"Rapture of the Deep"

[monant]

I think I was getting narc'd at 120ft on my first dive at that depth. At 90ft I slowed my descent and began doing mental exercises in hopes of detecting narcosis if I was going to experience it. At 120ft I noticed I had a very pleasant feeling. I could still do my mental exercises but decided that depth was my max. Since that dive, I've been to 120ft several times but have never exceeded it.

[texdiveguy]

On an air dive at the Valhalla Missile Silo near Abilene Texas.http://www.familyscuba.com/Valhalla/...7/Default.aspx
The waters are chilly in this large concrete tube.....dim light at best with a good dive light.....gray walls. Was about 80ffw is when I noted that my electronic dive watch was just flying through the numbers.....I remember attempting to stop it my pushing 2 buttons that are 'never to be pushed' while underwater! (I knew this but just kept after those buttons) LOL.....we made it to the bottom of the silo and began our ascent.....it was a mid point up when I really realized what had happened---narced!

[captain]

The only time I was aware of it was at 145 feet and deeper, I got a bit paranoid, kept checking my gauges. It was on and oil rig with a 400 foot bottom, and had the feeling of descending when I wasn't. I can't say I have ever been aware of it at lesser depths.

[bubbletrubble]

Originally Posted by 3rdEye

i've heard that people with high alcohol tolerance aren't very prone to getting narced...not sure if that's true, but maybe that's why

@3rdEye: You're talking about two separate physiological mechanisms. I believe that high alcohol tolerance is associated with an increased rate of alcohol metabolism in the liver. Although this increased metabolism decreases the amount of alcohol in the bloodstream (that eventually traverses the blood-brain barrier into the central nervous system), it results in increased fat accumulation in liver cells ("fatty liver") which can leave the liver acutely and chronically inflamed (hepatitis). Over time, fibrosis and nodules appear within the liver in response to the chronic inflammation. That's cirrhosis -- and that's bad.

FYI, many drugs are broken down/eliminated in either the liver or kidneys or both. This affects the amount of the drug circulating in the bloodstream and determines the magnitude and duration of the drug's effect.

Little is known regarding the basis of the physiological mechanism for narcosis. Some experts speculate that it is related to increased activation of NMDA receptors (excitatory) on central nervous system neurons. There's also a great deal of transitory cellular communication that occurs via diffusible messengers, like nitric oxide. Guess what? Nitric oxide is comprised of nitrogen. Something to think about.

In any case, don't expect to diminish your propensity for narcosis by increasing your alcohol tolerance. It won't work. And your liver will not like it one bit.

[navyhmc]

Actually bubble, the brain does create a tolereance to high alcohol, just like it can for narcotics when it takes more to get an effect. The liver does increase it's metabolism a little, but the true effect is that the brain tolerates it more. This is why some alcoholics with BACs of .400+ survive when young binge drinkers die at lower BACs when their respiratory center shuts down.

But, that said, I am not a heavy drinker-I can usually count the number of alcohol beverages in a year on one hand, but I have no had any real problems with narcosis yet and my max rec dive to date is 165'-didn't plan on going that deep, long story. I will admit I have felt the effects, usually at around 110'; I just note that it's a little harder to concentrate. So far, I haven't had any desires to do strange things nor had any hallucinations.

[wgt]

For the purposes of the current discussion, I will substitute "resistance to the intoxicating effects" for "tolerance," the latter term often relating to a process whereby repeated exposure to a substance leads to a reduced physiological impact of the substance.

1. Metabolic considerations constitute a restricted means of dictating resistance to the intoxicating effects of alcohol. Resistance to the intoxicating effects of both alcohol and pressurized nitrogen could thus easily be realized through non-hepatic mechanisms.

2. Some mechanisms subserving nitrogen narcosis are actually fairly well understood, with nitrogen increasing permeability of neuronal membranes to ions and water. This forms the basis for adding nitrogen to helium in tri-mix to minimize risks and severities of high pressure nervous syndrome (helium shakes) during extremely deep dives. Also, so far as I am aware, it is hypothesized that nitrogen under pressure suppresses rather than potentiates functionality of the NMDA receptor complex.

3. Inhaled nitrogen would seem to be an unlikely source of the nitrogen forming nitric oxide. The triple bond of the N2 molecule is too strong to be broken down metabolically in the human. This is the factor that determines the inert nature of inhaled nitrogen, rendering us vulnerable to decompression sickness. Rather, nitric oxide is a metabolite of L-arginine, which is available through dietary sources.

4. Alcohol and nitrogen appear to exert synergistic effects on cognition and motor skill. This is consistent with a shared mechanism of intoxication. This lends plausibility to the hypothesis that resistance to the intoxicating effects of alcohol predicts resistance to the intoxicating effects of nitrogen under pressure.

All-in-all, I see the makings of some interesting experimentation. However, considerable leg-work would be involved to ensure adequate operationalizing of high versus low resistance to the intoxicating effects of alcohol and pressurized nitrogen. Anyone up for getting tanked in the tank?!

Please note that the foregoing discussion does not relate to the development of cross-tolerance between alcohol and pressurized nitrogen with repeated exposure to one of the intoxicants.

Originally Posted by bubbletrubble

@3rdEye: You're talking about two separate physiological mechanisms. I believe that high alcohol tolerance is associated with an increased rate of alcohol metabolism in the liver. Although this increased metabolism decreases the amount of alcohol in the bloodstream (that eventually traverses the blood-brain barrier into the central nervous system), it results in increased fat accumulation in liver cells ("fatty liver") which can leave the liver acutely and chronically inflamed (hepatitis). Over time, fibrosis and nodules appear within the liver in response to the chronic inflammation. That's cirrhosis -- and that's bad.

FYI, many drugs are broken down/eliminated in either the liver or kidneys or both. This affects the amount of the drug circulating in the bloodstream and determines the magnitude and duration of the drug's effect.

Little is known regarding the basis of the physiological mechanism for narcosis. Some experts speculate that it is related to increased activation of NMDA receptors (excitatory) on central nervous system neurons. There's also a great deal of transitory cellular communication that occurs via diffusible messengers, like nitric oxide. Guess what? Nitric oxide is comprised of nitrogen. Something to think about.

In any case, don't expect to diminish your propensity for narcosis by increasing your alcohol tolerance. It won't work. And your liver will not like it one bit.

[texdiveguy]

With the exception of my story above (very pronounced on that one dive).... I don't suffer impairing narc. effects on moderate depth air dives.....there are so many factors that effect each of us differently and on each dive. I contribute good health//non drinker or smoker and active diving plus advanced training in air/nitrox extended range diving to be a factor for me at least. I do though recommend trimix as the breathing gas for deep diving, much better when all is as clear in your mind as possible!

[3rdEye]

Originally Posted by bubbletrubble

@3rdEye: You're talking about two separate physiological mechanisms. I believe that high alcohol tolerance is associated with an increased rate of alcohol metabolism in the liver. Although this increased metabolism decreases the amount of alcohol in the bloodstream (that eventually traverses the blood-brain barrier into the central nervous system), it results in increased fat accumulation in liver cells ("fatty liver") which can leave the liver acutely and chronically inflamed (hepatitis). Over time, fibrosis and nodules appear within the liver in response to the chronic inflammation. That's cirrhosis -- and that's bad.

FYI, many drugs are broken down/eliminated in either the liver or kidneys or both. This affects the amount of the drug circulating in the bloodstream and determines the magnitude and duration of the drug's effect.

Little is known regarding the basis of the physiological mechanism for narcosis. Some experts speculate that it is related to increased activation of NMDA receptors (excitatory) on central nervous system neurons. There's also a great deal of transitory cellular communication that occurs via diffusible messengers, like nitric oxide. Guess what? Nitric oxide is comprised of nitrogen. Something to think about.

In any case, don't expect to diminish your propensity for narcosis by increasing your alcohol tolerance. It won't work. And your liver will not like it one bit.

yeah, i realize that nitrogen one breathes isn't metabolized in the liver...but I think how one handles being just as drunk (as in blood alcohol levels) as another person differs. maybe i should hit the hippy crack to build up my tolerance?

[navyhmc]

Originally Posted by 3rdEye

yeah, i realize that nitrogen one breathes isn't metabolized in the liver...but I think how one handles being just as drunk (as in blood alcohol levels) as another person differs. maybe i should hit the hippy crack to build up my tolerance?

Actually, recalling a line out of the PADI Deep Diver book, it did say that while the exact reason isn't known, the diver who does a number of deep dives does build a tolerance just like the druggie and drunk.

So I say do some deep dives, get socially narc'd, it's cheaper than drugs... And confidentially, this is what drove me to deep dives as a teenager-it was cheaper than getting someone to buy alcohol for an underaged person (didn't really do this) it's legal, and when you surface, it goes away and you're safe to drive-no DUI!

[Rileybri]

Originally Posted by MSilvia

I have a pretty high tolerance to drugs and alcohol generally, but sometimes I get narced pretty easily. Then again, it might just be that I notice I'm narced easily.

It's not a predictable ting for me though. Sometimes I can feel it coming on at 80', other times I've been to 120' with no symptoms.

I can vouch for this personally!