea symptoms may be different for women compared with men. Women more often have the following symptoms:
  • Anxiety
  • Daytime sleepiness
  • Depression
  • Headaches, especially in the morning
  • Insomnia
  • Tiredness
  • Waking up often during sleep
Because you may not have common sleep apnea symptoms such as snoring, you may not think that you have this condition. It is important that you talk to your healthcare provider if you have any of these symptoms or if you have any risk factors for sleep apnea.

Sleep apnea and pregnancy

During pregnancy, changes to a woman’s upper airway or to the way the brain controls breathing raise a woman’s risk of sleep apnea or make it worse. Sleep apnea is often more serious in the third trimester of pregnancy and may improve after your baby is born. Pregnant women who are older or who have obesity have a higher risk of sleep apnea. In pregnant women, sleep apnea can cause many complications, including: Breathing devices such as CPAP machines are safe for treating sleep apnea during pregnancy. Because pregnancy causes changes to your body, you may need to see a sleep specialist to adjust the settings of your CPAP machine during and after your pregnancy.
A part of the U.S. Department of Health and Human Services, NIH is the largest biomedical research agency in the world.
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