Still Snoring With CPAP? This is my Experience
I have severe obstructive sleep apnea. My AHI was 51 at diagnosis, and I have been on CPAP for more than a decade. Most nights my ResMed AirSense 10 does exactly what it is supposed to do: it keeps my airway open, my apnea events stay low, and nobody in the house hears a thing. But every so often, I still snore with CPAP on. It is not common for me, and when it happens, there is almost always a reason I can point to afterward. If you are wondering why you or your partner is still snoring on CPAP.
This confuses a lot of people, understandably. CPAP is supposed to be the fix for snoring, not something you still snore through. If your machine is treating your apnea and your numbers look fine on the app, why would you still be making noise? The honest answer is that CPAP treats obstructive sleep apnea by holding your airway open with pressurized air, but that only works if the air is actually reaching your airway the way it is supposed to. When something interrupts that, whether it is a poor mask seal, a pressure setting that is not quite right for the night, or something going on in your nose or throat that CPAP was never designed to fix, snoring can slip back in even though your therapy is technically working.
I want to walk through the specific things that cause this, based on what actually happens to me and what shows up consistently in the research and in sleep medicine resources. I am not a doctor. My background is in computer science, and everything here comes from being a long-term CPAP patient who has been through most of these problems myself, combined with reading the clinical literature on it. If any of this sounds like your situation and it is not resolving, the right next step is always your sleep doctor or DME provider, not guesswork.
Why You Can Still Snore While Using CPAP
Snoring on CPAP is not the same problem as snoring without it. When you are not on therapy, snoring is caused by your airway partially collapsing and vibrating as air squeezes past. CPAP is designed to prevent that by splinting the airway open with continuous pressure. When you still hear snoring through the mask, it almost always means one of two things is happening: either the pressurized air is not making it to your airway the way it should, or something is narrowing your airway that CPAP pressure alone cannot fully compensate for that night. Below are the causes I have actually run into, in the order I would check them, plus one more that shows up often in the clinical literature even though it is not one I have personally dealt with.
A Mask That Needs Replacing
This is the one that catches me most often. CPAP masks are not built to last forever. The cushion is silicone or foam, and over months of nightly use it compresses, stretches, and slowly loses its ability to seal against your skin. When the seal degrades, air escapes around the edges of the mask instead of going where it is supposed to, which drops the effective pressure reaching your airway and can produce the same vibrating sound as ordinary snoring. It sneaks up on you because the change happens so gradually night to night that you do not notice it until it has become a real problem.
I use the ResMed AirFit F20 full face mask, since I am a chronic mouth breather and need something that covers both my nose and mouth. Even with a mask I know well, the cushion eventually wears out and needs replacing, and when I have let it go too long, snoring is usually the first sign. Manufacturers and insurers publish mask replacement schedules for a reason. If you cannot remember the last time you replaced your cushion, that is worth checking before anything else. I have written a full CPAP replacement schedule guide that covers how often each part of your setup should be swapped out.
Straps That Have Loosened
Related to mask wear, but a separate issue: headgear straps stretch out over time, and if you fall asleep before double-checking the fit, a loose strap can let the mask shift out of position during the night without you waking up for it. A properly fitted mask should feel snug, not tight, but a strap that has gone slack will not hold the seal even if the cushion itself is fine. This is a quick check most nights and one of the easiest fixes on this list. If straps are loosening faster than seems normal, it may be time to replace the headgear itself rather than just the cushion.
Alcohol Before Bed
This is the one I can predict every time. If I have had a drink or two in the evening, I am far more likely to snore through my CPAP that night, even with the mask sealed properly and the pressure unchanged. Alcohol is a muscle relaxant, and that relaxation extends to the muscles supporting your upper airway. This is not a new finding. A study published in the Journal of Neurology, Neurosurgery and Psychiatry found that alcohol increased the frequency and duration of airway obstruction in people with sleep apnea, and in some cases induced snoring and apnea events in people who did not otherwise have them.
CPAP pressure is set to counteract the airway resistance your sleep doctor measured during your titration or home study, not the additional relaxation that alcohol adds on top of it. That is part of why a fixed pressure can be enough on a normal night and not quite enough after a couple of drinks. For me, avoiding alcohol close to bedtime is the simplest and most reliable fix.
A Cold or Nasal Congestion
If I am sick with a cold, I usually snore through the CPAP no matter how well the mask is sealed. Congestion narrows the nasal passages, which changes airflow resistance and can cause noise even when your machine is doing everything correctly. It also makes the mask feel worse generally, since more of your breathing shifts toward your mouth when your nose is blocked. Auto-adjusting machines like the AirSense can compensate for some of this by increasing pressure automatically, but a bad enough cold can outpace what the algorithm is built to handle in a single night.
This is usually temporary and resolves once the congestion clears. If you are dealing with frequent congestion that is affecting your therapy on a regular basis rather than only during illness, that is worth mentioning to your doctor, since it may point to something structural like a deviated septum rather than a passing cold.
Sleep Position
Snoring, with or without CPAP, is often worse when sleeping flat on your back, since gravity allows the tongue and soft tissue to fall backward into the airway. CPAP pressure has to work harder to counteract that compared with side sleeping, and depending on how your pressure was set, it may not fully account for how much your position changes airway resistance. I notice this most on nights when I end up on my back for longer stretches than usual. I have written more about how sleep position interacts with therapy in my guide to sleep positions for sleep apnea, and about strap related side sleeping issues in this piece on sleep positions and CPAP strap marks.
Pressure That Is Set Too Low
This is not one I have personally dealt with, since my pressure has generally matched what I need, but it is worth covering because it is one of the more common explanations in sleep medicine resources. According to SleepApnea.org, your pressure is calculated from your titration study or your machine’s auto-adjusting algorithm, based on the minimum pressure needed to keep your airway open, and if that number was set some time ago and your weight, health, or sleep habits have changed since then, the original setting may no longer be enough. Your airway can start to narrow and vibrate again even though the machine is running normally.
This is different from a leak or a worn mask, since the machine can be sealed perfectly and still be delivering less pressure than you currently need. If nothing about your mask or routine has changed and the snoring is new or ongoing, a pressure review with your sleep doctor is usually the right next step, rather than swapping equipment.
What Actually Fixes It
The fixes mirror the causes above pretty directly, and none of them require guessing.
Tighten or refit the mask. Before assuming anything else is wrong, check the strap tension and make sure the mask is seated properly. A five-minute adjustment solves more snoring complaints than people expect.
Replace the mask cushion if it is old. If you cannot remember your last replacement, treat that as your answer. A worn cushion cannot hold a seal no matter how well it is adjusted.
Cut back on evening alcohol. If you notice the same pattern I do, this is worth testing deliberately. Skip a drink before bed for a few nights and see whether the snoring stops.
Treat congestion when it happens, and mention chronic congestion to your doctor. A cold will pass. Ongoing nasal blockage might not, and it is worth having evaluated rather than working around indefinitely.
Pay attention to sleep position. If back sleeping seems to correlate with your snoring, side sleeping may reduce it, though this is not a substitute for a properly fitted mask and correct pressure.
Ask about a pressure review if nothing else fits. If your mask is newer, your straps are snug, you have skipped alcohol, and you are not congested, but the snoring is still showing up, your pressure setting is the next thing to look at. This is not something to adjust yourself. It needs your sleep doctor or DME provider working from your actual data.
Check your data. Software like OSCAR lets you review your own CPAP data alongside your machine’s built in app, and can show you leak rates and pressure patterns on the specific nights you were snoring. Comparing a good night against a bad one is often the fastest way to spot the actual cause. I have a full guide on how to interpret your CPAP data if you want to dig into this yourself.
Talk to your doctor if it is not occasional. For me, this is rare, tied to specific circumstances like a cold or alcohol, and resolves on its own once the circumstance passes. If snoring is happening most nights regardless of what you do, that is a different situation, and it usually means your pressure setting needs a real review rather than a mask swap. Harvard Health notes that pressure needs can vary significantly by sleep position and sleep stage, and that a range which is too wide can leave the machine unable to adjust quickly enough to meet demand, which is exactly the kind of thing a clinician needs to look at with your actual data rather than guesswork.
When to Bring It to Your Doctor
Occasional snoring tied to an obvious cause, like the ones above, is generally not something to worry about. What is worth flagging to your sleep doctor is snoring that is frequent, that is not explained by anything you can identify, or that comes with other symptoms like gasping, choking, or excessive daytime sleepiness despite consistent CPAP use. Those can point to a pressure setting that no longer matches your needs, a mask that is no longer the right fit for your face, or in some cases a separate issue that CPAP alone will not resolve. Your CPAP data, especially the leak rate and pressure graphs, gives your doctor something concrete to work from rather than a subjective description of still snoring sometimes.
The Bottom Line
Still snoring with CPAP does not mean your therapy has failed or that something is fundamentally wrong with your machine. In my experience, it almost always traces back to something specific: a mask that needs replacing, straps that have loosened, alcohol, a cold, or an unusual amount of time spent on my back. None of those mean the CPAP itself is not working. They mean something is temporarily getting in the way of it working the way it is supposed to. Identify the pattern, fix the specific cause, and for most people, the snoring goes away as reliably as it appeared.
If you want to go deeper into any one of these areas, my guides on why your CPAP mask might be leaking and understanding your CPAP pressure settings both cover the mechanics in more detail.
⚠️ MEDICAL DISCLAIMER This blog provides general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Sleep apnea is a serious condition, and CPAP equipment should be used under proper medical supervision. Always consult your doctor or sleep specialist before starting, stopping, or changing any therapy. I share personal experiences as a CPAP user, not as a medical professional. Individual results vary. For medical guidance, please consult a qualified clinician or the American Academy of Sleep Medicine (aasm.org).
