Central sleep apnea is breathing disorder in which breathing repeatedly stops and starts during sleep. These pauses in breathing are called apneas.

Central sleep apnea happens when the brain doesn't send proper signals to the muscles that control breathing. This condition is different from obstructive sleep apnea, in which breathing stops because the throat muscles relax and block the airway. Central sleep apnea is less common than obstructive sleep apnea.

Central sleep apnea can happen because of other conditions, such as heart failure or stroke. Another possible cause is sleeping at a high altitude.

Sometimes, managing existing conditions helps improve symptoms of central sleep apnea. Other treatments for central sleep apnea may include using a device to help breathing or using supplemental oxygen.

Common symptoms of central sleep apnea include:

• Pauses in breathing during sleep, also called apneas.
• Sudden awakenings with shortness of breath.
• Not being able to stay asleep, known as insomnia.
• Excessive daytime sleepiness, known as hypersomnia.
• Trouble focusing.
• Mood changes.
• Morning headaches.
• Snoring.

Although snoring often means the airway may be at least partially blocked, snoring also can occur in people with central sleep apnea. However, snoring may not be as noticeable with central sleep apnea as it is with obstructive sleep apnea.

When to see a doctor

Talk to someone on your primary healthcare team if you have — or if your partner notices — any symptoms of central sleep apnea, particularly:

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

Ask a member of your healthcare team about any trouble sleeping that leaves you regularly fatigued, sleepy and irritable. Feeling overly drowsy during the day can be due to other conditions, such as obstructive sleep apnea or narcolepsy, a condition that causes sudden episodes of sleep. Daytime sleepiness also may be due to not getting enough sleep at night. An accurate diagnosis helps you get the right treatment.

Central sleep apnea happens when the brain doesn't send signals to the muscles involved in breathing.

The brainstem links the brain to the spinal cord. It controls many functions, including heart rate and breathing. Central sleep apnea can be caused by a number of conditions that affect the brainstem's ability to control breathing.

The cause depends on the type of central sleep apnea you have. Types include:

• Cheyne-Stokes breathing. This type of central sleep apnea is most commonly linked to congestive heart failure or stroke. During Cheyne-Stokes breathing, breathing effort and airflow gradually rise and then fall. During the weakest breathing effort, a total lack of airflow can occur.
• Medicine-induced apnea. Taking certain medicines such as opioids can make breathing irregular or stop breathing completely for a short time.
• High-altitude sleep apnea. A Cheyne-Stokes breathing pattern can happen to people at a very high altitude. The change in oxygen at a high altitude can cause fast breathing, known as hyperventilation, followed by taking in too little air.
• Treatment-emergent central sleep apnea. Some people with obstructive sleep apnea develop central sleep apnea while using continuous positive airway pressure, also called CPAP, for treatment. This condition is known as treatment-emergent central sleep apnea. It is a combination of obstructive and central sleep apneas.
• Central sleep apnea caused by other medical conditions. Several medical conditions, including end-stage kidney disease and stroke, may lead to central sleep apnea. This type of sleep apnea doesn't involve Cheyne-Stokes breathing.
• Primary central sleep apnea, also known as idiopathic sleep apnea. The cause of this uncommon type of central sleep apnea isn't known.

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

• Sex assigned at birth. People assigned male at birth are more likely to develop central sleep apnea than are people assigned female at birth.
• 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 conditions. People with heart conditions have a higher risk of central sleep apnea. An irregular heartbeat, known as atrial fibrillation, can increase the risk. Having heart muscles that don't pump enough blood for the body's needs, known as congestive heart failure, also can raise the risk.
• Brain conditions. Stroke, brain tumors or structural changes in the brainstem can affect the brain's ability to regulate breathing.
• High altitude. Sleeping at an altitude higher than you're used to may increase your risk of sleep apnea.
• Opioid use. Brain-related effects of opioid medicines may increase the risk of central sleep apnea.
• CPAP use. Some people with obstructive sleep apnea develop central sleep apnea while using continuous positive airway pressure, also called CPAP, therapy. This condition is known as treatment-emergent central sleep apnea. It is a combination of obstructive and central sleep apneas. For some people, this type of sleep apnea goes away with continued use of the 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 restorative sleep impossible. People with central sleep apnea often have severe fatigue, daytime drowsiness and irritability.

  You might have trouble focusing. You also may find yourself falling asleep at work, while watching television or even while driving.

• Heart conditions. Sudden drops in blood oxygen levels that occur during central sleep apnea can affect heart health.

  If you have heart disease, repeated episodes of low blood oxygen increase the risk of irregular heart rhythms.

You first may see someone on your primary healthcare team for your symptoms. You may be referred to a sleep specialist in a sleep disorder center.

A sleep specialist can help you decide whether you need more testing. 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 a 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 to start treatment for the second half of the night. Treatment might be positive airway pressure or supplemental oxygen.

Polysomnography can help diagnose central sleep apnea. It also can help rule out other sleep disorders, such as obstructive sleep apnea, repetitive movements during sleep or narcolepsy. These other conditions can cause daytime sleepiness but require different treatment.

Other specialists may be able to help detect central sleep apnea. These might include doctors trained in nervous system diseases, known as neurologists, or doctors trained in heart disease, known as cardiologists. You may need imaging of your head or heart to look for conditions that play a part in central sleep apnea.

You're likely to start by seeing a member of your primary healthcare team. 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 earlier sleep studies or other tests with you or ask that they be sent to your care team.
• Bring someone who has observed your sleep, such as a spouse or partner, to your appointment. This person will likely be able to give more information to your care team.
• 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 medicines, vitamins or supplements you take, including doses.
• Write down questions to ask your healthcare team.

For central sleep apnea, some basic questions to ask 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 short term 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 healthcare team is likely to ask you several questions, such as:

• Do you have symptoms all the time 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 a heart condition? Have you had a stroke?