A theory about dry mouth

[KatieW]

I know that the most common cause of dry mouth is mouth breathing. But if I tape mouth, and my leak rate is zero, and I still have dry mouth....and my S9 Humidifier is running high enough to cause rainout, then I'm wondering if could be anatomical.

I have ruled out other causes (like dehydration and meds), and don't have a dry mouth at all during the daytime, only when waking up after a few hour's of sleep.

So, in googling, I found this diagram. Looking at this diagram...is it possible that my tongue is blocking my mouth, the airway is still open, but my mouth is dry from not getting any humidified air?

Otherwise, I'm doing great--feeling good and numbers are good, my average for past 2 weeks is: AHI of .1, CAI of .1, no obstructive apneas, no hypopneas.

Is this a crazy idea?

[Marietjie]

is it possible that my tongue is blocking my mouth, the airway is still open, but my mouth is dry from not getting any humidified air?

I also mouth tape - no problem when sleeping on my side (left or right) BUT I dare not turn
onto my back (I do that in my sleep)- eish! that dry mouth is horrible and it wakes me.
The moment I turn back onto my side I can feel warm saliva flowing back into my mouth.
Katie, what is your sleeping position?

[roster]

...is it possible that my tongue is blocking my mouth, the airway is still open, but my mouth is dry from not getting any humidified air?

Do you need a CPAP humidifier during the day to keep your mouth moist? Of course not, so you should not need one at night to keep your mouth moist unless you are mouthbreathing.

This is one that comes up here fairly often and I always think that CPAP and breathing cannot dry your mouth out if it is taped shut. But the issue comes up often enough that something must be real about it.

If your mouth is taped shut and there is no air moving through it, then the saliva glands will be sufficient to keep it moist. There could be a separate health condition affecting the saliva glands or they could be effected by a drug you are taking. But then either one of those conditions might affect the mouth during the day.

Could it be that you drink a lot of water during the day or chew gum and the dry mouth is masked?

[DreamDiver]

Katie, I'm using the zzz full face. So while I'm not taping, the situation is similar. There seems to be something about the humidifier climate control system on the S9 that is inducing dryness of throat in me. Consequently, I end up having to swallow multiple times through the night in order to re-moisten the back of my throat. It becomes an arousal factor during sleep, making my mouth dryer than I'd like in the morning. I hypothesize that the higher air temperature still allows for drying of mouth and throat areas because even though there is more humidity in the air coming from the machine, the air temperature is high enough that it still allows for more water to be evaporated from the mouth and throat.

I'm amazed that you can induce rainout on the S9. What are your settings for the humidifier? Are you using auto or patient defined settings?

[ozij]

People have sivary glands beneath their tongue -- so the "tongue stops air humid air from coming into mouth" theory can't be right.

The reason you mouth dries is that air blows into your mouth - even when you tape -- sometimes more, sometimes less, and its the air movement that dries our tissues faster than out salivary glands can humidify them. Think of the drying effect of a fan - all it does is move air in your direction - and your sweat dries. In addition, a heathy mouth is wet - contains more humidity than the humidified air coming through a hose - so it's not surprising that it gets drier during CPAP therapy.

[DreamDiver]

In addition, a heathy mouth is wet - contains more humidity than the humidified air coming through a hose - so it's not surprising that it gets drier during CPAP therapy.

+1

[roster]

People have sivary glands beneath their tongue -- so the "tongue stops air humid air from coming into mouth" theory can't be right.

The reason you mouth dries is that air blows into your mouth - even when you tape -- sometimes more, sometimes less, and its the air movement that dries our tissues faster than out salivary glands can humidify them. Think of the drying effect of a fan - all it does is move air in your direction - and your sweat dries. In addition, a heathy mouth is wet - contains more humidity than the humidified air coming through a hose - so it's not surprising that it gets drier during CPAP therapy.

O, I have seen similar comments made by others and have yet to understand it. That the CPAP can create a pressure in a taped mouth is understandable. But how does it create an air flow? In what directions is the air circulating? It must enter from the throat but it can not get out through the taped lips I assume.

You make a good point about a healthy mouth moisturizing itself beyond the carrying capacity of a CPAP humidifier. CPAP humidifiers are designed to provide moisture to the nasal cavities. That is why those of us who use full face masks and breathe through our mouth often have dry mouth. There is a constant air flow back and forth through the mouth. I don't see how you get this air flow with taped lips.

[DreamDiver]

You make a good point about a healthy mouth moisturizing itself beyond the carrying capacity of a CPAP humidifier. CPAP humidifiers are designed to provide moisture to the nasal cavities. That is why those of us who use full face masks and breathe through our mouth often have dry mouth. There is a constant air flow back and forth through the mouth. I don't see how you get this air flow with taped lips.

They make vacation plant watering systems that use a wick or blotter sheet to water your plants when you cannot be there for a couple weeks. The same physical property may apply within the mouth. As the throat dries out, I wonder if moisture from the mouth is not wicking down to the throat in an effort to replace missing moisture evaporated by the constant positive air flow. Under normal circumstances, there is no constant positive air flow on any surface of the throat or lungs (naturally, without CPAP). I wonder if, in the case of the S9, whether the heated air, even though it's somewhat humid, is actually evaporating more water from the throat surface because it is heated.

[roster]

I wonder if, in the case of the S9, whether the heated air, even though it's somewhat humid, is actually evaporating more water from the throat surface because it is heated.

That would be a blow to the heated-hose cult!

I have seen somewhere in print that increased pressure will cause drying of tissues. I wonder if this statement was well thought out, but I do not have enough knowledge of physics to evaluate it. My first question would be, "If it is just pressure and not flow, where does the moisture go?"

[KatieW]

I was looking forward to your responses and ideas. To answer your questions:

Marietjie, I sleep on my side, and change sides every few hours, when I wake up. I have an elaborate but comfortable pillow arrangement, which keeps me in the same position.

Roster, yes, I do drink alot of water during the day, but less here in WA than I did in AZ. I've been in WA for a month, with a humidity of 40%, versus 25% in AZ.

Ozij, so if the mouth is wet, then it's at 100% humidity, so even at 80% humidity the humidified air is lower, thus drying. That makes sense to me. Thanks.

Dreamdiver, I was using the S5i on Auto at 80 degrees F, both in AZ and here. But when the dryness got worse after arriving here, I thought maybe the higher humidity here was triggering something in the H5i to prevent rainout, so I was getting less than the default 80% humidity. I noticed my my water usage dropped from 8 to 6 oz. So I switched to Manual, experimenting with temperatures from 76-80 and humidity from #4.5-6. The water usage went up to 7-8 oz. The mouth dryness actually got worse, and I got rainout above #5 and 77 degrees.

Last night I went back to Auto + 80 degrees, and the mouth dryness was a little better, than when on Manual settings, with water usage back to 6 oz.

Thanks everyone, your input is very helpful. I will work on this some more.

[Wulfman]

Where does the moisture go?

Other than mouth-breathing/leaking, my suspicions run toward things like blood pressure and diabetes conditions. If the person is getting up during the night to empty their bladder, that would be a clue.


Den

[ozij]

Don't you think the air in your mouth moves when you breathe in and breath out -- even when the lips are taped? Taped lips mean air isn't blowing wildly out of your mouth -- but the system is still open to the winds of change so to speak, when you inhale and exhale.

[Luc]

...The reason you mouth dries is that air blows into your mouth - even when you tape -- sometimes more, sometimes less, and its the air movement that dries our tissues faster than out salivary glands can humidify them. Think of the drying effect of a fan - ....

This explanations sounds the most reasonable to me. I too suffer from dry mouth. Sometimes it's so dry it actually hurts and it wakes me up. I do not have any medical conditions, no meds etc. And I do not mouth breath! So why is my mouth dry?From the fanning effect caused by the air flow. The wind comes into my mouth through the air ways and throat and has no place to go... so it twirls around on itself like a vortex. This actually increases its speed and drying effect. A mini huricane constantly blowing in my closed mouth! This explanation however goes against the diagram. I don't beleive the toungue closes off the airway.

[SleepingUgly]

What happens when you set the humidifier higher than 80%? Is that when you get rainout? That is very bad news that one can get rainout with the S9! I just got mine and haven't used it yet.

[KatieW]

What happens when you set the humidifier higher than 80%? Is that when you get rainout? That is very bad news that one can get rainout with the S9! I just got mine and haven't used it yet.

SU, the rainout is only when set on Manual Mode, and this is stated in the User Guide, that on Manual, rainout may happen, and to either turn the humidity down or the temperature up.

On Auto + 80 degrees, no rainout.