Central Sleep Apnea, and the Kind That Appears on CPAP
Central apnea is the opposite problem to obstructive: the airway is open and the signal to breathe stops. It can also appear after starting CPAP, which alarms people — and usually resolves within weeks.
Almost everything on this site concerns obstructive sleep apnea — the airway closes while you keep trying to breathe. Central sleep apnea is the mirror image, and confusing the two leads people to the wrong treatment.
The difference
Obstructive: the brain sends the signal, the muscles try, and the airway is shut. Effort continues throughout — which is why you strain, why the chest pulls inward, and why partners hear struggle.
Central: the airway is open and the signal to breathe stops. No effort, no struggle, no snoring during the event. Breathing simply pauses.
That distinction is why pressure fixes one and not the other. CPAP holds a collapsing airway open. It cannot supply a respiratory drive that is not firing.
It also explains a reporting quirk: central apnea is quieter. Someone with predominantly central events may not snore at all, so the usual bed-partner alarm is absent.
What causes it
Central apnea is usually a consequence of something else rather than a standalone problem:
Heart failure, where the classic pattern is Cheyne-Stokes respiration — a crescendo-decrescendo cycle of deepening then fading breaths. Its presence is clinically significant in its own right.
Opioids, which suppress respiratory drive directly. This is a common and under-recognised cause, and dose-related.
High altitude, where low oxygen destabilises ventilatory control. Usually temporary. Snoring and altitude.
Stroke and other neurological conditions affecting the brainstem centres that generate breathing rhythm.
Idiopathic, where no cause is found.
Underlying most of these is high loop gain — an over-responsive ventilatory control system that overshoots after a disturbance, blows off too much carbon dioxide, and then has no drive to breathe until it rebuilds. That is one of the four traits that shape how sleep apnea behaves in any individual. Why treatments work for some people and not others.
Central apneas appearing on CPAP
This is the version most people on this page are actually asking about, and the news is better than it feels.
You start CPAP for obstructive apnea, check your data after a few weeks, and find central events where there were none. It reads as the treatment causing a new problem.
A retrospective study of 1,286 patients diagnosed with obstructive sleep apnea measured how often this happens (Javaheri et al., Journal of Clinical Sleep Medicine, 2009).
84 of the 1,286 developed a central apnea index of 5 or more per hour on CPAP — an overall incidence of 6.5%, varying between 3% and 10% month to month [Javaheri 2009].
Then the important part. Of 84 patients, 42 returned for a second CPAP titration, and in 33 of them the central apnea was eliminated [Javaheri 2009]. In the remaining 9 the central apnea index stayed at 5 or above, averaging 13 per hour [Javaheri 2009].
The authors' conclusion: CPAP-emergent central apnea was generally transitory and eliminated within 8 weeks of therapy, and the prevalence of CPAP-persistent central apnea was about 1.5% [Javaheri 2009].
So: roughly 1 in 15 people see central events appear, and for most of them it settles on its own within a couple of months. Around 1 in 65 has a version that persists and needs a different approach.
Who was more likely to have the persistent kind: those with the most severe obstructive apnea, those who already had a central apnea index of 5 or more at baseline — 5 of the 9 did — and opioid users, of whom there were 2 among the 9 [Javaheri 2009].
Tier 1 for the incidence and natural history, from a large cohort. The limitation is that it is retrospective and only half the affected patients returned for retitration, so the resolution rate is measured in those who came back. How we grade evidence.
What this means practically
Do not stop CPAP because central events appeared. That is the instinct and it is usually wrong. The likeliest outcome is that they resolve, and stopping returns you to untreated obstructive apnea, which is the larger problem.
Do tell your provider. This is a data finding that warrants a conversation, and the response may be watchful waiting, a pressure change, or a switch of device mode. Some machines separate central from obstructive events; if yours reports a central apnea index, that is the number in question. How to read your CPAP data.
Mention opioids specifically. If you take them, that belongs in the conversation, because it moves you toward the group where central apnea persists.
Expect a review at around eight weeks rather than an immediate change, unless you are symptomatic or the index is high.
Treatment for genuine central apnea
Different from obstructive, and this is where the two must not be conflated.
Treating the underlying cause comes first — optimising heart failure management, reviewing opioid doses. Adaptive servo-ventilation is used for some patients, though notably not in those with symptomatic heart failure with reduced ejection fraction, where a trial found harm. That is a specialist decision and a genuine example of a treatment being contraindicated in the group it seems designed for.
Supplemental oxygen has a role in some central and hypoventilation syndromes, unlike in obstructive apnea where it does not substitute for treatment. Why oxygen cannot replace CPAP.
The line
No consumer product treats central sleep apnea, and the reasoning is even more direct than with obstructive apnea: tape and strips act on the airway, and in central apnea the airway is already open. There is nothing mechanical for them to do. Snoring versus sleep apnea.