Andy, I hold the greatest respect for you in this field, but that is what we lawyers call "counsel to perfection", ie. something that is great to advise people to do, but something we all realise is never likely to happen in the real world in which everyone lives.
The bullet points you list in your post are great for technical divers carrying multiple gases diving to a carefully crafted plan. But much less relevant for occasional casual divers wearing a single Al80 filled with air. For those people post-dive fatigue is not only a reality, but probably a normality.
I think saying that people diving on air shouldn't suffer post-dive fatigue if they just dive "properly" kind of begs its own question. If we are saying (even agreeing?) that one can stretch that tolerance by using EAN32 rather than air, then we are not saying actually anything about post-dive fatigue that we are not already saying about NDLs.
I understand your point, but all of the recommendations I made are actually available within
recreational diving syllabus. It just depends on the agency.
...it's just "
not the way the world learn's to dive"...
For instance, with ANDI, teach as standard to all divers:
1. Ascent with stops: 3 level safety stops / 6 minutes from 9m to surface (1min @ 9m / 2 min @ 6m / 2 min @ 3m)
2. 50% O2 as "ideal ascent gas" taught on 'Complete Safeair User' (CSU), which is Nitrox Diver equivalent course and pre-requisite for most level 2 (advanced recreational) courses (deep, wreck etc)
I disagree that recommending anything above, or beyond, the basic dross taught by McDiver agencies is 'counselling to perfection' or 'technical'.
"What I find alarming, is that some entry level training agencies (not to mention any names), given all this recent knowledge and changing trends, haven’t altered their tables since their inception. The question is whether as instructors we should alter our methods to take some of these things into account. I think that certainly as experienced divers we should adopt safer decompression strategies. The recommendations for entry level training are obviously more limited, but I think we have a responsibility to adopt the safest possible methods for our trainees given the knowledge available."
THE TROUBLE WITH BUBBLES. Richard Heads PhD. 9-90 Magazine: UK Diving in Depth
Like he said...
---------- Post added September 8th, 2015 at 12:13 AM ----------
Don't you think that this statement is playing the reference of words a little to much????? It seems that even your wording says on a scale of 0-10,, 0 being bad and 10 being good nitrox gets a higher score on the feeling scale. GEEESHMO BETTER OR LESS WORSE???????
Not really.... if we're talking about reducing decompression stress/sub-clinical DCS/micro-bubbles, rather than any physical property of nitrox that makes us feel better.What I'm suggesting is that many divers accept post-dive lethargy as a normal issue. It isn't, or should be.
If post-dive lethargy has become an accepted norm, but nitrox relieves that... it is "less worse". Assuming all else is equal.... and that the diver off-gasses efficiently.... then nitrox would have little discernable impact on post-dive vitality.
If, however, you compare two dives that result in decompression stress (inefficient off-gassing / higher micro-bubble frequency), then using nitrox would provide an additional barrier against decompression stress, reducing micro-bubbles... and the diver using nitrox would feel better than the diver using just air.
Nitrox DOES increase the efficiency of off-gassing (lower pN2 remember...), it's not just about longer bottom times and initial absorption rates...
In short:
1. Nitrox decreases decompression stress.
2. Decompression stress decreases post-dive vitality.
3. If a given dive induces decompression stress, nitrox improves post-dive vitality.
4. If there is minimal decompression stress, no improved post-dive vitality is witnessed.
ergo... nitrox does not make you feel 'better'.
