Reading your sleep data
Central vs Obstructive Apneas on Your CPAP Report
An obstructive apnea means your airway collapsed while you kept trying to breathe; a central apnea means your brain briefly did not signal a breath while the airway stayed open. CPAP treats obstructive events well, but frequent central events on your report are a reason to see your clinician, not to adjust settings yourself.
Obstructive events
In obstructive sleep apnea, the soft tissues of the throat collapse and block airflow even though your chest and belly are working to breathe. CPAP pressure holds the airway open, so these events usually drop sharply with therapy.
Hypopneas are partial blockages and are counted with apneas in your AHI.
Central or clear airway events
In a central apnea, the drive to breathe pauses. Machines label these as central apneas or clear airway apneas because the airway appears open. ResMed says the AirSense 11's advanced event detection identifies central sleep apnea events.
Raising pressure is not a treatment for central apneas, so these events are something for your clinician to interpret rather than a sign your pressure is too low.
Why centrals can show up on CPAP
A few central events are common, especially around falling asleep or after an arousal. Some people see more central events after starting CPAP. Whether that matters, and whether it settles, is a question for your clinician.
Opioid medicines, heart failure, stroke, and high altitude are associated with central sleep apnea, which is one reason the AASM recommends in-lab testing rather than a home test for people with those risks.
When to see your clinician
Tell your clinician if central or clear airway events make up a large share of your AHI, if your AHI stays high, or if you feel worse on CPAP. They may review your pressure, order an in-lab study, or consider other devices such as bilevel with backup rate or ASV.
Machine estimates are not a diagnosis. Only a clinician can decide what your central events mean.
Frequently asked questions
What is a clear airway apnea on CPAP?
It is a pause in breathing where the machine detects that the airway is open, which suggests a central rather than obstructive event. A few are common; many should be reviewed by your clinician.
Can CPAP cause central apneas?
Some people have more central events after starting CPAP. Your clinician can review your data and decide whether settings or a different therapy are needed.
Should I lower my pressure if I have central apneas?
No. Do not change your pressure yourself. Bring your data to your clinician, who can safely make that decision.
Are central apneas dangerous?
It depends on how many and why. Frequent central events can point to other health conditions, so they deserve medical review.
Sources
Last reviewed October 11, 2026. How we research · Report an error