Oxygen Narcosis

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johnny sea ranger

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Location
Freeport Bahamas
# of dives
100 - 199
Oxygen Narcosis
© Steven Thair 2014

You don’t have to look very far to discover that narcosis in diving is caused by oxygen as well as nitrogen, and the impairment from both gases starts long before 100 feet deep.

Why do “teachings” on trusted mainstream websites and mags persist in saying that:
a. narcosis won’t affect you in less than 100 or 130 feet; and,
b. nitrogen is the culprit? (Oxygen is too).

Bennett & Rostain, Bauer and Way, Hesser and Fagraeus, Petri. This research is 10 years old. Some of the research on the narcotic effect of gases and solubility in lipids (that seems to be the key) is over 40 years old. When are the operators of the main dive websites going to own up? Is it ignorance or some misguided effort not to scare new divers?

The National Ocean and Atmospheric Administration concluded in 2002 that oxygen should be regarded as having the same narcotic potency as nitrogen. This might be an underestimate since the solubility of oxygen in lipids is much higher than it is for nitrogen. ("Mixed-Gas & Oxygen". NOAA Diving Manual, Diving for Science and Technology. 4th. National Oceanic and Atmospheric Administration. 2002. "[16.3.1.2.4]

Likewise, there is the story that nitrox (which is an enriched air mix with a greater percentage of oxygen) reduces the effects of narcosis. Where’s the research that shows that? Anybody? I know where the theory came from: it was based on the (mistaken) belief that it was only nitrogen that caused narcosis. Now we know both nitrogen and oxygen cause narcosis. Show me the evidence that says narcosis is lower with nitrox.

Yes, it’s true you are usually free from the more intense effects of narcosis in less than 100 feet. But why not give students and webpage readers the context – that a diver at even 45 feet has a significant impairment occurring. This isn’t fear-mongering, it’s telling the truth and its useful. For instance, uw photography courses could teach that you should practice, practice, practice with your SLR camera buttons because even at 45 feet, operation of a camera that you haven’t used for a year can be difficult, even though you did it flawlessly a few times above water, because of narcosis. Do it 30 times above water. Practice interrupting yourself in the task and then picking it up again.

Better yet, practice at depth. Getting stuck or running out of air is more serious at 80 feet than 20 feet, your brain isn’t going to cooperate as well at 80 feet either. So why not practice safety procedures where you’ll really need them? Dive training should practice safety skills at depth.

Likewise, students in ‘search and navigation’ courses could be told the truth: it is going to be harder to figure out a new course underwater, and harder to handle ropes, distances, and plans, especially plans that have to change while you are underwater.

Narcosis is one of the reasons to plan for contingencies when you are still above the water. It’s because you will be stupid. Accept that. Remember this image: rats have more trouble rolling over off their backs at 2 atmospheres. Now if rats have to work harder to roll over on land at 2 atmospheres, how well are you going to do at your tasks underwater, at 3 bar, all geared up?

The research shows you can’t develop a physical tolerance for narcosis, but experience helps. And you can develop work-around strategies. For instance, research shows that focusing on a single task is least effected. So plan to KISS (keep it simple, stupid)

Here’s another strategy: if you’re at 60 feet and having problems switching your nifty little camera from 30 still shots per second to video of 1080 24 fps wide angle, go up to 30 feet, it will clear your head.

Hearing the whole truth might do something for diver self-esteem, too – to understand that the anxiety you felt on your last dive, and maybe your less than stellar performance wasn’t “yours” so much as it was caused by the environment. It’s yours to be responsible for, but it’s not you, it’s just happening to you.

Those professing to have knowledge of dive issues on some websites should do the same – go up to a shallower depth and take a clear look at your teaching intention, and the facts.

As you can probably tell from my tone, I am disappointed with some in the profession.
 
I don't know anything about the author of this article, but I wonder what "professionals" he has been reading that say that only nitrogen causes narcosis or that it only happens at depths below 100 feet. I guess I would be disappointed with such professionals myself, if I knew any.
 
I think I'm confused..

I think it's very common to call it Gas Narcosis now.. PADI literature clearly states that O2 & N2 both can cause narcosis...

I haven't heard any professionals saying that Gas Narcosis can't take place in less than 100 ft of water....

I would like to read the scientific research that allows for the claim that says "that a diver at even 45 feet has a significant impairment occurring"..

I guess it depends on the meaning of "significant impairment." I have participated in a gas narcosis study and it was my impression that typically the effects in shallow water are minimal, NOT significant.. But again, what does "significant" really mean? :)
 
1+ Not to mention what is this nonsense about going up thirty feet just to change from single to video? You'll have lost your shot by then and sawtooth profiles aren't recommended either.

OP? Where is this coming from?
 
Posts about significant narcotic impairment above 100' just make me chuckle.

I was right about at 100 feet when I had my most clear narcotic effects, and I know a tech instructor who had his worst moment (dark nark) at 85 feet. On the other hand, I do wonder about significant impairment at 45 feet. I am not going to go that far.
 
I was right about at 100 feet when I had my most clear narcotic effects, and I know a tech instructor who had his worst moment (dark nark) at 85 feet. On the other hand, I do wonder about significant impairment at 45 feet. I am not going to go that far.

I'm in no way saying it can't happen: it clearly does to some people, and if I try I can even tell a very slight difference between air and something like 10/50 at ~100' inside a wreck. So there's something there, and everyone experiences it differently.

But it's that last part that makes me chuckle. What makes me laugh is people talking about significant narcotic effects at the deeper end of the recreational range like it's a universal fact true for all divers. Which is (1) so wrong it's funny, and (2) potentially dangerous because it suggests to those who are just getting into deeper diving and happen to have a physiology that makes them much less disposed to narcosis that maybe they're just special snowflakes who needn't worry about it even if they decided to go another few ATA deeper (nope, sorry, eventually it catches up to us all--be ready for it).
 
I googled Steven Thair did not get a hit for a dive professional.

No, but you do find a Saskatoon diver with Caribbean experience.
I wonder what "mainstream websites" he is referring to?
 

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