Just to see what would happen, I tried doing a week of nitrox on air nsl dives. I did not feel any difference in fatigue.
It may well be personal. I've always felt far less fatigue diving nitrox than air.
There is a theoretical safety advantage to be gained through lower N2 loads, but when an already small risk is made smaller, it is pragmatically lost in the "noise" of everything else, and is thus not worth making a big deal over.
Not just lower N2 loads, but more O2, as well. The 'oxygen window' is often referred to on this forum by many participants. Well, the oxygen window principle forms an important part behind the reasoning when diving nitrox, not just lowering N2 loading. Negating the effect of the oxygen window when diving nitrox, but stressing its importance when urging decompression on pure O2 at 6 metres seems like an oxymoron ...
Which means that pragmatically, you dive Nitrox for the benefit of its longer bottom times, not to make an already tiny risk value incrementally smaller.
Again, another theoretical oxymoron.
Why should nitrox make longer bottom times safer, but not work on making bottom times within NDL:s
even safer?
The 2003 DAN Accident report states there is a slight increase in 'accident' rate for mixed gas users compared to 2002, but the actual numbers are not available.
Surely that would include the use of trimix, heliox and other gas mixes? And the use of mixes other than nitrox, e.g. trimix which very likely is on the increase, signifies vastly different and often more hazardous diving practices, e.g. deep diving, deep wreck etc.
In those who qualify, Triox offers potentially more safety, since in addition to the nitrox component, the He portion mobilizes faster than N2 and is more predictable for offgassing.
This is almost an 'established fact' in some technical dive circles, particularly if we look to certain Florida cave divers. However, the 'He is a benevolent gas' myth may be just that. I'm eagerly awaiting the on-line publication of the US Navy mixed helium gas trials which do not appear to bear out this opinion, but rather the opposite opinion that more incidences of neurological DCS may be expected with helium mixes. I certainly know of several decompression workers who do not buy the 'benevolent gas' theory. As an inert gas, shouldn't it be treated with the same respect decompression-wise as, say, nitrogen?
Don't get me wrong, I'm all for trimix. For the well-trained technical community, that is. Guess we'll get more data when triox hits the recreational community in force. Certainly, people get badly bent on trimix as well ...
Dive safety is very important to me, but I want to focus on what really works. One thing is Dr. Deco's advice regarding physical exertion.
On this I agree wholeheartedly. Not only do I find Dr Powell's advice here makes a lot of sense from all aspects and explain a lot of anecdotal decompression findings from other sources, but I follow this advice myself when diving. I'm looking forward to reading the NASA findings when published. In fact, I'd really like to sign up for his decompression class this autumn ...
