Narcosis-does nitrox make a difference? Does experience make a difference?

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1. If you want to reduce narcosis, add helium to your mix.
2. If you want to have longer ndl or shorter surface intervals, use Nitrox.
3. If you want to "feel better" or be less tired after diving, slow your ascent and add a stop midway.
 
I don't think that Nitrox will help that much, because as has already been said the depths you are likely to use Nitrox at are not the depths you are likely to have too many affects from being narced on an average dive.

I do think that some people can learn and practice skills to handle it better than others, a bit like the comments about regular drinkers not showing VISIBLE affects from the drink as quick as a casual drinker - I have absolutely no proof of this but I think that mental discipline can make a difference to how narcosis affects the outcome of your thinking - but not your however your motor skills.

For many years I worked long hours and often got called upon in the middle of the night to take charge of serious incidents and to make life critical operational decisions.

I found that no matter how tired I was I developed a set of mental tools which allowed me to 'operate' effectively whilst under pressure and VERY tired. When I started diving again, and started diving deep I found that the few times I have been narced the same mental tools still worked for me to allow me to work through problems.

My instructor deliberately took me deeper and deeper (within safe limits!) in order that I could experience the narcosis, and we had a long discussion afterwards because she was surprised that although I would slow down and become deliberate with tasks I could still function - albeit much slower, and she hadn't seen this often. I can only put it down to having been used to functioning when half asleep and tired.

I guess I am lucky I have never had a dark, brooding, paranoid narcosis, mine have always been the happy sort ! but each time (at least I think so) I have been able to recognise the problem myself and take the necessary action. I am not saying narcosis doesn't affect me, it does, and I hate feeling narced ! - I will not push the limit if I feel at all impaired I will immediately come up a bit, but I think that it is possible to mentally discipline yourself so the affects can be MANAGED and at least minimised.

Crash helmet now firmly in place for the flak I am sure this post will draw ! - P
 
I believe that narcosis destroys my fine motor skills, but that doesnt change my ability to "think through" a problem such as OOA, Free flow etc.
This is the essence of why we train. When your buddy is OOA, hopefully you're not "thinking through" the problem. It should be an automatic response, especially if you're diving at those depths. You're still following a path so you should do fine. But put a situation in front of you that you hadn't trained for and your ability to come up with a cogent, creative solution is doubtful.

The dumbest cows are the ones who somehow think they don't get narced and are just as sharp as they are at the surface. They get rather belligerent when you tell them that they are indeed impaired. I avoid diving with such prima donas. I was diving with a rather renowned instructor on the Speigel a few years ago. He inadvertently swam into a loop of mono that snagged his first stage. After a few kicks he started to kick more aggressively. When that didn't work he broke from his frog kick into a powerful flutter kick. About that time I had reached him and cut the mono with my trilobyte. Varooooom, he took off and then settled back into a lazy frog kick. On the boat he asked if anyone else had experienced that crazy strong current. I told him about the snag and he shook his head and muttered something about narcosis striking again. He was right. The most dangerous diver is the one who denies they get narced.

You don't have to feel narced to be narced. This is an area where simply relying on your feelings can have tragic results. The deeper you go, the more you should train for contingencies.
 
3. If you want to "feel better" or be less tired after diving, slow your ascent and add a stop midway.

+1 for planned deep stops !

P
 
Here's the set-up. It is relevant, I promise :)

As some of you know, I am one of the authors of the Tahoe Benchmark. This is a semi-annual test of scooters. We test scooters over the lengths of a surveyed 1/4 mile underwater track.

The track is exactly 36' deep on the side of a slope; there are markers every 100' that mark the length of the track. It's easy to run the track, just look at the depth gauge every once in a while and stay at 36', and follow the markers. Easy peasy.

I would estimate I have well over 100 miles underwater along this track testing scooters. I know it like the back of my hand (probabally better, actually). Well enough, that I can easily run the track without refering to a depth gauge.

>>>>>>>>>>

So, here's what happened:

We'd received a scooter from SS to test. It needed to be tested in tech gear, so I loaded up a set of doubles that were about 1/3 full of 21/35, I figured I may as well use it up.

When I arrived at the track, I realized I'd forgotten my computer. <shrugs> it's no big deal, 36 feet deep and 16 minutes max. So, in I went.

As I ran the track, I left one of the markers behind. The next one didn't show up when I expected it; then I realized with a shock, I'd just gone by a log that sits at about 60' deep! Wow. I angled uphill, and reaqquired the track. This happened twice more.

Afterwards, I realized that using nitrox gives me a subtle narc at track depth that I had learned to use in keeping depth. Using 21/35, this depth reference was gone.

The next day I ran the track twice, once using nitrox 32, and the other, air. Both times I was able to accurately run the track at a steady 36' without a depth gauge.

>>>>>

Here's what I learned from the weekend:

  • Depths as shallow as 36' do produce a narc that affects you.
  • Air and nitrox produce similar narcosis.


All the best, James
 
I tend to disagree netdoc, I am very capable of complex problem solving when narced....just not with the quickness that I could when clear headed . It's really a person by person capability. Some can push past the fuzz, some just get comatose. That being said I would rather dive voodoo gas at those depths and have a clear head....much more enjoyable that way.
 
Different agencies have different opinions about the narcotic effect of O2. The broader consensus seems to be that O2 does not contribute noticeably to narcosis. That said, there is very limited use of EANx at significant narcotic depths - so it's easy to understand why nobody spent $$$s on research for a definitive answer.

As for personal resistance to narcosis, I believe (but cannot remember a reference off my head) that this is disproven in study/ies. I do believe, however, that you can develop greater functionality under narcosis - but that critically differs from being 'immune' to it.
 
Andy, you just reminded me of another series of experiences I've had, regarding personal resistance to narcosis (so to speak).

In our area they have a new group of rookie Police Officers and Sheriff's Deputies periodically. Part of their training is how to recognize intoxicated drivers and evaluate them.

So, they need live, intoxicated subjects to practice on. :) Because of my job, I get invited to be a test subject. It is pretty cool - we are picked up at home by a Police Officer, and have a uniformed Officer mixing us drinks as our bartender! Every 15 minutes it's a new drink down the hatch, then they have us blow a blood alcohol machine and test us for impairment.

Pretty much after the first two drinks, I am usually very buzzed. It's similar to how a good narc feels.

Then, as I have more drinks, the "buzz" goes away. The tests they have us doing show that we are becoming more and more impaired, however, the lightheaded giddy narced feeling is gone.

I can't help but equate this to what happens when I do a bunch of dives. I'll get well narced for the first dive, then, similar dives I don't have the happy buzzed narced feeling. However I can still tell I'm impaired.

So, the difference is that when we're done with the intoxication tests, I get driven home by a very solicitous Police Officer. Cool, eh?

All the best, James
 
If you think you are "imune" to the effects, film a dive, and when you watch it, see how much you remember 100%. The details of the wreck I "saw" but didn't recall..... that was an eye opener to me.....

---------- Post added October 25th, 2013 at 01:10 PM ----------

I do believe, however, that you can develop greater functionality under narcosis - but that critically differs from being 'immune' to it.

functional alcoholic comes to mind.....

---------- Post added October 25th, 2013 at 01:12 PM ----------

As to experience making a difference; yes it will but not in the way people imagine. You cannot really build up a tolerance to narcosis. However narcosis is like being drunk in that in reduces short-term memory. The more experienced the diver the more their skills and abilities will reside in the long-term part of their memory. They will have built up a 'muscle-memory' of all significant drills and activities to the extent that they can do them without very much thought. This means they will appear to cope better with narcosis as fewer of their skills will be impaired. But, and this is the big problem, only regularly practiced routine skills will not be significantly impaired. Less well practiced skills, such as emergency ascents, are still likely to be affected just when you need them the most.

really liked that statement!
 
If you think you are "imune" to the effects, film a dive, and when you watch it, see how much you remember 100%. The details of the wreck I "saw" but didn't recall..... that was an eye opener to me.....

This is one of two 'enlightening' experiences that I had along the road with regards to narcosis. The other is doing the same dive deep air and then on trimix. The difference is startling, even if you didn't "feel" anything the first time around on air.

For the last year, I've been doing occasional survey/identification dives on a newly discovered WWII aircraft wreck at 45m/150ft. I've been filming those dives. Some dives were with trimix, but most on air. The trimix helped a lot, even though the dives were quite routine on air. When doing the air dives though, I was much more reliant on reviewing the video post-dive to see the 'small details'.
 

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