Nitrox and recreational diving.

At my favorite dive shop they are always asking divers if they want to do an introductory Nitrox dive. The deepest that they go is on a couple wrecks which are a maximum 125 feet to the sand and the dives usually lasts for 45 minutes to an hour with about 30 minutes bottom time. The deepest reef dive is about 95 feet up to 25 feet. With an AL80 I'll usually have at least 1000psi left over on the wreck dives and upwards of 1000-1400 on the shallower reef dives depending on how deep it is. Several times we have double-dipped a wreck with an hour SI, same results. Now I understand that there is a profit motive for the shop if they can sell a customer on a Nitrox card, which is OK. My point is that I usually dive with a group of six or less with a DM and either we'll come up or buzz around close to the boat when the worst airhog is low on air or our time is up. I do only two dives in the morning trip as it's too tiring for me at my age, 70, to go out twice in the same day though I have gone out with them on night dives and then did the afternoon dives the next day. So the question is how would using a gas mixture benefit me? If I used Nitrox on the morning dives do you think it would help me with my energy level for the afternoon dives?

The fundamental advantage of Nitrox (Increased % of Oxygen, Reduced % of Nitrogen) is to extend your NDL's. This is achieved by reducing your exposure to Nitrogen.

Nitrox does not improve your air consumption or allow you to dive deeper; infact the depth restrictions on Nitrox are more severe (shallower) than normal air.

There are different "theories" regarding the postitive effects of Nitrox and divers feeling less "tired" after diving on Nitrox. I would have to say that the effects are different for different people.

I have a doctor friend who is qualified as a dive doctor and her theory/opinion is that a large part of the risk related to diving is based on the exposure to Nitrogen under pressure, reducing this exposure where possible also reduces the risks and in the long term is a positive advantage.

Rest assured there will be mixed opinions on this thread, try to take from it what you require and form your own opinions.

Hope this helps

Best Regards
Richard

PS : From a personal perspective, my wife and I always dive Nitrox when possible and when we do not intend to dive deeper than about 30m.

Simple answer. Your dives.. you could stay down longer, and have a shorter SI than the air people. Since you're having 1000 psi remaining for gas supply, you'd get a great benefit from Nitrox.

Nitrox training is also a great way to further understand diving theory in general, and is the foundation for getting into technical diving.

As for energy level on subsequent dives. That's debatable and will most likely begin a debate. Nay-Sayers will say, "there's no measure effect", Others (like me will say) if you feel better, then you FEEL better. If it's a placebo effect or not. Who cares. The bottom line is - Learning to dive Nitrox is good training. The extra couple of bucks will give you extra bottom time with the profiles you posted, and you have the gas supply available based on your 1000 psi remaining in your tank. So - do it. You won't be sorry.

I'm not in your class yet but I am ordering from the seniors' menu. I was trying to do 4 to 5 somewhat aggressive dives per day on air and it was kicking my ass (and limiting my bottom time). I switched to nitrox and felt much better through those aggressive FGB dive trips. Now I still use air for easier diving but FGB and Bonaire get nitrox.

Nitrox increases NDLs. For many divers, the increase in NDL has little benefits as their dives are typically limited foremost by their air consumption. However, if you are conducting multiple deep dives over a single day, even the worst air-hogs can find themselves in a postion where they get frustrated by short NDL on the later dives.

Nitrox provides the biggest benefits where the reduced nitrogen absorbtion is cumulative over several dives.

Another big benefit of absorbing less nitrogen, whilst not extending your NDL, is that it makes your diving far more conservative (without any alteration to your desired diving itinerary).

If 2 divers conduct several identical dives in a day. Diver A uses nitrox and Diver B uses air. At the end of the day, Diver A has a lot less nitrogen remaining in his system. There is less likelihood of DCS.

When I have a particularly busy diving schedule, I like to factor some nitrox into my dives....just to increase my safety factor.

HowardE:

Simple answer. Your dives.. you could stay down longer, and have a shorter SI than the air people.

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Don't forget that the Nitrox course educated divers to aim for a minimum surface interval of 1 hour between nitrox dives. :cool2:

Garrobo:

So the question is how would using a gas mixture benefit me? If I used Nitrox on the morning dives do you think it would help me with my energy level for the afternoon dives?

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HowardE:

That's debatable and will most likely begin a debate. Nay-Sayers will say, "there's no measure effect", Others (like me will say) if you feel better, then you FEEL better. If it's a placebo effect or not. Who cares. ... You won't be sorry.

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Placebo or not, I also feel better after diving Nitrox. Take the class then sip the gas.

The greatest benefit will be realized when doing multiple dives over several days in the 70-120 depth range. You won't see much benefit on a two tank dive.

Also, you can use enriched air to get increased NDL time or increased safety factor but you can't get both at the same time.

Why not try it and see if you get more energy? You will then have both options available. I personally subscribe to the placebo effect with EANx. You could post a follow up with a comparison at some point. Not very scientific, but it would be interesting to see how you feel.

awap:

I'm not in your class yet but I am ordering from the seniors' menu. I was trying to do 4 to 5 somewhat aggressive dives per day on air and it was kicking my ass (and limiting my bottom time). I switched to nitrox and felt much better through those aggressive FGB dive trips. Now I still use air for easier diving but FGB and Bonaire get nitrox.

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Like awap, I'm also not in your class yet - but am getting there fast.

There is a lack of evidence yet regarding the extent to which age plays a role in diver's physiological behaviors.

There is considerably MORE evidence, however, that oxygen tends to be beneficial to the body (within reason), while nitrogen tends to be a liability.

As the others have suggested, my opinion is that Nitrox can do no harm and may possibly yield a significant amount of benefit. As Howard said, if you feel better then you FEEL better, whether that intangible benefit may be absolutely measured or not.

I'd give the nitrox a try. At the very least you are increasing the O2 in your breathing mix and providing yourself with longer potential bottom times, and in general thats all good. Just my opinion.

Best,

Doc