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I know that this one has probably been beaten into the rug, however I wish to have a deeper knowledge of nitrogen narcosis. I understand the rudimentary concept that is taught in classes; what I am in search of is a in-depth discussion of physiology; what are the common and uncommon signs and symptoms?; if medications affect the suseptibility of narcosis, which medications do so and what are their affect?; what's the difference of a nice clear warm ocean dive versus a cold, dark lake dive in terms of onset and/or suseptibility?
I have a strong knowledge base in physiology and anatomy; I have read the DAN article and the one in Dive Training; I have read past posts on this board an others; I want some knowledge beyond the basics. Please offer books, articles, links, or personal experiences with this topic.
I have over 400 hours of bottom time in various diving conditions. I have always been comfortable and relaxed underwater, until late. This past weekend I went diving and hit 97 feet and suddenly I felt this impending doom and perceptual narrowing, increased heart rate, and nervousness. This same feeling overcame me in July when I went to Cayman; it happened at 70 feet after a 115 foot dive. I regained composure at about 50 feet on both dives. I have been deeper in the past, but have never experienced these feelings. The only affects of narcosis that I have noticed have been sluggish thought processes. I am curious if this kind of thing is a normal narcotic effect. Furthermore, this year I haven't been real deep on a regular basis and am wondering if the type and depth of previous dives can affect tolerance levels?
I know that's a lot of questions in one post; please take on the ones that you can and leave the others to other people. Thanks in advance for any insight and offering of knowledge.
I can't help you too much jmsdiver, but I'm sure the Docs will give you more information soon.
I too am curious about whether or not one can develop a "tolerance" to narcosis. I've heard alot of tec divers talk about building a tolerance to nitrogen by going a little deeper each dive. They also talk about meditation and using minimal effort at depth to decrease the "loopy" feeling. Is this possible?
It is funny how it can effect you. One one dive (that I have done many time...130-140ft) it hit me one day, and it was like I forgot how to dive..and I was very close to panic. I've felt slightly "stoned" before, but that was the first time I had a "bad" nitrogen trip. NOT a good experience!
-Your body can not "adjust and become tolerant of it, from experience, sometimes it is even the other way around. During the time I was working as an instructor, and did at least 3-4 dives a day I becam very self-aware, and started feeling the narcosis as early as 18 meters (about 58 ft), It somewhat harder for me to keep a trak of time, so I held my computer infront of my eyes whenever I got this deep.
I can tell you some more stories about it- A friend of mine is a veteran instructor, diving for over 40 years. He had a break of a few years and returned, but in a really bad shpe. in his first dive after the break he becam drunk at about 20 meters, and was afraid he won't be able to teach. on his next dive he was ok at 30 meters.
What you ate, drank and did in the 24 hrs before the dive also affects the way you react to the narcosis. as a general rule, you get narked all the time, the deepr you go the harder it gets.
I can tell you the simptoms for me (may vary from diver to diver)
-Losing track of time, the first thing to apear, even though everything else is normal
-Becoming "generaly happy" I just keep feeling very happy, telling myself how fortunate I was to dive today (more than usual )
-Feeling that something is not ordinary, hard to explain, not like something is wrong, but close.
-Becoming VERY happy (now we'r talking deep- 40 meters i think it's about 125 ft) to VERY VERY happy.
-Loughing seizure: happened to me twice, I used 30 bar in a minuete of seizure.
-Being EXTREMLY happy, like after smoking weed (dont ask me how I know it )
The last one refers to DEEPER water. the deeper you go- the happier you are, In general.
now-one remark: Diving deep, into narcosis area is DANGEROUS, just think of someone stoned diving. For VERY experianced divers, the risk is significantly reduced becouse they are so used to what they are doing that they operate their gear without thinking about it, as a reflex. I also select my buddy very carefully for any dive beyond 60 ft- There are very few people I will dive with when knowing I am bound to get narked-people that I know can help me If something goes wrong, and that are professional enough with their gear that I know the chances of something going wrong with them is very small.
The most problematic sympthom is loss of common sense, and fixation. For example people who decided to go to 60 m' and somewhere arounf 45 they notice their pressure gage is at 10 bar but still go on.
Also about the N2 narcosis you can get it from any depth greater than 24 m' and there have been cases of even 18 m'
the problem is that there are no rules as to when you get it
it can change from day to day from dive to dive.
What can make it come sooner than ussualy is, effort and cold water dives which may cause hyperventilation and by that hypercapnia(CO2 build up) also descent with head down which may cause the same thing. Also an extremely rapid descent. A hidden illnes like a developing cold or something alike may also affect you, as well as a poor night sleep and etc'
As to the mechanizm look in to the book I recommended it will do a better job than me explaining it.
Medications- Aspirin helps building the narcosis, a lot of other medications do the same.
About the couses- I know of a few theroies, the one that sounded to me the most logical was that when oxigen and niterogen get to dense togethere they start reacting and behave like lough gas, that is made of the two. however- this theory was proved wrong, as advanced researches showed that other gasses (most of the noble gasses, for example, which off course, can't react with anything) couse the same simptoms as niterogen narcosis, usualy at greater depth.
As much as Iknow, with narcosis it is all just theries, and there are several opinions, none proved the right so far.
As for depth- It actualy starts when you start descending.
As the amount of dissolved niterogen in your blood increases, your level of judgement decreases from the first centimeter. the shalowest I felt it is 18 meters, and on a regular basis.
Another intersting thing is, that in me the effect of a seriouse Narcosis, wont come off completly aas I ascend, and some of it stays even I go out of the water, but I am the only one I know that feels that way.
As I know the most common theory on this subject is the Mayer Overton hypothesis dating 100 years ago and has to do with anestethycs.
In general as I was once explained, N2 causes the release of proteins from a layer surrounding the nerve cells, which sattels in the synapsess between two nerve cells and captures the particles (don't recall the name -I think newrons) resposible for neoro transmitions.
Ok, narcossis is known as "inert gas narcosis" That means that different inert gases have different narcotic affects at different depths/pressures. But you already know this. Here is something you may not know. Last year I read an article that talked about some dive med docs perscribing anti-depressents to some divers doing deep air dives. I'm not sure what finally happened to the story, but it is something to ask DAN about or your doctor.
Next, I've found that C02 can prduce alot of the same symptoms as N2 narcosis.
Next, I happen to know for a fact that an improperly fitted wetsuite can cause problems. If it is too tight around the neck or chest it can give you the same feeling that you described. That happened to me on a 130fsw in 36degree water.
Finally, if you are in to deep diving and don't like the whole narcosis scene then maybe it's time to look at normoxic trimix certification. The gas is more expensive, the narcosis is a fraction what it would be on air, the training can be a little tough and your voice sounds funny after you take a hit. But it is worth it molecular weight in gold.
Interested if anyone else has something to add to this topic...
I completed my PADI advanced course last year in Boracay in the Philippines and immediately did a deep dive down to a reef that started at 37 metres (120 feet). We dropped off the side of a little boat, just me and the instructor and the current was ripping so we had to kick real hard to get down onto the reef or we'd miss it - ended up having to hang onto the reef and then the narcosis kicked in, but not in a good way... just felt confused, and not happy.
Stuck it out for 10 mins but wasn't happy so I aborted the dive before I got into a panic - glad I did. As soon as I went a few metres up I was happy.
I realise now that the fast, head-down descent and the exertion built up the CO2 - exacerbating the narcosis.
Wondering if anyone has been able to learn to manage the symptoms - obviously I would NEVER dive in anything but a comfortable & safe state but I would like to be able to do the rare deep dive and see cool stuff....
Hackler, do a search on "deep air" and you'll find any number of threads (the most recent, I believe, started by DCBC) discussing whether it is possible to learn to tolerate and function with narcosis.
I dive an END of 100 feet, so you know on which side of the issue I fall.