Northwest Dive Club

Just asking, at what depth do you start to feel the effects of narcosis? I know everyone's a bit different and it depends on your gas. Just wondering because I've been to 135 feet and didn't feel any different.

I don't feel any different when I'm narced.

What happens is that I make mistakes and overlook things. It's more of a "d'oh" feeling than anything else, and I don't recognize it at all. My buddies do, because they catch my errors.

I think most people are looking for a distinctly drunk feeling to know that they are narced. I believe that, by the time you actually notice feeling that way, you are so far beyond where you are safe in the water that it is scary.

BTW, I have repeated proof that I am farm animal stupid at 100 feet. I won't go there except on an easy open water dive with no complex navigation, no decompression calculations, and no overhead -- unless I have helium in the mix.

At 115 ft in St Lucia I started to feel " different". Things were very quiet and peaceful...I colors seem to almost become friendly and mesmerizing. Not sure if this is the onset of Narcosis, but I took it as a warning and went no further. In the Sound, I have been to 125 ft and never felt any difference, but I now use 115 ft as a reality check just for safety.

I believe the water temps come into play as well as air mix and individual physiology.

just my 2 psi.

I don't necessarily feel any different at depth (100') on air - I just don't remember much about the dive and typically get tunnel vision. I dive consistently with 32 %. It seems to alleviate the problem. I would like to try 25/25 or even 21/35 at recreational depths and see how it feels.

Of course using 32% to mitigate narcosis assumes oxygen is not narcotic. It is not known whether or not O2 is narcotic because it is used by the body. However, some training agencies assume it is both toxic and narcotic at depth and therefore introduce helium into breathing mixes for depths often considered recreational.

I consider myself narced at 70 FSW but then I don't consider myself an expert either.

Jonathan

Depends on the dive and amount of stress... (more stress = much more narc'd)

On a typical low-stress dive, in terms of microbrews:

Start to feel it at 100ft. One beer.
A bit narc'd and relaxed at 120ft. Two beers.
Things get a bit whacky at 145ft. Three beers. I've had quite enough, thank you.
Literally hearing a loud buzz at 165. Giggling. Bad juju. Four+ beers.

Depth is only one of the factors in narcosis, IMO. I've dived air...well, much deeper than you're supposed to. I probably couldn't have given you the square root of pi or anything at the time, but I was checking my gas, monitoring depth and time, and keeping track of my buddy the whole time. I was wired tight and felt pretty focused the whole time. (in hindsight, I'm lucky nothing serious went wrong on that dive.)

On the other hand, the worst narc I ever had was on a dive less than half as deep as the first one I mentioned. I was around 70' with a newer diver, and we turned around to start our ascent and swam into a swirling silt cloud that the divers behind us had left....their lights were bouncing off the silt in swirly patterns that reminded me of driving in a blizzard. All of a sudden, my head was spinning, and I felt that sense of impending doom. When I spun around to look for my buddy, he was starting to cork. One of the hardest things I've ever had to do was swim up, grab him, and drag us both down to the bottom. He was totally freaked, and so was I. After checking our gas and seeing we had plenty to breathe, we both more or less crawled upslope to get out. I still felt narced in the parking lot. Both dives were at night in similar conditions, about a month apart.

Joshua Smith wrote:Depth is only one of the factors in narcosis, IMO. I've dived air...well, much deeper than you're supposed to. I probably couldn't have given you the square root of pi or anything at the time, but I was checking my gas, monitoring depth and time, and keeping track of my buddy the whole time. I was wired tight and felt pretty focused the whole time. (in hindsight, I'm lucky nothing serious went wrong on that dive.)

On the other hand, the worst narc I ever had was on a dive less than half as deep as the first one I mentioned. I was around 70' with a newer diver, and we turned around to start our ascent and swam into a swirling silt cloud that the divers behind us had left....their lights were bouncing off the silt in swirly patterns that reminded me of driving in a blizzard. All of a sudden, my head was spinning, and I felt that sense of impending doom. When I spun around to look for my buddy, he was starting to cork. One of the hardest things I've ever had to do was swim up, grab him, and drag us both down to the bottom. He was totally freaked, and so was I. After checking our gas and seeing we had plenty to breathe, we both more or less crawled upslope to get out. I still felt narced in the parking lot. Both dives were at night in similar conditions, about a month apart.

Eww.... The "Dark Narc". No thank you. I'll pass.

Mongo wrote:

Joshua Smith wrote:....their lights were bouncing off the silt in swirly patterns that reminded me of driving in a blizzard. All of a sudden, my head was spinning, and I felt that sense of impending doom.

Eww.... The "Dark Narc". No thank you. I'll pass.

Or a nasty case of vertigo that can amplify narcosis. Yeah, yuck.

I don't "feel" anything, but I start obsessing over my gauges when I reach ~100 fsw in the sound. In Bonaire, I've gone deeper and never had the obsession come on. I always dive with 32%.

at 68' i can taste it... odd metallic flavor... not like the flavor of high PPO2. kind of more bitter.

I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

well said

that is exactly why i try to describe physical sensations as i note them as opposed to when i 'think' i'm impaired

airsix wrote:I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

60south wrote:Depends on the dive and amount of stress... (more stress = much more narc'd)

On a typical low-stress dive, in terms of microbrews:

Start to feel it at 100ft. One beer.
A bit narc'd and relaxed at 120ft. Two beers.
Things get a bit whacky at 145ft. Three beers. I've had quite enough, thank you.
Literally hearing a loud buzz at 165. Giggling. Bad juju. Four+ beers.

Lightweight!

airsix wrote:I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

Dead on... I used to dive a shipwreck in Hawaii quite regularly (about 105ft deep), and after 50 or so dives on it I tried 21/35 and it was a completely different wreck. I was surprised how much I was noticing that I never really saw before.
Also I love having conversations with guys who haven't dove since their "Deep Air" training in the 90's. The argument that repeated exposure to narcosis can help manage it is like saying a high tolerance of alcohol will make you a better drunk driver. I have a feeling that the increasingly easy access of recreational trimix will be like the nitrox boom in the 90s.

Beefcake wrote:Lightweight!

Yup. I'm a cheap dive date.

But isn't that the thing with narcosis? Body mass doesn't seem to be a predictor.

I've never felt the textbook description of narcosis. Instead, below about 100 feet I get so paranoid about everything I start to freak out and have to come up shallower. Going down, I can play around at 80-90 feet just fine, but once I get into the paranoia zone, it takes until about 70 feet for it to really go away. I've only experienced this twice, and I don't care to experience it again. Both dives were on air, so it might be different with 32%. I'm nitrox certified, just haven't had occasion to try it at that depth. Baring my soul a bit, I'm scared to try it. As I said, I don't ever want to feel that sensation again, and since there's no guarantee that nitrox will alleviate the problem, I've been loath to test it.

For my money, there's a lot more to see in terms of life at the 40-50' level anyway...

airsix wrote:I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

+1

I notice myself checking my gauge alot at depth, unable to recall the number from just a few minutes before. That's my most obvious "symptom" to me, but I'm sure my overall reaction times are sloooow. Actual depth is just a number and I don't really want to perpetuate the myth that a number means much (like Josh said it can be really bad when you least expect it)

Mine depends on descent. A gradual descent to 100+ and I feel nothing, except the uphoria that comes with diving. However a rapid descent to 100+ fsw such as down a buoy line or anchor line and I tend to feel a little hazy and can certainly tell I am feeling "different". After diving for a while now I can proactively prepare for the narcosis and have not had any high anxiety moments..


my 2 psi

short term memory starts to get noticeably impaired around 80 feet for everyone.

the "math tests" in a lot of AOW courses are also testing the wrong thing since they're testing recall at 100 feet of something that you learned on the surface. they should really be showing you word lists and asking you to memorize them at 100 feet and then testing recall later and comparing to your baseline.

CO2 is also a huge factor in narcosis, particularly when added to additional stressors like cold and dark and low viz. that is probably the leading reason why warm water isn't as "narcotic" as cold water.

+ 1 on CO 2

CO 2 is the "silent" narcotic gas. I believe it is the main contributor to "dark narc"


Furthermore, I don't race to the bottom anymore (thanks bdub). I find a slow, controlled descent is easier to stop and I don't get the momentary brain fog when I get to the bottom.

CaptnJack wrote:

airsix wrote:I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

+1

I notice myself checking my gauge alot at depth, unable to recall the number from just a few minutes before. That's my most obvious "symptom" to me, but I'm sure my overall reaction times are sloooow. Actual depth is just a number and I don't really want to perpetuate the myth that a number means much (like Josh said it can be really bad when you least expect it)

My experiences with narcosis are almost exactly as Capt. Jack described. I become incredibly forgetful. I'll look at my SPG, and then 2 or 3 minutes later be checking it again becuase I don't have a clue as to what it read. I also do this with a compass at depth. I can remember being in a 160 ft. and swimming a compass heading back to Magic Island. I was a few kicks into the swim and thought I had the bezzle backwards on the compass.

1 factor people haven't mentioned is dehydration. I have found that Narcosis is more acute for me when I've been out drinking the night before. I've dove with cotton mouth and a headache - the headache was way worse after the dive and I remember noticing the effecets of memmory loss and disorientation at a much shallower depth. Definately don't recommend diving with a hang over. Also, puking into a reg or mask at depth is totally over-rated.

airsix wrote:I'm of the belief that being narked is not a "feeling", it's a physiological state brought on by specific conditions and when you're narked you're narked whether you feel it or not. "I'm not narked at 100ft" just means you have not been made AWARE that you are narked (IMHO). How many times have we heard an intoxicated person lecture us about how drunk they aren't? How many times have we all seen an intoxicated person THINK they are doing something flawlessly when in reality they are a train wreck? Same thing. An elevated blood alcohol level creates impairment whether you feel it and acknowledge it or not. It's a physiological reality and while our conscience may affect how we react to it, it does not have the power to simply mitigate the cognitive impairment with will-power or self-confidence. Well, that's what I think anyway.

Ben

I think this is basically true, in that one can feel "fine", but, in reality, be impaired. But I know that at least for me, there's a huge variability in how that impairment might manifest. And that variability is independant from depth.

For me it is a feeling of anxiety. I get obsessed with my computer, and my breathing. When it hits, it is usually around 85' or deeper. Doesnt seem to matter if it is in the Puget Sound, or the Carribean. However, it is hit and miss. Sometimes I feel it, other times I feel fine. Im sure that probably I have been impaired in some fashion when I feel fine, but am not aware of it. Sure makes the dive less fun when I am feeling it.

I had a different narcosis experience on a recent dive. When comparing notes after the dive my buddy and I both got cold at about the same depth on the way up and it was when the narcosis haze went away. That was a first for me.

Narcosis is an insidious thing ... I often don't feel it, even when I'm doing something really dumb.

I remember a time I checked my gauges ... a few seconds later I couldn't remember what they said, so I checked them again. My buddy was looking at me kinda funny, and I'm thinking "what's his problem?" He reaches over, unclips my primary second stage, and hands it to me. I sheepishly exchanged it for the bungied backup I'd been breathing from. Thinking to myself "so this is narcosis", I looked him in the eye, gave him the thumbs down ... and we quietly slipped beneath the surface ...

... Bob (Grateful Diver)