CPAP therapy is highly effective for treating sleep apnea, but like any medical treatment, it can come with side effects. Most issues are mild, manageable, and tend to improve as you adjust to therapy. Understanding what to expect—and how to address problems when they arise—can help you stick with treatment and get the rest you need.
Dry Mouth and Throat
Dry mouth is one of the most frequently reported CPAP side effects, affecting roughly 40% of users. Waking up with a parched mouth, sticky saliva, or scratchy throat is uncomfortable and can make therapy feel unappealing.
The causes vary. Air leaking through your mouth (especially with nasal masks), reduced saliva production from the airflow, or inadequate humidification can all contribute to dryness.
Solutions include using a heated humidifier, which adds moisture to the pressurized air. If your machine has one built in, try increasing the humidity setting. If you’re using a nasal mask and breathing through your mouth, a chin strap can help keep your mouth closed, or you might consider switching to a full-face mask that covers both nose and mouth.
Staying well-hydrated throughout the day and using a saline nasal spray before bed can also help prevent dryness.
Nasal Congestion and Irritation
The constant airflow can irritate nasal passages, leading to congestion, runny nose, or even nosebleeds in dry climates. Some users find their nose feels stuffier after starting CPAP therapy than before.
Heated humidification is typically the first-line solution. The warm, moist air is gentler on nasal tissues than cold, dry air. Some users also benefit from heated tubing, which prevents the air from cooling as it travels from the machine to the mask.
For persistent congestion, a saline nasal rinse before bed can clear passages and add moisture. If allergies are contributing to the problem, addressing those with appropriate treatment may help. In some cases, prescription nasal sprays might be recommended—discuss this with your provider.
Mask Discomfort and Skin Irritation
Wearing a mask all night can cause discomfort in several forms. Red marks on the face, particularly across the bridge of the nose, are common. Some users develop pressure sores, rashes, or acne in areas where the mask contacts the skin.
Proper fit is crucial. A mask that’s too tight will leave deep marks and cause discomfort; one that’s too loose will leak air and still cause irritation from constant movement. You should be able to slip a finger or two under the straps when the mask is properly adjusted.
If your mask fits well but still causes skin problems, try a different style. Nasal pillows eliminate pressure on the nose bridge; full-face masks distribute pressure differently than nasal masks. Mask liners and cushion covers can provide a barrier between silicone and skin for sensitive users.
Regular cleaning also matters—oils and bacteria can build up on mask cushions and contribute to skin irritation.
Air Swallowing (Aerophagia)
Some CPAP users inadvertently swallow pressurized air during the night, leading to bloating, excessive belching, gas, and abdominal discomfort. This side effect, called aerophagia, can be quite uncomfortable.
Aerophagia often results from pressure settings that are either too high or too low. When pressure is too high, excess air gets forced into the esophagus. When it’s too low, you may subconsciously gulp air trying to get enough. Mouth breathing with a nasal mask can also contribute.
Solutions include checking your mask seal to minimize leaks, trying a different mask style, sleeping with your head slightly elevated, and discussing pressure adjustments with your provider. Switching to an auto-adjusting (APAP) machine, which varies pressure based on your needs, helps some users.
Claustrophobia and Anxiety
The sensation of having a mask strapped over your face can trigger claustrophobia, even in people who don’t typically experience it. Some users feel anxious about the airflow, struggling with the sensation of breathing against pressure.
Gradual acclimation often helps. Try wearing the mask while awake—first with the machine off, then on but at low pressure. Practice relaxed breathing. Use the ramp feature to start at lower pressure and let it gradually increase as you fall asleep.
Mask selection matters too. Nasal pillows and minimal-contact masks are less likely to trigger claustrophobic feelings than full-face designs. For some users, cognitive behavioral techniques or even short-term use of anti-anxiety medication can help during the adjustment period.
Difficulty Exhaling
Some users find breathing out against the constant pressure uncomfortable, particularly at higher settings. This can feel like working harder to breathe, which is counterproductive for a therapy designed to improve sleep.
Pressure relief features, available on most modern CPAP machines under names like EPR (expiratory pressure relief), C-Flex, or A-Flex, temporarily reduce pressure during exhalation. This makes breathing feel more natural while maintaining therapeutic benefit during inhalation.
If pressure relief features don’t provide enough comfort, BiPAP (bilevel positive airway pressure) therapy provides distinctly different pressures for breathing in and out. This requires a prescription change but can make high-pressure therapy much more tolerable.
Dry or Irritated Eyes
Air leaking from the top of a poorly sealed mask can blow directly onto your eyes, causing dryness, irritation, and redness. This is particularly problematic for contact lens wearers.
The solution is almost always improving mask fit. A mask that seals well around the nose shouldn’t direct air toward the eyes. If you can’t achieve a good seal with your current mask, try a different style or size.
Noise
While modern CPAP machines are remarkably quiet, the machine, mask, and tubing can produce sounds that disturb light sleepers. A hum from the motor, whooshing air through the tubing, or whistling from mask leaks can all be noticeable in a quiet bedroom.
For machine noise, ensure the device is on a stable, level surface and that filters are clean. For mask noise, check for proper fit and look for air leaks. Some users find white noise machines helpful for masking CPAP sounds.
When Side Effects Persist
Most CPAP side effects improve with time, proper equipment fitting, and appropriate settings. However, if you’re experiencing persistent problems that affect your ability to use therapy consistently, don’t give up—contact your sleep specialist or equipment provider.
Your healthcare team can adjust pressure settings, prescribe different equipment, recommend accessories, or suggest techniques to improve comfort. The goal is finding a configuration that controls your sleep apnea while remaining comfortable enough for nightly use. That sweet spot exists for most users; sometimes it just takes some troubleshooting to find it.