Question Ever experienced Nitrogen Narcosis?

[boulderjohn]

Lots of divers report not “feeling” narc’ed at depths where narcosis is possible.

Similarly, lots of drunk people report not feeling drunk.

Sure. As I said, I have never felt that I was narced, but I have had clear evidence of being narced even when feeling perfectly fine. Examples:

• I was in the engine room of a wreck in Truk Lagoon at only about 100 feet with a buddy and a guide. The guide went through a hole in the bulkhead, and I saw a little finger-like piece of pipe sticking down from the upper right corner. I warned myself that it would be easy to catch my regulator hose on it. (I was using a conventional regulator set back then.) My buddy went through and caught his regulator hose on it. He pulled it down and went on. I went through and caught my regulator hose on it. When I did, I wondered which hose it was that I had caught. When I figured out it was probably my regulator hose, I wondered if I should pull it down or up. The situation was made worse by the audible laughter from the guide. I thought, "These are really easy questions. I should know the answers to them. I must be narced."
• Also at Truk Lagoon, we explored a hold of the San Francisco Maru at 181 feet. Back on the boat, I was disappointed to realize I had not seen the store of land mines we were told to expect. Then we saw the video one of the other divers made, clearly showing the land mines. When he took that video, I was probably 3 feet away from him, looking in the same direction.
• I was diving on air with a buddy at about 130 feet, and my buddy flashed me. He wanted to know why I was breathing from my alternate (bungeed) regulator instead of my primary. I had no idea I was doing that. I am sure I know why--I had adjusted the regulator on the surface to stop a slight free flow, so I had probably tried it out just to see how it was breathing, left it in, and forgotten I was no longer on the primary.

In all of those cases, if I had not had an event showing me I was narced, I could have sworn I had had no narcosis.

 

[Celt]

Poor peripheral vision is one I don't see mentioned much, but I believe I experience it, along with light-headedness. My field of vision seems narrower, maybe grainier. Things just look surreal.

Yeah there's an oily look to the water on the edges of your vision, it's a great benchmark for me, and a sign to watch the depth. If you go deeper it will get worse and you'll start to get double vision. When you look at your gauge you'll see a faint number beside the real number.

 

[admikar]

@Vicko will know exact location, Fortunal.
While I was narced at 150 ft, I know exactly what triggered it.
I had only one hour of sleep and traveled through most of the night. It was first serious dive of the trip.
While I didn't feel any effects while deep, once I got above 90 ft, my mind suddenly cleared and I immediately figured what happened.
Doing same-ish dive on Vassilios next day, after a nice, long sleep provided no noticeable effects.

 

[billgraham]

This may have been mentioned as well, but there is also a variation of narcosis often called dark narcosis. That's when the euphoric feeling is replaced by anxiety and perhaps fear. My opinion is that there are other factors at play with this... likely CO2 buildup. The only time I've really felt this was a deeper dive, on air, in really dark water... and a ripping current. Fighting to avoid being blown out to Newfoundland had me working REALLY hard. This was probably 30 years ago and I would NEVER attempt that dive without helium today. I legitimately thought I might die on that dive. It was stupid...

If you're comfortable at a certain depth one day it can all change quickly when environmental conditions or exertion levels change so it is very important to dive within your comfort level and training.

In the story I relayed earlier in the thread, I was having a wonderful dive at around 180 fsw on air, everything was fabulous, it got dark and I got spun around and all of a sudden it was NOT fun and I was scared, so that's how fast it goes to "dysphoria" (the opposite of euphoria).

 

[Akimbo]

Some might find the history of Nitrogen Narcosis interesting. It was first mentioned in medical literature in 1834, but the information was largely unknown to countless divers.

Even though the first practical diving rig was made around the same time, it wasn't until the late 1800s that divers could get deep enough to experience NN. This was because the hand-operated air pumps could not deliver the pressure or volume — and the hoses couldn't take the pressure either.

Commercial and military divers all over the world experienced what we now know as Nitrogen Narcosis, which developed endless folklore about the cause and how to deal with it. The problem was seriously compounded because the helmets were often under-ventilated so CO2 was higher than what we now accept.

One of the first times that NN became a significant enough problem to prompt action by a government was the salvage of the Submarine F-4 that was lost in 306'/93M. This resulted the first research into substituting Helium for Nitrogen.

As near as I can determine, the name "Nitrogen Narcosis" was coined in a 1935 paper from the US Navy's Experimental Diving Unit published by Behnke, Phillips, Thompson, and Motley. Dr Albert Behnke is one of the most important names in diving physiology, but not nearly as well know as his contributions deserve.

 

[Vicko]

@Vicko will know exact location, Fortunal.
While I was narced at 150 ft, I know exactly what triggered it.
I had only one hour of sleep and traveled through most of the night. It was first serious dive of the trip.
While I didn't feel any effects while deep, once I got above 90 ft, my mind suddenly cleared and I immediately figured what happened.
Doing same-ish dive on Vassilios next day, after a nice, long sleep provided no noticeable effects.

I have yet to feel any impairment above 50m, even in a chamber.
The dives were on Svetac island, around 15 miles away from Fortunal
For the rest of the people Fortunal is a small fishing trawler at 40-50m depth and a great way to get narced, mostly because the site has current and there is no shot line to the wreck, you follow a wall straight down and I bet that most of the people who get narced there get it from a combination of o2 and co2, not nitrogen, as you drop down fast and usually swimming hard.

 

[ginti]

I get narced quite easily below 30m. Depending on the conditions, I may get narced shallower (I can think of at least two dives when I got narced at roughly 25m). Below 35m I am always narced, and although I can manage problems (even relatively serious ones***), I hate it, which is why I love helium even for relatively shallow dives.

*** I had a stuck inflating wing at 40m, this was a relatively serious problem at that time, at least in my opinion.

If you don't normally get narced at 130 but on a day you are dehydrated and working harder in a current it may affect you more.

That would likely be CO2, not nitrogen narcosis.

Indeed, not only nitrogen is narcotic. Oxygen is too, in a way comparable to nitrogen, according to some people... Although comparing narcotic power isn't easy and necessarily meaningful.

CO2 is extremely narcotic, it is probably THE ENEMY.

In fact, I think it makes more sense to speak of "narcosis" instead of "nitrogen narcosis"

 

[ginti]

Less partial pressure of nitrogen compared to air. EAD would have been around 90’. So some help. Each diver brought their own gas, EAN was not required.

Oxygen is narcotic too, so no help. It seems like you are pretty good at mathematics, or quite resistant to narcosis. Both sounds good, right?

As a matter of fact, the purpose of nitrox is not to diminish narcosis, but to increase NDL time and/or reduce surface intervals and all that stuff related to decompression.

 

[Eric Sedletzky]

To me, narcosis feels exactly like being under the influence of nitrous oxide at the dentist.
My ears start to ring like crazy and a euphoria sets in. It’s not unpleasant but it really does slow your brain down. Higher mixes of O2 to me are way more disturbing at depth. I really don’t like taking nitrox to the max. I get some very dark disturbing narcs, even though I know it’s technically better for me removing some of the nitrogen, I get a horrible paranoia that I don’t get on air.
Generally I start to feel air narc about 120-130 mildly. Once at 150’ it was pretty strong, but it was a deep air training dive and I had to look after a few other divers who had never been that deep before. They were feeling it really bad. Responsibility set in looking after those two guys making sure they stayed on our line we laid out and getting them back to the anchor line safe with no freaking out, so that seemed to sober me up a bit.
Once I was diving locally in our 15’ viz 48 degree green water and I shot a fish at about 70’ deep. After removing the fish and getting it on the game hook, I for the life if me could not figure out how to get my spear back in the gun or remember the sequence on how the wind up the shooting line on the gun. I had done this hundreds if not thousands of times in the past. My mind just drew a complete blank?
So narc can happen shallow too without ringing ears, euphoria, or any other mental signs.
The amount of sleep you get the night before, the amount of alcohol or other substances consumed the night before, and how physically in shape you are plus what you eaten that morning can all have an affect on if and how bad you get narced. It’s really a moving target.

 

[100days-a-year]

High 02 deep risks the narcosis impairing the ability to notice oxtox symptoms. So it's a plain no for me.