CPAP Therapy

What Is CPAP?

CPAP stands for continuous positive airway pressure. It’s a therapy, delivered by a small bedside machine connected to a mask, that has been the standard first-line treatment for obstructive sleep apnea (OSA) for decades. Rather than a medication or a one-time procedure, CPAP works every night it’s used: a machine draws in room air, pressurizes it gently, and delivers a steady stream through tubing and a mask worn while you sleep.

It’s worth being direct about one point: CPAP treats OSA, it doesn’t cure it. The airway anatomy and reduced muscle tone that let the airway narrow during sleep are still present when the machine is off, which is why nightly use, not a one-time fix, is what sustains the benefit.

How CPAP Keeps the Airway Open

Think of the pressurized air CPAP delivers as a kind of pneumatic splint. During sleep, the muscles supporting the throat relax more than they should in OSA, letting soft tissue fall backward and narrow or close the airway. CPAP’s steady air pressure pushes back against that collapse from the inside, keeping the airway space open so airflow can continue uninterrupted.

This is a mechanical effect, not a change in the airway itself: the pressure doesn’t alter muscle tone or anatomy on its own. It simply holds the space open while it’s applied, which is why the therapy has to run continuously through the night to keep working.

What CPAP Treats

CPAP is primarily used to treat obstructive sleep apnea, where the airway itself repeatedly narrows or closes. It’s typically the first therapy discussed once a sleep study, such as a home sleep apnea test or an in-lab sleep study, confirms the diagnosis, and it remains the most extensively studied treatment across the full range of OSA severity, from mild to severe.

CPAP can also be used, under physician direction, in some central sleep apnea contexts. But central sleep apnea, where the brain’s signal to breathe is irregular rather than the airway being physically blocked, more often calls for a different, more specialized approach. If that’s your situation, our central sleep apnea page covers those treatment options in more depth.

The Equipment: Machine, Tubing, and Mask

At a conceptual level, a CPAP setup has a few core parts. The machine itself generates the pressurized airflow and, on most modern devices, includes a heated humidifier that adds moisture to the air so it feels less drying overnight. Flexible tubing carries that air from the machine to the mask, or interface, worn on the face.

Mask choice is genuinely individualized, not one-size-fits-all. Which fits best depends on how you breathe, whether through your nose or, at times, through your mouth, your facial anatomy, and personal comfort.

Nasal Mask

Covers just the nose. A common choice for people who breathe primarily through the nose during sleep.

Nasal Pillows

Small cushions that rest at the nostril openings, for a lighter, more minimal fit.

Full-Face Mask

Covers both the nose and mouth, often preferred by people who breathe through their mouth or have chronic nasal congestion.

A chin strap paired with a nasal interface is another option some people who breathe through their mouth prefer. Finding the right mask is often part of the early adjustment period, and it’s reasonable to try more than one style, and sometimes more than one size within a style, before settling on what stays comfortable through a full night.

Fixed CPAP vs. Auto-Adjusting PAP (APAP)

Pressure can be delivered in one of two general ways.

Fixed CPAP

Delivers one steady pressure, determined in advance, throughout the night.

Auto-Adjusting PAP (APAP)

Senses airflow moment to moment and adjusts pressure automatically within a range your physician sets, responding as sleep position or sleep stage changes how much pressure is needed.

Your physician determines which approach, and what settings, fit your situation, often informed by a PAP titration study; see our in-lab sleep study page for more on how that testing works. This isn’t something to figure out on your own: pressure settings are prescribed and adjusted by your care team based on your testing and how you respond to therapy.

Getting Started: What to Expect

Getting used to CPAP is a gradual process, and an adjustment period is normal, not a sign that something is wrong. Early nights can feel unfamiliar: the sensation of the airflow, the mask on your face, the sound of the machine.

1. 01→Diagnosis & PrescriptionA sleep study confirms OSA, and your physician prescribes CPAP along with a pressure approach, fixed or auto-adjusting.↓
2. 02→Mask & Equipment FittingYou're fitted with a machine and a mask style suited to how you breathe and your facial anatomy.↓
3. 03Initial AdjustmentComfort typically improves over the first several weeks as mask fit and pressure settings are refined.↓
4. 04→Early Follow-UpYour care team reviews initial device data, usage, and comfort to fine-tune the therapy.↓
5. 05→Consistent Nightly UseComfortable use most nights, not a single hours target, is the practical goal that sustains CPAP's benefit.↓
6. 06Ongoing MonitoringYour care team continues reviewing device data at periodic follow-up visits, adjusting as needed.

Rather than aiming for a single number of hours, the practical goal is consistent, comfortable use most nights, since that’s what sustains the therapy’s benefit over time. If a particular night feels harder than expected, that alone doesn’t mean CPAP isn’t working for you; it’s a normal part of finding what fits.

Potential Benefits

For many patients, consistent CPAP use meaningfully reduces the breathing pauses that define OSA, with benefits that extend beyond sleep itself.

Daytime Sleepiness & Sleep Quality

Fewer breathing pauses translate into improved daytime sleepiness and overall sleep quality for many patients.

Snoring & Bed Partner Impact

Bed partners often notice quieter, steadier breathing before the patient notices a change in how they feel during the day.

Concentration, Mood & Headaches

Improvements in concentration, mood, and morning headaches are commonly reported as sleep becomes less fragmented, though timing and degree of improvement vary from person to person.

Cardiovascular & Blood Pressure

Some patients see improved blood pressure control alongside effective OSA treatment. This is an area of ongoing clinical interest, not a guaranteed outcome or a reason CPAP is specifically prescribed to prevent a cardiovascular event.

Common Side Effects

Most CPAP side effects are common early on and are usually manageable.

Dry Mouth & Congestion

Frequent, especially before humidification and mask fit are dialed in.

Mask Leak

Around the seal or through the mouth, leak can disturb sleep and reduce effective pressure.

Pressure Discomfort

Particularly on exhale; settings can often be adjusted by your care team.

Aerophagia

Swallowing air, which can cause bloating or gas; a recognized and usually manageable side effect.

Skin Irritation

Where the mask contacts the face; mask fit and cushion choice both play a role.

Claustrophobia

A feeling of confinement from wearing a mask; a different style or gradual desensitization often helps.

None of these are unusual, and most have practical solutions; see our CPAP troubleshooting guide for adjustments to try for these and other common issues.

If CPAP Is Difficult to Tolerate

Difficulty with CPAP is common, and much of it is addressable through the practical troubleshooting covered in our CPAP troubleshooting guide: mask fit, pressure comfort, congestion, and dryness can often be improved without abandoning therapy.

When tolerance remains a genuine problem even after those adjustments, alternative therapies exist. Oral appliance therapy uses a custom-fitted device to reposition the jaw and keep the airway open without a mask, and hypoglossal nerve stimulation is an implanted device option for appropriate candidates who haven’t tolerated or benefited from CPAP.

Which alternative, if any, fits your situation depends on your OSA severity, airway anatomy, other health conditions, and personal circumstances, decided together with your physician.

Follow-Up Care

Ongoing follow-up is a normal part of CPAP therapy, not a one-time setup that’s simply done. Modern CPAP machines record data that your care team reviews at each visit:

Residual Events

An estimated AHI: the breathing pauses still occurring on the device.

Mask Leak

How much air is escaping around the seal.

Hours of Use

How consistently the device is used each night.

Pressure Data

The settings actually delivered during sleep.

Reviewing this data matters because it confirms whether therapy is actually controlling your OSA, rather than assuming it is simply because a mask is being worn. If residual events remain elevated, or leak is high, your care team can adjust the mask, settings, or approach based on what the data actually shows, not on symptoms alone.

Repeat sleep testing is sometimes, but not always, necessary; whether it’s needed depends on your individual circumstances, such as whether symptoms return, your weight changes significantly, or there’s meaningful uncertainty about whether your current therapy is adequately controlling your OSA.

Traveling with CPAP

CPAP machines are designed to travel. Most are compact enough to carry as a personal item, and many airlines allow CPAP machines separately from your regular carry-on allowance; it’s worth checking your specific airline’s policy ahead of a trip.

Some patients travel with a smaller travel-specific machine, while others simply pack their regular device. Planning ahead, bringing any necessary power adapters for international travel, and considering how you’ll manage water for the humidifier if distilled water isn’t readily available, can make travel with CPAP considerably smoother.

Caring for Your Equipment

Basic equipment care is straightforward: the mask, tubing, and humidifier chamber should be cleaned regularly, generally following the schedule and method your manufacturer recommends, since buildup in any of these parts can affect comfort and hygiene. Filters and mask cushions also need periodic replacement over time.

Your equipment supplier or care team can walk you through the specific cleaning routine and replacement schedule for your particular device.