What is CPAP and how does it fix sleep apnea?

You've come to the right place if you want to know "what is CPAP?" CPAP is forced air ventilation and air-conditioning for your face.

OK, that sounded weird.

CPAP stands for "Continuous Positive Airway Pressure". It's an electric air-pump hose and mask. You wear it at night, while you sleep. It's purpose is to give you air to breathe, at higher than normal atmospheric pressure, so that the air keeps your throat, your air-hole, open.

If you suffer from obstructive sleep apnea, your airway tries to close up while you are asleep, mostly by being flaccid and collapsing. Normally, when you breathe, you expand your chest, and atmospheric pressure pushes some air in, to fill up the increasing volume. Your throat stays open enough to let that air in.

In obstructive sleep apnea, your muscles (including the ones surrounding the inside of your throat) are flaccid during sleep, as are the tissues surrounding the airway, so there's less tendency to keep that passage open. Any extra flesh (if you are fat), or any damaged flesh (from long-term alcohol consumption or smoking) tends to sag into the already restricted opening. If that doesn't close off the pipe, then your tongue flopping back into your throat will do the trick.

Your chest expands, but the ambient air pressure isn't enough to overcome all that flaccid, sagging fleshy stuff, and you slowly strangle.

A properly-fitted CPAP machine pushes extra air, under increased pressure, through a face-mask and into your breathing passages, which is enough to overcome the blockage and keep your airway open.


Damn right. If your condition is serious enough, CPAP saves your life.

Any more to say on "what is cpap?"

Well, it's almost a last resort. The only thing more drastic is surgery on your throat, and that often ends badly.

CPAP is a prescription item.

You get referred by your doctor to a sleep study.

The sleep study determines that you suffer obstructive sleep apnea.

Based on that determination, you go for another sleep-lab session, in which you are fitted for a CPAP machine, and suitable settings are determined. When you leave, the next morning, you probably have a prescription in your hand.

You go to a supplier and buy a CPAP machine that matches the requirements of the prescription. You get a mask fitted to your face.

You take the whole thing home, set it up, and try some conservative settings for flow and pressure, until you are comfortable and you are breathing all night with no apneaic episodes.

Anything else?

Well, that's the basic answer to "what is cpap?" There are options and additions that you can get - add-ons. Some machines warm the air. Some add extra humidity - or you can get inline reservoirs from which the air in the tube picks up some moisture, or perhaps some medicine (we hate saying "medication").

Really, we would rather that you didn't get to the point of needing CPAP.

If you need it, you need it. It will save your life and/or your quality of life - if it keeps you from having a debilitating stroke, or a deadly stroke, or heart failure.

But, before you've done yourself permanent damage, that only a CPAP machine can help, there's usually a lengthy period during which you suffer reversible obstructive sleep apnea (not to mention severe snoring) because:

  • you're fat, and/or
  • you smoke, and/or
  • you drink heavily or near bed-time, and/or
  • you consume milk or other dairy products near bed-time, and/or
  • you keep yourself overtired all the time

We think you should give a good shot at eliminating those contributing factors first, before you go all the way to (pretty much) the last resort.

There's not much left to say on the "what is cpap" topic, before we go to the Pros and Cons. Each manufacturer has several models of machine, of accessories, and of masks, to suit a variety of users and their needs. For example, some people don't like having a mask over their nose and mouth, so there are also nose-only "masks" for delivering air directly into your nose. Some masks are better than others for side-sleepers - some won't leave as much of a 'perma-dent' in your face every morning.

Here are the basic Pros and Cons of CPAP.


  • It works immediately, or is quickly adjustable so it does work.
  • It saves your life and prevents grave health consequences.
  • It's often covered by insurance.


  • It's more costly than other approaches - from many hundreds, to thousands of dollars.
  • It requires medical evaluation, inconvenient overnight testing (several times) and prescription.
  • It works only where electric power is available (so not if you go camping, not during power failures, etc. *).
  • It's obtrusive and requires setup each night.
  • It's obtrusive and can interfere with your favored sleeping positions.
  • It's noisy - not loud if you have a good machine, but still it's a constant noise in the otherwise quiet of a bedroom, so your partner might be disturbed.
  • Like any electro-mechanical device that's expected to work eight hours a day (night) every day, it suffers wear-and-tear and will eventually need replacing, several times through your life.
  • If the underlying causes are not fixed, eventually even CPAP can't overcome your apnea - they can blow the air only so hard, y'know... there's an upper limit to the settings, and when you reach that, you've reached the end of your rope.

(* It is possible to get small, portable CPAP machines [example Puritan-Bennett GoodKnight 420s] which accept DC power input, and connect them to large-capacity batteries, but who really wants to lug a 60-pound marine, deep-cycle Absorbed Glass Mat battery on a camping trip? Not us, thanks. However, that might be a good backup to keep at your home or your cabin-in-the-woods in case of extended power failures, since you don't have to carry it.)

What is CPAP?

Until it stops working for you, it's the difference between life and death.

Still, we really prefer that you not let things get that far out of hand - if you haven't already. Please.

If this page wasn't where you wanted to be, then from this 'what is cpap' page, go back to the home page.

Or, return to the snoring section intro page where we have a table of links to all the other snoring-related pages in this section of MHT.

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