Question about Nitrogen Narcosis

[Dive n00b]

Hey All,

I've been reading the forum avidly for several weeks now and have run across many posts (like the one a few posts down) about people's first experiences with the Narc.

I've got some questions...

At what depth do you begin to increase your likelyhood of experiencing the Narc? I understand that factors such as water temp, exertion, air intake etc... all play a role, but is there a general rule of thumb that says for example: below 60' your likelyhood begins to increase?

For those of you that are deep dive certified and not diving gas... is the narc a normal thing that you guys have trained yourselves to manage through experience? Do you sense it kicking it and just deal with it? Just curious... I suspect that if its a regular occurence when hitting 100' or whatever, thats a depth that I may not be so inclined to visit (I would obviously get the training before I attempt it, but this whole Narc thing seems like a non-starter to me).

If it is normal and you have learned to manage it, is the transition from happy narc to dark narc where you guys decide to call it quits?

Sorry for the obviously n00b questions... I'm just extremely curious and have not come across direct answers to the above in my reading of the archives.

Also, we are heading out to Stuarts Cove on our first post-cert dives on Saturday. I know some of the guided dives get down deeper than I have been in my OW test dives. Although I'll be clear with the DM's about my experience, I want to know for myself where to limit my exploration in terms of depth. So if you say Narc becomes a concern at 60' I'll be sure to keep it to 50' until I grow more confident in my skills, and have DM/Instructor with me.

Thanks!

 

[ToddK]

You have a good question, and it sounds like you are approaching it cautiously. First the obvious disclaimer. As a new diver, don't be in a rush to go deep. In deeper diving, your air supply goes much faster, you have to be more aware of your surroundings, more careful with ascent, etc. You might run into task loading problems even before getting narc'ed. In general keep your depth to 60' or less, at least until you have a chance to do a AOW course where they take you on a deeper dive, or you build up 20-40 dives. There is a lot of cool life to see in the less than 60' range, and as you go deeper, you see less. Diving is a great sport, and is extremely fun, until you have an experience that scares the crap out of you.

In terms of narcosis, the deeper you go, the more narc'ed you get. I don't think there is a magic barrier of 50', or 60', or any other number. I'd hazard to say the average diver doesn't have "dark narc" attacks in the 60-100' range, but rather suffers from some degree of perceptual narrowing, degraded ability to think and perform skills (I think this is what you mean by "happy narc"). Going deeper, at some point (which, as I'm sure you've read there are different views on when it happens), you get the sudden realization that you are really narc'ed. At this point, it is a good idea to move shallower.

Most of my dives have been in the 60-120' range, without noticable narcosis effects most of the time, which is not to say they aren't present. I personally believe that water temperature and clarity do affect narcosis. Folks debate how much you can adapt to narcosis.

Enjoy your vacation. I've been letting work get the better of me for the last 6 months, I need to get out and go diving! -Todd.

 

[rstofer]

From the US Navy Dive Manual:

<Quote>

3&#8209;9.1.1 Causes of Nitrogen Narcosis.

Breathing nitrogen at high partial pressures has a narcotic effect on the central nervous system that causes euphoria and impairs the diver&#8217;s ability to think clearly. The narcotic effect begins at a nitrogen partial pressure of approximately 4 ata and increases in severity as the partial pressure is increased beyond that point. A nitrogen partial pressure of 8 ata causes very marked impairment; partial pressures in excess of 10 ata may lead to hallucinations and unconsciousness. For a dive on air, narcosis usually appears at a depth of approximately 130 fsw, is very prominent at a depth of 200 fsw, and becomes disabling at deeper depths.

There is a wide range of individual susceptibility to narcosis. There is also some evidence that adaptation occurs on repeated exposures. Some divers, particularly those experienced in deep operations with air, can often work as deep as 200 fsw without serious difficulty. Others cannot.

3&#8209;9.1.2 Symptoms of Nitrogen Narcosis.

The symptoms of nitrogen narcosis include:
Loss of judgment or skill
A false feeling of well-being
Lack of concern for job or safety
Apparent stupidity
Inappropriate laughter
Tingling and vague numbness of the lips, gums, and legs

Disregard for personal safety is the greatest hazard of nitrogen narcosis. Divers may display abnormal behavior such as removing the regulator mouthpiece or swimming to unsafe depths without regard to decompression sickness or air supply.

3&#8209;9.1.3 Treatment of Nitrogen Narcosis.

The treatment for nitrogen narcosis is to bring the diver to a shallower depth where the effects are not felt. The narcotic effects will rapidly dissipate during the ascent. There is no hangover associated with nitrogen narcosis

3&#8209;9.1.4 Prevention of Nitrogen Narcosis.

Experienced and stable divers may be reasonably productive and safe at depths where others fail. They are familiar with the extent to which nitrogen narcosis impairs performance. They know that a strong conscious effort to continue the dive requires unusual care, time, and effort to make even the simplest observations and decisions. Any relaxation of conscious effort can lead to failure or a fatal blunder. Experience, frequent exposure to deep diving, and training may enable divers to perform air dives as deep as 180-200 fsw, but novices and susceptible individuals should remain at shallower depths or dive with helium-oxygen mixtures.

<End of Quote>

To my knowledge, I haven't experienced it during short dives to 113 fsw. But, the NDL at 113 fsw is only 12 minutes and that includes (for NAUI) both the ascent and descent. So maybe 8 minutes on the bottom.

And this points out my objection to deep diving: For all the effort and increased risk (if any) there is no bottom time. In my view, it is seldom worth the effort. If I'm going to get wet, I want to stay a while.

Richard

 

[scubak]

In my opinion (disclaimer here...don't want to get flamed)...Narcosis depends on alot of factors.
1.Whether you are diving cold or warm water
2. Your own comfort level and experiance as a diver.
3. Your own feeling of the day and dive. Are you tired, is this a new site?, are you hydrated?, conditions?, etc...
There are many more varibles to Nitrogen Narcosis and these all can vary day to day and dive to dive.
I got it when I first started diving past 60fsw in the cold dark waters of the PNW and Canada. I was taught though to get the muscle memory to equalize, check the gauges, air in drysuit, check buddy, etc...so this all became a "habit" which we called a hail mary on deep dives to 130ft and beyond.
I got used to it (the Narcosis, because I believe any diver experiances some type of impairment at 60fsw or deeper) and was able to work with it, not overcome it and dive safe in these parameters. However, I also got narc'd recently at 104fsw because I had not been there for quite some time and had to really work through the dive and get my head right.
I also have a friend who has many more dives than I that cannot got past 90 to 100 fsw in the cold waters of the PNW. She dives upside down, is a danger to herself and others and really has no clue. In warm waters with a 100ft of vis she is a champ to 130ft on air. Go figure!
It all depends on training, education, experiance and comfort and always remember safety first to yourself and your dive buddies.
Hope this helps you.
Kirsten

 

[TSandM]

I'm with Kirsten. When I took my OW, somebody mentioned the "Martini rule": For every ATA you go down, it's as though you had chugged a martini. By 100 ft, you've chugged four of them. This is precisely my experience, which is that even in shallow depths, my ability to remember and execute are compromised, and it gets worse as I go down. The 100 foot range in cold water and limited viz is my personal hard deck. When I was first diving, I got frank hallucinations at that depth. I suspect it was a combination of nitrogen narcosis and CO2 retention due to stress. I no longer hallucinate at those depths, but I don't delude myself that I am any more COMPETENT there than I was before. Below 100 feet, I have some helium in my mix. I don't do those dives very often.

For a new diver, I'd say that, if you are staying at or above the 60 foot range that you saw in class, you will probably be okay from a narcosis perspective. Those are good depths for new divers, anyway, because their gas consumption rates tend to be very high, and deeper dives would be quite brief as a result.

 

[Dive n00b]

You have a good question, and it sounds like you are approaching it cautiously. First the obvious disclaimer. As a new diver, don't be in a rush to go deep. In deeper diving, your air supply goes much faster, you have to be more aware of your surroundings, more careful with ascent, etc. You might run into task loading problems even before getting narc'ed. In general keep your depth to 60' or less, at least until you have a chance to do a AOW course where they take you on a deeper dive, or you build up 20-40 dives. There is a lot of cool life to see in the less than 60' range, and as you go deeper, you see less. Diving is a great sport, and is extremely fun, until you have an experience that scares the crap out of you.

In terms of narcosis, the deeper you go, the more narc'ed you get. I don't think there is a magic barrier of 50', or 60', or any other number. I'd hazard to say the average diver doesn't have "dark narc" attacks in the 60-100' range, but rather suffers from some degree of perceptual narrowing, degraded ability to think and perform skills (I think this is what you mean by "happy narc"). Going deeper, at some point (which, as I'm sure you've read there are different views on when it happens), you get the sudden realization that you are really narc'ed. At this point, it is a good idea to move shallower.

Most of my dives have been in the 60-120' range, without noticable narcosis effects most of the time, which is not to say they aren't present. I personally believe that water temperature and clarity do affect narcosis. Folks debate how much you can adapt to narcosis.

Enjoy your vacation. I've been letting work get the better of me for the last 6 months, I need to get out and go diving! -Todd.

Thanks Todd...

Good feedback... of course I would dive within my limits, and unlike many, I'm in no hurry to go deep. Started diving with the wife just recently... I really enjoy seeing the marine life which is one of the main reasons we started diving. Although reading SB on a regular basis has got me thinking way ahead, I think it will be quite a while before I become really interested (and can covince the wife to be interested as well) in more technical diving which I suspect is the stuff that necessitates going deep.

Definately plan to keep up above 60' until we get a bunch more dives under our weight belts or are on our AOW course.

Cheers!

 

[Hank49]

Twice last week I was diving on, not in, some wrecks in Coron, Philippines. I was floating along on my back looking up at the fish and the sunlight coming down in the water. All of a sudden I was dizzy and disoriented. I knew what it was, turned over and was still a bit out of it. But the good thing about narcosis is, for me anyway, that an ascent of a few meters makes it "turn off", almost immediately, which it did in this case. After a few seconds, I went back down to the original depth with no further incident. (30 meters or so)

 

[Dive n00b]

I'm with Kirsten. When I took my OW, somebody mentioned the "Martini rule": For every ATA you go down, it's as though you had chugged a martini. By 100 ft, you've chugged four of them. This is precisely my experience, which is that even in shallow depths, my ability to remember and execute are compromised, and it gets worse as I go down. The 100 foot range in cold water and limited viz is my personal hard deck. When I was first diving, I got frank hallucinations at that depth. I suspect it was a combination of nitrogen narcosis and CO2 retention due to stress. I no longer hallucinate at those depths, but I don't delude myself that I am any more COMPETENT there than I was before. Below 100 feet, I have some helium in my mix. I don't do those dives very often.

For a new diver, I'd say that, if you are staying at or above the 60 foot range that you saw in class, you will probably be okay from a narcosis perspective. Those are good depths for new divers, anyway, because their gas consumption rates tend to be very high, and deeper dives would be quite brief as a result.

Agreed, and thanks for your valuable feedback (once again... I've read lots of your posts). For what its worth though... we only got down to about 45' on our OW test dives. I just wanted to make sure there would be no significant difference between 45 and the 60' bottom that I wish to self impose on my first dozen or so dives.

 

[Dive n00b]

Twice last week I was diving on, not in, some wrecks in Coron, Philippines. I was floating along on my back looking up at the fish and the sunlight coming down in the water. All of a sudden I was dizzy and disoriented. I knew what it was, turned over and was still a bit out of it. But the good thing about narcosis is, for me anyway, that an ascent of a few meters makes it "turn off", almost immediately, which it did in this case. After a few seconds, I went back down to the original depth with no further incident. (30 meters or so)

I've often read that just coming up a few meters is all it takes to shake off the Narc... My concern was making sure I am able to identify its onset and take measures to rectify before anything negative can occur.

 

[Sas]

At what depth do you begin to increase your likelyhood of experiencing the Narc? I understand that factors such as water temp, exertion, air intake etc... all play a role, but is there a general rule of thumb that says for example: below 60' your likelyhood begins to increase?

I think the answers to your questions varies quite significantly between people. I don't think many people get severely narced between 60'-100' though. I think the shallowest I have ever felt narced was at 28m and it was cold (11C or so) and I was a puffed out. In cold water, if you are retaining CO2, if you are tired, dehydrated, make a fast descent, etc, those will all increase your chances of feeling narcosis.

For those of you that are deep dive certified and not diving gas... is the narc a normal thing that you guys have trained yourselves to manage through experience? Do you sense it kicking it and just deal with it? Just curious... I suspect that if its a regular occurence when hitting 100' or whatever, thats a depth that I may not be so inclined to visit (I would obviously get the training before I attempt it, but this whole Narc thing seems like a non-starter to me).

Not sure what you mean by 'not diving gas'? What gas in particular are you talking about? I've only done a few deep dives but I sense it kicking in but I usually get very euphoric so don't start to freak out or anything. I just keep reminding myself to pay attention to what I am doing and usually I just slow down my pace to match how my thinking has slowed down. You just have to be cautious about how stupid it can make you. One time my mask was continually flooding and I just kind of swum around for a few minutes continually clearing - didn't even think to check the seal. It was actually leaking because my strap had come off and it was starting to fall off my face - I would have figured this out on the surface in a second but it took about four minutes at 32m! I pay a lot more attention to the signs of narcosis now, usually my vision narrows and I feel really happy, so that I know I am impaired and I become more cautious.

If it is normal and you have learned to manage it, is the transition from happy narc to dark narc where you guys decide to call it quits?

I have not had to call it quits, even when I had a dark narc. I just reminded myself I was narced and I calmed down very quickly. I will also ascend slightly if I feel narced as usually when I go down again I feel less narced. Not sure if other people are the same...

Also, we are heading out to Stuarts Cove on our first post-cert dives on Saturday. I know some of the guided dives get down deeper than I have been in my OW test dives. Although I'll be clear with the DM's about my experience, I want to know for myself where to limit my exploration in terms of depth. So if you say Narc becomes a concern at 60' I'll be sure to keep it to 50' until I grow more confident in my skills, and have DM/Instructor with me.

Thanks!

I would not worry about narcosis at a depth of 60'. I am sure some people have been narced at this depth but it would be rare. Anyway, get lots of rest the day before, stay hydrated, and just stay relaxed, swim slowly so you don't get puffed out and you should be fine