Nitrox!

[Reg Braithwaite]

Well, I didn't really expect the thread to blow up like that! But I learned a lot from it and want to thank you all for giving your opinions. I'm going take the course and start diving nitrox. I really want to learn as much as I can about diving. So again, Thank you all.

I would also strongly recommend the online Ratio Deco class from UTD Diving and the Deco for Divers book. Both explain a lot of the theories behind decompression. I am taking Ratio Deco right now, and so far it has blown my mind twice in the first two and a half chapters (not that you care, but its explanation of why the surface tension of bubbles drives stop depths and why the ratio of bubble volume to diameter drives exponential deco shapes are both wonderful).

Anyhow, each discusses the mechanics of breathing Nitrox as well as off-gassing with Nitrox, and both go far beyond the text I read as part of my NAUI certification.

JM2C...

 

[MMM]

Heh. An interesting read. Although I didn't tell this to my non-divingspouse, I got nitrox certified to extend my dive times. As some have said, you need to go out with an op that will let you dive your air however if you want to fully maximize that benefit. I told my spouse I wanted to increase my safety margin and he bought it. Heh.

 

[Matthew Mandziuk]

Nitrox is the most beneficial specialty to a newer diver. You can get more bottom time, you feel a lot better after and in between dives and it's a great stepping stone to other diving endeavours that would require you to be utilizing nitrox to make it worth your while (wreck, deep, multilevel, etc). It's also a great stepping stone as mentioned for cave, rebreather and mixed gasses.

If you take your air diving table and subtract approximately 20 feet from each of your max depths from 60-110', you can get an idea of how much more bottom time you'll get.

For example, what does your dive table give you for an NDL at 100' on air? 20 mins? Subtract 20 puts you at 80'. What's your NDL at 80? About 30 mins?

Nitrox is great. Especially if you're on a week long liveaboard doing 5 dives a day. You're wiped on air.

I don't dive air, it's all or nothing. Nitrox, Helitrox, Trimix.

Air is what we were given to breath on land, but no one said it was the optimal mix.

Get Nitrox, it's well worth it.

 

[String]

I used to dive nitrox all the time then gradually realised it wasnt worth it. Most of the dives here are max 2 per day, if there's deco theres not a lot of it (20 mins usually less per day) and often we dont know the exact depths until on the boat so effectively useless for local diving.
Liveboard maybe ok but at $5 per dive extra it adds a fair bit to the price and again, deco if any wasnt a lot so wasnt cutting into the no stop time much.

So for me air is far more flexible than nitrox so im back to diving air unless i specifically know my dive site well in advance and bother with the extra expense of getting the gas.

 

[dpaustex]

To me, the real benefit to diving Nitrox is you don't feel so doggone tired!!!! Basically, your breathing about 50% more oxygen, with an EAN 32 mix. Your respiration is still basically the same, but your tissues are reaping the relative benefits of a relatively oxygen rich environment.

If you take a Nitrox class, you'll learn when you exceed a certain depth, based on the mix you're using, you can get oxygen toxicity. This is where you'll learn about what limits you want to dive with on Nitrox. Generally, your dives are shallower with Nitrox, due to MOD (maxiumum operating depth, which is directly affected by the mixture), but you can stay longer at the equivalent depth (see examples in other posts, above), due to their being less nitrogen built up in your system. However, if you stay longer, the nitrogen works out to be the same. But minute for minute at a given depth, the EAN has less Nitrogen buildup than air.

It's kind of fun to play with the EAN tables and formulas, and compare them to air. If you do a side-by-side comparison, you'll see the increased bottom time (which doesn't mean the same volume of air lasts "longer").

Check out a class, it's kind of interesting stuff.

 

[Meng_Tze]

Nitrox reduces N2 loading in the tissues. As a result of this, when riding table limits - whether they be NDL or not- you see benefits of this lower uptake of N2. Regardless of anything you will take up N2.

So what does that mean to a dive? Your time spent at depth can increase before you hit your set limit. If you get out before you hit your limit, one could argue that you have 'increased your safety margin'.

Ascend rate is the catalyst by which you force the N2 to come out of the tissues. The faster you ascend, the bigger the force. Not allowing tissues to properly 'off gas' will have an effect on your physiology. This can be tiredness, skin bends, AGE, or spinal/nervous system damage and all kinds of combinations. Going beyond NDL dramatically increases these risks, but they can be managed.

The ascend rate is the driver of this, the culprit is N2 coming out of the tissues through pressure differences. It is the combination of the two, not one in it's own.

Having a higher O2 level of this gas, now also brings you to your set PO2 level at shallower depth than Air. Breathing higher gases with higher O2 content brings risks of O2 toxicity through depth and time. This, as with Air, needs to be managed.

 

[MaxBottomtime]

To me, the real benefit to diving Nitrox is you don't feel so doggone tired!!!! .....If you take a Nitrox class, you'll learn when you exceed a certain depth, based on the mix you're using, you can get oxygen toxicity.

You will also learn in the class that it is a placebo effect about feeling less fatigued. As previously mentioned, the fatigue factor is due to the nitrogen bubbles expanding too quickly. Making deep stops and slowing your ascent down takes care of that. You can dive air all day and not be tired if you slow your ascents. Nitrox doesn't do that for you.

 

[Puffer Fish]

You will also learn in the class that it is a placebo effect about feeling less fatigued. As previously mentioned, the fatigue factor is due to the nitrogen bubbles expanding too quickly. Making deep stops and slowing your ascent down takes care of that. You can dive air all day and not be tired if you slow your ascents. Nitrox doesn't do that for you.

Max..I don't get the less fatigued feeling.. but I am not sure there is more to that, than just going up slower.

Some recent work has shown that breathing higher O2 can cause a drop in blood sugar levels...resulting in the potential in some people to pass out. Depending on a huge number of factors from individual to individual. As no one was looking for that, they were unaware it was happpening.

I would not be surprized if there is a lot of very real effects going on that make some people feel better later.

Part of the reason it was not looked at was because it was assumed that we knew what all the effects were... and further assumed that if something happened, it must have been from something else.

 

[MaxBottomtime]

In Richard Pyle's article about deep stops he tells about fish collecting in deep waters of Hawaii. Most of the time, his catch was either dead or distressed upon surfacing, and he usually needed a nap after diving. One dive he had an issue which caused him to stop for a couple of minutes during his ascent. His catch was in perfect health after surfacing and he felt great. After more research he found this to be the case every dive.
I've always been amazed at how many divers say that nitrox makes you less fatigued, despite the fact that every course book tells them it's a placebo.

 

[Teamcasa]

Nitrox reduces N2 loading in the tissues. As a result of this, when riding table limits - whether they be NDL or not- you see benefits of this lower uptake of N2. Regardless of anything you will take up N2.

So what does that mean to a dive? Your time spent at depth can increase before you hit your set limit. If you get out before you hit your limit, one could argue that you have 'increased your safety margin'.

Ascend rate is the catalyst by which you force the N2 to come out of the tissues. The faster you ascend, the bigger the force. Not allowing tissues to properly 'off gas' will have an effect on your physiology. This can be tiredness, skin bends, AGE, or spinal/nervous system damage and all kinds of combinations. Going beyond NDL dramatically increases these risks, but they can be managed.

The ascend rate is the driver of this, the culprit is N2 coming out of the tissues through pressure differences. It is the combination of the two, not one in it's own.

Having a higher O2 level of this gas, now also brings you to your set PO2 level at shallower depth than Air. Breathing higher gases with higher O2 content brings risks of O2 toxicity through depth and time. This, as with Air, needs to be managed.

I thinks this sums it up pretty well.