Deep Diving on Air

[Kevrumbo]

On adaptation to Deep Air and Nitrogen Narcosis:

Moreover, our results suggest that experienced divers can discriminate between the behavioral and subjective components of narcosis. . .It has been proposed that the intensity of narcotic symptoms could be used by divers to gauge the extent of performance loss (10). The present results indicate that this advice is inappropriate for adapted divers because the two components of narcosis [behavioral and subjective] uncouple in a direction that could lead to an overestimation of performance capabilities --a potentially dangerous situation. On the other hand, the question arises as to whether adaptation confers any benefits on the diver, since performance efficiency is not directly improved and could be overestimated. In this regard, it could be argued that a reduction in symptom intensity reduces the possibility that attention will be focused on subjective sensations rather than the task at hand. [i.e. Subjective, sensations awareness vs. Situational, task-at-hand awareness???]

http://cradpdf.drdc.gc.ca/PDFS/zba24/p154358.pdf

 

[drbill]

There is no doubt that people do learn to manage narcosis (not make it stop or irrelevant), but it requires a slow and repeated exposure that allows individuals to recognize symptoms and develop a mindset that makes the effect far less hazardous. Sure it changes daily and is heavily influenced by harsher environments. That just intensifies the need to progress deeper slowly, contemplate experiences, and recognize moving boundaries. No class can provide that level of experience, only the knowledge of how to safely self-educate.

Precisely my point in my previous post. As I mentioned, I spent several months going to deeper and deeper depths to test my response to narcosis before hitting my max depth of 200 ft. I was also doing many more dives a year (300-350) during that period. Today I'm lucky to get in 100 dives a year (due to being a true divebum and the cost of an air fill). I would probably be narced significantly at any depth beyond recreational.

 

[FL-Jack]

FL up until now I was the only diver that can do those kind of dives. I wonder how many other Deep Air Divers there are.

I think most folks diving down 150+ for fish are too busy eating for posting on SB.

 

[Akimbo]

Precisely my point in my previous post. As I mentioned, I spent several months going to deeper and deeper depths to test my response to narcosis before hitting my max depth of 200 ft. I was also doing many more dives a year (300-350) during that period. Today I'm lucky to get in 100 dives a year (due to being a true divebum and the cost of an air fill). I would probably be narced significantly at any depth beyond recreational.

I think there are two things a play. The experience to self-diagnose narcosis symptoms and the more disputable theory that narcosis tolerance increases with near-term exposure. I was describing the former, but I am personally believe that your point is also true.

The tolerance observation/theory is a tough thing to prove and may not apply to the vast majority of individuals. There isn’t much economic justification to perform the expensive research and would probably produce some rather squishy data. However, I have never discussed the subject of near-term increasing narcosis tolerance with any experienced deep air diver that didn't agree. Let’s face it, only a small percentage of people are in a position or get the opportunity to conduct ten or more deep air dives in close succession.

 

[MXGratefulDiver]

I'm not so sure that narcosis tolerance increases so much as that you just get used to operating that way. Humans are amazingly adaptable critters, and we can "learn" how to operate impaired by simply doing it often. It doesn't make us any less impaired ... it just makes us more able to function that way.

Remember years back there was a famous video of a guy who put on glasses that made him see everything upside down. At first he couldn't do anything ... he kept experiencing vertigo. But over time he adapted to the point where he was able to "see" normally. Of course, the optics didn't change ... he was still seeing things upside down ... he had just gotten used to the condition.

... Bob (Grateful Diver)

 

[MauiScubaSteve]

Let’s face it, only a small percentage of people are in a position or get the opportunity to conduct ten or more deep air dives in close succession.

From the perspective of discussing the OP's dive, how would you define "deep air dives" and "close succession"?

If two buddies with better than average SAC dive larger than 80 cf tanks, does that constitute redundancy?

If taking a couple pictures is the only planned "work", could the recreational "bar" be set lower than Scientific Diving's "bar", as is done at every other depth from 132' up?

 

[dumpsterDiver]

I'm not so sure that narcosis tolerance increases so much as that you just get used to operating that way. Humans are amazingly adaptable critters, and we can "learn" how to operate impaired by simply doing it often. It doesn't make us any less impaired ... it just makes us more able to function that way.

Remember years back there was a famous video of a guy who put on glasses that made him see everything upside down. At first he couldn't do anything ... he kept experiencing vertigo. But over time he adapted to the point where he was able to "see" normally. Of course, the optics didn't change ... he was still seeing things upside down ... he had just gotten used to the condition.

... Bob (Grateful Diver)

Does it really matter which is correct? If the deep air diver regains "functionality" due to a reduction in narcosis or an immunity to it or just because he has trained himself to function in an impaired state....

I have tried to make the case that narcosis is the most dangerous and unpredictable variable in deep air diving (within reasonable depths and times). Just because some relatively out of shape, "old guy" who has been diving for 20-30 years can function resonably well 40 or 50 feet past the recreational depths does not mean that a new diver with 50 or 100 dives to 80-90 feet will also be "functional".

There is some functional adaptation to the depth after repeated and frequent exposures, but we also have to recognize that there is somewhat of a self-selection process occuring....the divers who, for whatever reason get wasted at 125 feet, are hopefully smart enough to avoid 175 feet and will never become deep air divers.

 

[PfcAJ]

It does matter. A lot. You get used to operating in a certain way while impaired. Its analogous to the drunk driver who can keep it between the lines but rear ends a stopped car in an unusual place.

Most dives don't have a lot of curve balls thrown at you. Equipment failures, entanglements and the like are (well, should be) rather uncommon. If you're used to diving problem free while impaired, but suddenly have a novel situation presented, what happens?

Risk w/o reward.

 

[dumpsterDiver]

It does matter. A lot. You get used to operating in a certain way while impaired. Its analogous to the drunk driver who can keep it between the lines but rear ends a stopped car in an unusual place.

Most dives don't have a lot of curve balls thrown at you. Equipment failures, entanglements and the like are (well, should be) rather uncommon. If you're used to diving problem free while impaired, but suddenly have a novel situation presented, what happens?

Risk w/o reward.

What happens if you get in a pickle when you are impaired and compromised??? Well it is unusual, but certainly the stakes are higher and you will just have to come up with a resolution or you will die.... similar to what happens in 60 feet.

BTW, you are preaching to the choir. Maybe you didn't see an ealier post? I link back to a deep air solo dive in which I describe in detail the mistakes I made and how I survived only by not going into full panic and by having very strong abdominal muscles.

 

[boulderjohn]

What happens if you get in a pickle when you are impaired and compromised??? Well it is unusual, but certainly the stakes are higher and you will just have to come up with a resolution or you will die.... similar to what happens in 60 feet.

Here's the difference.

In the worst case scenario, a diver at 60 feet with no overhead environment diving within NDLs can go straight to the surface with no serious threat of a problem.

A diver who has gone deep enough and/or long enough to incur a deco obligation is at increasing risk of DCS or drowning in the same situation should he or she exercise that option. If Opal and Gabbi had run out of gas at 60 feet, we wouldn't even know it happened. They would be happily diving today. Instead, they ran out at 200 feet, and we have a tragedy.