Many people afflicted with sleep apnea use a CPAP machine to help them get a good night sleep, and once you've found a good machine, you certainly don't want to lose the benefits of it by having your mask come off at night. If you're frequently waking up and finding your mask out of position, you'll be losing all the terrific benefits from the machine, and your good night's sleep will be out the window. There are some specific reasons why a CPAP mask will get out of position during your sleeping hours, and some things you can do to prevent that.
Acclimate to wearing a mask
After you've purchased a CPAP machine and mask, you should quickly try to acclimate yourself to wearing the mask by having it on during the daytime, and getting used to its presence. That should also help you determine the ideal fit for your face, so that it will be less likely to come loose at night while you're sleeping.
Improper seal on mask
When you don't take the time to acclimate your face to the mask during the daytime, you may find that it doesn't have the right seal when you go to bed at night. The best way to correct this is to tighten up the straps of the mask as much as possible without actually pinching areas of your face. You can also purchase a mask liner which will provide a better fit, or you can buy a CPAP pillow which has a cutout that accommodates your mask and minimizes any movement.
Wrong level of pressure
It can sometimes be difficult to get used to wearing a mask over your face and breathing pressurized air, which is intended to help keep open your airway. If you find that your mask is falling off at night or that you're snoring while sleeping, these are usually good indicators that the pressure you're using is incorrect. Explain the situation to your CPAP vendor, and they should be able to make the appropriate adjustments.
Some sleep apnea patients find themselves waking up at night because the mask has caused their mouth to dry out, which leaves them uncomfortable. This is generally caused because mask users might be sleeping with their mouth open, and this would cause it to dry out. One way to correct this is to purchase a chin strap, which will help you to keep your mouth closed while sleeping, and to prevent your mouth from drying out.
It's fairly common for a sleep apnea patient to feel somewhat claustrophobic when wearing a mask. In these cases, the wearer will not even realize that they're feeling claustrophobic until they wake up and find that they have unconsciously taken the mask off while sleeping. A good way to overcome this claustrophobic feeling is to get into the habit of taking deep, calming breaths to begin the sleep period. This will help you to unconsciously accept the fact that you're not going to suffocate while the mask is on. Another solution might be to purchase a smaller mask which leaves more of your face uncovered, and will minimize the claustrophobic feeling.