If your CPAP has worked well for years and you’re suddenly noticing rough patches specifically while falling asleep — rather than throughout the night — you’re not imagining it, and you’re also not alone. This is a common enough complaint that sleep clinics have a standard checklist for it. Here’s what’s usually behind it, and when it’s worth calling your sleep specialist rather than waiting it out.
Why sleep onset is different from the rest of the night
The transition into sleep is when your upper airway muscles are relaxing for the first time that night, and it’s also when many people unconsciously shift position, breathe irregularly for a few minutes, or haven’t fully seated their mask yet. According to the Cleveland Clinic, obstructive sleep apnea events happen when throat muscles intermittently relax and narrow the airway — and that muscle relaxation is often most pronounced right as you drift off, before your body has settled into a steady breathing rhythm.
A CPAP that’s been reliable for years hasn’t necessarily “stopped working” in a global sense if the issue is concentrated at sleep onset. It may simply mean the pressure ramp, mask seal, or your sleep position at the moment of falling asleep has changed.
Common, fixable causes
Mask fit and leaks. Cushions and headgear straps lose their seal over months of washing and wear, and a leak that’s tolerable mid-sleep can be more noticeable — and more disruptive to airway pressure — right as you’re drifting off and moving into a new position. SleepApnea.org’s guide to mask leaks is a good starting point for troubleshooting fit before assuming anything more serious is going on.
Pressure settings that no longer match your needs. Weight changes, alcohol use, nasal congestion, and even the position you fall asleep in can all shift how much pressure you actually need. The Sleep Foundation notes that pressure that was correctly titrated at one point can become too low (or, less commonly, uncomfortably high) as circumstances change — this is worth flagging to your provider rather than adjusting yourself if your machine has a fixed pressure setting.
Ramp features and auto-adjusting machines. Some machines gradually increase pressure over the first several minutes to help you fall asleep more comfortably (a “ramp”). If your device or settings changed recently, that ramp window is exactly when sleep-onset events would show up on your data.
Side effects that mimic or accompany apnea events. Aerophagia (swallowed air), dry mouth, or a mask that startles you awake can all disrupt the sleep-onset window in ways that feel similar to an apnea event even when the underlying cause is different. The Sleep Foundation’s overview of common CPAP side effects covers several of these and how they’re typically managed.
When it’s worth a call to your sleep specialist
Because a CPAP machine’s own reporting (AHI, leak rate, usage data) can only tell you so much, a change in symptoms after years of stability — especially one that’s new and specific to falling asleep — is a reasonable reason to request a data download review or a repeat titration study rather than guessing. This is especially true if you’ve also noticed new snoring, restless legs, or daytime sleepiness returning. A sleep specialist can distinguish between a mechanical fix (mask, pressure, humidity) and something that may call for a fresh evaluation.
This article is general information, not a diagnosis or a substitute for a conversation with your prescribing physician or sleep specialist — if your symptoms are new, worsening, or paired with daytime impairment, it’s worth getting it looked at rather than troubleshooting solo indefinitely.
— Gemifys
