Was I Narc'd?

[gcbryan]

The limit on nitrox is based on the concern about the O2 in the mix. You introduce helium into the mix as depth increases so that you can limit both the nitrogen (for narcosis) and oxygen (O2 toxicity). I believe you are confusing this with the idea of a 100 foot equivalent narcotic depth: the mix you use on a given dive should have a nitrogen partial pressure no greater than if you were diving air at 100 feet.

Maybe I misunderstood you.

I've read many posts on this board (most of them DIR) talking about how much narcosis has affected them at depths as shallow as 80fsw-100fsw. Most say that they won't dive deeper than that without helium due to narcosis.

The average (non-DIR) diver will have stories of how on occasion they have noticed narcosis at shallower depths and have felt greater effects by 150fsw.

Both groups acknowledge it but one group seems to have been affected by it more. I'm just wondering if one isn't affected by it more if you already believe you will be affected by it more.

I wear a seatbelt and feel that it adds to my safety. If it became unbuckled while driving I wouldn't suddenly believe I was going to die if I didn't buckle it immediately. Someone who had been taught that you may well die without a buckle may feel differently. They may be able to recount how the belt became disconnected one time and they almost had a wreck. It may be true but it's not really about the belt even though it's also true that belts add to your safety.

 

[Zosimus]

Were you in Florida? Did you ever look back to see if a gator had you by the fin?

 

[boulderjohn]

Both groups acknowledge it but one group seems to have been affected by it more. I'm just wondering if one isn't affected by it more if you already believe you will be affected by it more.

A study cited in a recent issue of Dive Training Magazine divided a group of test subjects into three groups, all of which were given the same task to do at 200 feet. Each of the groups were given different training prior to the dive. At one extreme, a group was told that narcosis was inescapable and severely debilitating. At the other extreme, the group was told that narcosis could be overcome by discipline, etc. The three groups performed in accord to their training--one group was almost incapable of performing the task, and at the other extreme the group did just fine.

This indicates to me that the effects of narcosis can be overcome to a certain extent by one's mental attitude. It also suggests to me that experience can be helpful. I do not, however, believe it goes completely away in any circumstance.

Of course, no one really knows anything for sure.

 

[UntamedSpirit]

wow, learned a lot more than expected. (it seems like everytime i learn something, it shows how much more I have to learn) Thanks for all the info.

 

[captron]

You Are narced to some degre.

 

[Thalassamania]

I thought that I might share a story about memory loss at depth that might be instructive:

I have heard reports of poor post dive memory for details but not large gaps in time. I once had to do a dive to recover a wave gauge, it was embedded in a large clump of concrete, about six foot, by four foot by three foot. It was supposed to be in 140 feet of water. My task was to take a heavy line down and tie it to a bar in the clump that was there for that purpose. It was a dark and cold New England dive. The bottom turned out to be at almost 180.

When I got there I found the clump on the bottom and right next to it was a Goosefish almost as large as the clump. I had to lay across the top of the Goosefish to tie the line. I was on surface supplied air and talking to my tender the whole time, he kept reiterating the need to tie a secure bowline. When I got back to the surface he wanted to know, "did you tie a bowline?" For the life of me I could not remember, I remembered tieing something, but what knot? ... turns out that I did tie a bowline, but did I do it on autopilot? Did I forget? What exactly went on?

To this day I can remember stretching out over the Goosefish, but I can not focus on a single detail of tieing the knot. I know that I was not unconscious, even for just a moment, else I'd not have tied the line off at all, especially not correctly, which I could see later that I had done.

 

[TSandM]

Maybe it's not that DIR divers are conditioned to believe they are going to be narced. Maybe we face ourselves with a lot more problem solving at 100 feet or deeper than most (at least recreational) divers do? It's pretty clear that, if you aren't trying to solve novel problems, you may be completely unaware of any impairment.

 

[Thalassamania]

I suspect that I've had to do a fair amount of novel problem solving a depths well in excess of 100 feet while on air. I expect there to be some narcosis, and that's what I (subjectively) experience. So I try to work slowly and methodically, that line tying issue I described earlier is an anomaly.

Dark Nark (more typical of cold dark wreck dives off New England), on the other hand, is very real, but very controllable ... telling yourself, "don't go there." and taking three slow, full breaths is enough to push it away.

It is interesting to consider how much of narcosis is self generated by expectations, like when I was in college and others would smoke green tea, but appear to get very high.

 

[gcbryan]

I suspect that I've had to do a fair amount of novel problem solving a depths well in excess of 100 feet while on air. I expect there to be some narcosis, and that's what I (subjectively) experience. So I try to work slowly and methodically, that line tying issue I described earlier is an anomaly.

Dark Nark (more typical of cold dark wreck dives off New England), on the other hand, is very real, but very controllable ... telling yourself, "don't go there." and taking three slow, full breaths is enough to push it away.

It is interesting to consider how much of narcosis is self generated by expectations, like when I was in college and others would smoke green tea, but appear to get very high.

Exactly, I remember reading about a study while in college where people were told that a punch bowl was "spiked heavily". Some people said they didn't feel drunk, some said they felt drunk but were able to handle it and some did things they wouldn't have normally done because they "had a little too much to drink".

It's just human nature. Some people are more susceptible to the powers of suggestion.

What I think is more interesting is the concept that a frequent diver can perhaps adjust or cope at a higher level than a less frequent diver. I know that when I was diving a lot more frequently it seemed to have less effect than now when I dive less.

It still exists and novel problems still are more difficult to deal with than expected ones but I think there (may) be something to this concept.

I know the way to do deeper diving on air if at all is to do it progressively. Most of those who have strident opinions on how debilitating it is to dive at 100fsw on air or deeper are usually those with no experience to any great degree with deeper dives on air.

Of course, it's true that there are now better choice available (helium) most places and perhaps no particular reason to develop any deep air skills but the concept is still interesting.

It's certainly my experience that narcosis is a gradual thing and that it can make other problems worse but in most cases it doesn't cause those problems so what is called getting narc'd is usually narcosis plus other distinct things. I've never experienced anything other than a gradual narcosis experience...sometimes very unpleasant, usually not but never any out of my mind experiences. I think anxiety is mislabeled and/or combined with the term narcosis quite frequently.

 

[Thalassamania]

But let's recognize that narcosis is a real phenomena, it's not just in peoples' head.