Originally Posted by
jj1987
In our OW class we discussed that oxygen tox, and were told that dives below 100ft had an increased risk to the central nervous system, causing convulsions and other things of that nature. I don't think we went into what caused this, but were given the guidelines and told to obey them. Maybe I was a bad student, or maybe it wasn't covered, but I was under the impression that your body absorbed an exponentially greater amount of oxygen as more pressure builds up, but I never fully understood why.
Were you saying that the ppo2 formula is incorrect after a certain depth and the danger becomes higher, or that the effects of being narced increase with depth due to other factors like lack of light, color shifts as certain wavelengths dissapear, more pressure on your body, etc (I know these types of things can increase the effects of alcohol and drugs)?
The reason I'm wondering here, is that the ssi nitrox class I'm currently in doesn't seem to enforce depth limits as much as it says to just watch out for your ppo2, and keep it under a 1.4. Let's say you're diving air at 100ft, your ppo2 is .85, and a 36% nitrox blend is higher than that at 57ft with a ppo2 of .98, yet you're well within the "safe" limit, as you're still under 1.1 (or 1.4). I'm sorry if I'm being ignorant here, it just seems there's an external factor I'm not considering.