CPAP Side Effects: Common Issues and How to Fix Them

The Reality of CPAP Side Effects

CPAP therapy is one of the most effective treatments for obstructive sleep apnea. Research consistently shows that it reduces cardiovascular risk, improves daytime alertness, and can be life-changing for millions of users. But that does not mean it is always comfortable, especially at first.

Most CPAP users experience at least one side effect during their first few weeks of therapy. A study published in the Journal of Clinical Sleep Medicine (Baltzan et al., 2009) found that over 65% of new CPAP users reported at least one bothersome side effect in the first month. The good news: nearly all of these issues have practical solutions. The key is identifying what is causing your discomfort and addressing it specifically.

Here are the most common CPAP side effects, what causes each one, and how to fix them.

Aerophagia: Swallowing Air and Bloating

What it is: Aerophagia literally means "air swallowing." Instead of all the pressurized air going to your lungs, some of it goes down your esophagus and into your stomach. The result is bloating, gas, abdominal distension, belching, and sometimes stomach pain. It can happen during the night or be most noticeable when you wake up in the morning.

Why it happens: CPAP pushes air at a set pressure. If that pressure is higher than what your airway needs, excess air has to go somewhere. Your esophagus is right next to your trachea, and at higher pressures, air can be forced past the esophageal sphincter into your stomach. Research published in Sleep Medicine Reviews (Shepherd et al., 2013) found that aerophagia is more common at pressures above 15 cmH2O and in patients who breathe through their mouth.

How to fix it:

• Talk to your provider about EPR (Expiratory Pressure Relief). EPR lowers the pressure during exhalation, which can reduce air swallowing. This is a setting your sleep physician can adjust. Learn more about how pressure settings work.
• Sleep with your head elevated. Raising the head of your bed 30 degrees (or using a wedge pillow) uses gravity to keep air moving toward your lungs rather than your stomach.
• Avoid eating large meals close to bedtime. A full stomach puts pressure on the esophageal sphincter, making it easier for air to enter.
• Check your pressure. If you are on a fixed-pressure CPAP, the pressure may be set higher than necessary. Your provider can evaluate whether switching to auto-adjusting (APAP) mode or lowering the maximum pressure is appropriate.

When to see your doctor: If aerophagia is severe enough to disrupt your sleep or cause persistent abdominal pain, bring it up at your next appointment. Your provider may recommend a pressure adjustment or a switch to a bilevel (BiPAP) device, which uses lower pressure during exhalation.

Dry Mouth and Nose

What it is: You wake up with a mouth that feels like sandpaper, a nose that is raw and congested, or both. This is one of the most commonly reported CPAP side effects.

Why it happens: Your CPAP delivers a continuous stream of pressurized air that evaporates moisture from your nasal passages and throat faster than your body can replace it. If you use a nasal mask and your mouth falls open during sleep, the drying effect intensifies dramatically as humidified air escapes through your mouth.

How to fix it:

• Turn up your humidifier. Most modern CPAP machines (including the ResMed AirSense 10 and 11) have built-in heated humidifiers. Start by increasing the setting by one level. Give it 2 to 3 nights before adjusting again. A setting of 5 or 6 works well for most people.
• Use a heated CPAP hose (opens in new tab). A heated tube maintains the air temperature between the humidifier and your mask, preventing moisture from condensing in the tubing (a problem called rainout, covered below). The ResMed ClimateLineAir is the standard option for AirSense machines.
• Try a CPAP chin strap (opens in new tab) if you use a nasal mask and tend to mouth-breathe. Chin straps keep your jaw closed so humidified air stays in your nasal circuit.
• Consider a full-face mask if mouth leak persists. Full-face masks cover both nose and mouth, so mouth opening does not cause air loss.
• Use saline nasal spray before bed to pre-moisturize your nasal passages.

For a deeper dive into this topic, see our complete guide on CPAP dry mouth and nose.

When to see your doctor: If dryness persists despite a humidifier set to maximum and heated tubing, or if you develop frequent nosebleeds, consult your provider. Persistent dryness can sometimes indicate a medication side effect or an underlying nasal condition that needs separate treatment.

Skin Irritation and Pressure Sores

What it is: Red marks, skin breakdown, or sore spots where your mask contacts your face. Common locations include the bridge of the nose, cheeks, and forehead. In severe cases, prolonged pressure can cause actual skin ulceration.

Why it happens: Your mask needs a seal to deliver therapy effectively. That seal requires contact pressure against your skin for 6 to 8 hours every night. Over time, this can irritate sensitive skin, especially if the mask is too tight, the wrong size, or worn with a dirty cushion. Silicone allergies (rare but real) can also cause irritation.

How to fix it:

• Do not overtighten your mask. This is the most common cause of skin irritation. Your mask should be snug enough to seal, not tight enough to leave deep impressions. Fit your mask while lying down in your sleeping position, not while sitting up.
• Use CPAP mask liners (opens in new tab). These soft fabric barriers sit between the mask cushion and your skin, reducing direct silicone contact and absorbing moisture. They can dramatically improve comfort for people with sensitive skin.
• Replace your cushion regularly. Silicone degrades over time. Facial oils break down the material, and a degraded cushion requires more pressure to seal. Most manufacturers recommend replacing mask cushions every 1 to 3 months. Check our guide on mask types for more on cushion options.
• Wash your face before bed. Removing oils and moisturizers improves the mask seal, which means you can wear it looser. Avoid petroleum-based products near mask contact areas, as they degrade silicone.
• Make sure your mask is the right size. Many mask models come with sizing templates. An undersized mask presses harder against a smaller area, increasing irritation.

When to see your doctor: If you develop open sores, persistent redness that does not resolve within a day, or a rash that looks like an allergic reaction (widespread redness, itching, hives), contact your provider. You may need a different mask material (memory foam options exist) or a different mask style entirely.

Claustrophobia and Anxiety

What it is: A feeling of panic, confinement, or anxiety when wearing your CPAP mask. Some people feel it immediately when they put the mask on. Others develop it gradually. It is one of the most common reasons people abandon CPAP therapy.

Why it happens: Having something strapped over your face while you try to sleep triggers a natural claustrophobic response in many people. The feeling of pressurized air can also feel unnatural, especially for new users who are not accustomed to breathing against positive pressure.

How to fix it:

• Try a less invasive mask style. Nasal pillow masks sit only at the entrance of your nostrils, with minimal facial contact. Many people who feel claustrophobic in a full-face mask find nasal pillows completely comfortable.
• Use the ramp feature. Most CPAP machines start at a lower pressure and gradually increase to your prescribed setting over 15 to 30 minutes. This lets you fall asleep at a comfortable low pressure before the machine ramps up.
• Practice wearing the mask while awake. Desensitization works. Wear your mask while reading, watching TV, or relaxing for 15 to 20 minutes during the day. This helps your brain learn that the mask is not a threat.
• Start with just the mask. Before connecting the hose, wear the mask alone. Then add the hose without turning on the machine. Then turn on the machine at the lowest setting. Graduate each step over several days.
• Try the exhale pressure relief setting. EPR reduces the pressure when you breathe out, which can make the experience feel more natural and less like breathing against resistance.

When to see your doctor: If mask anxiety persists after 2 to 3 weeks of consistent desensitization practice, talk to your sleep physician. They may recommend a behavioral sleep medicine referral, or in some cases, a short course of anti-anxiety support to help you through the adjustment period.

Ear Pressure and Discomfort

What it is: A feeling of fullness, popping, or pressure in your ears during CPAP use. Some people describe it as similar to the sensation during airplane descent.

Why it happens: Your ears, nose, and throat are connected via the Eustachian tubes. Pressurized air from your CPAP can travel through the nasopharynx into these tubes, creating a pressure differential in your middle ear. This is more common at higher pressure settings and in people with narrow or congested Eustachian tubes.

How to fix it:

• Address nasal congestion first. Swollen nasal passages increase the likelihood of pressure being redirected toward the Eustachian tubes. Saline rinses and nasal sprays can help keep passages clear.
• Use the ramp function to start at a lower pressure and ease into your prescribed setting.
• Try swallowing or yawning before settling in for the night with your mask on. This opens the Eustachian tubes and can equalize pressure.

When to see your doctor: If ear pressure is persistent, painful, or accompanied by hearing changes, see your provider. Chronic ear pressure on CPAP can sometimes indicate a Eustachian tube dysfunction that needs evaluation by an ENT specialist.

Nasal Congestion

What it is: Your nose feels stuffy, swollen, or completely blocked during or after CPAP use, even though you were not congested before putting on the mask.

Why it happens: When pressurized air flows through your nasal passages, it can trigger an inflammatory response in the nasal mucosa. This is your body's protective reaction to a continuous airflow that is faster and drier than normal breathing. The nasal tissues swell, producing more mucus to compensate for moisture loss.

How to fix it:

• Increase humidifier settings. Dry air is the primary driver of CPAP-induced congestion. Higher humidity counteracts the drying effect that triggers the inflammatory response.
• Use a heated hose (opens in new tab) to deliver warm, moist air consistently.
• Try saline nasal spray or a saline rinse (such as a neti pot) before bed. This pre-moisturizes your passages and reduces the reactive swelling.
• Check your mask and tubing for cleanliness. Dirty equipment can harbor bacteria and allergens that worsen nasal inflammation. Follow a regular cleaning routine.
• Consider a nasal corticosteroid spray. Products like Flonase (fluticasone) are available over the counter and can reduce nasal inflammation. Use as directed on the packaging, and mention it to your provider at your next visit.

When to see your doctor: If nasal congestion is severe enough that you cannot breathe through your nose on CPAP, or if over-the-counter remedies are not helping after 2 weeks, your provider may refer you to an ENT specialist to rule out structural issues like a deviated septum or nasal polyps.

Rainout: Condensation in Your Hose

What it is: Water droplets accumulate inside your CPAP tubing and drip onto your face or into your mask during the night. It is startling, uncomfortable, and can wake you up.

Why it happens: Your humidifier heats water to add moisture to the pressurized air. As that warm, humid air travels through an unheated tube in a cool room, the temperature drops and moisture condenses on the inner walls of the tubing, just like condensation on a cold glass on a humid day.

How to fix it:

• Use a heated hose. This is the most effective solution. Heated tubing maintains the air temperature along the entire length of the hose, preventing condensation from forming. The ResMed ClimateLineAir heated tube (opens in new tab) is designed for AirSense machines and includes a built-in temperature sensor.
• Keep your CPAP machine at or below pillow level. If the machine is higher than your mask, gravity pulls condensation toward your face. Placing the machine on a nightstand at bed height or slightly below allows condensation to drain back toward the humidifier.
• Lower your humidifier setting slightly. If the room is warm or you are using a heated hose, you may not need maximum humidity.
• Insulate the hose. CPAP hose covers (fabric sleeves that wrap around the tubing) provide basic insulation and can reduce condensation in mildly cool rooms.
• Raise the room temperature. A warmer room means less temperature differential and less condensation. Even a few degrees can make a difference.

When to see your doctor: Rainout itself is not a medical concern, but if it is disrupting your sleep frequently and the solutions above are not helping, your equipment supplier may be able to recommend compatible heated tubing or alternative humidification approaches for your specific machine.

How to Track Side Effects in Your Data

Many CPAP side effects leave traces in your therapy data. When you import your SD card into CPAP Clarity, look for these patterns:

• High leak rates often correlate with dry mouth (air escaping through your mouth or around the mask seal), skin irritation from overtightening, and reduced therapy effectiveness. See our guide on fixing CPAP leaks.
• Frequent awakenings visible in your session data may correspond to rainout episodes, mask discomfort, or claustrophobia-related mask removal.
• Pressure spikes in auto-adjusting mode can trigger aerophagia and ear pressure in sensitive users.

Tracking your data alongside a simple side-effect diary (even just a note on your phone each morning) can help you and your provider identify what is causing discomfort and whether the fixes you try are actually working.

Track your CPAP therapy data for free with CPAP Clarity →

When to Talk to Your Doctor

Most CPAP side effects are manageable with the adjustments described above. But some situations require professional guidance:

• You are considering stopping CPAP because of side effects. Your provider has options you may not know about (different machines, different masks, pressure adjustments, bilevel therapy).
• Skin breakdown that is not healing, open sores, or signs of infection.
• Severe aerophagia causing significant abdominal pain or interfering with sleep.
• Persistent ear pain or hearing changes that do not resolve with basic measures.
• Claustrophobia or anxiety that is not improving after 2 to 3 weeks of desensitization.
• Any new or unexplained symptom that appeared after starting CPAP.

Never stop CPAP therapy on your own without discussing it with your sleep physician. Untreated sleep apnea carries serious long-term health risks. Research shows that consistent CPAP use supports cardiovascular health, cognitive function, and overall quality of life. Your provider can almost always find a solution that makes therapy tolerable while keeping you protected.

The Bottom Line

Side effects are a normal part of adjusting to CPAP therapy. They are common, they are well understood, and in the vast majority of cases, they are fixable. The users who succeed long-term are the ones who identify their specific issues, try targeted solutions, and work with their providers when self-help measures are not enough.

Your CPAP data is your best diagnostic tool for many of these problems. Import your SD card, review your leak rates and pressure trends, and bring that data to your provider visits. The more specific information you have, the faster you and your doctor can find the combination of settings, equipment, and habits that makes therapy comfortable and effective.