Nitrox extends NDL but does it have other benefits?

[Bob DBF]

By the way, we clearly disagree on what "evidence" means. You say there is none; I say there is plenty of anecdotal evidence, and nothing "scientific" that is relevant to the multiple dives over multiple days scenario.

I don't have the last study handy, however it did note that the divers on Nitrox showed an indication of less fatigue, but not nearly enough for proof. They immediately concluded that it was due to sub clinical DCS, not fatigue.

It seems, with this kind of reasoning, the standard scientific answer is not likely to change regardless of the results.

In any event, it makes no difference to me why I'm fatigued or why Nitrox helps,when I'm doing 3+ dives a day for multiple days.



Bob
---------------
I may be old, but I'm not dead yet.

 

[MaxBottomtime]

Before anyone else takes offence or views any study that gives results that differ their beliefs as irrelevant I strongly suggest you read the entire PDF at http://archive.rubicon-foundation.o.../123456789/8005/AAUS_2008_1-11.pdf?sequence=1

 

[TSandM]

I read the paper. Boulderjohn's criticism is valid -- two 60 foot dives for thirty minutes is such a minimal test of the difference in nitrogen loading that I don't think you can conclude much from this. My typical 60 foot dive will be between 50 and 70 minutes (shore diving, no-deco). Those of us who do THAT sort of diving may be the ones noticing a significant difference with Nitrox.

 

[Tigerman]

I read the paper. Boulderjohn's criticism is valid -- two 60 foot dives for thirty minutes is such a minimal test of the difference in nitrogen loading that I don't think you can conclude much from this. My typical 60 foot dive will be between 50 and 70 minutes (shore diving, no-deco). Those of us who do THAT sort of diving may be the ones noticing a significant difference with Nitrox.

except 60 minutes max depth of 30m dives is what I tend to do 3 of a day for 2 weeks with the odd nightdive thrown in and I feel no difference diving air or nitrox - beyond the fact that I can stay deep for longer on the nitrox that is..

 

[TSandM]

You may not, but the plural of anecdote is not data. I'm just saying that the paper that was cited does not involve dives that I would expect to result in any significant decompression stress, so any effect of Nitrox on same would not be seen in that particular model.

 

[rhwestfall]

..the plural of anecdote is not data.

love that statement....

 

[BRT]

except 60 minutes max depth of 30m dives is what I tend to do 3 of a day for 2 weeks with the odd nightdive thrown in and I feel no difference diving air or nitrox - beyond the fact that I can stay deep for longer on the nitrox that is..

And if in fact you extend your nitrox dive time so that you are as close to the NDL's as you would be on air then I would not expect a difference in how you feel if subclinical DCS is the issue. The way we usually dive nitrox takes us so far away from the NDL's that they are not an issue. Other people on the boat on air may be into deco. I can't prove it but I feel better in the evening if I dive nitrox.

One guy I talked to on the beach in Seattle had a green nitrox labled tank on. When I talked to him he said it was filled with air. Didn't need nitrox there. I told him I fill my own and only fill nitrox. He said if he filled his own he would only dive nitrox too. I kind of think if you take the extra cost out of it most people would take the nitrox unless they were just diving too deep to be safe with it. I hate paying the extra $12/tank in Coz because I know how much extra they are making on it. But in the big picture of what each dive costs there when you factor in the flights, hotels, transportation and the dive boat that $12 isn't a blip on the screen.

Kind of interesting that people will pay $6 extra per tire to get 95% nitrogen and a green valve cap instead of 79% nitrogen and then balk at the extra cost for going from 79% nitrogen to 64% in their scuba tank.

 

[DaleC]

But why go for nitrox if the dive does not require it? If one only dives a couple of times a year tropically I can see the lack of concern in spending a couple of bucks but I dive year round, 2-4 tanks a week. that means $10-$20/week compared to $20-$40. Times 52 weeks means an additional cost of between $500-$1000. For what?

Sometimes it doesn't seem to matter when the cost is small, or if it's just what you want to do, but as a larger scale policy it just doesn't make sense. I'm not at the point where I can toss money like that away on whimsy.

People like to think they need something special to dive but it really is a pretty basic activity. Occasionally EAN makes sense but most of the time, the air you always breath is fine. Most people also don't need vitamin supplements and protein shakes for breakfast either.

 

[RickyF]

Locally I use EAN32 for almost every recreational dive I do. It allows me to do a lot of the profiles I prefer to do without the need to bring a deco bottle. Sometimes my dive computer registers that I'm in deco, but usually it clears before I reach 20 fsw. In those cases I tend to hang around in the 15-20 fsw range a few extra minutes anyway.

I tend to feel less tired after diving nitrox rather than air. People tell me it's all in my head. That's OK, if my head makes my body feel better then it's working for me ...

... Bob (Grateful Diver)

Same here Bob! MY head and body is what counts! LOL

 

[BRT]

But why go for nitrox if the dive does not require it? If one only dives a couple of times a year tropically I can see the lack of concern in spending a couple of bucks but I dive year round, 2-4 tanks a week. that means $10-$20/week compared to $20-$40. Times 52 weeks means an additional cost of between $500-$1000. For what?

Sometimes it doesn't seem to matter when the cost is small, or if it's just what you want to do, but as a larger scale policy it just doesn't make sense. I'm not at the point where I can toss money like that away on whimsy.

People like to think they need something special to dive but it really is a pretty basic activity. Occasionally EAN makes sense but most of the time, the air you always breath is fine. Most people also don't need vitamin supplements and protein shakes for breakfast either.

The reason that you might go for it even if the dive doesn't require it would be that it keeps you further away from the NDL's. I don't think anyone could argue that it is better to get close to your NDL than to not get close to it. I realize the risk of the bends is so low that it is hard to calculate the difference but very possibly the risk of subclinical DCS is not so low and very likely it does have effects on the body. Very possibly nitrox reduces these effects. It is cheap insurance.