[John Gulliver]

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Having read several people's comments on this subject in another thread, I began to wonder about this. I can honestly say that I have never experienced "the raptures of the deep". I've done two "dry dives" to 50 m and was completely unaffected both times. I felt perfectly normal and was able to carry out various tests (mathematical calculations etc) without difficulty. Many of the other divers were out of their minds – couldn't write their own names, didn't know their date of birth, just sat there giggling. I dive regularly on air to almost 40 m and have occasioanlly dived to almost 50m, without feeling anything at all. Many people tell me I must be affected without knowing it as everybody is affected over 30m, because that's what it says in the books. I don't believe it! Last time I dived (Thursday evening) my max depth was 37m and I tried to test myself by asking myself various questions: What's the name of that fish? How many of that kind of anenome have I seen on this dive so far? What year was my father born etc? I didn't need to think more than a second to come up with the right answer. One's susceptibility to nitrogen narcosis probably varies from day to day, like one's susceptibility to alcohol intoxication, depending on many factors, but I believe it varies even more from individual to individual and that I am one of the fortunate people that is hardly affected, if at all, at normal sports diving depths. There! I've stuck my neck out. What do you think?

 

[Hobby]

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Hi John,IMHO I think the fact that you dive regularly has a lot to do with it,as you're well aware there are other factors.
So much of it I think can be to do with this "mindset"that I always harp on about.I don't know how much research has been done into this but I reckon that somebody's psychological state can have an effect on a narcosis hit,esp,when combined with other "stressors"such as cold,poor vis task loading etc.
If you're competent and familiar with what you do I beleive you stand less chance of being affected.
As for the 30m limit,I've seen this too.I don't know where it comes from(altough I could hazard a guess)and I agree it is (I beleive)to be absolutely untrue and potentially dangerous.If people have a beleif that when diving,if they keep above 30m they'll be OK where does that leave them the day it taps them on the shoulder? I know of and have seen people suffer the effects of narcosis at much lower depths,can't comment on the physics of it,just what I,ve seen.
As I recounted once,I suffered a big hit once.All through my training etc.I too had had nothing even at 50m or so on air.This day however after spending months in a canal,I ended up hitting over 50m in less than a minute(somebody dropped the shackles that were being lowered and I was wrapped up in it all)I actually "beat"the reg on the way down and managed to equalise once.The fear arising during this time,the pain from my ears,the pressure to complete the job and the fact I did'nt want to do it anyway combined and I experienced alternate moods of over confidence and sphincter clenching worry.I knew I was narked,that was the funny thing,my ability to deal with that was marred by the over confidence though until I kicked it into touch and strated a descent.
God forbid John that you may one day be affected,I can't honestly say you won't,however,you have wide experience in what you do and I beleive you may well know what is happening as a result and thus be able to deal with the situation.Hopefully.Take care,Hobby.

 

[John Gulliver]

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Thanks for the input, Aaron. That must have been a VERY nasty moment. Thank God you coped with it.

 

[Dr Stevil]

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I've never really had what I would call the "rapture" aspect of narcosis as for me seeing an interesting beast is the thing which makes me think "wow..." this can, and has, happen(ed) at 6 metres or less so I couldn't claim that was due to NN.

However, trying to do "work" at 30 metres showed me how narc'ed I could be without realising it; I was trying to put several cable ties together to make a bigger loop in order to fix things (corals) to a perspex sheet: you know the "can't get the key in the door after a few bevvies" scenario? that's what it was like, plus it didn't help having a renowned bad-tempered dive buddy who's idea of a dive brief is shouting at people underwater thru his reg
The stress of dealing with that just makes you more "punchy"
Cheers
Steve

 

[Dominic]

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Deepest I've dived is 36 meters, at which I feel noticeably narked - hence the reluctance to go any deeper.

Not incapacitated or "must share air with fishes or they'll drown" type narks, but still noticeable - like I've had just enough alcohol to start feeling the effects.

Since I aim to always be in control when I'm in the water, I don't like to be at depths where I feel I'm not. So I tend to the DIR view on this one - I'd prefer not to go below 30ish without being on mix.

 

[andy2tanx]

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I always thought I never got narked.  At any depth, be it 10 m right down to 45m on air I always thought I was cool, (which I was as always!).

however, I went to Hodge with andy h one day recently and at the bottom I switched from air to his mix, just to see you know.  And blow me if everything didnt become clearer and my vision widened out and i generally felt 10 times better.

So there it is.  I was ok on air.  never had feelings of rapture, never felt scared, suicidal, or drunk.  But my reactions ARE slower on air, and that gentlemen leads me to believe I was/do get narked at depth.

How your body deals with it is just down to the individual.

Dive safe, drink happy!!

 

[Dr Stevil]

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My deepest ever was a shade under 40m in Loch Fyne, cold, dark but clear viz with a decent torch. Afterwards my buddy asked me how I liked the narcosis, I hadn't felt any of it, usual discussion ensued "you WERE narc'ed but didn't realise it" etc...

Other times I've been pootling around a muddy hole at 4-6 metres and I've felt like I was tripping out of my tree, seeing faces and shapes in the silty water the way you can make shapes out of clouds. I think it all depends on your state of mind (IMVHO)
Cheers
Steve

 

[John Gulliver]

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"I think it all depends on your state of mind (IMVHO) "
Quite possibly, but I would have thought I ought to have felt it at least once during my 1220+ dives if that was the only important factor. I dive all the year round, sometimes in seawater round about zero Celsius and with vis of only a metre or two at times, so it's not that I'm diving under "soft" conditions either. I'm not claiming to be Superman, though. I'm quite aware it could happen to me too.

 

[Dr Stevil]

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1200+ dives ? Perhaps that's it then! you've awakened some form of dormant adaptation in your genome

Science nerd corner: during foetal development, humans go through a phase where the the embryo clearly shows our fish ancestry, strange, but true...

 

[John Gulliver]

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That must be it! Whoever heard of a narced foetus?

 

[189]

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Weird one the old Narcosis thing!

Done around 250 odd 30/35 meter dive both cold and Med waters plus a few a bit deeper and as far as I recall I've never had the joys either - maybe on one occaision when about 10 of us did a negative free fall down to a 40m bottom (in skydiver formation!) - laughing my face off but that may have been more to do with the situation than narcosis !

However, I've been hit a lot shallower on one occaision - leading a dive in the Med when a guy got a bit floaty in a cavern and his belt was slipping badly - by the time I'd finned to him, wrapped round him and done it back up I did feel a bit light headed - that was at around 25m ish

Some times you get, other times you dont it seems !

Paul

 

[Jay]

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I guess the answer lies in your question John - "am I unique?"

Is there something about you that, unlike the rest of the diving fraternity, makes you immune from narcosis. The answer is, logically, no. Although narcosis is not exactly understood, the principle is believed to hinge on the partial pressure of nitrogen acting on your CNS in the same way as nitros oxide (laughing gas). This is definitely dependant on your mood and surroundings and can affect you to different degrees on different days (like alchohol). As Andy has suggested, if you ge the opportunity to switch from air to trimix at depth, you'll see the difference (even if you weren't aware there was one).

 

[Gunna Do]

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Well im up to about 60 dives I reckon ( Ive never logged a dive since ive done my ticket)..
So I am just estimating, most of my dives are about 25 - 30 mtrs and the deepest Ive hit is about 35mtr...
And #### it i havent had the joys of Narc yet..It could save going to the boozer after the dive...
But on the other side of the coin, I still find myself occasionally suffering claustrophbia on the odd occasion when vis is pretty bad. on the way down..
I am immediately fine the minute I see the bottom..
very strange
Steve

 

[John Gulliver]

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Sorry to be sceptical, Heads Up, but, although I haven't tried trimix, I really don't see how you can be soberer than sober! I wasn't seriously suggesting I am unique, in fact I know I'm not. I have several very experienced friends who also say they've never felt anything. As I said before, one's susceptibility to nitrogen narcosis probably varies from day to day, like one's susceptibility to alcohol intoxication, depending on many factors. I don't believe I'm completely immune but, having dived so long and done so many relatively deep dives without ever feeling in the slightest bit affected,  I do believe that some of us are far less affected at normal sports diving depths than the textbooks and most diving instructors seem to believe. Hope this doesn't sound too cocky. Actually, I offered on a Swedish forum to submit myself to tests but nobody took me up on it. Pity. It would have been interesting to resolve the issue once and for all.

 

[andy2tanx]

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All I have to say is if you get the chance to do it then switch from air to trimix at depth, then tell us if you felt the same!!

 

[Jay]

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I hear what you are saying John - no problem being sceptical and no problem thrashing it out on the forums - thats what we're here for! Lets look at the process of narcosis (easier to understand it when compared to drinking alchohol).

1. You don't believe you are completely immune - good, so you accept that, at some depth you will eventually 'feel' the effects.

2. Like alchohol, narcosis does not suddenly kick in at a certain depth (i.e. you do not sudddenly start being impared by alchohol after 4 beers - its a gradual process)

3. Some people handle the effects of narcosis (alchohol) better than others to the point of not noticing the early onset of either.

Contrary to some beliefs, narcosis does not happen around the 30m mark or any other set depth - the PROCESS of narcosis starts as soon as you start descending and breathing ANY mix with nitrogen in it. The EFFECTS may not be discernable for quite some time and maybe not at all to the diver BUT the PROCESS is still there with that diver.

Its like the driver who drives home from the pub every night:

1 beer and he's fine (ok to drive but no one would deny that there is alchohol in his system and that it has had some effect on him).

3 beers and he still feels fine (in fact he feels better than fine - euphoric effect of alchohol). His perceived concentration levels are up and he is still able to drive home without problem. His mate, though, always gets a little giddy at this point.

5 beers - he still feels fine to drive. After all, he regularly drinks this amount and, unlike his mate, never feels drunk. He's still able to drive his car home in this state every night.

This guy is able to do tasks that have become automatic to him without (in his opinion) any impairment. However, should something unexpected happen, his reactions will be seriously impaired - and he may suddenly feel very pissed indeed.

Ok, for the above scenario, exchange the beers for metres (ie 1 beer = 10 m, 3 beers = 30m, 5 beers = 50m)

I agree with you that some people have different perceived tolerances for narcosis and are able to perform automatic tasks MUCH better than others (with over 1200 dives, most of your normal diving tasks are now automatic). But in a situation of serious task loading, you may feel the onset of narcosis in a very big way, VERY QUICKLY.

 

[martz]

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i've always used this  www.octopus.au.com/narcosis.htm
please let me know if it fits in well with your findings!

 

[John Gulliver]

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Sorry, only just seen your post. Fun site but, no, it doesn't agree with my experience. My maximum depth ever is 48 m, at which "Confusion, hallucinations and feelings of euphoria may be clouding your judgement". Sorry, but I'm prety sure they weren't. And I'm definitely not light-headed at 30 m (or at 40 m).

 

[andy2tanx]

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John, YOU ARE the man, dive god!!

 

[Dominic]

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Here's an idea: Next time you're at 48m, ask the singing purple giraffes if THEY think you're affected by the narcosis.
They never seem to answer me tho...