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W. Trubridge: Narcosis rears its ugly head

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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trux

~~~~~
Dec 9, 2005
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William Trubridge just released an interesting wisdom about narcosis he experiences during his training in the Dean's Blue Hole in Bahamas, in dives below 100m. There is also another comment about narcosis from Guillaume Nery: William Trubridge News
 
On the Narcosis, I came accros the comment the cold water down in the hole was a factor worsening the Narcosis. Has anyone an idea of what the temperture down there is?

Personally I like diving in cool(er) water, like there is at Nordic deep in Sweden :D
Though I've once experienced narcosis at a depth of 40m, in a very slow and stressfull dive, I've not had noticeble narcosis in years, going down to 60m.
Like Guiliamme says there are many factors weighing in. And there are different types of narcosis, CO2, N2.

Since I plan on going deeper than 60 this year I'm very intrested in this subject.

Love, Courage and Water!

Kars
 
I am not quite sure if the narcosis experienced by freedivers is a CO2 narcosis. It is true that all gases have narcotic effects (you can see narcotic factors of some gases used in technical diving in this document: Exotic diving gases). I do not know though what the narcotic factor of carbon dioxide is, and am not sure if it plays a more important role than that of nitrogen. However, it is well known that elevated CO2 levels play a significant role in oxygen toxicity and in triggering nitrogen narcosis. See for example [ame="http://en.wikipedia.org/wiki/CO%E2%82%82_retention"]COâ‚‚ retention - Wikipedia, the free encyclopedia[/ame] or the document http://scuba-doc.com/CO2acclim.pdf.
 
Kars - Will has told me there are no thermoclines in the blue hole. However it is very dark down there.

Trux - I don't know either, but I do know that if I over-ventilate before a dive then the narcosis is lessened. Will has also mentioned this. This would indicate it is related to CO2?

I have been diving in a NZ lake this weekend to just under 90m. It's pitch black at that depth and 10 degrees. No narcosis at all. Yet last year in the warm clear water of Egypt my head was spinning at that depth...
 
Just a few quick (subjective) observations.

The subjective feeling of narcosis seems to vary greatly from day to day. For example the worst experience for me was a dive to 67m in egypt, while on the same trip I made many dives much much deeper with pretty much the same prep etc.

I do believe you can build up a tolerance for it. Maybe not objective, but subjective (ie. you learn to deal with the feeling).

Certainly amount of air, amount of o2, co2, water temp and especially visibility make a difference. I've had clear symptoms on a dive to 30m in very cold and dark conditions. And probably there are factors we just don't know about. That's why I prefer not to talk about nitrogen narcosis, but "depth narcosis".

Last but not least - for the subjective feeling of narcosis, at least for me, it makes a huge difference what mental baggage you bring down with you. If something is stressing you already in the surface, or the mind is not "pure", all this is multiplied at depth and can lead to pretty ugly feelings down there. How much of this is narcosis and how much just you head in physiological sense? Who cares, because it all makes a huge difference.

I find Guillaumes advice the best so far. Make increments gradually through experience and repetition. It prepares both the mind and body for it and there is less chance of encountering something ugly down there.
 
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Trux - I don't know either, but I do know that if I over-ventilate before a dive then the narcosis is lessened. Will has also mentioned this. This would indicate it is related to CO2?
Yes, as I wrote above, it is very well known and tought to all deep scuba divers, that CO2 retention amplifies nitrogen narcosis, so it indeed is very much related (and freedivers experience much higher CO2 levels than most deep scuba divers). And of course, hyperventilation, physical effort, stress, and cold, influence the strength of the effect. However, physiologically taken, it is still considered nitrogen and not carbon dioxide narcosis.
 
Yes, as I wrote above, it is very well known and tought to all deep scuba divers, that CO2 retention amplifies nitrogen narcosis, so it indeed is very much related (and freedivers experience much higher CO2 levels than most deep scuba divers). And of course, hyperventilation, physical effort, stress, and cold, influence the strength of the effect. However, physiologically taken, it is still considered nitrogen and not carbon dioxide narcosis.

I wonder if Herbert experiences such strong narcosis as he hypervetilates before his dives...
 
As I was one of the first freedivers to experience debilitating narcosis in 2001, I did extensive research & experiments on it.

My conclusion is that pure CO2 narcosis is absolutely possible. I can get pure CO2 narcosis from STATIC APNEA during a dry static CO2 table. Once I pass 10.0% CO2, then the symptoms I get are very similar to the type of narcosis I would get on 80m+ dives with fluid goggles and brain freeze and blackness.
 
Also keep in mind that during the Duke University study on pure oxygen freediving, subjects would experience severe CO2 narcosis while doing apnea bike in a gym, holding their breath on 100% O2. This allows much higher CO2 levels to be reached. As their was 0% nitrogen, you cannot blame their narcosis on nitrogen.
 
Yes, pure CO2 narcosis definitely exists - you can find plenty of documents about it on the web. In common medical praxis it is usually associated with pure O2 breathing. And I believe you, of course, that you can experience CO2 narcosis when doing statics - that's likely what many describe as a sudden comfort at the end of a difficult breath-hold or before a blackout.

However, at depth disciplines, the narcosis is more likely always a combination - a nitrogen narcosis amplified by the increased CO2 level. Around the half of the dive (and before the more physical effort of the ascent), the CO2 level is not yet high enough to cause narcosis alone despite the higher partial pressure. Together with the highly narcotic nitrogen, it is another case, though.
 
I'm curious as to how a diver returns to the surface while experiencing narcosis. What the diver goes through sounds like pure confusion, even dream-like. Is s/he aware of the problem at the time? Does the body automatically swim up or does it require a conscious effort?

Dave, I recall reading about your comp dive where you spent several seconds staring at the tag before making the grab for it and swim up. Did you simply snap out of it? What went through your mind?

Eric, can you share your experience with that dive in 2001?

What about Will's hallucination? Is he at the very least aware that he IS pulling himself up?

I realize these questions may sound trivial or even rude. I'm genuinely interested and hoping to learn more.

Edit: I posted too early before doing basic searches (sorry, still a newbie :eek:). Eric wrote a very detail description of his experience here. Eric, it sounds like, for the most part, your legs wouldn't move while your mind was very willing. How does that tie in with narcosis? Also, do you believe that, with all your dives being done on FRC now, your muscles are much better at working anaerobically as well as dealing with the latic build up? And, that the issue encountered during that dive is less likely to happen again?
 
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I get narcosis quite a bit on constant weight dives, I really notice it on 70m+ dives, it's often worse on the way up then on the bottom. I get it worse when I haven't been diving in a while. (Unlike Dave I was getting a good buzz down there in the lake few weeks back :) )
I have done 15min statics on pure O2, and got strong CO2 narcosis on those. It's a very gradual build up, would first start feeling a little at around the 10 minute mark up until feeling really out of it at the 14-15minute mark. I have to say the narcosis feels very much the same. It does also feel similar to the classic "Nitrogen narcosis" with scuba diving, been narked plenty times there.

If the symptoms of CO2 and Nitrogen narcosis are the same it makes it harder to say which is which, or perhaps it is a combination effect some of the time?
If getting narcosis while doing an O2 static is purely from CO2, is there even a way for a freediver or scuba diver to get purely Nitrogen narcosis ?
(Short of inhaling Nitrous oxide ie laughing gas. :) )

In cold water and under high workload's (classic NO2 narcosis) you would probably also have higher CO2 levels. Some of the theory on scuba could be wrong in that the classic narcosis could be combinations of CO2 and NO2 narcosis.

On constant weight dives I tend to get more narked on the way up, that to me implies CO2 narcosis. I've had really bad narcosis on 70-80m dives and didn't really go away until the last 20-30m or so. If Nitrogen narcosis was the dominant factor wouldn't you get less and less narked as soon as you start ascending ?


Cheers,
Wal
 
sucinimad: to function under narcosis there's several things you need. Most important of which is experience, ie you know what to expect.

You also need a very clear goal and breaking down the dive stage into as simple pieces as possible, and a lot of routine and training. When you have that, you do things sort of automatically. It's not a state or place where you want to be making tough decisions that require logical thinking.

Personally, I try to do a perfect turn and at least simulate a tag grab even on the shallowest, easiest dives - the same on surfacing (I do the same recovery breathing and surface protocol on 15m cw dive as I would do on a max attempt). Just to build up the routine so that when things get on the edge, I will be able to function automatically.

Basically, if you know what to expect and have a clear goal for each stage, you can push through it.

The scary thing about co2 is that if you were to get unconsious from acidosis (for example from o2 statics), it gets a lot uglier than a o2 blackout, from which you usually recover in a matter of seconds. It really is not something you want to play around with. It's not far away from comatose and ultimately death.
 
The best thing about FRC diving is that you don't ever get any narcosis. This makes me feel MUCH safer when I do deep dives, and I think that because of that, the 'required' safety for deep FRC dives is different than the required safety setup for deep packing dives.
 
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