CPAP Side Effects (And What Actually Fixes Them)

Nobody warns you properly. You get a machine, a mask, a pamphlet, and a cheerful “you’ll get used to it” — and then at 2am you’re awake with a dry mouth, a hissing leak, and air in your stomach, wondering whether this is worth it.

Most of it is fixable. Here is the list, organised so you can jump to whatever is ruining your night.

The NIH is upfront that side effects are part of the picture, listing “congestion, dry eyes or mouth, nosebleeds, or a runny nose” among them¹ . Common does not mean you have to live with it.

Dry mouth

Why it happens. Usually not because the humidifier is too low. Usually because your mouth is falling open at night and pressurised air is running straight through — in the nose, out the mouth — drying everything on the way.

The fix ladder:

1. Turn the humidifier up a notch. Free, and occasionally that’s all it is.
2. Add a chin strap if you’re on a nasal mask or pillows. Cheapest real fix.
3. Switch to a full face mask, which seals nose and mouth together.
4. If you’re congested and forced to mouth-breathe, treat the congestion — that’s a doctor conversation, not a CPAP one.

Full detail in CPAP and dry mouth.

Red marks and skin irritation

Why it happens. Almost always over-tightened straps. Silicone pressing hard into skin for eight hours leaves marks; do it for months and you can get genuine skin breakdown on the nose bridge.

The fix:

• Loosen the headgear. Fit the mask lying down with the machine running and tighten only until the leak stops. Counter-intuitive, effective.
• Check the cushion size. A mask that only seals when tight is the wrong size.
• Put fabric between silicone and skin.
• Replace a cushion that’s gone soft, shiny, or sticky — worn silicone grips instead of sealing.

Air in your stomach (aerophagia)

Why it happens. You’re swallowing air instead of, or as well as, breathing it. It shows up as bloating, belching, and gas that will surprise you.

What helps:

• Sleeping on your side rather than your back, and slightly elevating the head of the bed.
• Making sure your mask isn’t leaking — fighting a leak encourages swallowing.
• Exhale relief settings (called EPR, Flex, or similar depending on the machine) reduce pressure when you breathe out, which many people find helps.
• If it persists, the pressure may genuinely be higher than you need. That is a clinician conversation.

More in aerophagia and CPAP bloating.

Sore, dry, or watery eyes

Why it happens. A leak from the top of the mask blowing air directly across your eyes all night. You often won’t notice it while asleep — you’ll just wake up with eyes that feel scratched.

The fix. This is purely a seal problem. Re-fit the mask lying down, check the cushion isn’t worn, and consider a mask that doesn’t sit over the nose bridge if the leak keeps recurring there. See fixing mask leaks.

Water in the hose (rainout)

Why it happens. Warm humid air from the humidifier travels down a cold hose, condenses, and pools — then gurgles, or worse, arrives in your face.

The fix, in order:

1. Insulate the hose. A fleece cover is a few dollars and solves most cases.
2. Run the hose under the covers rather than across a cold room.
3. Turn the humidifier down slightly.
4. Heated tubing, if your machine supports it, holds air temperature all the way to the mask and largely eliminates the problem.

Nasal congestion, runny nose, and nosebleeds

Why it happens. Pressurised air is drying and irritating to nasal tissue. Some people react with congestion, some with a constantly running nose, and some with dryness bad enough to cause nosebleeds.

What helps:

• Increase humidity. This is the one where the humidifier really is the answer.
• Use distilled water so the chamber doesn’t scale up and lose efficiency.
• Saline nasal spray or a rinse before bed.
• Talk to your doctor about the congestion itself — untreated allergies or rhinitis make CPAP far harder than it needs to be.

Claustrophobia and panic

Why it happens. You are strapping a device to your face and it pushes air at you. A lot of people find that genuinely distressing, and it has nothing to do with willpower.

What helps:

• Desensitisation: wear the mask while awake, watching TV, for a few minutes a day. Then with the machine on. Then in bed. Build up over a week or two.
• Use the ramp feature so the machine starts at a lower pressure.
• Choose a mask with less on your face — nasal pillows are far less enclosing than a full face mask.
• Take the pressure of “eight hours or bust” off yourself. Four hours tonight is better than zero.

Noise

Modern machines are quiet; a noisy one usually means something is wrong. Check for a whistling leak at the mask, a hose connection that isn’t seated, or a filter that’s overdue. A machine that has genuinely become loud is worth reporting — it may be failing.

Sore teeth or jaw from a chin strap

Chin straps work by holding your jaw closed, and some people find that pressure genuinely uncomfortable over months. If your jaw aches, ease the tension, try a different design, or move to a full face mask instead. Persistent jaw or dental pain is worth mentioning to your dentist.

The one “fix” to avoid

Ozone and UV sanitising gadgets are heavily marketed to CPAP users as a solution to cleaning. The FDA has determined these devices are “not legally marketed for this use” and that “it is unknown if these CPAP cleaners are safe and effective,” noting that ozone exposure “may worsen a patients’ existing chronic respiratory diseases or increase the chance of a respiratory infection”² .

If your equipment smells odd or your airways are irritated after using one, that is a reason to stop, not to buy a better one. The FDA’s recommendation is to follow the manufacturer’s instructions, which “normally include regular cleaning with soap and water”² . See how to clean your CPAP.

When to stop troubleshooting and call someone

Call your clinician or DME provider if:

• You’ve worked through the fixes and something still hurts every night.
• Your machine’s AHI has been climbing steadily for weeks — see reading your CPAP data.
• You have chest pain, severe shortness of breath, or a skin sore that isn’t healing.
• You are about to give up. That is exactly the point at which a different mask or a setting change from your clinician most often rescues the whole thing.