What Is CPAP Therapy?
CPAP, which stands for continuous positive airway pressure, is the most common and one of the most effective treatments for obstructive sleep apnea (OSA). The machine blows a steady stream of air through a mask, and that air pressure holds the airway open while you sleep so it cannot collapse and block your breathing.
See it work: the interactive guide to how CPAP works follows the air from the filter at the back of the machine, through the water tank, the hose and the mask, to the back of the throat, where the pressure holds the airway open.
The equipment is the easy part. The first couple of weeks are what tell us the most about whether someone will stick with CPAP. Studies have found that how people use CPAP in the first few days strongly predicts how they are using it a month later. So most of this guide is about getting through those first weeks.
The One Thing to Know Before Night One
A rough first night does not mean CPAP is going to fail. Sleeping with air blowing through a mask feels strange at first for almost everyone.
The biggest thing is consistency. Do not take a night off, even after a bad night. If you wake up and find the mask off, put it back on rather than giving up for the rest of the night. Every night of use makes the next one easier.
The First Two Weeks: What Usually Goes Wrong
The mask
Most people do not stick with the first mask they are given. It is common to try several styles before finding the right one, and that is part of the process, not a failure. Fit, style, and comfort are hugely important, and everyone has different preferences.
There are three main styles:
- Nasal pillows sit at the opening of the nostrils
- Nasal masks cover the nose
- Full face masks cover the nose and mouth
In the research reviewed for the AASM's guideline, nasal masks were linked to better long-term use than full face masks, so a nasal style is often worth trying first. People who breathe through their mouth during sleep may still do best with a full face mask.
If your mask is not working, ask your equipment company about other sizes and styles. Sleep clinics often keep different masks on hand to try, and it can help to bring your mask and machine to an office visit so the fit can be checked.
The settings
Getting the settings right matters as much as the mask, and the finer settings are a matter of personal preference:
- Humidity. A heated humidifier reduces dryness and congestion. Some people need more, some less.
- Pressure relief. Many machines can lower the pressure slightly each time you breathe out. On some machines this is called EPR, for expiratory pressure relief. Some people like it set high; others prefer it off.
- Ramp. The ramp starts at a low pressure and builds up over several minutes as you fall asleep. Some people find it essential; others find it makes them feel short of air.
- Starting pressure. A starting pressure that is too low can be just as uncomfortable as one that is too high, because it can feel like you are not getting enough air.
If something about the pressure feels wrong, your physician can adjust the settings for comfort. You do not have to put up with it.
Getting used to it
For some people, getting used to CPAP simply takes time. One way to speed it up is to practice wearing the mask while you are relaxed and awake, such as while watching TV in the evening. A quick check-in with your care team after a couple of weeks helps catch problems early, while they are easy to fix. Support and troubleshooting during this period make a measurable difference: in the AASM's review, education, behavioral support, and troubleshooting each improved how much people used CPAP.
Setting Up Your Machine
What's in the box
- CPAP machine (the main unit with the motor and controls)
- Humidifier chamber (often built into the machine)
- Tubing (typically 6 feet of flexible hose)
- Mask with headgear and straps
- Power cord and filters
- SD card or wireless connection for recording your usage data
Step by step
- Choose the spot. Put the machine on a flat, stable surface near your bed, at or below the level of your head so water cannot run back down the tubing. Keep it near an outlet, close enough that the tubing reaches without pulling, and away from curtains that could block the air intake.
- Fill the humidifier. Use distilled water up to the fill line and never above it. Tap water leaves mineral deposits that can damage the machine.
- Connect the tubing. One end goes to the air outlet on the machine, the other to your mask. Both connections should be secure without being forced.
- Fit the mask. Put the mask on with the machine running, then adjust the straps until it seals without feeling tight. You should be able to slide one or two fingers under the straps. Lie down and check the seal again, because fit changes when you shift positions. For a full face mask, place it over your nose and mouth before attaching the headgear, and tighten the straps gradually from the top.
- Check the settings. Your prescribed pressure is usually set ahead of time. Start the humidifier at a middle setting. If you have a heated tube, its temperature setting helps prevent water from collecting in the tubing.
On the first night, put the mask on while sitting up and breathing normally, turn the machine on, then lie down. If something is uncomfortable, make small strap adjustments rather than big changes.
Common Problems and Fixes
Air leaks
Small leaks are normal. Large ones reduce how well CPAP works. The usual causes are a mask that is the wrong size, straps that are too tight (overtightening actually makes leaks worse), and sleeping with the mouth open, which may call for a chin strap or a full face mask.
Dry mouth or nose
Turn up the humidifier, use a heated tube if you have one, and consider a full face mask if you breathe through your mouth.
Feeling closed in
Practice wearing the mask while awake and relaxed, try the ramp, or try nasal pillows, which cover less of the face.
Noise
Modern machines are quiet. A new noise is usually an air leak, so check the mask seal and connections first.
How Much Is "Enough"?
The goal is simple: every night, all night, and for naps too. Whenever you sleep, you have sleep apnea, and CPAP only works while you are wearing it. Leaving it off for naps is one of the most common mistakes.
You may hear that 4 hours a night is enough. That number comes from Medicare's rule for continuing to cover the machine: at least 4 hours a night on 70 percent of nights during a 30-day stretch within the first 90 days. It is a coverage threshold, not a health target.
Most machines record your nightly hours, mask leak, and AHI (apnea-hypopnea index), the number of breathing events per hour, the same measure reported in your sleep study. Many connect to an app. An AHI under 5 on the machine's report generally means your sleep apnea is well controlled.
Who to Call, and What Can Wait
Call your equipment company for mask fit, leaks, broken parts, and replacement supplies.
Call your sleep clinic if you are still sleepy during the day despite using CPAP well, if your machine shows a high AHI, or if the pressure is hard to tolerate.
What can usually wait a few days: mild dryness or strap marks in the first week. These often settle as you adjust the settings and the fit.
Cleaning and Maintenance
Daily: wash the mask cushion with warm water and mild soap, empty and rinse the humidifier chamber, and let everything air dry.
Weekly: wash the headgear and tubing in warm, soapy water, rinse well, and hang them to dry. Check the cushion for wear.
Monthly: replace disposable filters, rinse reusable filters, replace the mask cushion or nasal pillows, and check the tubing for cracks.
Every 3 months: replace the tubing and the mask frame. Replace the humidifier chamber about every 6 months, or sooner if it shows mineral deposits.
For a printable version, download our free CPAP Supplies: Replacement Schedule & Cleaning Guide, an 8-page PDF with checklists and a full replacement schedule. Download the PDF.
Key Takeaways
- The first two weeks matter most, and a rough first night does not mean CPAP will fail
- Most people try more than one mask; nasal styles are often worth trying first
- Humidity, pressure relief, ramp, and starting pressure can all be adjusted for comfort, so tell your care team what feels wrong
- Use it every night, all night, and for naps
- Four hours a night is an insurance threshold, not a health target
- Call the equipment company for masks and parts, and the sleep clinic for ongoing sleepiness, a high AHI, or pressure you cannot tolerate