Did you quote a body of peer-reviewed scientific literature then, or did you just say that? If it's the latter, then there is a name for this one too: proof by assertion.
Diving air to 60m
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Did you quote a body of peer-reviewed scientific literature then, or did you just say that? If it's the latter, then there is a name for this one too: proof by assertion.
Dark Wolf
Contributor
@mac64 at 60m we are discussing, I think it's safe to say it's not only 'talking oneself into it' 
@dmaizuk oh my apologies, I did not expect I need to specifically quote source for industry-wide acknowledged facts such as being narced at 60m - when I get to actual PC when I get back from a current diving trip (tomorrow) I'll quote something for you ;-)
Are you gonna hold the other side in this argument to the same standard?
FTR: I am not saying that 60m air dives should not be done at all. Many divers are in fact capable of carrying these out, often as they have no other option for a logistical reason. What is a fact, though, is that these dives carry significantly higher risk and small to non-existent safety margins in case SHTF due to WOB and narcosis.
My problem with this thread is that there is a ton of novices/rec divers on SB that might get an idea from several ppl in this thread that 'some people just don't get narced' or 'I might be narced but can get away with it' ect. It's OK if you accept some risks based on educated decision, it's not OK when you oversimplify/dismiss them for beginners. Shame on you.
@dmaizuk oh my apologies, I did not expect I need to specifically quote source for industry-wide acknowledged facts such as being narced at 60m - when I get to actual PC when I get back from a current diving trip (tomorrow) I'll quote something for you ;-)
Are you gonna hold the other side in this argument to the same standard?
FTR: I am not saying that 60m air dives should not be done at all. Many divers are in fact capable of carrying these out, often as they have no other option for a logistical reason. What is a fact, though, is that these dives carry significantly higher risk and small to non-existent safety margins in case SHTF due to WOB and narcosis.
My problem with this thread is that there is a ton of novices/rec divers on SB that might get an idea from several ppl in this thread that 'some people just don't get narced' or 'I might be narced but can get away with it' ect. It's OK if you accept some risks based on educated decision, it's not OK when you oversimplify/dismiss them for beginners. Shame on you.
tjeastgate
Registered
This post has gone all the way off of the OP, but it's been pretty interesting. The entire reason I decided to go trimix earlier was to reduce narcosis, as I've identified myself as highly susceptible at times. There has been plenty of dives to the 40M range that I felt just fine, but I've also had a select few where I had a little bit of adversity (swimming through the Big Blue Bubble on the way to a wall, going against current, etc...) and I felt off. Like, way off. I understand this is highly subjective, so I never judge or try to tell anyone what they should or shouldn't dive.
That being said, I know quite a few people that also believe that they are way better drivers after a few beers, but a quick reaction test would prove otherwise.
That being said, I know quite a few people that also believe that they are way better drivers after a few beers, but a quick reaction test would prove otherwise.
johndiver999
Contributor
I also know a few experienced divers who seem particularly susceptible to narcosis. It is not popular to say "I can handle narcosis or I am good deep", but the fact remains that there DEFINITELY are some people who are the complete opposite and they probably shouldn't be diving past 120 ft - ever.
I firmly believe that there can be a wide variability in tolerance to narcosis, and there are some people who have pulled off hundreds of dives at over 200 ft on air, but novices at least, should be cautioned that this is a unique and somewhat unusual subset of the population. People that dont feel right on deeper dives are (hopefully) going to stop going deep on air. This means that the population is probably going through a very significant self selection process.
I doubt there are many people who can do 100 meters every day before breakfast and live longer than grasshopper.
Narcosis is dangerous and you are playing for keeps.
TrimixToo
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LMGTFY...
"The effects of nitrogen narcosis are highly variable among divers with all divers being significantly impaired while breathing air at 60 to 70 meters, whereas some divers are affected at 30 meters. The effects are not progressive with time while depth is maintained, but symptoms progress and new symptoms develop as a diver descends deeper to greater pressures. The narcotic symptoms observed are quickly reversible upon ascent.
"The symptoms seen in nitrogen narcosis begin first with effects of the higher function such as judgment, reasoning, short-term memory, and concentration. The diver may also experience a euphoric or stimulating feeling initially similar to mild alcohol intoxication. Further increases in the partial pressure of nitrogen in the blood from descending deeper lend to impairments in manual dexterity and further mental decline including idea fixation, hallucinations, and finally stupor and coma."
"Nitrogen Narcosis In Diving," Patrick J. Kirkland; Jeffrey S. Cooper."
Nitrogen Narcosis In Diving - StatPearls - NCBI Bookshelf
Add some physical workload that demands more respiration with the high WOB created by a gas density well North of 6g/l, leading to CO2 retention that exacerbates the narcosis and creates an even more urgent need to breathe harder, add some problems to solve...
"The effects of nitrogen narcosis are highly variable among divers with all divers being significantly impaired while breathing air at 60 to 70 meters, whereas some divers are affected at 30 meters. The effects are not progressive with time while depth is maintained, but symptoms progress and new symptoms develop as a diver descends deeper to greater pressures. The narcotic symptoms observed are quickly reversible upon ascent.
"The symptoms seen in nitrogen narcosis begin first with effects of the higher function such as judgment, reasoning, short-term memory, and concentration. The diver may also experience a euphoric or stimulating feeling initially similar to mild alcohol intoxication. Further increases in the partial pressure of nitrogen in the blood from descending deeper lend to impairments in manual dexterity and further mental decline including idea fixation, hallucinations, and finally stupor and coma."
"Nitrogen Narcosis In Diving," Patrick J. Kirkland; Jeffrey S. Cooper."
Nitrogen Narcosis In Diving - StatPearls - NCBI Bookshelf
Add some physical workload that demands more respiration with the high WOB created by a gas density well North of 6g/l, leading to CO2 retention that exacerbates the narcosis and creates an even more urgent need to breathe harder, add some problems to solve...
johndiver999
Contributor
I see that paper indicates that Co2 may be additive rather than synergistic with respect to impairment from N2 narcosis. I would accept that correction, since my only real experience is that working hard while deep will kick your butt.
No one in their right mind would tell a novice to dive to 60 meters on air. New diver are going to learn the effects of narcosis long before that and it’s up to them to deal with it. If a divers feels impaired they simply ascend a few meters and the symptoms will immediately subside. Narcosis is not some boogie man waiting in the darkness to pounce on you. Learn to recognize it and deal with it.
John the Pom
Contributor
Just a personal anecdote, but many years ago we did air dives to ~50 msw to look at wrecks off Sydney. We were diving on tables, with detailed dive profiles & air consumption planned out on slates. We were all affected by narcosis to varying degrees at that depth, but all the divers were able to follow the dive plan fine. On one dive though we had a person who became badly narc'ed. He was diving on independent twins, and he simply couldn't work out the relation between his SPGs and the regulators. He kept removing one regulator and then putting the same one back in, and he couldn't understand why the pressure in one tank was dropping and the other one was still full. He knew something was wrong, but he couldn't work out how to fix it. His buddy helped him and after they ascended a short distance he was fine again.
Afterwards we had a good laugh about it, but he obviously couldn't dive to that depth safely on air. There was nothing in terms of age, fitness, etc. that set him apart from the rest of us, but his ability to reason his way through simple tasks just evaporated once he hit about 45 m.
Afterwards we had a good laugh about it, but he obviously couldn't dive to that depth safely on air. There was nothing in terms of age, fitness, etc. that set him apart from the rest of us, but his ability to reason his way through simple tasks just evaporated once he hit about 45 m.
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