Po2?

[nitroxbabe]

I've only been severely narc'd once - and no, it was nothing like a light switch. (although I did enjoy it quite a bit!) My recollection of the dive was fuzzy (tunnel vision), and my head didn't seem to entirely clear until we were back on the boat. It did improve as I ascended, but slowly.

 

[lanun]

spectre, i get drunk on two beers so bear with me on the analogy.

the first time i was narked bad it was like after three shots of tequila (again, let me remind you i get drunk on two beers).

sip, sip (hmmm, the instructor said to focus because i will get narked) ... hmmm good tequila (2nd shot glass) ... not narked yet (sipping third tequila) ... nice things here. what is that ? looks like some kind of sponge. i guess i'll STAND here for a while to watch this.

someone is staring at me. oh, better return the ok sign. (probably grinning like a monkey at this time). wait a minute - this looks familiar. ah, follow him. okay.

bzzzzzz focus on the guy in front ... bzzzz ...

hmm. nice boulder. ahhh, nudibranch. oh oh, OOA drill again.

back on the boat - 'you were narked at 80 feet'. yikes !

so i guess it could have been like a light switch that time. it wasn't my deepest dive, and with hindsight, it probably wasn't the first time i am hit with symptoms of narcosis either.

since then, i am able to sense the onset, or rather, be on the lookout for the onset and then sense the onset of narcosis.

best investment i ever made taking the class.

 

[DiverBuoy]

Spectre once bubbled...
Well, which is it? Progressive or 'light switch'?

They're not mutally exclusive. There are small effects that are almost unnoticible without a comparitive test. However, when you hit that magic depth usually within 5-10 feet, you can hit it again and again in the future - on the same mix. Ascending just a few feet (outside that magic mark) immediately symptoms begin to subside - like a switch. Within seconds most of the effects (for that depth) are gone.

I've never heard of anyone with nitroxbabe's experience. Namely where the symptoms persisted until the dive ended ...

So extending Rodale's illustration, by coming back up it's like instantly sucking every trace of that last martini out of your system - rise another atmosphere lose another martini - thus the cumulative effect. Some people don't get toasted on X beers but have X+1 and they're over the top.