Central Sleep Apnoea Symptoms: Causes and Signs

Central sleep apnoea symptoms can be easy to overlook, yet they often signal an underlying heart or neurological condition that requires prompt attention. Unlike obstructive sleep apnoea, central sleep apnoea (CSA) occurs when the brain temporarily stops sending signals to the breathing muscles during sleep, causing repeated pauses in breathing, frequent night-time awakenings, and excessive daytime sleepiness. Because these symptoms overlap with many common conditions, CSA is frequently missed. This article explains the key symptoms, how CSA differs from obstructive sleep apnoea, who is most at risk, and when to seek medical advice.

What are the main symptoms of central sleep apnoea?

The main symptoms of CSA are repeated pauses in breathing during sleep, frequent night-time awakenings with breathlessness, excessive daytime sleepiness, morning headaches, and mood changes. Snoring is often absent or mild, unlike in obstructive sleep apnoea.

The main symptoms of central sleep apnoea (CSA) include repeated pauses in breathing during sleep, frequent night-time awakenings, and excessive daytime sleepiness. Unlike some sleep disorders, CSA often causes the person to wake suddenly with a feeling of shortness of breath or an urge to breathe, rather than simply snoring loudly.^[1][2] A bed partner may notice that breathing stops and restarts without any obvious physical struggle; this observation is suggestive but not diagnostic on its own.

Common symptoms include:

• Recurrent awakenings during the night, sometimes accompanied by a sensation of breathlessness

• Excessive daytime sleepiness and difficulty concentrating, even after a full night in bed

• Morning headaches, which can result from reduced oxygen levels overnight^[2][5]

• Difficulty staying asleep (insomnia), particularly in the second half of the night

• Mood changes, including irritability or low mood linked to disrupted sleep

Snoring is less prominent in CSA than in obstructive sleep apnoea, and some people with CSA report little or no snoring.^[17] However, the absence of loud snoring does not exclude obstructive sleep apnoea or a mixed pattern, as both types can coexist. Because the symptoms overlap with many other conditions, including depression, heart failure, and anaemia, CSA is frequently missed or attributed to other causes. If you or someone close to you notices repeated pauses in breathing during sleep, this warrants medical assessment rather than being attributed to ordinary tiredness. Keeping a sleep diary and asking a bed partner to observe your breathing pattern can provide useful information for a GP or sleep specialist. Your GP may also ask you to complete a validated sleepiness questionnaire, such as the Epworth Sleepiness Scale, as part of the initial assessment.

How is central sleep apnoea different from obstructive sleep apnoea?

In CSA the brain fails to send breathing signals, so no respiratory effort occurs during apnoea episodes, whereas in OSA the airway is physically blocked despite continued effort. Distinguishing the two requires a sleep study recording respiratory effort, airflow, and oxygen levels.

Central sleep apnoea differs from obstructive sleep apnoea (OSA) in its underlying mechanism: in CSA, the brain temporarily fails to send the correct signals to the muscles that control breathing, whereas in OSA the airway becomes physically blocked despite continued breathing effort.^[17][18] This distinction matters because the two conditions require different investigations and treatments.

In OSA, the soft tissues of the throat collapse during sleep, causing the characteristic loud snoring and gasping that many people associate with sleep apnoea. The person continues to make breathing efforts, but air cannot pass through the narrowed airway. In CSA, there is no such obstruction. Instead, the respiratory drive from the brain stem is intermittently absent, so breathing simply stops without any accompanying struggle or snoring.

Key differences at a glance:

• Snoring: loud and frequent in OSA; often absent or mild in CSA

• Breathing effort: present but obstructed in OSA; absent during apnoea episodes in CSA

• Underlying cause: anatomical in OSA; neurological or cardiovascular in CSA

• Associated conditions: OSA is strongly linked to obesity and large neck circumference; CSA is more commonly associated with heart failure, stroke, or opioid use

Some people have a mixed picture, with features of both types occurring in the same night. Accurately distinguishing CSA from OSA requires a sleep study that records respiratory effort, typically using thoracoabdominal movement belts, as well as airflow and oxygen levels.^[19][20] Home sleep testing may be appropriate for straightforward suspected OSA, but suspected or complex CSA generally requires full in-laboratory polysomnography, which allows more detailed monitoring.^[3][4] A formal sleep study is needed to distinguish between the two accurately, as treatment with continuous positive airway pressure (CPAP), which is standard for OSA, may not be sufficient or appropriate for CSA.

What causes central sleep apnoea and who is most at risk?

CSA is caused by instability in the brain's respiratory control system, most commonly linked to heart failure, stroke, kidney failure, neurological conditions, and long-term opioid use. Men aged over 65 and people with established cardiovascular or neurological disease are at greatest risk.

Central sleep apnoea is caused by instability in the brain's respiratory control system, which leads to intermittent failure to signal the breathing muscles during sleep. Several underlying conditions and circumstances can disrupt this control system, making certain groups of people significantly more vulnerable.

Medical conditions associated with CSA include:

• Heart failure: one of the most common causes, particularly Cheyne-Stokes respiration, a cyclical pattern of breathing that waxes and wanes

• Stroke or brainstem injury: damage to the areas of the brain that regulate breathing can directly impair respiratory drive

• Kidney failure: metabolic disturbances can affect the chemical signals that control breathing

• Neurological conditions: including Parkinson's disease and multiple system atrophy

• Atrial fibrillation: has been associated with CSA, likely through shared cardiovascular mechanisms^[16]

Medications and substances are also an important cause. Long-term use of opioid analgesics (such as morphine or oxycodone) is a well-recognised risk factor, as opioids suppress the brain's respiratory centres.^[9][10] This is particularly relevant for people on long-term pain management programmes. Sedative medicines, including benzodiazepines, may also contribute to disordered breathing during sleep. If you are taking any of these medicines and are concerned about sleep-related breathing problems, speak to your prescriber before making any changes to your dose, as stopping opioids or sedatives abruptly can be harmful.

Other risk factors include:

• Being male and over the age of 65

• Sleeping at high altitude, where lower oxygen levels can trigger periodic breathing

• Having previously been treated for OSA with CPAP, which can occasionally unmask or induce a central component (sometimes called treatment-emergent CSA)^[23]

Idiopathic CSA, where no clear underlying cause is identified, also occurs but is less common. Because CSA is so closely linked to serious cardiovascular and neurological conditions, identifying and managing the underlying cause is central to treatment, rather than focusing solely on the sleep disturbance itself.

When should you see a GP about your sleep apnoea symptoms?

See a GP promptly if you experience repeated night-time awakenings with breathlessness, persistent daytime sleepiness, or a bed partner reports pauses in your breathing. People with heart failure, stroke, or long-term opioid use should raise sleep concerns at their next specialist appointment.

You should see a GP if you experience persistent daytime sleepiness, repeated night-time awakenings with breathlessness, or if a bed partner reports that your breathing stops during sleep, as these symptoms warrant prompt clinical assessment. While occasional disturbed sleep is common, symptoms that affect your daily functioning or that occur alongside a known heart or neurological condition should not be left uninvestigated.

Contact your GP if you notice:

• Waking repeatedly at night feeling short of breath or with a strong urge to breathe

• Persistent daytime fatigue that does not improve with adequate time in bed

• Morning headaches occurring regularly

• Difficulty concentrating, memory problems, or mood changes linked to poor sleep

• A bed partner reporting pauses in your breathing, particularly without loud snoring

If you have an existing diagnosis of heart failure, have had a stroke, or are taking long-term opioid medication, you should mention sleep-related breathing concerns to your GP or specialist at your next appointment, as CSA is more prevalent in these groups and may affect your overall management.

Driving safety: if you have excessive daytime sleepiness that could affect your ability to drive safely, you must stop driving and seek medical advice. People diagnosed with sleep apnoea may also have a legal obligation to notify the DVLA, depending on the severity of their condition and whether it is being treated effectively.^[14][15] Your GP or sleep specialist can advise you on your individual situation. Further information is available from the DVLA's guidance on assessing fitness to drive.

Seek urgent help via 999 or attend A&E if you experience sudden severe breathlessness, chest pain, or loss of consciousness, as these may indicate a cardiac or neurological emergency rather than a sleep disorder.

Your GP can refer you to a sleep clinic or respiratory specialist for a formal sleep study. Home sleep testing may be suitable for straightforward suspected OSA, but suspected or complex CSA typically requires full in-laboratory polysomnography to record respiratory effort and other detailed measurements.^[3][4] Early diagnosis allows treatment to be tailored to the underlying cause, which is the most effective way to manage central sleep apnoea and reduce associated health risks.

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