Key Takeaways

 

Almost everyone who starts CPAP therapy runs into at least one of these CPAP side effects in the first few weeks. Dry mouth, a stuffy nose, marks on your face when you wake up, maybe something stranger like bloating you didn't expect. None of it means you're doing something wrong, and none of it means CPAP therapy isn't right for you.

Most side effects come down to a handful of causes: fit, humidity, pressure, or simply the adjustment period your body needs. This list covers 15 of the most common ones, why they happen, and a practical fix for each.

The Top 15 Side Effects

1. Dry mouth

This usually means air is escaping through your mouth instead of staying in your nasal passage, which dries out the tissue quickly. It's especially common with nasal and nasal pillow masks. Try increasing your humidifier setting first, and if it continues, CPAP Comfort tape is designed specifically to keep the mouth closed during sleep as a comfortable alternative to a chin strap.

2. Dry or stuffy nose

Unhumidified air moving through your nasal passages all night can leave them dry and irritated, which your body sometimes responds to with congestion. Increasing the humidifier setting is the first fix. If it persists, check the mask seal for small leaks that might be drying out one side more than the other.

3. Skin marks or irritation from the mask

Marks after waking usually mean the headgear is too tight, or the cushion has stiffened with age and is no longer sealing the way it should. Check headgear tension first; it should be snug, not tight enough to leave a deep impression. If the cushion is old, it may be due for replacement.

4. Bloating or gas (aerophagia)

This happens when you swallow air during sleep, usually from higher pressure settings or from breathing through your mouth. Comfort tape can help if mouth breathing is the cause. If bloating is frequent or uncomfortable, it's worth discussing your pressure settings with your provider.

5. Claustrophobia or anxiety wearing the mask

Feeling closed in is a common early reaction, especially with full face masks. Try wearing the mask for short periods during the day, while watching TV or reading, before using it to sleep. This builds familiarity without the added pressure of trying to fall asleep. A different mask style may also help if the feeling doesn't ease.

6. Mask leaks

Leaks usually trace back to fit, cushion wear, or headgear that's stretched out and no longer holding tension. For a full breakdown of causes and fixes, see our guide on comfortable and effective CPAP therapy, which covers fit troubleshooting in detail. See Your Guide to Comfortable and Effective CPAP Therapy.

7. Eye irritation

If air is leaking upward from the top of the mask seal, it can blow directly into your eyes overnight, leaving them dry or irritated by morning. Refitting the mask and checking the cushion for wear are the first steps. This is often the same root cause as general mask leaks.

8. Difficulty falling asleep

The unfamiliar sensation of air pressure and having something on your face can make falling asleep harder at first. If your machine has a ramp feature, which starts at a lower pressure and increases gradually, using it can ease the transition. This usually improves within the first couple of weeks.

9. Chest discomfort

A mild feeling of pressure or tightness in the chest can occur as your body adjusts to positive airway pressure. This typically resolves within the first few weeks. If it's significant, sharp, or doesn't improve, mention it to your provider rather than waiting it out.

10. Noise disturbance

A machine or hose that's gotten louder over time is usually a sign of aging equipment rather than a problem with the machine itself. A worn hose or a dirty filter can both increase noise. See our equipment care guide for replacement timelines.

11. Headaches

Headaches during the adjustment period are sometimes linked to pressure settings or simply dehydration from sleeping with drier air. Staying hydrated during the day helps. If headaches are frequent or severe, discuss your pressure settings with your provider rather than adjusting them yourself.

12. Excess condensation ("rainout") in the hose

When warm, humidified air moves through a hose in a cooler room, condensation can build up inside the tubing, sometimes enough to drip. A hose insulation wrap helps regulate the temperature difference, and lowering the humidifier setting slightly can also reduce it.

13. Sinus pressure

This can result from congestion, dry air, or pressure settings that feel too high for your sinuses to adjust to comfortably. A saline rinse before bed and an adjusted humidifier setting are the first things to try. If it persists, it's worth mentioning at your next follow-up.

14. Nosebleeds

Dry air, especially during winter months or in low-humidity climates, can dry out nasal tissue to the point of minor bleeding. Increasing humidification is the most effective fix. A saline gel applied before bed can also help protect the tissue.

15. Feeling like therapy isn't helping yet

This is one of the most common and most discouraging side effects, and it's usually just timing. Most people need two to four weeks of consistent use before they notice a real difference in how they feel during the day. Give it that window before assuming something is wrong.

When to Talk to Your Sleep Specialist

Most of what's on this list resolves with a small adjustment and a bit of time. A few situations are worth a direct conversation with your sleep specialist or DME provider rather than continuing to troubleshoot on your own.

• Any side effect that persists past four to six weeks despite trying the fixes above.

• Chest pain, as opposed to mild chest discomfort.

• Severe or worsening headaches.

• Any symptom that's getting worse over time rather than easing.

None of these mean you're doing something wrong. They're simply the point where a specialist's input is more useful than continuing to adjust things yourself.

 

Frequently Asked Questions

Is it normal to have side effects when starting CPAP?

Yes. Most people experience at least one side effect during the first few weeks of therapy, and the large majority resolve with a small adjustment to fit, humidity, or routine.

How long do CPAP side effects last?

Most side effects related to the adjustment period improve within two to four weeks of consistent use. Side effects tied to fit or equipment condition can persist until the underlying issue, like headgear tension or cushion wear, is addressed directly.

Can side effects mean my mask doesn't fit?

Often, yes. Skin marks, leaks, and eye irritation are frequently fit-related. If you're experiencing several of these together, it's worth reviewing your mask fit and headgear tension before assuming anything else is wrong.

Should I stop using CPAP if I have side effects?

Generally, no. Stopping therapy removes the treatment that's helping your sleep apnea without addressing the side effect itself. Most side effects have a direct fix. If something feels serious or doesn't improve, talk to your provider rather than stopping on your own.

When should I contact my doctor about CPAP side effects?

If a side effect persists past four to six weeks despite trying the relevant fix, or if you experience chest pain, severe headaches, or any symptom that's worsening rather than improving, reach out to your sleep specialist.