whither nitrox revisited

[roakey]

doole once bubbled...
Been trying to talk my lds into offering ean, and he said (yes - this is PURE hearsay) that in a "blind taste test" the divers were generally unable to identify whether or not they had been given nitrox, after a typical rec dive dive.

Seeing that Nitrogen ongassing and offgassing is asymptomatic if you do it correctly, why the heck are they even considering "being able to identify Nitrox" as an argument in the first place?

If nitrox is not important, I'd have whoever told you this compare 21% Nitrox against pure Nitrogen at depth, and see if he still doesn't think Nitrox or not matters...

Roak

 

[Diver0001]

doole once bubbled...
Been trying to talk my lds into offering ean, and he said (yes - this is PURE hearsay) that in a "blind taste test" the divers were generally unable to identify whether or not they had been given nitrox, after a typical rec dive dive.

Anyone know if there's any truth to this?

Some people say it makes a difference. I've never noticed but I never feel crappy after diving air either.

I'd venture a guess that if you did an aggressive dive profile on air and then did exactaly the same profile on Nitrox that you could notice a difference because of the lower levels of residual nitrogen (asymptomatic bubbles or whatever).

On the other hand I think if you dove profiles that left you with a comparable nitrogen load then I can't see hyow you would feel a difference..... Maybe you'd even feel worse on Nitrox because your dive would probably have been longer and in you could be more fatigued.

R..

 

[chrpai]

roakey once bubbled...

Seeing that Nitrogen ongassing and offgassing is asymptomatic if you do it correctly, why the heck are they even considering "being able to identify Nitrox" as an argument in the first place?

Roak

Perhaps that is the key point to explain his opinion. He worked in a military diving environment where I suspect getting the job done took precedence over offgassing right. So he probably saw profiles where it sure as hell made a difference.

 

[5615mike]

Mo2vation once bubbled...


Yeah, sign me up for that test. Can you imagine signing the waver for that one? "here, breathe this... TRUST us..." I analyze all gas I breathe, Air or EAN. Scary.

Back to the topic - I dive EAN. I've never "felt" a difference, as many of my friends do. However, many of these same folks recently 'tasted' bad air...and I didn't taste it.

Maybe I'm a doofus, or maybe my senses aren't that sharp.

I'm confident of this - I've never "felt" NOT being bent. I've never "felt" any differnece being close to bent or being far from bent. I've never "felt" fatugued after 3 days of diving air. And I've never "felt' mo bettah after 3 days of diving EAN.

A lot of smart people tell me its good for me. I believe them.

K

I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing.

 

[jviehe]

5615mike once bubbled...


I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing.

Oh, come off your high horse. Would you really ask the Coke people whether thats really Pepsi in the one, or could it be arsenic?

I dive nitrox most of the time now, but I've been able to tell the difference in regards to fatigue vs air.

 

[cyklon_300]

The decrease in fatigue using EAN becomes noticeable after MULTIPLE days of MULTIPLE dives...

A single tank nitrox dive probably doesn't involve enough ongassing/offgassing to be produce detectable results in most individuals.

 

[doole]

Yes, it would make sense that it becomes more noticeable as the series of dives gets longer.

BTW I like your moniker - my first adult reg was a Cyklon, so it keeps a special place in my heart. Not a smooth reg, though - kind of like driving a Shelby Cobra.

 

[Don Burke]

5615mike once bubbled... I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing.

I can think of a couple of ways to safely do the test double blind.

I recall a test where the only first dive difference was a slight improvement in gas consumption on a shallow dive which involved swimming. I attribute that to regulator performance.

My guess is that the improvement in fatigue on repetitive dives is due to the reduction in subclinical DCS.

 

[Damselfish]

jviehe once bubbled...


I dive nitrox most of the time now, but I've been able to tell the difference in regards to fatigue vs air.

And can you tell the percentage?

Actually, if everyone in the test had the same profile enforced, one that was considered safe for any of the mixes involved, seems like you'd be pretty much set here. Aside from trusting someone else to make sure all tanks used in the experiment were within range. But if someone was actually attempting a real study, being careful about analysis, having it doublechecked, keeping precise records of everything, that would probably be ok too. There is some level of trust involved in all of this. Some people may check air tanks, but this is not common. If I'm diving air, I trust that someone hasn't accidentally filled it with Nitrox.

 

[doole]

Well I know I can.

"Swiiish - aaaah! 32%. A good year, too."