MASS-Diver:
I don't follow, why? Is Co2 rentention become more of problem just because you are there longer. IME, Co2 retention is an acute problem, developing (and resolving) pretty quickly.
Sorry, has nothing to do with CO2 and off the main topic. More precisely, I should say, has little to do with CO2. All are interelated. Your exposure is measured in depth and time, not depth alone. However, for recreational dives in both depth and time, I wouldn't think twice about using EAN32 at 60.' All things being equal, you can clear CO2 buildup by resting and doing nothing for a few minutes or just slow things down. In that regard, it's acute. If you've got complex gear, ill-fitting drysuit, harness, etc...or anything that causes you to work excessively hard such as the environment or causes the lack of O2 to your organs, CO2 will build up rapidly and exponentially. Since the rate of production is faster than the rate it's being metabolized and exhaled, symptoms of hypercapnia will eventually present itself. That is not an acute problem that is easily resolved without assistance. Of course each body is different. We USUALLY never want to get to that point...no headaches, no tiredness, nothing but feeling refreshed after the dive.
You are right on, everyone gets narced, it's a matter of degree not kind. The instant you are below the surface, physiologically your body is absorbing higher partial pressures of all gases. A sip of wine has varying effects on each body. Some people are finely tuned or aware of their BAC going from 0.00 to 0.01 to 0.02, etc... Some people aren't aware until 0.08 before feeling effects. Let's say you're the pilot of a small plane, flying a simple route across the state and you are getting ready to take off and are thirsty. Wine is free, bottled water costs $5, and vitamin infused water costs $10, and an energy drink costs $15. You'll be billed at your destination. That's all that's on board and you're traveling with a co-pilot only on a sightseeing flight. Weather appears to be clear, but its always unpredicatable in this state. You've flown this route plenty of times and it's easy. You're generally well rested and feeling ok. Pick your drink. There's are argument to be made with which drink and how you approach potentially changing conditions & environment. How sharp do you want your mind and body to be when executing emergency procedures? Bottomline, you've got some flexibility without compromising other procedures.
On the flip side, sometimes, you've got extra energy drinks, that you need to consume. I've had 21/35 mix that I've needed to 'burn-up' and used that in a recreational environment. Is it ideal? No, since I don't get any time advantage that EAN32 gives me, but there's nothing saying that I must only dive 21/35 in a certain band (excluding MOD).
Sincerely,
H2
