Nitrogen narcosis and time

[Scuba]

Everything I've seen on this subject points to nitrogen narcosis being caused soley by depth. Higher pressure.

Dive to a certain depth where diver experiences a certain level of narcosis. Is the full narcotic effect reached immediately or a very short time after arrival at that depth, remaining unchanged regardless of duration spent at that depth?

Does time at depth have any impact on narcosis?

 

[Zippsy]

I may have been too narc'ed to notice but I believe when I felt it, I usually stopped descending any further. The drunken feeling stayed with me the whole time I was at that depth and it did not seem to get better or worse until I started to ascend - then it went away quickly. Hope that helps.

 

[BigJetDriver]

is an odd thing. It varies from individual to individual, and on a day to day basis within one individual's range.

It is known that increasing narcosis is directly related to the fraction of N2 in the mix, and the depth of the exposure. Hence, we can use the formula to relate our "narcosis depth" to that of air (Equivalent Narcosis Depth formula). Also, we know that reducing the fraction of N2 in our mix will reduce our subjective feeling of narcosis at any given depth. Thus, another part of the rationale for Nitrox.

BJD

 

[H2Andy]

scuba, i think once you hit 40 or 50 feet, you already are under the effects of
narcosis, though you might not notice them. as you descend, they keep getting
worse with depth. so my guess would be that time at depth is not really a factor.
rather, the effects continue to accumulate as you descend. when they get
significant enough (due to depth), you notice them and say "wow, i just got narced."

in reality, you've been narced for quite a while, you just didn't notice.

this is just based on my experience. i dont' really know the answer.

 

[Dr Deco]

Nitrogen narcosis develops very quickly at depth. It also remits quickly upon ascent.

Dr Deco

 

[Rick Inman]

Also, we know that reducing the fraction of N2 in our mix will reduce our subjective feeling of narcosis at any given depth. Thus, another part of the rationale for Nitrox.
BJD

Dr. D, is this true? Forget the "subjective" part, and tell us what you think about N2 reduction and narcosis.
Thanks!

 

[H2Andy]

i don't agree. there is sufficient nitrogen in Nitrox, at least up to 40% 02, to make use of Nitrox have next to no impact on narcosis. there's more than
enough nitrogen in Nitrox to get you narced no problem.

but i am not a doctor (etc. etc.)

 

[MikeFerrara]

There is some debate about whether or not O2 is narcotic.

In my calculations I consider it as being narcotic. It errs on the conservative side and simplifies the END equation.

On dives where I've felt narcosis I felt less narced as time went on. However I wouldn't argue that I was less narced. My guess is that I jest got used to the feeling.

Narcosis is something that I like tp avoid with the generous application of helium.

 

[Scuba]

Thanks for the replies.

I would guess doing some research in a chamber to enlighten the subject would be fairly easy and not very expensive.

Dr. Deco, is narcosis an issue for the astronauts?

 

[DA Aquamaster]

There would be a lot of potentially confounding variables in such a study including participant effects such as the expectation of the diver regarding narcosis.

I have found that an ascent 10-20 feet for a couple of minutes followed by a re-descent to the depth where I felt more narced than usual normally helps as does a slower ascent at least in the upper 100 ft of the water column. That is my opinion, but then I am also a believer in, if not exactly adaptation to narocsis over the course of several days or weeks of deep diving, at least the ability to develop accomodations to the affects of narcosis over severl day or weeks of deep diving.