Ever narked? Never!

[DIVE BUDDHA]

i can honestly say that narcossis probably affects me like many other divers i

suppose some of us have a higher threshold before we really start to notice the

slow down or not notice as the case may be .

i can remember doing a dive out in egypt a few years back when i did the first

arch on thomas canyon, and remember feeling this urge to get shallow as fast as

i could not a nice feeling at all although on the boat with us was a woman doing

some filming anyway she filmed me coming through the arch at 45 metres and

looked like i was swimming through molasses, i was that slow i can only put it

down to being very off my face

[al kennedy]

Originally Posted by principia

Can some explain the thinking or science behind the fast descents and C02 that people keep mentioning?

I tend to descend pretty quick and the last dive I did out of Brid I got really bad narcosis but put that down to the previous 40 dives being in warm clear water.

J.

Originally Posted by Mal Bridgeman

I shall attempt a layman's description ... but if Mr Hobbs is reading I am sure he can do a much better job.

I think it's to do with increasing partial pressures of the gases acting upon tissues (synapses) in the brain and causing them to constrict and process info more slowly. The amount of constriction seems to vary with the speed at which you increase the partial pressure so the faster you descend the quicker the pp changes and the more befuddled you get. Adding Helium to the breathing mix, which is a very "thin" gas, has the effect of "relaxing "those tissues and reducing the narcotic effect.

CO2 is a much more dense gas than nitrogen so when the ppCO2 starts to become significant then it's impact on the tissues is much greater. Rather than causing a befuddled forgetful effect of nitrogen, though, it causes the fear dread and panic feelings described.

HTH
Mal

And you tend to be working harder at the start of the dive, which increases the amount of CO2 in the body and lungs (kitting up, swimming to the shot, swimming down the shot, holding your breath while clearing ears). So more CO2 around to give you the hebbie-jebbies.

[access]

The first time I noticed the effects of nitrogen was on a dive where I realised that I was only going through the rituals of checking my air,
depth etc but not actually taking any notice of what the gauges said. I had to steady myself to make sure that I actually read the things.
I do believe that building up your depth is one way of reducing the effects although over exertion can still bring it on.
On one build up dive to a planed depth of 50m on a drop off my buddy took off flying and I just couldn’t keep up with him.
As he disappeared about the 45-50m mark I made my way to the surface and waited nervously in the boat for what seemed like ages.
Eventually he surfaced and when back in the boat he told me that he just felt that he wanted to go deeper so just kept going to he heard a drum banging,
he then stopped and thought “what’s that?” then realised it was his heart, looked at his computer and seen that he was at 63m and started to climb up the drop off.

[Polyphemus]

I get narked, when i first started diving and i didn't understand it very well it was shit. I found that first dive of the day on a liveaboard, just woke up. munch a toast, coffee....Negative entry to 35m in 2 mins is really good for getting me narked. anyone else experience early morning narcosis?

it sucks. im asleep,zzzz,im awake, im having a whitey at 35m

now i understand it, i have slowed down my decent. even on negatives.
slow the breathing right down at depth, relax and concentrate on what your doing, then you can really relax when you rise a touch.

on one dive, it was a nice narc, giggles and a leopard shark waiting for me at 42m. but these were on air so.

once i had it so bad my entire vision flickered so much when i moved my head i had to keep it really still, that made me chuckle. it was like a spinning tv.

i am looking forward to trying Trimix and seeing the difference.

i have never understood the ego bullshit, "oh im shy when it comes to admitting the forces of physics also apply to me"

[Mal Bridgeman]

Originally Posted by Polyphemus

i have never understood the ego bullshit, "oh im shy when it comes to admitting the forces of physics also apply to me"

Fantastic! .... though many on here will argue that they are immune from the laws of physics
Mal

[Sixsquid]

Originally Posted by Mal Bridgeman

Fantastic! .... though many on here will argue that they are immune from the laws of physics
Mal

"Ye canna change the laws of physics cap'n"

[denismc66]

I find narcosis gets worse after even half a glass of wine the night before or even if i have a bad nights sleep. I was in a club once where out of 50 divers only me and another guy admitted to being narked! ( double check spelling)

[Ahmed Adly]

Originally Posted by Brian of Aquanauts

As Mal said really but...

Narcosis is not a feeling, you ARE narked you just don't know it yet.



Now there is also a mistaken belief that work up dives and experience can get rid of narcosis. Well in the same way that a drunk can learn how to manipulate their car properly and with practice they can probably get better at it, a diver can learn how to dive while narked. However the drunk still can't stop the car when someone steps out of front of him, just as the diver will have problems dealing with an unexpected problem.


One of my friends is currently running a narcosis study at a chamber, and it's showing some quite interesting results about risk taking. Can't wait to see the paper.

I don't know if I have told this here before but here is an interesting story.

While doing teaching the PADI Adv. for my wife and a client the darndest thing happened at 40 meters.
The exercise was tying a knot with a bit of rope at the surface and then doing it again at the bottom. The guy (Sasha) started it upon reaching 40 meters and completed the task perfectly. he then gave the rope over to my wife.
At this point we where around 5 minutes into the dive.

I noticed that his long hair was standing on end and kind of thought that to be funny looking. With closer inspection, I noticed a huge plume of bubble gushing from behind him! It was his low pressure inflator hose that had burst..... Bloody Scuba Tec cheapskate lousy lowdown......%$^&@$^^@
After checking Sasha's pressure, I discovered he only had 130bar left so I thumbed the dive. My wife was upset cause she didn't get to perform the assigned task she and her buddy (Sasha) exchanged glances and she obviously did not notice he was close to death either .
I grabbed their hands and started our way up the slope and gave Sasha the sign that he is OOA. He thought "oh cool a suprise skill" and performed it as I shut his cylinder.

Back at the surface, I showed what had happened and we all sailed home laughing...... Sasha bought the most expensive Reg he could find...... (from Scuba Tec mind you and they had one of the dodgy LPI hoses on it too..... it ruptured 3 days later AAAAAAHHAHAHAHAHAHAHA)

[Ahmed Adly]

Originally Posted by Brian of Aquanauts

One of my friends is currently running a narcosis study at a chamber, and it's showing some quite interesting results about risk taking. Can't wait to see the paper.

This would be nice to see for sure.
We made several past attempts for the same but the papers kept evaporating. I think they told us it had something to do with too much water absorbtion due to being under water I think such an experiment would more effective in the chamber.

[MattS]

Originally Posted by Polyphemus

I get narked, when i first started diving and i didn't understand it very well it was shit. I found that first dive of the day on a liveaboard, just woke up. munch a toast, coffee....Negative entry to 35m in 2 mins is really good for getting me narked. anyone else experience early morning narcosis?

No, not specifically early morning. Any sort of stimulant (like caffiene) is likely to aggrevate narcs so I avoid it before deeper dives. If you need to wake up, try something that will raise the blood pressure, but not too quickly - like gentle exercise. It takes a while for blood pressure to get up in the morning (allegedly slower in blokes). On livaboards I find a walk around the deck a couple times before breakfast can make a big difference.

now i understand it, i have slowed down my decent. even on negatives. slow the breathing right down at depth, relax and concentrate on what your doing, then you can really relax when you rise a touch.

I don't rush any descents these days. A brief stop at 3m to get my crap together and relax, a gentle fin down and a pause on the shot whenever I feel I am working too hard.

once i had it so bad my entire vision flickered so much when i moved my head i had to keep it really still, that made me chuckle. it was like a spinning tv.

Yep, done the tunnel vision thing. It is not so bad, I just stop, breathe and hang on tight until it subsides. The total blackout is what scared the crap out of me. There is 2 minutes, a 10m descent (from 30m ish) and a 20m ascent, completely missing from my life. My computer assures me I was there. I was not very experienced in those days - not enough to know when to stop following a buddy.

i am looking forward to trying Trimix and seeing the difference.

Helium is not a panacea. We often hear of Trimix divers watching Air divers do stupid things. I can assure you I have watched Trimix divers do stupid things while I was diving Air. Helium is a useful tool, but it lacks the magical power to transform you into a better diver than you already are.

i have never understood the ego bullshit, "oh im shy when it comes to admitting the forces of physics also apply to me"

There is more to it than the laws of physics. There is a brain in the way and everyone's is different. Personally I never understand why some divers have so much trouble admitting they have one.