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This page gives detailed information about Continuous Positive Airway Pressure, also called C.P.A.P.. CPAP is the main treatment for obstructive sleep apnea.

How does CPAP work?

The CPAP machine delivers a constant flow of air through tubing and a mask and into your airway. The CPAP machine creates enough pressure in your airway to hold the tissue open, so your airway doesn't collapse.

The soft, steady jet of air from the CPAP machine creates enough pressure to keep the airway open.

Your sleep specialist will prescribe a particular CPAP pressure for you, based on how much pressure you need to keep your airway open. Your sleep specialist may have you try different levels of CPAP pressure when you’re in the sleep laboratory, to see which is the right level for you.

CPAP is a treatment, not a cure. While you’re using CPAP, your sleep apnea symptoms stop. Your breathing and your sleep are healthy. If you stop using CPAP, your sleep apnea symptoms will come back. Your breathing and sleep will be interrupted again.

If your doctor says you need to use CPAP, you must use it every time you sleep.

How to choose your CPAP equipment

There are now many models of CPAP machines, masks and accessories available. Your doctor and medical supplier can help you find the ones that fit you best.

Most people buy CPAP equipment through a home oxygen company. Look in the phone book under “Oxygen” for a list of suppliers.

For CPAP therapy, you need:

  • a prescription from your doctor
  • a CPAP mask
  • a CPAP machine

Many people also use a humidifier, or a heated humidifier.

You may also want to buy a battery pack so you can use your CPAP machine in places where you can’t plug it in (camping, etc.) or during a power outage.

Your prescription for CPAP

To buy a CPAP unit, you need a doctor's prescription. Your doctor’s prescription will say what pressure your CPAP machine needs to be set at. For insurance purposes, the prescription should also mention your CPAP mask and humidifier.

How to choose your CPAP mask

The key to using CPAP therapy successfully is a good mask fit. Your mask needs to be comfortable. When you’re choosing a mask, pick one that feels comfortable as soon as you put it on. Remember: it takes time to get used to wearing any mask for an extended period of time.

There are several kinds of CPAP mask on the market:

  • nasal mask
  • masks with nasal pillows or cushions
  • full face masks
  • masks for children

To figure out which type of mask is right for you, ask yourself these questions:

  • Can I breathe through my nose or do I breathe through my mouth? If you breathe through your mouth, a full face mask or chin strap may be better.
  • Am I claustrophobic? If so, nasal pillows may suit you better.
  • Can I handle something inside my nose? If not, a nasal mask would be better.

How should your CPAP mask fit on your head?

  • The top of the mask should be at the bridge of your nose.
  • The bottom of the mask should be about halfway between the bottom of your nose and the top of your upper lip.
  • The edge of the mask should be close to the sides of your nose without actually touching it.
  • The smallest mask that fits is usually the best choice.
  • It’s okay if a little air leaks from the mask, as long as it’s not blowing into your eyes.
  • You shouldn’t have to pull the headgear very tightly to control leaks.

Advice for trying on and choosing a CPAP mask

  • Do not be in a rush at the CPAP store. Take your time.
  • When trying on different masks, be sure to lie on your back and also on each side to see how it will feel when you are in bed.
  • Try the mask with a CPAP machine attached.
  • Make sure the headgear is easy for you to use.
  • Ask about a trial period for a new mask or a trade-in policy in case the mask does not work out.

Making your CPAP treatment comfortable

CPAP is the best treatment for obstructive sleep apnea. It can make your symptoms totally disappear, as long as you keep using it. But many people find it hard to use CPAP at first. They may find the mask uncomfortable, or they may be bothered by a dry nose. It is possible to be comfortable wearing CPAP, but it often takes some adjustments until you get the right mask and the right fit.

We understand that wearing CPAP can be difficult, especially if you still feel tired. It’s really important to stick with CPAP and make adjustments until it feels comfortable. Your doctor and equipment supplier can help solve any problems you may have. It may be a bit of trial and error at first, but it’s worth it.

Once you start getting restful sleep, you’ll feel so much better. You will realize that all the discomfort you went through to get used to CPAP was worth it.

Solutions to some common problems with CPAP

If you have a dry nose

If you have a dry nose, try using a humidifier that attaches to the CPAP machine. It helps by adding moisture to the air. If that doesn’t help, try a heated humidifier. It adds even more moisture to the air. Do not put a regular humidifier in your room because it could damage the CPAP machine’s motor.

If you have a stuffy nose

It’s common for people to have a stuffy nose when they start CPAP. Adding a humidifier or heated humidifier to your CPAP machine can help.

If you’ve added a humidifier and your nose is still stuffy, see a doctor. Your nasal stuffiness could be cause by sinusitis (swelling in your sinuses), allergies or rhinitis (swelling in your nasal tissues).

You may also have partly blocked nostrils because of nasal polyps (growths) or old fractures (breaks) in your nose bones. If you have either of thee problems, get treatment from an ear, nose and throat specialist. A full face mask may be the best mask for you.

It’s important that your nose is as clear as possible to make wearing your CPAP mask more comfortable.

If you have red marks on your skin

Any marks from your CPAP mask and headgear should disappear soon after you remove the mask. If they don’t disappear, or if you have sore or red skin, your headgear could be too tight or you mask might not fit right.

Adjust your headgear until it is just tight enough to make a seal without any large leaks. A small air leak that does not blow into your eyes is fine. If that doesn’t help, try a different style of mask. Ask your doctor or supplier to help you chose one that’s right for you.

If your skin is irritated

  • Wash your mask with warm, soapy water and air dry every day.
  • Wash your face and dry well before putting the mask on.
  • If you have a rash, call your doctor. You may need a prescription skin cream.

If those tips don’t help, try a different style of mask.

If you use nasal CPAP and the air leaks around your mouth

The pressure of the CPAP makes most people sleep with their mouths closed. But some people still sleep with their mouths open. This is a problem: it means you’ll wake up with a dry mouth and you may no be getting the most from your treatment.

To keep your mouth closed while you sleep, try wearing a chin strap (available from your medical supplier). If that doesn’t work, ask your doctor about using a full face mask.

If you use a full face mask and you have a dry mouth

Try using a heated humidifier that attaches to the CPAP machine. It adds moisture to the air and cuts down on dryness.

Ask your pharmacist for artificial saliva or oral lubricant products that can help with a dry mouth.

If you remove the mask during the night

Most people find they will occasionally knock off their CPAP mask during sleep. This is normal. But you do need to keep your CPAP treatment going all night long.

  • If you move around a lot in your sleep, add a chin strap may keep the mask on your face.
  • If you’re pulling off the mask because you have a stuffy nose, see the advice for a stuffy nose, above.

Humidifiers and heated humidifiers

Many people use a humidifier or a heated humidifier to help make CPAP more comfortable.

Humidifiers add moisture to the air before it goes into your CPAP mask. This makes it more comfortable for you to breathe.

A heated humidifier delivers more moisture than an unheated humidifier.

Without a humidifier, you may have a dry throat, a dry or stuffy nose, or a bleeding nose. Using a humidifier with your CPAP will help prevent these problems.

How to care for and clean your CPAP equipment

It’s important to keep your CPAP equipment clean and in good shape. To find out how to care for your particular model of CPAP equipment, read the instructions in the owner’s manual. These are some general instructions

Clean your CPAP mask every day

  • Wash your CPAP mask with pure soap and warm water.
  • Do not use soap that contains bleach, chlorine, alcohol, moisturizers, scents or antibacterial agents.
  • Rinse your mask in plain water or in water mixed with plain white vinegar. Vinegar in the rinse water will cut down on smells and germs.
  • Don’t put your mask in direct sunlight.

Wash your headgear and tubing every week

  • Hand wash the tubing and headgear with pure soap and warm water.
  • Gently towel dry the tubing and headgear, then leave them out to air dry.
  • Check to see if your tubing and headgear are worn. If they are, get new ones.

Change the filter on your CPAP machine every 2 months, or as needed.


Don’t let water from your humidifier to spill into the CPAP machine.

Empty the humidifier before moving your CPAP machine.

If you have a heated humidifier:

  • Use distilled water. Replace the water each night.
  • Follow the instruction manual for cleaning your humidifier.

Frequently asked questions (FAQs) about CPAP treatment

How long will it take me to get used to CPAP?

Some people are able to use their equipment with no problems from the very first night. They wake up feeling much more rested. Others can have trouble getting used to the mask and the pressure. It may take up to 6 weeks to adjust. It is important to keep trying – do not give up.

What happens if I stop CPAP treatment?

If you stop using CPAP, your sleep apnea symptoms come back. CPAP treatment only works when you use it.

Will the pressure level on my CPAP machine ever need to be changed?

If you gain or lose 30 pounds or more, see your doctor. He or she may have to adjust your CPAP pressure. To find the right pressure for you at your new weight, the doctor may order another sleep test or may ask you to use an auto-titrating (self-adjusting) CPAP machine for a few days.

I use my CPAP every night, but I’m still sleepy. What else can I do?

There are some people who are still sleepy even though they use their CPAP properly. The first step is to make sure that your equipment is working. You can take the CPAP machine back to the supplier to have it checked. Second step is to speak to your sleep doctor about other possible sleep problems. Your doctor may send you for more tests. Usually the problem can be solved.

Some people who are still sleepy might be prescribed a stimulant medication called Modafanil (a stimulant is a medicine that makes you more alert and awake). Modafanil is not a replacement for your treatment. It is used along with CPAP to help you with daytime sleepiness. Always talk to your sleep doctor about any problems that you have.

What if I just can’t get comfortable using CPAP?

If you are having trouble with your CPAP equipment, talk to your sleep specialist. He/she can suggest some tips or test for other problems.

Treating sleep apnea is very important for your overall health. If you’re having problems getting used to your CPAP equipment, please do not give up. It may take a few weeks, or even months to be comfortable wearing a mask. Be patient. Return to your supplier to look for ways to make CPAP more comfortable. Talk to your sleep doctor about any medical concerns. Don’t give up.

How can I pay for my CPAP treatment?

Many insurance policies will cover CPAP equipment that has been prescribed by a sleep doctor. Your insurance company will ask for a copy of your prescription when you make the claim.

The Lung Association believes that everyone who needs CPAP treatment for sleep apnea should have it paid for.