Doc, you're entire argument is based on the imaginary CNS clock which is not a valid measurement of oxygen exposure. You keep repeating yourself and dodging questions. Give it a rest.
Care to enlighten us all with your omniscient understanding of the relationship between inspired PO2 and time of exposure? Because until you do, I’m a bit confused as to your insistence that an arbitrary PO2 limit is really important for avoiding a CNS hit, but that length of exposure to PO2(s) is irrelevant to avoiding the same thing.
I’m perfectly happy to answer for you: you don’t understand how it works, but so far ignoring the clock has worked for the size of the dives you’re doing, so it’s not a hard and fast rule. No disagreement from me, I’ve done dives where my CNS ended in the 400% range. You won’t catch me doing that kind of stuff back to back to back, though, and I make no suggestion that just because I’ve gotten away with it, the whole CNS clock concept is “bunk.”
PO2 matters, but it's obviously not everything - or I'd be dead from a lot of air dives in the 240' range. Length of exposure matters, but it's obviously not everything, or a whole bunch of us would be dead from just doing our deco. But the idea that CNS is somehow completely useless is horse
.
Remind me again who breathes water?
I'll indulge you for one reply more, since I should have maybe used smaller words in my earlier post. You submit that if 80% were "better" than 100% it'd be used in chambers, and then seem to think you've spiked the football by pointing out that
OMG it isn't! However, you're missing (for your sake, I hope deliberately) the fact that in water deco and a chamber are two very different environments.
In the chamber, you’re likely warmer, certainly not submerged, and a whole lot less likely to have elevated CO2 levels due to breathing through a regulator – three things that, shockingly, have all been shown to increase human tolerance to elevated PO2s. And of course, you won’t
ing drown in the chamber if you do suffer a hit. In the water, conversely, all the factors I just mentioned
favor a CNS hit happening and you’re probably going to drown if it happens. This kind of
‘probability of harm’ times ‘magnitude of harm’ equals ‘risk’ way of thinking is something you might want to explore further on your own…I’m told it comes in handy in life sometimes.
Now, pay attention, because this next bit involves you…where it
really comes in handy is when you want to use a big word like “better” without sounding like you may have, on occasion, lost points otherwise awarded for not drooling on the paper. This is because determining whether one option (say, 80% O2) is better than another option (say, 100% O2) really requires that one look at all the possible risks and benefits involved in a given context. So, while the marginal deco efficiency of 100% O2 might make it
better than 80% in a chamber, where CNS hits are much less likely and much less of a problem, the same marginal deco efficiency difference might be quite irrelevant in the water, where CNS hits are significantly more likely and generally result in death, and you’re not trying to treat existing bubbles to boot.
Did I clear that up for you, or would you like to try being glib once more?
