inhale from reg exhale from nose

[ezadel]

I agree you should get a new mask. Without the purge valve you'll probably find that exhaling too much through your nose contributes to mask
leaks. Every time the mask skirt opens up to let out air a little water can leak in. This is especially true when the air in your mask leaks out the top if you are in a head up position. Then you have to keep clearing the mask....

So having a mask without the purge valve might help train you to limit your nose-exhaling just to help stop leaks.

I really would not worry about CO2 retention caused by exhaling through your nose.

I guess I dont have this habit and/or trying to break it. I should have been more clear I usually breath in/out from my mouth..only last dive, i tried this technique and it felt really good so thats why I startes the thread. I do like the purge valve ans i think I can control myself not to exhale from nose if I wanted to

 

[ezadel]

For scuba, it seems that resistance to exhaling through the mask is bad for breathing.

Maybe on the surface, with no real water pressure, exhaling through the mask isn't that big a deal.

It does seem like Id prefer to breath in some nice fresh air, instead of a snorkel full of my exhaust.

I actually once googled this as a snorkeling technique and didn't find anything. I'd love to hear some authoritative approval of this as a snorkeling technique.

Dont think it matters matter.. volume of the snorkle is around 0.1 liters, lungs take about 6 liters AND "stale" air already containes 80% of the oxygen (body only metabolizes 20%)...i could do the calculation but too lazy

 

[John C. Ratliff]

Interesting discussion. I had always wondered why for SNORKELING, that exhaling through the nose wasn't taught, as I thought it would reduce or eliminate the "stale air" that you exhale in the snorkel, and then inhale again. That seems like it would be a real benefit.

I figured that there had to be a reason it wasn't a widespread technique. I guess I know the reason now.

The only way to decrease the amount of CO2 in a snorkel is to cut down the length of the snorkel. I used to cut it off at the top of my head, so as to reduce the amount of "dead air" I was inhaling while finswimming on the surface (competitive swimming for time, or competitive open water swimming).

SeaRat

 

[John C. Ratliff]

Dont think it matters matter.. volume of the snorkle is around 0.1 liters, lungs take about 6 liters AND "stale" air already containes 80% of the oxygen (body only metabolizes 20%)...i could do the calculation but too lazy

Actually, the exhaled air does not contain "80% of the oxygen," as the oxygen only starts out in un-breathed air as about 21% of the air (nitrogen being the rest of the composition of air, with some small components of CO2, CO, and other gases). So you inhale about 21% oxygen in air, and exhale air with something like 16% oxygen (which is why mouth-to-mouth artificial respiration works), which represents approximately 76% of the available oxygen in the exhaled air. But, that may not hold for athletes under exertion, or divers also under exertion.

SeaRat

 

[John C. Ratliff]

I guess I dont have this habit and/or trying to break it. I should have been more clear I usually breath in/out from my mouth..only last dive, i tried this technique and it felt really good so thats why I startes the thread. I do like the purge valve ans i think I can control myself not to exhale from nose if I wanted to

You must have one of those masks with a diverter for the purge valve. Note that these are meant to "purge" the mask, and as a means of exhalation. What Akimbo and others are saying is that under high exertion, the much smaller diameter of the purge valve will cause some increase in exhalation resistance, which is reflected in higher work loads, and possibly the mask lifting off your face too. It is not a good idea, and the U.S. Navy School for Underwater Swimmers used to teach us very good glottis control by having us flood our mask, get out of the pool with our tanks on our backs, laying down on our tanks face-up, and doing flutter kicks on land with the mask still flooded. We either learned to close off the glottis or we drowned!

SeaRat

 

[Patoux01]

which represents approximately 76% of the available oxygen in the exhaled air.

Come on man, 76, 80, it's the same there.

 

[Vicko]

Sooner or later the purge valve will break, either closed or open and will ruin your dive. Sooner or later you will probably switch to a low(er) volume mask.
With those you will find that breathing out trough the nose is more difficult, that the dry air flow makes your eyes water and that every time a bubble leaves the mask a bit of water comes in.
When every other diver breaths trough their mouth there is probably a good reason behind it.

 

[Bob DBF]

...U.S. Navy School for Underwater Swimmers used to teach us very good glottis control by having us flood our mask, get out of the pool with our tanks on our backs, laying down on our tanks face-up, and doing flutter kicks on land with the mask still flooded. We either learned to close off the glottis or we drowned!

They wouldn't let you drown, even though you you were USAF, probably because of all the paperwork. In any event it would have changed your military career path.


Bob

 

[John C. Ratliff]

They wouldn't let you drown, even though you you were USAF, probably because of all the paperwork. In any event it would have changed your military career path.


Bob

Yes, Bob, we wouldn't have died, but we would have washed out of the course, which for us was almost the equivalent of dying. Water trickling down to the larynx would produce spasms, heading to all sorts of hilarious episodes with the instructors. It did make us rather impervious what is now known as "water boarding." If someone tried that on us, we probably would have simply smiled through the whole thing.

John

 

[Sub a Dub Dub]

Great thread.

First day in the pool of my PADI OW. In the morning I was going out my mouth. The afternoon, more often my nose. I just preferred the the fact is was quieter and the bubbles didn't obscure my vision.
I guess I was using a regular dive mask, but experienced no problem with leak.
At the end I asked my instructor if it was bad practice, and he said it was as it could lead to fogging. I asked if there was any other reason to do with CO2 or the way the regulator operates and he said from that point of view, no.

So to find this thread was really interesting. Was I more fatigued in the afternoon, yes for sure but it would be unfair at this stage to correlate the 2, it was my first bit of excecise in 3 weeks, I'd eaten lunch, and we were taking it a lot of information. And since my goggles were fogging anyway I guess I'll keep switching methods, and if I don't notice any negatives with the nose breathing when we move to depth, I'll continue with that.

Neil