Deep Air - Here we go again....

[Anti-Hero]

I've never seen so many "technical divers" botch simple math.

 

[dumpsterDiver]

......
Does one attempt to understand their response to narcossis at all or just ignore it
That's the question for me. If one chooses to try to understand their response to narcossis what course/training should they pursue? any takers? .

I think that diving deep on air is relatively unsafe compared to using Helium mix, but the question is raised about understanding your response to narcosis. I can speak from my personal experience, which is not different from what i have read elsewhere.

If you are a good experienced diver and you are not excessively scared or stressed by diving somewhat "deep", then the activity of scuba diving is not challenging. Bouyancy control, breath control, swimming, using a light or shooting a speargun is not that difficult at all. If these skills have been practiced many times in shallower water and many times when slightly narced, the simple act of "scuba diving" is pretty trivial; for me anyway.

However, the problem with narcosis for me is that I am stupid, easily distracted, and I feel like what I presume serious attention deficit disorder must be like. I can look at a guage, a scene, a situation and then look away and then quickly realize that I received some sensory input, visual, auditory, navigational, temporal data etc.but the information did not register. Very poor short term memory, perceptual narrowing, I look at my pressure guage read it, think that it looks OK and then drop it and immediatly say to myself "what was the pressure?" I know it "felt" good or within the expected range, but the actual numerical value didn't register. I am also prone to setting things down and forgetting them and have made "stupid errors" that I have never made before on shallower dives (some of which were pretty dangerous).

It is sorta like staring at the entire cereal section in the grocery store and all the colors and boxes are so dazzling that you are looking at them, but you forget what type of cereal you are looking for. You're looking, but you are not seeing everything.

These higher level functions are affected the most. I have no trouble with physical coordination: swimming, doing bouyancy control, trim, controlling breathing rate are all fine. This means that if everything goes perfect on a deep dive, the narcosis is not a problem at all.

Conversely, if you do have a problem and you have an entanglement issue, a complex gear problem to solve or maybe an aggressive shark comes in and you know you can't run for the surface, these are the situations that narcosis can really compromise your safety. If you get yourself in a situation where you have to move against a hard current and solve a novel problem, the carbon dioxide buildup can very quickly change everything from "classical music" to head banging rock and roll quicker than you can change a radio station. If you don't have the experience, confidence and skills to deal with the situation, then you can be in very serious trouble in a very short period of time.

I think there is a very broad spectrum of narcosis tolerance as well, even with experienced divers. I have a buddy who just won't go below about 155 or so and another (who i think pushes the limit too hard) dives solo on air to around 230-235 feet every weekend. I know of another technical diver, who made it down to 180 feet and became "frozen in place", totally unresponsive, just breathing and standing and another diver had to physically drag him up an ascent line a considerable distance before he awoke from a total stupor. I know another commercial diver who catches lobster for a living and dives 3-4 days a week, 3-4 tanks per day and totally blows off required deco stops on his nitrox dives in 90-120. But this guy says he won't dive below 140, because he gets really narced and it scares him and he feels really bad, even though he has thousands of hours of diving.


For these reasons, I think that divers should be very careful and experiment very slowly and progressively IF they want to dive deeper on air. It is a personal mental game, that can't be taught by reading a book or doing a few dives. It is hard for me to comprehend how some deep air instructors will take 'just about anybody" and try to teach them to dive deep on air in a course which spans a very short time and a few dives.

 

[nadwidny]

Also, what's with all the name calling towards commercial divers? You guys must realise that you are insulting an entire profession and not just one person and more than anything it just makes you look... well... small. Perhaps you just have your own little club and the only important thing for you is to high five each other for "the slams"?
Pathetic.

Newbies. Sigh....

You're new. Someday you will understand.

 

[jtivat]

Also, what's with all the name calling towards commercial divers? You guys must realise that you are insulting an entire profession and not just one person and more than anything it just makes you look... well... small. Perhaps you just have your own little club and the only important thing for you is to high five each other for "the slams"?
Pathetic.

The only issue I have with the commercial divers is that they are acting like what they do has anything to do with scuba.

I am a scuba diver so I guess I can go start commercial diving right??

 

[Blackwood]

However, the problem with narcosis for me is that I am stupid, easily distracted, and I feel like what I presume serious attention deficit disorder must be like. I can look at a guage, a scene, a situation and then look away and then quickly realize that I received some sensory input, visual, auditory, navigational, temporal data etc.but the information did not register. Very poor short term memory, perceptual narrowing, I look at my pressure guage read it, think that it looks OK and then drop it and immediatly say to myself "what was the pressure?" I know it "felt" good or within the expected range, but the actual numerical value didn't register. I am also prone to setting things down and forgetting them and have made "stupid errors" that I have never made before on shallower dives (some of which were pretty dangerous).

It is sorta like staring at the entire cereal section in the grocery store and all the colors and boxes are so dazzling that you are looking at them, but you forget what type of cereal you are looking for. You're looking, but you are not seeing everything.

These higher level functions are affected the most. I have no trouble with physical coordination: swimming, doing bouyancy control, trim, controlling breathing rate are all fine. This means that if everything goes perfect on a deep dive, the narcosis is not a problem at all.

That's as good a description of my own experiences with narcosis as I've read.

 

[Tortuga68]

The only issue I have with the commercial divers is that they are acting like what they do has anything to do with scuba.

SCUBA stands for Self Contained Underwater Breathing Apparatus. While commercial diving is different to recreational diving, it's not correct to say it has nothing to do with scuba

 

[DaleC]

Because I dive coldwater, and sometimes solo, narcossis is a real issue to me. I don't pack a redundant brain solo so I actually have a pretty firm END on air of 100'. When I buddy dive I will go below 100' on air but when I do the clock is ticking and the radar is on (so to speak) I don't just lolly gaggle about for the fun of it. When the time is right I see trimix in my future so I am not an intentional "deep air" proponent per se.

But when it comes to narcossis I wonder which is better - having every diver reinvent the wheel and discover the effects for themselves in an uncontrolled setting with the resultant screw ups and errors or having a training regime that subjects the diver to narcossis in a controlled and supervised manner. One can argue that current/mainstream deep air training is lacking in its scope or duration but I wonder if the idea of deep air training is, in itself, a bad idea.

I suppose it depends on what motivation is ascribed to deep air training - learning to recognise and react to narcossis as it occurs or learning to dive deep despite it.

 

[Kevrumbo]

Why not get trimix certified first, learning all the skills & drills and using that as a cognitive/performance baseline . . .and then take an extended range deep air class to gauge how much impairment you're experiencing at a particular depth, learning to mitigate any task loading risks beforehand, and knowing when & practicing contingencies to abort the dive.

 

[InTheDrink]

Slightly leftfield, but one recurring remark/analogy that has been stated like a truism earlier in this thread is that you can't teach someone to handle alcohol, that drunk is drunk.

If this really is the analogy that some are trying to make it seems an unusual one as it's clearly not true.

Tolerance to alcohol, narcotics etc. builds over time and use (plus other factors). A junky can handle amounts of heroin that are lethal in the non-user.

Of course, this doesn't mean that the tolerant user is not intoxicated - however they may be able to function adequately where someone without tolerance could not function at all. Could narcosis be similar? In which case you may indeed be able to teach someone how to handle it and given the constraints in getting He, then why not?

And as for criticising it, is it not the same argument for criticising any other form of diving, e.g. solo diving, cave diving etc.? There are increased risk levels in any of these kinds of diving but it doesn't make any of them bad in an absolute sense. And no-one is forcing you to dive this way.

I'm not way advocating deep diving on air and it wouldn't be my thing. But I do notice that my narcdness at say 30-40m (on air/nitrox), decreases over a period of a week of diving. This could just be increased comfort in the water after this period? Or it could be my body adjusting to the effects of narcosis.

One unpleasant aspect about this thread has been the personal attacks and insults. I'm not sure they really advance anything in particular apart from certain egos perhaps, especially those criticising others egos.

J

 

[Reg Braithwaite]

Slightly leftfield, but one recurring remark/analogy that has been stated like a truism earlier in this thread is that you can't teach someone to handle alcohol, that drunk is drunk.

If this really is the analogy that some are trying to make it seems an unusual one as it's clearly not true.

Tolerance to alcohol, narcotics etc. builds over time and use (plus other factors). A junky can handle amounts of heroin that are lethal in the non-user.

I agree that the comparison not particularly accurate, although it is still useful for explaining narcosis. Alcohol tolerance is governed by alcohol dehydrogenase, an enzyme. So in effect, the people who have adapted haven't produced an ability to function with higher blood alcohol levels, they've adapted to break the alcohol down faster and thus get sober faster. Different people have different abilities to produce this enzyme and some people produce proportionally more in response to stimulus over time.

The mechanism behind nitrogen narcosis is different in that there is no simple way for an enzyme to remove the nitrogen from the body tissues. Therefore, it is not a case of the body producing more of a certain enzyme in response to repetitive exposure to nitrogen narcosis.

There may be other mechanisms that provide a physical adaptation, but so far in my cyber-diving research I haven't come across them. So from the comfort of my ignorant armchair, I agree that some people adapt over time to some degree to alcohol, but that isn't an ability to handle blood alcohol but rather an ability to break alcohol down. I am not aware of a mechanism to break inert gasses down or get them out of the tissues other than decompression

Of course, people learn to drive themselves home from the bar while blind drunk. This is not the same thing as reducing their reaction time or improving their ability to handle novel tasks. take any drunk who declares they are fit to drive and teach them to play a new sport. The results will be comical.

Summary: Reg believes that people don't get better at handling blood alcohol, they just sober up faster. Reg believes that people don't get better at handling nitrogen narcosis. Reg does believe that rote physical tasks can be practiced while drunk.