Gas Narcosis in those who are absent-minded

[Nasser]

It's a fair question, and the answer is that my friend has much more experience diving than I do so I'm comfortable diving with my friend as my buddy. My friend is also good at staying calm and level-headed, even if he does not have the fastest reaction time.

The concern that I have (justified or not) was whether, at depths where narcosis starts to become an issue, my friend would be more pre-disposed to being "forgetful." Like, < 100 ft, great buddy; > 100 ft, not so great buddy? But maybe this is where repetitive training comes in and muscle memory takes over?

I'm going to copy a post a made on another thread regarding narcosis that may have some relevance to your question:

The thing about narcosis is that there really are several variables - environmental as well as personal that will affect your susceptibility. For example, I routinely conduct dives to 55m on air in warm water, with plenty of light and visibility and virtually no current... I hardly notice anything. However at times I have performed the exact same dives (or shallower) but in colder water temperatures and have felt noticeable effects. Environmental factors such as water temp, visibility, light, and work load at depth in addition to your own physical characteristics will all play a part. These can all change on a dive per dive basis... even at the same site.

If, however, I know that I will be diving to the same depth but doing a wreck penetration, or the water temp is colder, or there is going to be a significant work load (currents) etc.. then I will most definitely be on mix or if that's not available, not make the dive.

Therefore it's important to consider that your deep training coupled with experience should allow you to make a judgement call as to whether it is wise to perform any given dive by assessing the various conditions (personal and environmental) for that dive.

So in other words, although we have a general idea of the causes and symptoms of narcosis it's not easy to predict how an individual may be affected and how this can change due to so many variables... and BTW not noticing it doesn't mean you're not a little impaired.

If you're concerned about how your friend is going to react to being narc'd I would suggest avoid going deep (i.e. beyond 15 meters) on the first few dives and then very gradually work your way up to greater depths over several dives... but keep in mind that the diving conditions can change and if they are vastly different from your previous dives, you should proceed with caution or avoid going deeper on subsequent dives.

Hope that helps.

 

[Subcooled]

This is my personal experience (dry camber, 6ATA)(also similar experiences while diving at 6ATA):

Compressed air narcosis does make it harder to memorize things. Recalling known facts is less affected.

This means that if you try to calculate (1+2+3-4)/2 you will probably fail in the attempt, as you will have hard time remembering that a) that sum was 3 and that b) it is followed by a p-l-u-s (+), When you finally manage to get both additions done and stored, the + stays firmly in your short term memory and you have difficulty overwriting it with a minus. Hence, you get 1+2+3+4=10 as a result. On your second attempt you might correct it to =2, but won't notice the /2. You won't remember things unless you really try to. If you do not pay attention to your surroundings then you wont remember much and it gets worse at depth.

And some people believe that cows drink milk.

There are less distractions underwater though, so someone might be more attentive, at least down to a certain depth.

 

[Bob DBF]

Without knowing your buddy, it is hard to make a call. Sometimes what you may believe are slow reflexes is just doing something methodical and correctly the first time. In some things speed is not an asset, you have heard of stop, think, act.

As for narcosis, I suggest a series of dives progressively deeper learning how it effects you and your buddy. It is all about how much task loading you can keep track of, if you get down to only depth, pressure, NDL time, and time to surface, it is about time to end the dive. If the information is not making sense or you loose track of any of them for any time, it's time to go up.

Over time you can learn to function at deeper depths and stay safe, it is when you go too deep too fast and don't notice that you are narked until you find yourself well outside the parameters of your dive plan that the feces hits the rotating device.


Bob

 

[The Chairman]

I haven't noticed narcosis between depths of surface to 130'

Which doesn't mean you weren't narced.

We rely on a number of symptoms to determine if we are impaired on the surface. Probably the two main ones are slurred speech and imbalance. It's how cops pick up on who is too impaired to drive, but we don't really talk under water on Scuba and the water acts as a buffer preventing us from stumbling. So, how do you really know? You probably don't.

As Nasser pointed out in his excellent replies, people react differently to narcosis. Some get all happy, some get paranoid and still others just check out. However, we all get dumb. That's the real problem with narcosis and it makes this a silent killer. I mean really: how do you know when you're dumb or even dumber? Narcosis starts with the initial descent. Gearing up and splashing will knock 20 points off of anyone's IQ. The IQ keeps decreasing with depth but it's anything but quantifiable, because we learn to adapt to our situation. Someone earlier wrote about becoming tolerant to narcosis, and I don't think that's it. We just devise ways to accommodate our new found dumbness. We adapt but we're still impaired.

IOW, stop relying on your feelings to determine if you're narced. That you don't feel narced doesn't mean you're not as dumb as a bag of hammers. In fact, the most dangerous diver to buddy with is the one who adamantly claims that they are immune to diving deep. They're already suffering from surface narcosis and are too stupid to realize that they can actually get worse in that regard. I can tell you that they certainly aren't going to get any smarter or less deluded as you descend, so find a better buddy!

As for your friend getting even more forgetful? That's why we clip everything to our body. You'll never know how anyone will react to depth, until you dive with them there. Extrapolation due to pressure never seems to work right. Take your time and build up experience slowly. See what works and what doesn't. There's no other way to know.

 

[NAM001]

I dont think there is a constant.

For example on one dive i watched a diver taking pics at around 100 ft. Upon returning to the boat she did not realize what the pics were of or that he had taken them. Another one took pics and when he looked at it on the boat he remembered the pic of the hole in the ship's side but not till now did he realize there was a big time grouper looking out of the hole in the shot. I have had pics taken of me around 100 ft and i don't remember posing for them. Other times i remember everything. At least so i think. I imaging many people just blow it off as just an age thing.

I haven't noticed narcosis between depths of surface to 130', but I've read that it is noticeable at 100' for a fair number of people, and for some considerably shallower than that. I wonder if there is a precise shallow depth where there is none at all?

 

[Subcooled]

That relaxed feeling at depth could be due to narcosis
Do you find diving addictive?

 

[dumpsterDiver]

Which doesn't mean you weren't narced.

We rely on a number of symptoms to determine if we are impaired on the surface. Probably the two main ones are slurred speech and imbalance. It's how cops pick up on who is too impaired to drive, but we don't really talk under water on Scuba and the water acts as a buffer preventing us from stumbling. So, how do you really know? You probably don't.

.

I often dive below 150 ft.. Sometimes it is an easy dive everything is going OK and I will realize that I feel ZERO Narcosis. This is always a big warning sign to me that I am probably MORE narced than normal. Typically I will feel the narcosis and it will be in the back of my mind the whole time.

When I find myself "feeling fine" and forgetting about the narcosis is when I have to remind myself that you really are narced. Failure to recognize your own impairment is another sign of narcosis.

Everyone is different, but narcosis will make itself known when you have to solve a novel problem or get in a decision making situation,,,As Pete says.. if you are just a little drunk "stumbling along underwater in a neutrally buoyant condition" how would you be able to tell?