Diving Deeper

[rstone]

Originally posted by uwsince79
With everything I have read and studied on Narcosis I feel you are incorrect. (I am very opinionated) You cannot build a tolerance to it period

Dr. Tom Neuman. Dr. Neuman is the current Editor in Chief of the Society's journal- "Undersea and Hyperbaric Medicine". He is also a pulmonologist and emergency physician at the University of California, San Diego School of Medicine. Dr. Tom Neuman stated "To keep clear in mind that data gathered to reach a scientific conclusion are usually a wide scattering of points that may not reflect the narrow best fit curve mathematically generated. Therefore, be skeptical about what you are told about human response."

Renee Duncan Westerfield, Director, DAN Communications stated "individuals have varying levels of susceptibility" to nitrogen narcosis.

Lawrence Martin, M.D. Author of Scuba Diving Explained stated
"There is also some evidence that some divers can become partially acclimated to the effects of excess nitrogen; the more frequently they dive the less each subsequent dive appears to affect them."

OSHA position states that "The severity of nitrogen narcosis symptoms listed in Table 1 depends primarily on depth; however, severity also depends strongly on personal susceptibility, experience, training, rate of descent, and level of exertion."

Table 1
Increasing severity of nitrogen narcosis symptoms with depth in feet and pressures in atmospheres.

Depth P Total P N2 Symptoms
100 4.0 3.0 Reasoning measurably slowed.
150 5.5 4.3 Joviality; reflexes slowed; idea fixation.
200 7.1 5.5 Euphoria; impaired concentration; drowsiness.
250 8.3 6.4 Mental confusion; inaccurate observations.
300 10. 7.9 Stupefaction; loss of perceptual faculties.

Hamilton K, Laliberte MF, Fowler B. of the Defence and Civil Institute of Environmental Medicine investigated adaptation to nitrogen narcosis by compressing 11 highly experienced divers in a hyperbaric chamber to the equivalent of 54.6 meters of seawater once a day for 5 consecutive days. The behavioral component of narcosis was assessed with a serial choice-reaction time (RT) task, and the subjective component with a global magnitude estimate. Supplementary magnitude estimates were obtained with adjectives describing work effectiveness and body sensations. The results showed that there was no adaptation on the RT task, although learning was evident. In contrast, the global estimate dissociated from RT and showed clear adaptation by Day 3. The work effectiveness adjectives followed RT and did not show adaptation. Some body sensation adjectives showed clear adaptation, but others did not.

uwsince79 I may not be a expert in this field, but i would say the conclusion of experts in the field would suggest that some divers can and will in fact build a tolerance and adapt to some of the sensations of nitrogen narcosis.

 

[The Chairman]

I guess the reason that -I- feel so strongly about the universality of narcosis, is that I have seen those who knew they were narced and those who were narced and believed otherwise. The effects can be completely transparent to the person who is narced. Many times, they just don't realize it. For most divers that I know who are in this category it just boils down to machismo, pure and simple. "I am just too gol-darned good to be narced... it's for wimps! You might get narced, but -I- can handle it" is the attitude that most of these people who claim they don't get narced that easily have. To a diver, they have only fooled themselves. Everyone around them can tell they are narced, but they live in some macho denial that they are too manly or whatever to be affected like the rank and file.

As I said before, you have the right to feel that you are immune to the laws of nature and will therefore be impervious to narcosis... I for one will not dive with someone who has that cavalier attitude toward their personal safety and the safety of their buddy.

 

[Se7en]

Arrived late at the party, and it seems everyone is having fun...

Also seems that you all essentially agree, but are busy splitting hairs for amusement value.

What we actually know:
1. Nitrogen (N2) becomes more narcotic with increased partial pressure.

2. We don't know nuthin' else.

So from that we have two schools of thought here, succinctly expounded by rstone - "I don't get narced 'til x depth", and by net doc "Everyone gets narced, and you are an idiot if you dive to depths where you get narced"

(I apologise for the gross paraphrasing, which may not reflect the subtle nuances of what each person was trying to express. Tough)

Hey - you are both wrong

See fact 1.
At 10m / 30 feet, we are all breathing approx 1.6 atm partial pressure of N2. This is more narcotic that breathing air at 1 atm. At this depth we are ALL (even you Mr Stone) affected by narcosis. HOWEVER, for the vast majority of people the effect will be so slight as to be un recognisable.

To use an oft quoted analogy, it's like you have drunk just one of those weak american beers. You are not 'drunk', there is probably no effect that you or anyone else can discern, but you are still affected by alcohol.

At this point, all those who follow the net doc line of thought should get out of the water. You are affected by narcosis, and recieved wisdom has it that only an idiot dives while affected by narcosis. So, hop it. Out of the Pool - all of y'all.

(Wow - it's quiet now, only a few of the 'deep air' divers left)

For those of us who are left, all is left is to define the point at which each of us feel that we are affected by narcosis to the point that we do not feel comfortable / safe / whatever. rstone is happy that he is comfortable and safe, at 100+ fsw. That narcosis, although present, is not affecting him enough to impair his diving.

And that's the whole point. Each individual will have a certain depth, or range of depths, at which they feel their comfort level decreasing. This varies wildly from individual to individual, and may be subject to conditioning (*more on this later). It will also vary from time to time, and in different conditions - and the only way to work it out is to experience the conditions.

It is stupid to say that people are 'narced' at 100 fsw. Sure, everyone will be subjected to some narcosis, but the effect will be markedly different. For some it will almost not be noticible, for a large number, simply indication to slow down and think calmly, for others, well... where did that naked mermaid go? Back to the beer analogy, it is recieved wisdom (and therefore true) that different people have different tolerances.

Conditioning:
There is no 'provable fact' on this one. Experience seems to tell us that we can condition ourselves to narcosis, and that this conditioning occurs through two mechanism.
Mechanism 1 - cognative experience. We learn to recognise the feeling and act accordingly. Slow down, think things through a bit more, and question our own actions. Most people would accept this component of conditioning, and it has been experimentally shown to work.
Mechanism 2 - physical tolerance. It is suggested that our bodies can develop a tolerance to high partial pressures of N2, in much the same way that they develop tolerance to alcohol. If it exists, it is though that the effect is shortlived, a duration of days to weeks only. Most habitual deep air divers tend to believe in this one, however I am unaware of any double blind experimental work.

As for Net Doc not diving with anyone who is narced - I guess I'll never be diving with him, as I can detect narcosis in myself as shallow as 60fsw, but still go to the bottom. Happy to dive with rstone, within both of our personal limits for the conditions and the day...
For whatever my opinion is worth...

Mike

 

[rstone]

Originally posted by NetDoc
As I said before, you have the right to feel that you are immune to the laws of nature and will therefore be impervious to narcosis... I for one will not dive with someone who has that cavalier attitude toward their personal safety and the safety of
their buddy.

While i have never said i was immune to the laws of nature or impervious, i only believe what i see or has been proven. People may run around yelling the world is flat and the sky is falling, but until you show me proof, ill stick to what is shown to be true by the experts. None of my previous post was based on my opinion or speculation, but yet those of experts in the field. You are more then welcome to doubt their expertise, and come to your own conclusions as this is a free country. I have never disagreed that nitrogen narcosis may be present, it has always been my contention that its the degree of the effect that matters and that varies from diver to diver, and not that we are all equally effected the same as some people seem to contend. NetDoc dont get me wrong.. I would never do anything that I feel is unsafe as I hope you wouldnt, I feel strongly that safety in diving should always be everyones number 1 priority, and I will continue to stress this in every class I teach, but I will not promote something that is not proven, It is as simple as that.

 

[The Chairman]

Some seem to have majored in this subject. 7, using your logic, we should break out the helium mix right now and get rid of all nitrogen we are breathing even on the surface. Extending that logic to alcohol, I guess we had best not take wine at communion, since we would be drunk at that point. Maybe that beer during the game should go too.

I never said there are not varying amount of tolerances within individuals. Heck, any individual's personal tolerance can be affected by fatigue, hydration, etc. etc.

I never said conditioning was not a factor in personal tolerance of n2.

I never said you can't dive even if you feel the effects of narcosis.

I DID SAY...

That everyone that I have known that believed that they did not get narced at depth was in denial. Everyone else could see they were narced... just not them! If you don't believe me, just do a kid's puzzle at 120fsw and THEN at the surface. Don't practice ahead of time and the result will be far more dramatic.

I also contend that the person who accepts without question the fact that they are mentally impaired (whether they FEEL it or not) when they descend below 100fsw is far safer to dive with than a yahoo who thinks (and believes) that it doesn't affect them.

7, you can twist my words however you want. You can use them with faulty logic to paint me as being the most sissyfied diver in the free world. That's your choice and I don't care. We are not all that welcome under the water. It's a fairly hostile environment. I think that -I- will err on the side of caution and safety every time. Nature does not suffer fools for long.

 

[Blargh]

rstone, you werent, perchance, the diver mentioned in THIS article:

http://www.divernet.co.uk/opinion/1200deepb.htm

??


......................................................

Disclaimer - the rest of this post is *not* intended for members of the "I dont get narced" club. Neither is it intended for members of the "I can deal with being narced" club either. Unfortunately, human nature and statistics being what they are, arguing with members of the above two clubs is about as fruitful as arguing with the radio.

For everybody else, *especially* folks that are reading the posts made by rstone and other "heroes" on this (or other) board(s) and are tempted to actually believe them, here is a nice article, written by a veteran diver, on how he "didnt" (note the quotes) get narced at the measly depth of 30 meters (approx 100f).

Enjoy. Or not. Don't argue with me about unique conditions, individual tolerances, etc. Mention me in your will.

http://www.divernet.com/technique/10000narked.htm

 

[syruss32]

Wow I finally got caught up on this thread that I started so many millions of words ago.

That's it, I am only diving in the kids pool hehehe!

I still have not seen the effects of Narcosis at the depths that I have dove, but that isn't but 78 feel. And I assume I had some affects though they were probably very mild at that point.

When I get to 100 I will probably start to see those affects more dramatically.

Thanks for all the information!

 

[Butch103]

http://www.divernet.co.uk/opinion/1200deepb.htm
I guess this answers some questions.......lol

But I have a nother...and this is more for intelligent and not a p*****g contest as it has been put.......

It has been stated thet you can or cannot build up a tolerance for nitrogen narcosis. We have also compared in some posts alcohol and nitrogen narcosis ( tolerances).

It was stated that one cannot build up a tolerance for alcohol......

Why is it that some alcoholics can drink their face off all day and never look like they are drunk ??? I would assume like the narcosis arguement and comments that some can and will be affected by alcohol at earlier times (less alcohol) than others.

All htis to say that I believe from reading many artucles posted by some on this thread, that we do all indeed suffer from narcosis but at very different levels and depths. There is no hard and fast rules regarding. It would depend on your genetic makeup....................

Now I think I will go have a turkey sandwich for lunch........everyone talk nice while I am gone.....

 

[uwsince79]

First Point you wrote "Dr. Tom Neuman. Dr. Neuman is the current Editor in Chief of the Society's journal- "Undersea and Hyperbaric Medicine". He is also a pulmonologist and emergency physician at the University of California, San Diego School of Medicine. Dr. Tom Neuman stated "To keep clear in mind that data gathered to reach a scientific conclusion are usually a wide scattering of points that may not reflect the narrow best fit curve mathematically generated. Therefore, be skeptical about what you are told about human response."

Great statement, by one doctor and generally agreed to. I have my conclusions, which are drawn on drawn on BOTH scientific & personal experience, and you have yours. My first question to you in regards to your first statement written above is, Do you dive or have you ever dove mix? I have repeatedly dived beyond the 200-fsw mark many times on AIR. I have thought through the years that I had built a tolerance to Narcosis; I will admit I was wrong (a easy thing to do when your in the way over 30 club)and an I was an ass (me I was the ass, not anyone else nor am I calling anyone that) for preaching such things. Can you learn to work under the influence? Hell yes, ask any alcoholic or former alcoholic who did their job every day. A learned task can be done quite well under the influence even on hard drugs.

What is proven is and I will repeat myself again is that, “What you can do is to be able to function with LEARNED TASKS.” In an emergency and under a heavy tasks load you will have problems (those problems might be very slight but they are there. So at 2 bars you may not feel it but it is there. And it will slow things down. Remember sometime the reaction needed to an emergency that is life threatening can happen in milliseconds. If you would like I can elaborate on these events for you. Can you operate and function without question YES. But that does not mean it is not there and it does not state you have a tolerance to it.

Second I agree with the statement by Duncan Westerfield, "individuals have varying levels of susceptibility" to nitrogen narcosis. And stated so in my comment “varying conditions in the body will give varying effects of narcosis at different times.”

Next you wrote “OSHA position states that "The severity of nitrogen narcosis symptoms listed in Table 1 depends primarily on depth; however, severity also depends strongly on personal susceptibility, experience, training, rate of descent, and level of exertion." Yes all these factors affect Narcosis but narcosis still begins at 2 bars, you may not feel it but it is THERE. Also experience & training go back to learned tasks.

Next “Hamilton K, Laliberte MF, Fowler B. of the Defense and Civil Institute of Environmental Medicine investigated adaptation to nitrogen narcosis by compressing 11 highly experienced divers in a hyperbaric chamber to the equivalent of 54.6 meters of seawater once a day for 5 consecutive days. The behavioral component of narcosis was assessed with a serial choice-reaction time (RT) task, and the subjective component with a global magnitude estimate. Supplementary magnitude estimates were obtained with adjectives describing work effectiveness and body sensations. The results showed that there was no adaptation on the RT task, although learning was evident. In contrast, the global estimate dissociated from RT and showed clear adaptation by Day 3. The work effectiveness adjectives followed RT and did not show adaptation. Some body sensation adjectives showed clear adaptation, but others did not.”
A.What were the tasks at hand and were they learned tasks or known?
B.Secondly, the learning curve was three days making it repetition (another set of learned tasks (this would not work in an emergency, three days and underwater problem solving & you are dead). Plus what is the curve for the same RT task learned at the surface? Three days to adapt to being under the influence does not convince me you can build tolerance to narcosis. Tolerance to me means you can function normally after being affected which is not the case here
C.Last Item “uwsince79 I may not be a expert in this field, but I would say the conclusion of experts in the field would suggest that some divers can and will in fact build a tolerance and adapt to some of the sensations of nitrogen narcosis.” I do not see a conclusion at all in what you posted, maybe you can clarify this as I am a simple man and get lost very easy. I see the word “adaptation” which I agree with, but they all are still under the influence of narcosis. None of them have built a tolerance to it. In repetitive dives, in the above experiment were the results replicated over and over again? What were the controls? Was it the same group of divers? All this continues to prove to me is narcosis is there. They just learn to operate with it. I do not think any of these commercial divers would say “I have a tolerance to nitrogen” I have learned to work under it’s influence (along with a dive supervisor, teather, etc.) Which I feel is a lot safer than a dive to 200 on scuba.

Oh well I have spent too much deep time on air I guess my brain just doesn’t get
it….
(For my own edification I posted here the definitions of two words from the American Heritage Dictionary used in this post only for clarity)

Tolerance (n).
1. The capacity for respecting the beliefs or practices of others. 2. Leeway for variation from a standard. 3.The capacity to endure hardship or pain. 4. Resistance to a drug.

Adaptation (n)
1. The act or process of adapting or the state of being adapted. 2. A composition recast into a new form. 3.An alteration or adjustment by which a species or individual improves its condition in relationship to its environment

 

[GreenDiverDown]