Scared of Nitrogen Narcosis

[SoccerJeni]

I took a refresher course today because it's been 3 years since I dove. It was wonderful and I LOVE diving! But, during our discussions the instructor was talking about how a woman was narc'd out and starting just diving straight down and he had to rescue her. He said when he finally caught her she was at 130 feet. He said she didn't even remember doing it.

This just scares the heck out of me. I've logged 7 dives, and the deepest I've gone is 55 feet. I have a basic certification right now and do not plan to EVER go down past 60 feet (probably not even that far) without getting Advanced Cert.

But, do you notice the effects of being Narc'd before you do something insane? Have you ever experienced being narc'd? Can you help me settle my nerves about this craziness?

 

[noreastDIVER84]

I do feel when I am narc'd, and it just makes me a bit more paranoid about checking my air and depth. I have been to 90' and I start feeling narc'd around 70'. I don't dive deep for the sake of diving deep though, if I am doing a deep dive it is to see something worth my while. I spend more time around the 30-50' range, it just gets darker as you get deeper.

 

[Amphiprion]

Narcosis increases with depth and generally you notice it. It makes some giddy and some paranoid. Effects for me include numbing of the face, decreased problem solving ability, decreased short term memory and some anxiety.

You won't be experiencing this at 60 feet. I start to notice it around 100 and find it unplesant (I'm a nervous narc) around 140 feet.

Perhaps a good way of thinking about it would be to compare it to drinking. You generally start to notice when you have had a few before doing something stupid (unless you are drinking a long island iced tea). Unlike alcohol, you can back off by going shallower and quickly clear your head.

 

[Lee Taylor]

I think its a gradual thing that grows the deeper one goes. I have felt a touch of narcosis at 110 feet. Nothing serious, just a little mental slowness. I personally have never noticed narcosis above 100 feet. I have heard that almost everyone experiences it at 160 feet.

 

[SoccerJeni]

So you think it's rare to have the effects above 60 feet?

I mean I love diving, but I'm a very cautious diver because I'm new and I know it could be deadly if you make a mistake.

 

[Dyno Bill]

It used to come to me around 130, maybe a little sooner but not much. I don't feel a dive under a hundred within NDL limits will generate anything too strongly.

 

[Cave Diver]

So you think it's rare to have the effects above 60 feet?

I mean I love diving, but I'm a very cautious diver because I'm new and I know it could be deadly if you make a mistake.

You'll have some effects, but the effects will generally be minimal. Things that tend to make the effects of narcosis worse are diving in dark water, being cold, physical or mental stress or retaining CO2 by not breathing properly. It also clears rapidly by ascending a bit shallower.

Narcosis is not something to really be scared of. It's something that should be understood, respected and planned for.

Different people narc in different ways. Some kinda of zone out, some get giddy/happy, some tend to focus on a specific thing, like staring at their gauges.

There is no reason to rush going deep. Stay within the depth your comfortable with and plan your dives. If you find yourself deviating from your plan during a dive, you need to go back to basics and Stop, Breathe, Think, then Act. If you feel uncomfortable, call the dive and head for the surface. There is always another day to dive.

It's good to be aware of the effects of narcosis and concerned, but don't let fear control you. With experience, you'll learn your limitations. Just take it slow and don't let anyone rush you or push you past your comfort zone.

 

[BTravlin]

Some people are more susceptible to it than others and different people experience it starting at different depths. I've rarely heard of anyone experiencing it at less than 90 feet though. As noted above, generally you'll notice your thinking is a little off and can quickly clear it by ascending a little.

I don't generally feel it until about 110' and when going that deep I tell myself beforehand that I will now begin to monitor my computer and SPG more closely than usual. Has not been a problem except when taking photos where it's easier to lose track of time.

More dives and experience will help you to overcome the paranoia. It's a good thing to be respectful of but you shouldn't let it ruin your diving.

 

[TSandM]

The way somebody ends up being rescued, the way your instructor described it, is that they haven't built good diving habits BEFORE they went somewhere where narcosis was significant.

Think about it -- if the diver was checking her depth and her proximity to her buddy at regular intervals, she wouldn't have gotten deep enough or far enough away from her buddy to get into trouble.

Spending time diving in the shallows (and narcosis is not a major issue above 60 feet) and building good buoyancy control and good situational awareness, will give you a good foundation to do deeper dives safely.

 

[Cleavitt]

Nitrogen narcosis doesn't usually happen instantly.

Technically, nitrogen narcosis starts as soon as you drop below the surface and the partial pressure of nitrogen starts increasing. However, it doesn't have a measureable effect on most people until around 100'. At that point most people don't even notice it unless they really pay attention or find a way to test themselves. By 130' the effect is noticable for most people, but rarely are they 'brain dead' at that point (although they might be getting pretty paranoid, silly, or stupid). Some people do get narced pretty easily, but I think in some cases people assume nitrogen narcosis is at fault when in reality it's just someone doing something unexplainably dumb.

Nitrogen Narcosis affects each person differently. The story you described would be a fairly extreme example and there may have been other contributing factors. For example, maybe the diver didn't remember descending to 130' because she never actually looked at her depth gauge during ANY part of the dive. In other words, she may not have been paying attention to her basic dive info while shallow and wasn't aware of her depth or even aware of the fact that she was descending. Narcosis may have become an issue only after she cluelessly descended to 130'. For a diver with no experience deeper than 60', "dive bombing" from 60' to 130' is a good way to get narced and get "in over your head" before you have a chance to realize what is going on.

Having said all that, the secret to deeper diving (in addition to proper training) is to take it slow and progress a little bit at a time. If your deepest dive to date is 70' it's not a great idea to go straight to 110' on your very next dive. Take small steps so that you have a chance to find out how nitrogen narcosis (and gas comsumption, no deco limits, etc) works for you at each new depth. You will probably find that up to 90' or more nitrogen narcosis is not affecting you noticably.

BTW: narcosis is exacerbated by other factors including low visibility, tannic water, cold water, and physical exertion. In those conditions you might be more likely to notice the effects of narcosis.