Please Educate A Newbie on Nitrox :)

[Stu S.]

Dropping off cylinders for nitrox today, I ran across a local instructor. Mr. Net Doc himself. I got a short and free nitrox lesson. A person's metabolism changes with age, making the transfer of gasses in and out of the body less efficient as one gets older.

Doc says he dives nitrox only, as the extra oxygen is better for man his age. At Alexander Spring with a max depth of 30 feet? Yes. All the time.

He says it was all researched by DAN, and he uses that as his guidance. Now.... you got a free lesson, too.

 

[DrakoWarkan]

Hello,
I agree with the others, I dive nitrox all the time normally 32% PO, as far as price at out local shop the Nitrox course cost $90.00 and is well worth the price.

 

[String]

Would love to see references for that. And anyone postulating any sort of mechanism where a healthy human who has no saturation problems can benefit from increased oxygen somehow.

 

[rk288]

$130.00 NAUI live course in Buffalo, NY 8/17/10 6-10 PM.

 

[Cougar281]

No evidence to back that up at all. People have tried and failed to find any statistically significant reduction in the rate of DCS.

DCS is already relatively rare. If you dive nitrox, but use "air" tables or setting in your computer, you'll get a MUCH larger No-Stop margin (at 50 feet you get 80 minutes on air, but 155 on EANx32, so you get a 75 minute margin), thus being a very conservative dive. The main thing you would need to keep in mind is your MOD, which would obviously be shallower on EANx32 than air.

 

[scubadobadoo]

The major benefit of Nitrox is increased allowable time before hitting NDL limits. In theory, if you dive air limits on Nitrox, you have improved safety, but it is difficult to show this, since few people dive air limits and DCS is rare to begin with. Many of us will claim that we "feel" better diving Nitrox (less post-dive fatigue) but the only study to have looked at this did not find it to be true.

The risk of Nitrox is central nervous system and pulmonary oxygen toxicity. The first is controlled by not exceeding safe depth limits for the mix you are using, and the second is really not an issue for recreational divers, as the required times are quite long, and the clock basically resets in 24 hours.

The increased bottom time you can get from diving Nitrox in the middle recreational range (70 to 100 feet) is substantial. I think it's well worthwhile to get the certification. Nitrox is available a lot of places nowadays.

Bingo as usual.

I also agree with everything String has said. Nitrox is only a tool that I use to extend my bottom time when needed. That's it for the most part unless I am diving multiple times in the same day. I don't rely on it for anything else. It has in no way been shown to decrease the already VERY low number of DCS cases in any significant way, even when used on air tables. Theoretically, yes of course it does help. (but) I think it is wrong to sell Nitrox as a cure all for bad diving habits and poor life choices that will magically make you safer if you use it. I can't tell you how many times I have heard a diver mention that it was okay for him to dive with a hangover because he was using nitrox or some other silliness. Any dive shop or instructor who ABOVE ALL ELSE emphasizes the "nitrox safety margin" should not be teaching Nitrox but rather selling used cars. I have heard some instructors say scary things about Nitrox and how it will help.

String, TS&M and others have mentioned several ways to give yourself a more reliable safety margin. Slower ascents, hydration, sleep, being in shape etc... Nitrox can be added to this list certainly but it is just one thing in the list and not THE LIST as some sell it to be.

All that said, from the right instructor, a nitrox course is wonderful simply for the educational value and for further discussion of dive tables and decompression theory that is lacking from many OW courses in the first place. TS&M does an excellent job of basically explaining Nitrox in a few short paragraphs above.