Almost everything on this website is about obstructive sleep apnea — the throat that collapses. But there is another, rarer kind that works in the opposite way: central sleep apnea. Here the airway stays open; the problem is that the brain briefly stops sending the order to breathe. It is the gap this site has not covered, and it matters because it usually points to a different cause and a different treatment.
The short answer
- ·Obstructive apnea = the airway collapses (there is effort to breathe). Central apnea = the airway is open but the brain pauses the command (there is no effort to breathe).
- ·It is much rarer than the obstructive kind and is usually a sign of another problem: heart, brain, a medicine or high altitude.
- ·The treatment starts by treating the cause. The advanced device (ASV) is contraindicated in heart failure with a weak heart.
Central vs obstructive: the key difference
Obstructive apnea
The brain keeps sending the order to breathe, and the chest and belly keep trying — but the airway has collapsed, so no air gets through. It is a plumbing problem in the throat. This is the common one, the one CPAP, oral appliances and surgery are designed for.
Central apnea
The airway is open and clear, but the brain briefly stops sending the signal, so for a few seconds the chest does not even try to breathe. It is a control problem, not a blockage. The fix is not to open the throat but to stabilise the signal — and that depends on why it became unstable.
If you are still working out which one applies to you, our guide on snoring vs sleep apnea and the symptoms of sleep apnea are a good place to start — although central apnea, importantly, often comes with little or no snoring.
What causes central sleep apnea
Central apnea is almost never a disease on its own — it is usually the consequence of something else that destabilises the brain’s breathing control. The main causes are:
- Heart failure. A weak heart with slow circulation delays the signals that regulate breathing, which makes the control system overshoot and undershoot. This produces the typical Cheyne-Stokes respiration (see below). It is the classic cause of central apnea in adults.
- Opioids. Strong painkillers (morphine, methadone, oxycodone and similar) depress the brain’s respiratory drive and can cause central apneas — a distinct pattern, with a blunted, not over-sensitive, breathing control.
- Stroke and other neurological conditions. Damage to the areas that govern breathing can leave central apneas behind.
- High altitude. In the thin air of the mountains, low oxygen makes breathing oscillate between deep breaths and pauses (high-altitude periodic breathing). It affects healthy people too and eases on returning to lower ground; the drug acetazolamide can help.
- Treatment-emergent (on CPAP). In some people central apneas appear precisely when CPAP starts treating their obstructive apnea (see below).
Cheyne-Stokes respiration: the heart’s fingerprint
Cheyne-Stokes respiration is a very recognisable breathing pattern, typical of heart failure. Breaths grow steadily deeper and faster, reach a peak, then fade away until breathing stops altogether for a few seconds — a central apnea — and then the whole crescendo-decrescendo starts again, cycle after cycle through the night. It happens because the slow, weak circulation delays the feedback the brain uses to set breathing, so the system keeps overcorrecting.
Why it matters: finding Cheyne-Stokes respiration on a sleep study is often the first clue that the heart needs attention, so the priority is to optimise the heart failure itself, not just to treat the breathing at night.
Apnea that appears on CPAP (treatment-emergent)
A frequent and disconcerting situation: someone starts CPAP for ordinary obstructive apnea, the airway opens up — and central apneas appear or become obvious that were not the main problem before. This is treatment-emergent central sleep apnea, also called complex sleep apnea. It is detected in roughly 5 to 15 percent of patients during CPAP titration.
The reassuring part: in most people it settles on its own over weeks to months as the body adapts to the therapy. It does not mean the CPAP has failed — it means the treatment needs proper follow-up. Only a minority, in whom the central apneas persist, need a change of approach. If you are struggling with your CPAP for any reason, our guide on CPAP intolerance and alternatives may help — though central apnea, unlike the obstructive kind, is not solved with an oral appliance or throat surgery.
How it is treated — and a vital safety rule
Because central apnea is the consequence of something else, the first and most important step is always to treat the cause: optimise heart failure, reduce or switch opioids, manage the neurological condition, come down from altitude. CPAP is a reasonable first device option for several types of central apnea. A more advanced machine, adaptive servo-ventilation (ASV), tracks your breathing breath by breath and smooths out the central pauses — it controls central apneas well.
The crucial exception (SERVE-HF)
ASV must NOT be used in patients who have heart failure with a weak heart — a reduced ejection fraction of 45% or less — and predominantly central apnea. In a large randomised trial (SERVE-HF, 1,325 patients), adding ASV did not improve outcomes and, worryingly, increased both all-cause and cardiovascular death in this specific group. Since then, ASV is contraindicated for them. This is exactly why central apnea is not a do-it-yourself problem: the right treatment depends entirely on the cause and on your heart.
Honest note: there is no single pill or device that fits all central apnea. Newer options exist for selected cases (for example, an implanted phrenic-nerve stimulator), but they are specialised, not for everyone, and always come after assessing the cause. The aim of this page is to explain the difference clearly, not to replace the individual evaluation a central apnea always needs.
References: Badr MS, Khayat RN, Allam JS, et al., Treatment of central sleep apnea in adults: an American Academy of Sleep Medicine clinical practice guideline (Journal of Clinical Sleep Medicine, 2025); Cowie MR, Woehrle H, Wegscheider K, et al., SERVE-HF — Adaptive Servo-Ventilation for Central Sleep Apnea in Systolic Heart Failure (New England Journal of Medicine, 2015; 1,325 patients, LVEF =45%, ASV increased all-cause and cardiovascular mortality); MSD Manual Professional Edition, Central Sleep Apnea (causes, Cheyne-Stokes respiration, opioid-related and high-altitude central apnea).
Not sure whether your apnea is obstructive or central? The starting point is a proper assessment of your sleep and, when needed, of your heart.
Frequently asked questions
What is the difference between central and obstructive sleep apnea?
In obstructive sleep apnea the brain keeps sending the order to breathe, but the airway collapses and the air cannot get through — there is effort to breathe against a blocked throat. In central sleep apnea the airway is open, but the brain briefly stops sending the command, so for a few seconds there is no effort to breathe at all. Almost everything on this website is about the obstructive kind, which is far more common; central apnea is rarer and is usually a sign of another problem (the heart, the brain, a medicine or high altitude).
What causes central sleep apnea?
The most common causes are heart failure (which produces a typical waxing-and-waning pattern called Cheyne-Stokes respiration), opioid painkillers, stroke and other neurological conditions, and being at high altitude. There is also a particular form called treatment-emergent central sleep apnea, which appears in some people precisely when they start CPAP for obstructive apnea. In each case the underlying problem destabilises the brain’s breathing control.
What is Cheyne-Stokes respiration?
It is a breathing pattern, typical of heart failure, in which breaths grow deeper and faster, then fade away until breathing stops for a few seconds (a central apnea), and then the cycle starts again — a smooth crescendo-decrescendo that repeats through the night. It happens because a weak, slow-circulating heart delays the signals that regulate breathing, so the control system overshoots and undershoots. Finding Cheyne-Stokes respiration is often a clue that the heart needs attention.
Why did central apnea appear when I started CPAP?
This is treatment-emergent central sleep apnea (also called complex sleep apnea). In a minority of people the central apneas appear or become obvious only after CPAP opens up the airway. It is detected in roughly 5 to 15 percent of patients during CPAP titration, and in most of them it settles on its own over weeks to months as the body adjusts to the therapy. It does not mean CPAP has failed; it means the treatment needs follow-up, and only a minority need a change of device.
How is central sleep apnea treated?
The first step is always to treat the cause: optimise heart failure, reduce or change opioids, manage the neurological condition or come down from altitude. CPAP is a reasonable first option for several types of central apnea. Adaptive servo-ventilation (ASV) is a more advanced device that controls central apneas well, but there is one crucial exception: it must NOT be used in patients with heart failure and a weak heart (reduced ejection fraction, 45% or less), because a large trial (SERVE-HF) found it increased the risk of death in that group. The right treatment depends entirely on the cause, so central apnea needs an individual medical assessment.
Related: snoring vs sleep apnea · CPAP alternatives