"Drowning" effect went away - thoughts?

[cpap450]

One of the phenomena I experienced on starting CPAP a year ago this month, was a "drowning" sensation if I opened my mouth, followed by, essentially, a "suction" that would close my mouth. Which is as it probably should be; I use nasal pillows, so the CPAP benefits are delivered 100% through the nose.

Once masked, if my wife said something to me, even a one-syllable grunted yes or no reply would trigger the drown > vacuum > suction > close mouth cycle.

But I now realize that phenomenon has been long gone. Longer than I can remember, I've carried on normal conversations with my wife while wearing the mask. Even if I open my mouth wide and breathe, there's no "force" sensation pulling it shut.

No big deal because I sleep well and with good numbers. But I'm curious how this happened. Is this just some sort of adaptation my body or the machine made? I've changed none of the machine's settings in the past nine months, and I was experiencing the "drowning" - as always - during that time, but since then, with no machine changes made, for several months I realize I'm now not experiencing it.

Anyone else have this happen? Any theories as to why?

[chunkyfrog]

Totally common.
It is exactly like riding a bicycle or swimming.
Some call it muscle memory.
Whatever it is--you have to learn from experience.
Once they can do it, most people cannot explain how it works--but it does anyway.

[Pugsy]

Totally normal. There is a reflex action that closes off the back part of the oral cavity which prevents the pressurized air from entering the mouth. You do it when you talk now and don't realize what you are doing.
I had the same thing happen to me. When I first started therapy couldn't talk or anything without air rushing out the mouth but now I can talk, yawn, open my mouth wide and stick out my tongue and even blow raspberries and no air enters the mouth.
It's more of a reflex and no way to describe how to do it but lots of people seem to figure it out.
For those that don't....I wish I could market it because I would be very rich.
It's similar to what happens when we blow up a balloon and no air comes out the nose but in reverse. There's a valve in there that shuts off.

[cpap450]

Thanks. I sort of figured/hoped this was normal, but wanted to get my arms around what had happened.