Is the severity of narcosis greater when diving cold water?

[rsingler]

When I was doing my PADI Deep Diver cert, my very first descent to 130' was accompanied by a sudden onset of mild anxiety. Like prickles on the back of your neck. I was alarmed by it, and a bit frightened. Our time at 130' was brief, and the sensation completely disappeared on ascent.
I was not sure I really wanted to do the second dive of the cert, thinking "If deep diving is like this, I'm not sure I want to do more of this." But having some modest circulating testosterone, and having paid for the course, I did the second dive.

And it didn't happen again.
???

Fast forward to twenty years later, doing Advanced Wreck on my CCR. We descend to 135' on EAN28 (diluent) in the sand under the stern of the Spiegel Grove. It gets a bit dark, and for the second time in my life, that "feeling" creeps back in. This time, I'm a bit more analytical about it, and try not to let it bother me, knowing we'll ascend shortly to 120' to enter the wreck. So I try to remember the dive plan (which was 5 min at 130, 10min at 120, 10min at the 110' deck and then back to the anchor line for brief deco ascent).

For the life of me, I couldn't remember the plan.
And that was when I knew I was narc'ed.

My next cert was Helitrox CCR, needless to say, and I don't worry much about it any more, once I've done the END calcs.

 

[boulderjohn]

Maybe my advantage is always being stupid

Nah! It is all in having something happen to highlight the stupidity. As I wrote in my example, if I had not caught that hose, I would have sworn I had not been narced. I have only had a few instances (I have another story like the other), but in other cases where narcosis would be expected, I felt fine. That does not mean I was fine.

I have also had a couple instances where I have been at around 150-160 feet and experimented by breathing air for a while before switching back to trimix. In each case, I have not been able to feel a difference, but in each case those experimenting with me said they could.

 

[Edward3c]

How cold is too cold before one begins to feel narcosis?

Until your qualified (and done deep training) you’re unlikely to experience narcosis.

Research done by marine conservation scientists established that narcosis effects most people from 15m onward, but isn’t noticeable to most until around 30m.

 

[wetb4igetinthewater]

It has been a long time, but I'd like to paraphrase @Bob DBF

The problem with narcosis is that you may not realize your impaired when you are in an emergency and are unable to take the steps to save yourself. Let's remember that increased respiration results in greater CO2 generation and that is far more narcotic than nitrogen. So when things go sideways, it may be difficult to maintain calmness/slow respiration and deal with the problem(s) at hand. That extra CO2 generation may push oneself over the threshold where it is too difficult to deal with the problem(s).

 

[Still Kicking]

When I was doing my PADI Deep Diver cert, my very first descent to 130' was accompanied by a sudden onset of mild anxiety. Like prickles on the back of your neck. I was alarmed by it, and a bit frightened. Our time at 130' was brief, and the sensation completely disappeared on ascent.
I was not sure I really wanted to do the second dive of the cert, thinking "If deep diving is like this, I'm not sure I want to do more of this." But having some modest circulating testosterone, and having paid for the course, I did the second dive.

And it didn't happen again.
???

Fast forward to twenty years later, doing Advanced Wreck on my CCR. We descend to 135' on EAN28 (diluent) in the sand under the stern of the Spiegel Grove. It gets a bit dark, and for the second time in my life, that "feeling" creeps back in. This time, I'm a bit more analytical about it, and try not to let it bother me, knowing we'll ascend shortly to 120' to enter the wreck. So I try to remember the dive plan (which was 5 min at 130, 10min at 120, 10min at the 110' deck and then back to the anchor line for brief deco ascent).

For the life of me, I couldn't remember the plan.
And that was when I knew I was narc'ed.

My next cert was Helitrox CCR, needless to say, and I don't worry much about it any more, once I've done the END calcs.

In my experience narcosis seems to magnify your pre-exisiting state of mind. I have found that if I am a little nervous, stressed etc. about the dive, I will get the "dark narc" reaction, which is most unpleasant. Cold, low vis, lack of experience contribute to stress and therefore tend to result in the dark narc feeling.

If I am confident and having fun, on the other hand, I get the "martini effect" mild intoxication, which is pleasant but dulls awareness, memory and reaction time, none of which are positives for deep diving.

I vividly remember my first dive on helium (30/30), to a wreck in 130' during a heavy red tide. My buddy was on air.

We dropped in and when we broke through the red tide layer at 30' to find ~100' vis, but it was dark as night. We got down to the wreck and it was spectacularly clear. My HID light was punching through the darkness as far as I could see. I was having a blast.

I turned to my buddy and he thumbed the dive ... he was having a bad narcosis reaction and made the right decision (much to my disappointment at the time).

The experience was a revelation to me -- diving at 130' on helium, I felt as though I was diving at 30'.

 

[Scubagermany]

How cold is too cold before one begins to feel narcosis?

How many questions about diving can someone have before he even starts his OWD course....

 

[JMBL]

How many questions about diving can someone have before he even starts his OWD course....

Don't be so rough. Asking demonstrates a will to learn, doesn't it ? And enthusiasm, as well. So, is that a real problem ?

It might also denote some worries about diving. Is that so unnatural ? At least, breathing underwater, from a tank is TRULY unnatural, so being prudent about it seems a wise attitude to me.

 

[Bob DBF]

You may be confusing the term narcosis with symptoms of severe hypothermia.

The symptoms can be identical.

My first hypothermia rescue was only because they acted narked, so I assisted them shallower. Now I was confused because we weren't deep to start with, and even shallow the symptoms remained, so I got them up and out of the water as fast as practical, to find out what was going on, which was evident out of the water.

The symptoms were slowing and stopping and staring off, it was very hard to get their attention to start them moving again, and then the cycle would repeat. I had seen it deep when someone was narked, but getting them shallow always fixed it.

I've helped a couple of other divers out since that, but only the first had me confused, All three knew they were cold, but decided to tough out the dive. The first was my dive buddy, the other two were later, off the same boats I was diving at different times, and they had already lost their buddy. Afterwards they got my cold low viz water is dangerous lecture, 'cause it scared the crap out of me.

 

[Bob DBF]

How many questions about diving can someone have before he even starts his OWD course....

All of them. There is a lot of information, and misinformation, available for those that are interested.

 

[Boarderguy]

Deep air is fun. Proper sized tank with a bailout or deco bottle and enjoy the rush. My first time to 150 I didn't feel anything. My second trip a few weeks later I felt a warmth wash over me around 140. I was slower to react in the 150-160 fsw range and slower to reason out the plan (7 minutes at depth and work back up). I was able to note the time we hit depth, do the math for when we ascend, acknowledge when the time came, and signal my buddy to go. Everyone is different. My buddy didn't think we were down for the full 7 until we looked at our logs.

This is in sub 50° water, YMMV...