Unable to concentrate on "deeper" (27-30m) dives

[theiszy]

I've only done 4 dives down to 27m or lower, and each time I find I have trouble concentrating on the dive. What I mean buy this is I'm too obsessed with my buoyancy, air and other gear, and when I surface I really don't recall much of the dive (by this i mean the stuff i saw). I figure its narcosis (because its similar to how I am then I've had a few beers), but it feels like I "waste the dive" when I go that deep. Is this excessive narcosis for the depth? (one time at 30m I couldn't understand the depth reading on my watch & if it was getting deeper or shallower, so I ascended to 27m and felt better) and will it get better? or am I just one of those divers will have to avoid going any deeper unless I want to risk going full retard?

 

[NAM001]

The effects you describe i would say is narcosis related however a 3 meter change in depth and the problems are going away seems to be not consistent with it. I would not expect narcosis to have that severe of change in effect with such little depth change. Im no med expert but i think there is something else involved or a group off things involved that you are looking to combine in to one explanation. . Could it be that you are not comfortable with the depth and are concentrating on a group of skills much more than at shallower depths and then calling it narcosis. Its a stretch that however does not explain the not understanding the depth gage part of your post. Have you made these dives on nitrox yet?

 

[PsyWulf]

Sounds pretty par for a newly minted deep diver

My 2nd dive to the 30s for deep nav I didn't understand how my compass worked or why I had it with me initially.

The course dives generally expose you in a safer way to the effects of narcosis so you can learn how your body reacts and how to respond. Slow down,breathe,think

Everybody reacts different so not so easy to say if you can improve or not. I certainly have since those initial dives

Sent from my GT-I9500 using Tapatalk

 

[Redshift]

Like KWS, I think narcosis is there, but maybe exacerbated by some discomfort or fear of being at that depth? How are the diving conditions usually? And how do you feel when you're going to do a deeper dive?

 

[DevonDiver]

Dive within your comfort zone. Narcosis exacerbates the impact of task loading on your situational awareness and stress management. Get fully comfortable with your kit, your procedures and your comfort zone BEFORE progressing to deeper depths. It's advice you were given at entry level training. It's prudent. It's based on reality. AND IT APPLIES TO US ALL. No plastic c-card/s in your wallet change that reality.

 

[Storker]

I, too, see this as classic nitrogen narcosis. Forget those stories about happy drunk and donating air to the nearest fish, IME the classic narc is just as you describe: Molasses for brains and mental tunnel vision (lack of ability to concentrate on more than one task at the time).

Some people are more susceptible to narc. IDK if that's because there's a real difference in susceptibility, or if it's because some people are better at noticing it, or if it's a combination of the two. I can often feel the onset of narc somewhere between 25m and 30m, but normally I don't think it's impacting me significantly at that depth. But the response varies a lot. I've been (IMO, of course) completely clear-headed at 30+, and I've been thinking a bit sluggishly and/or felt the whiffs of dark narc shallower than 30m. So, being of the careful type, I've set my personal depth limit at 30m to maintain a decently clear head. Besides, for a single tank rec diver, deeper dives than that would become very short, so I don't really see much point in going deeper. IMO, of course.

When I did my AOW deep dive, I wasn't noticeably impaired on the math test, but on the letters test, I could notice my brain working somewhat slower. I'm a math person, not a language person, so the math was more hard-wired into my brain and less affected by the narc. Any new, unfamiliar task will be more difficult when you're DUI (diving under the influence), while stuff you've done hundreds of times are more easily managed. At least until you have a situation, then it might more easily escalate to an emergency. Which is why doing drills often is a good thing, you move the exercise of those drills from the conscious part of your brain to the unconscious part.

I'm not particularly surprised that things improved for you by an ascent from 30m to 27m; I've had similar experiences. IME narc can hit suddenly, and it can go away quite suddenly by a moderate adjustment of the depth.

I've heard a guide just blow off any suggestion of narc at 29m, because "you don't get drunk shallower than 30m". Even though it was a clear case of molasses for brains, just as you describe it. That guide didn't understand that narc is a continuum, and that there are both personal differences and differences from day to day, from one set of conditions to the other.

 

[Kevrumbo]

The more dangerous condition is when you start to physically exert & breath harder at those depths (for example, kicking hard into an opposing current at 30m); this sets off the spiraling & vicious cycle of CO2 Retention/Hypercapnia /Hyperventilation, and a form of Narcosis due to CO2 which is much more acute than that caused by Nitrogen alone.

Exertion CO2 narcosis can come on either insidiously or suddenly, and is described as the panicky feeling "Dark Narc", as opposed to the euphoric experience of Nitrogen narcosis. Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . . In order to break this CO2 build-up cycle, you have to relax with a few minutes of full slow controlled inspiration-expiration breathing: --cease & desist all physical exertion that stimulates hyperventilation and abort the dive if necessary.

Taken from Undersea Biomedical Research, Vol 5, No. 4 December 1978 Hesser, Fagraeus, and Adolfson:"Studies on the narcotic action of various gases have shown that the ratio of narcotic or anesthetic potency of CO2 and N20 approximates 4:1, and that of N2O and N2 30:1. From these figures it can be calculated that CO2 has at least 120 times the narcotic potency of nitrogen. Our data would suggest that the narcotic potency of CO2 is even greater, i.e., several hundred times as great as that of nitrogen.

Originally Posted by TSandM
Overbreathing the regulator MEANS a CO2 hit . . . It means the increased work of breathing of using a regulator is enough, at the current demand, to prevent you from exhausting all your CO2. All regulators can deliver more gas, faster than you can use up oxygen, but the small increase in resistance involved in trigger the inlet valve and opening the exhaust valve can make the difference between being able to keep your CO2 normal under heavy work loads, and not being able to keep up.
Panic in the experienced diver?

Originally Posted by TSandM
CO2 in the bloodstream is completely determined by minute ventilation, assuming the gas you are breathing does not contain additional CO2. Bailing to open circuit definitely makes it POSSIBLE to reduce the blood CO2 level, assuming you can achieve a higher minute ventilation than what's required to keep the CO2 where it is (which is in part related to level of exertion). It may not, however, be possible to reduce CO2 fast enough to clear your head and get rid of the panicky feeling, in part because the natural tendency when panicky is to breathe as fast as possible. On scuba, this means reducing the efficiency of the ventilation, because too much of it is just going to exchange gas in the trachea and large bronchi, which don't exchange gas. That's why we are taught in OW that, if we begin to "overbreathe our regulator" (meaning the diver feels short of breath despite breathing as much as he can), we are to STOP, hang onto something (reduce exertion) and breathe SLOWLY and DEEPLY. It is then possible to reduce CO2. What may not be possible is to stay rational long enough to do it. Panic in the experienced diver?

 

[Bob DBF]

^^^what Kevrumbo said^^^

Only you don't have to be exerting yourself, all you have to do is change your breathing pattern, or have a pattern that does not clear enough CO2 at higher pressures. The first is easier, if your pattern changes because you are apprehensive at depth just work your way deeper over more dives as you address your apprehension. If that isn't the case, learn how to breathe deeper so you can clear the CO2, which may not show as a problem on shallower dives. So forget your SAC rate for the moment as a short dive is preferable to one where your are impaired.


I must admit that I am also obsessed with my buoyancy, air and other gear..., my attitude towards these functions has been one of my gauges of whether I stay at depth or head up, and I believe has kept me out of serious trouble over the years. It takes time to expand your ability to handle more tasks underwater even without the effects of CO2 and Narcosis, and as DevonDiver said "Dive within your comfort zone", the further you get away from it, the less chance you have to make it back. Babysteps are the trick.



Bob

 

[tbone1004]

so I think there are two factors going on. One is the narc, the other is something we observe in a lot of cave diving especially when people really haven't mastered the fundamentals. On a lot of dives for new cave divers, they are so focused on the diving that they forget why they are there. Trim, kicks, buoyancy, breathing, etc etc are all they are focused on and they aren't able to pay attention to what is going on.

You could be having a bit of both going on. Try getting into a swimming pool or other shallow area to practice. This exacerbates the buoyancy control because the pressure differentials are much larger the shallower you are. If you can do all of the skills in the shallow end of a pool in 3ft of water, then doing them in 30m of water is a cake walk. The point here is you need to get your skills to the point that they are truly second nature, otherwise you'll never be able to get where you want to go no matter how much of it is narcosis influenced.

 

[uncfnp]

Google stress, situational awareness and tunnel vision.