Central sleep apnea is a disorder in which your breathing repeatedly stops and starts during sleep.

Central sleep apnea occurs because your brain doesn't send proper signals to the muscles that control your breathing. This condition is different from obstructive sleep apnea, in which you can't breathe normally because of upper airway obstruction. Central sleep apnea is less common than obstructive sleep apnea.

Central sleep apnea can result from other conditions, such as heart failure and stroke. Another possible cause is sleeping at a high altitude.

Treatments for central sleep apnea might involve treating existing conditions, using a device to assist breathing or using supplemental oxygen.

Common signs and symptoms of central sleep apnea include:

• Observed episodes of not breathing or abnormal breathing patterns during sleep
• Abrupt awakenings accompanied by shortness of breath
• Difficulty staying asleep (insomnia)
• Excessive daytime sleepiness (hypersomnia)
• Difficulty concentrating
• Mood changes
• Morning headaches
• Snoring

Although snoring indicates some degree of airflow obstruction, snoring can also be heard in the presence of central sleep apnea. However, snoring may not be as prominent with central sleep apnea as it is with obstructive sleep apnea.

When to see a doctor

Consult a medical professional if you have — or if your partner notices — any signs or symptoms of central sleep apnea, particularly the following:

• Shortness of breath that awakens you from sleep
• Pauses in your breathing during sleep
• Difficulty staying asleep
• Excessive daytime drowsiness, which may cause you to fall asleep while you're working, watching television or even driving

Ask your doctor about any sleep problem that leaves you chronically fatigued, sleepy and irritable. Excessive daytime drowsiness can be due to other disorders, such as not allowing yourself time to get enough sleep at night (chronic sleep deprivation), sudden attacks of sleep (narcolepsy) or obstructive sleep apnea.

Central sleep apnea occurs when your brain fails to transmit signals to your breathing muscles.

Central sleep apnea can be caused by a number of conditions that affect the ability of your brainstem — which links your brain to your spinal cord and controls many functions such as heart rate and breathing — to control your breathing.

The cause varies with the type of central sleep apnea you have. Types include:

• Cheyne-Stokes breathing. This type of central sleep apnea is most commonly associated with congestive heart failure or stroke.

  Cheyne-Stokes breathing is characterized by a gradual increase and then decrease in breathing effort and airflow. During the weakest breathing effort, a total lack of airflow (central sleep apnea) can occur.

• Drug-induced apnea. Taking certain medications such as opioids — including morphine (MS Contin, Kadian, others), oxycodone (Roxicodone, Oxycontin, others) or codeine — can cause your breathing to become irregular, to increase and decrease in a regular pattern, or to temporarily stop completely.
• High-altitude periodic breathing. A Cheyne-Stokes breathing pattern can occur if you're at a very high altitude. The change in oxygen at this altitude is the reason for the alternating rapid breathing (hyperventilation) and underbreathing.
• Treatment-emergent central sleep apnea. Some people with obstructive sleep apnea develop central sleep apnea while using continuous positive airway pressure (CPAP) for their sleep apnea treatment. This condition is known as treatment-emergent central sleep apnea and is a combination of obstructive and central sleep apneas.
• Medical condition-induced central sleep apnea. Several medical conditions, including end-stage kidney disease and stroke, may give rise to central sleep apnea of the non-Cheyne-Stokes variety.
• Idiopathic (primary) central sleep apnea. The cause of this uncommon type of central sleep apnea is unknown.

Certain factors put you at increased risk of central sleep apnea:

• Sex. Males are more likely to develop central sleep apnea than are females.
• Age. Central sleep apnea is more common among older adults, especially those older than age 60. This could be because people older than 60 are likely to have other medical conditions or sleep patterns that are linked to central sleep apnea.
• Heart disorders. People with irregular heartbeats (atrial fibrillation) or whose heart muscles don't pump enough blood for the body's needs (congestive heart failure) are at greater risk of central sleep apnea.
• Stroke, brain tumor or a structural brainstem lesion. These brain conditions can impair the brain's ability to regulate breathing.
• High altitude. Sleeping at an altitude higher than you're accustomed to may increase your risk of sleep apnea. High-altitude sleep apnea resolves a few weeks after returning to a lower altitude.
• Opioid use. Opioid medications may increase the risk of central sleep apnea.

• CPAP. Some people with obstructive sleep apnea develop central sleep apnea while using continuous positive airway pressure (CPAP). This condition is known as treatment-emergent central sleep apnea. It is a combination of obstructive and central sleep apneas.

  For some people, complex sleep apnea goes away with continued use of a CPAP device. Other people may be treated with a different kind of positive airway pressure therapy.

Central sleep apnea is a serious medical condition. Some complications include:

• Fatigue. The repeated awakenings associated with sleep apnea make normal, restorative sleep impossible. People with central sleep apnea often have severe fatigue, daytime drowsiness and irritability.

  You might have difficulty concentrating and find yourself falling asleep at work, while watching television or even while driving.

• Cardiovascular problems. Sudden drops in blood oxygen levels that occur during central sleep apnea can adversely affect heart health.

  If there's underlying heart disease, these repeated multiple episodes of low blood oxygen (hypoxia or hypoxemia) worsen prognosis and increase the risk of abnormal heart rhythms.

Your doctor might evaluate your condition based on your signs and symptoms or refer you to a sleep specialist in a sleep disorder center.

A sleep specialist can help you decide on your need for further evaluation. That might involve overnight monitoring of your breathing and other body functions during a sleep study called polysomnography.

During polysomnography, you're connected to equipment that monitors your heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while you sleep. You may have a full-night or split-night sleep study.

In a split-night sleep study, you're monitored during the first half of the night. If you're diagnosed with central sleep apnea, staff might wake you and give you positive airway pressure for the second half of the night.

Polysomnography can help your doctor diagnose central sleep apnea. It can also help your doctor rule out other sleep disorders, such as obstructive sleep apnea, repetitive movements during sleep (periodic limb movements) or sudden attacks of sleep (narcolepsy), which can cause excessive daytime sleepiness but require different treatment.

Doctors trained in nervous system diseases (neurologists), heart diseases (cardiologists) and others might be involved in evaluating your condition. You might undergo imaging of your head or heart to look for contributing conditions.

Treatments for central sleep apnea might include:

• Addressing associated medical problems. Possible causes of central sleep apnea include other disorders and treating those conditions might help your central sleep apnea. For example, therapy for heart failure might improve central sleep apnea.
• Reduction of opioid medications. If opioid medications are causing your central sleep apnea, your doctor might gradually reduce your dose of those medications.

• Continuous positive airway pressure (CPAP). This method, also used to treat obstructive sleep apnea, involves wearing a mask over your nose or your nose and mouth while asleep.

  The mask is attached to a small pump that supplies a continuous amount of pressurized air to hold open your upper airway. CPAP may prevent the airway closure that can trigger central sleep apnea.

  As with obstructive sleep apnea, it's important that you use the device only as directed. If your mask is uncomfortable or the pressure feels too strong, talk with your doctor. Several types of masks are available. Doctors can also adjust the air pressure.

• Adaptive servo-ventilation (ASV). If CPAP doesn't effectively treat your condition, you might be given ASV. Like CPAP, ASV also delivers pressurized air.

  Unlike CPAP, ASV adjusts the amount of pressure breath-by-breath during inhalation to smooth out your breathing pattern. The device might also automatically deliver a breath if you haven't taken a breath within a certain number of seconds.

  ASV isn't recommended for people with symptomatic heart failure.

• Bilevel positive airway pressure (BPAP). Like ASV, BPAP delivers pressure when you breathe in and a different amount of pressure when you breathe out. Unlike ASV, the amount of pressure during inspiration is fixed rather than variable. BPAP can also be set to deliver a breath if you haven't taken a breath within a certain number of seconds.

  BPAP could worsen central sleep apnea in people with heart failure. Talk to your doctor about the potential risks of BPAP if you have heart failure.

• Supplemental oxygen. Using supplemental oxygen while you sleep might help if you have central sleep apnea. Various devices are available to deliver oxygen to your lungs.
• Medications. Medications such as acetazolamide have been used to stimulate breathing in people with central sleep apnea. These medications might be prescribed to help your breathing as you sleep if you can't tolerate positive airway pressure.

Surgery or other procedures

A newer therapy for central sleep apnea is transvenous phrenic nerve stimulation. A system approved by the U.S. Food and Drug Administration (remedē System) delivers an electrical pulse to the nerve that controls the diaphragm (phrenic nerve) during sleep, which causes you to take a breath. This involves a battery-powered pulse generator that's implanted under the skin in the upper chest.

Used for moderate to severe central sleep apnea, this system produces a steady breathing pattern. More study is needed.

You're likely to start by seeing your primary care doctor. You might then be referred to a sleep specialist.

Here's some information to help you get ready for your appointment.

What you can do

• Bring results of prior sleep studies or other tests with you or ask that they be sent to your sleep specialist.
• Ask someone, such as a spouse or partner, who has seen you sleeping to come with you to your appointment. He or she will likely be able to provide your doctor with additional information.
• Write down your symptoms, including any that may seem unrelated to the reason for which you scheduled the appointment, and when they began.
• Write down key personal information, including major stresses or recent life changes.
• Make a list of all medications, vitamins or supplements you take, including doses.
• Write down questions to ask your doctor.

For central sleep apnea, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• Are there other possible causes for my symptoms?
• What tests do I need? Do these tests require special preparation?
• Is this condition temporary or long lasting?
• What treatments are available, and which do you recommend?
• How will treating or not treating my central sleep apnea affect my health now and in the future?
• I have other health conditions. How can I best manage these conditions together?
• Are there brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

• Have your symptoms been continuous or do they come and go?
• Can you describe your typical sleep schedule?
• How long do you sleep, and do you sleep soundly? How many times do you wake during the night?
• Do you know if you snore?
• How do you feel when you wake up? Are you short of breath?
• Do you fall asleep easily during the day?
• Has anyone ever told you that you stop breathing while you're sleeping?
• Are you short of breath when you wake up at night?
• Do you have heart problems? Have you suffered a stroke?