CPAP Side Effects: What's Normal and What Helps
By Treatments for Sleep Apnea · Published June 8, 2026
Side effects are the number one reason people abandon CPAP, and the frustrating part is that nearly all of them have a fix. A side effect is a problem to solve, not a verdict on whether the therapy is for you. Here is what tends to go wrong and what actually helps.
Dry mouth and congestion
These top the list, and they usually trace back to humidity and mouth breathing. Turn on the heated humidifier and add heated tubing to stop condensation. If you breathe through your mouth at night, a chin strap or a full face mask keeps the air where it belongs. Congestion that lingers may need allergy treatment alongside the humidifier.
Mask leaks and skin irritation
A leak that blows air across your face or into your eyes wrecks sleep and, ironically, gets worse when you tighten the straps. The real fixes are a fresh cushion, the correct size, and fitting the mask while lying down. For red marks, a fabric liner or a different cushion usually solves it faster than any strap change. This overlaps heavily with choosing the right CPAP mask.
Air swallowing and bloating
Swallowing air, called aerophagia, leaves you bloated and gassy in the morning. It often signals pressure that is higher than you need, so an auto-adjusting machine or a pressure tweak from your clinician can help, as can sleeping with your head slightly elevated.
Claustrophobia
Feeling boxed in is common early and usually fades with exposure. Daytime practice and a smaller mask, like a nasal pillow style, help a lot. The habits in how to get used to CPAP are built for exactly this.
When a side effect means something more
Most side effects are nuisances. A few deserve a prompt call: chest discomfort, significant ongoing nosebleeds, or eye irritation that suggests a persistent leak. And if you have worked through the fixes and still cannot tolerate the machine, that crosses into CPAP intolerance, which has its own paths forward.
Questions to ask a clinician
- Could my pressure be set higher than I need?
- Is an auto-adjusting machine or a different mask worth trying?
- Are my leak and usage numbers in a good range?
This is general information, not medical advice. For how CPAP stacks up against other options, see the treatments hub.
Disclosure: This article contains affiliate links. If you buy through them we may earn a small commission at no extra cost to you. We only recommend accessories we would use ourselves. This is not medical advice.
| Accessory | Why it helps | |
|---|---|---|
| CPAP mask cushion replacements | A fresh cushion fixes most leaks and the red marks that come with them. | Check price |
| Heated humidifier chamber | The first-line fix for dry mouth, nosebleeds, and congestion. | Check price |
| CPAP chin strap | Keeps the mouth closed so a nasal mask user stops drying out at night. | Check price |
Frequently asked questions
What are the most common CPAP side effects?
Dry mouth, nasal congestion or runny nose, mask leaks, red marks or skin irritation, swallowing air that causes bloating, and a sense of claustrophobia. Most are mild and fixable, and they tend to ease as you adapt and dial in your setup.
How do I stop CPAP from drying out my mouth?
Turn on or increase the heated humidifier first. If you breathe through your mouth, a chin strap or a full face mask keeps the air from escaping and drying you out. Persistent dryness despite these is worth raising with your clinician.
Why does CPAP make me feel bloated?
Swallowing air, called aerophagia, causes the bloating and gas some users notice. It often comes from pressure that is higher than you need or from swallowing during the night. Lowering pressure, switching to an auto-adjusting machine, or adjusting position can help, so flag it to your clinician.