To Nitrox or not to nitrox ,Why and how ?

[MakatiNick]

I wrote a newsletter article on this topic for my dive club a couple of years ago. While the article does not go into detail on the certification process, it lists some of the benefits of using Nitrox for recreational diving. If you're interested, you can find the article at http://montereybayseaotters.org/images/stories/newsletters/2009/feb_09.pdf -- the article starts on page 5.

 

[daniel1948]

This has been an interesting thread, thanks for all the information.
I have a question, slightly off topic, but am curious.
In COZ, I do two dives, first dive to a max of 90' for a BT of 60-65' (multilevel), then a SI of roughly 1:00.
Second dive at a max. of 60-70' for BT of 60-65'.
I find myself with plenty of air, but out of time (at NDL) always on the second dive.
So, would it help to extend BT to dive the first dive with air (.21), and use Nitrox, (either .32 or .36) on the second dive?
Or just use Nitrox on both dives?
Thanks, now back to topic.
I don't notice any difference in Nitrox versus Air in terms of feeling tired or fatigued.

Since nitrox results in absorbing less nitrogen, you'll get the most benefit from using nitrox on both dives. You'll have less nitrogen when you surface after the first dive, and therefore less when you begin your second dive, and you'll absorb less during your second dive.

My situation is exactly the same as yours: In Cozumel we'd do an 85 foot dive (multilevel) and I'd have enough NDL time to stay down until I'd started to run low on air. But on the second, shallower dive, I'd run out of NDL time when I still had plenty of air. I have not been back to Coz since, but I've dived the same kind of profiles on nitrox and never even came close to my NDL limits. And I have reasonably good SAC.

So the answer to your question is: Use nitrox on both dives, unless you want to go deeper than the MOD for the nitrox mix available. With EAN 32, ninety feet is no problem.

By the way, some divers I've talked to call it "geezer gas" because we old geezers get tired easily, and as noted above, some folks feel nitrox is less tiring. I don't notice that, but I like it for the extended bottom time.

 

[blue steal]

Thanks Daniel1948. Makes perfect sense to me now. I will ask for Nitrox on both dives.
Never really have any desire to go deep these days, 90' being about the max and only briefly.
And now back to our regular programing:focus:

 

[herbdb]

I leave for Bonaire tomorrow night and am looking forward to the placebo effect of diving Nitrox. The shortened surface intervals over a long dive day will just be a bonus.

 

[electrix]

Isnt placebo great... There have been studies on this and no link what-so-ever found. There is also no scientific reason as to why you would feel less fatigued either.





Its the same gas with the same moisture content as normal. You bung O2 in then you bung filtered, dried air in. No difference. There is no difference there at all.

Wow, now I am bumfuzzeled , so it is all in my head huh? Oh well I hope it works this weekend but now that I know that it does not work will that ruin the placebo effect, all knowing one?

I wonder why breathing more oxygen with each breath would not have any effect on muscle, please enlighten us all knowing one.

 

[Blackwood]

Wow, now I am bumfuzzeled , so it is all in my head huh? Oh well I hope it works this weekend but now that I know that it does not work will that ruin the placebo effect, all knowing one?.

Maybe, maybe not.

http://m.guardian.co.uk/science/201...t-patients-sham-drug?cat=science&type=article

 

[electrix]

Maybe, maybe not.

m.guardian.co.uk

I am not sure that article helps maybe they have irritable bowl because they have their head up their *** more research is needed and on another part of the body.

 

[windapp]

Don't let this guys scare you out of learning about Nitrox on the internet. There are plenty of really informative web pages, and nobody will fill your tank with nitrox until you take the course anyways. Basically all it comes down to is that at depth, your partial pressure of a given gas increases, and you absorb more of that gas. Absorb too much nitrogen, and you can get decompression sickness. Absorb too much oxygen, and you can get CNS oxygen toxicity and drown when you pass out after spitting your regulator out. At recreational depths, the partial pressure of oxygen is too low to cause any problems, so you can add a little more oxygen and absorb less nitrogen. You take the course so the person filling your tank can be assured that you know how deep you can go and for how long. It's a big liability thing since very few people survive an attack of CNS oxygen toxicity. From what I understand, rescuing someone in this state is one of the most difficult skills taught in the rescue diver course. You also learn how to analyze the percentage of oxygen in your mix so that you know your calculations are correct.

All this from someone who hasn't taken the course...yet.

 

[ade_eccles]

On fatigue, I found these 2 papers.

Both say no link but then again both are very limited in what they tested (small sample - only 11 divers / shallow - only down to 18m / not over a number of days etc).

So, maybe the jury is still out but for me I still reckon that Nitrox can reduce fatigue and not by being a placebo

2003
http://archive.rubicon-foundation.org/dspace/bitstream/123456789/3975/1/14756231.pdf

2008
http://archive.rubicon-foundation.org/dspace/bitstream/123456789/8005/1/AAUS_2008_1-11.pdf

 

[k ellis]

Wow, now I am bumfuzzeled , so it is all in my head huh? Oh well I hope it works this weekend but now that I know that it does not work will that ruin the placebo effect, all knowing one?

I wonder why breathing more oxygen with each breath would not have any effect on muscle, please enlighten us all knowing one.

What you have to remember is its a two sided sword. People say that there is no scientific evidence to support the less fatigue but at the same note there is no evidence disproveing this theory.

Your right though as I too feel refreshed post dive on nitrox so its no a placebo so much as it is a fact that placebo has no effect other then psychological. Again this is not been proven to neither be true or not true.

Oxygen on muscle mass is a positive note and one that the nay say crowd does not want to recognize. Oxygen is used in the medical field to provide more life sustaining energy when people are in need of it. Hence its one of the most readily available medical tools any where that practices medicine or greater.

Dont let people rock your boat. If it works for you then its authentic if it does not work for them well to them its placebo. Have fun and ignore the nay say and go get some bottom time!