Too shallow to get narced?

[freeflowigb]

Hi there.

So today I was doing my first wreck dive. I loved it immensely and I am going to pursue that further - found it much more exciting than observing reef fish.

One thing that took me by surprise today is the following. As I approached the bottom of the wreck which sits at around 80 feet I suddenly felt lightheaded and weird. There was no fear of depth, as I looked up and saw no surface, but my actions were uncoordinated and in retrospect a bit chaotic - I would approach the same window multiple times, then drop to the bottom and start digging in the sand. Then turn on and off my camera, lose my GoPro and forget to look for it, etc.

My breathing was also getting rapid and shallow, so once I hit 100 bar I signalled to the guide and we began to turn back.

Is it possible I could get narced that shallow? What was that in your opinion. I was perfectly normal as soon as I got to about 65 feet.

For what it’s worth I was diving on regular air.

Attaching some photos just to share my excitement

 

[Marie13]

Yes, it’s possible.

 

[MaxBottomtime]

The rapid and shallow breathing would indicate CO2 narcosis from overworking. Perhaps you had to kick to go down or were fumbling with your camera. If that was the case, a couple of deep, slow breaths would have cleared your head at 80 feet.

 

[freeflowigb]

The rapid and shallow breathing would indicate CO2 narcosis from overworking. Perhaps you had to kick to go down or were fumbling with your camera. If that was the case, a couple of deep, slow breaths would have cleared your head at 80 feet.

There was about 1 knot of a current down there, but it went with us, so I was not really moving much. And my camera is just a little Olympus tough 6 without a housing (surprisingly it worked at that depth), so I am not really sure about that. But thanks for the idea, CO2 narcosis sounds like an option. And apparently way more dangerous than nitrogen narcosis.

 

[BoltSnap]

Apprehension, anxiety, fear, excitement, anticipation, etc.

 

[freeflowigb]

Apprehension, anxiety, fear, excitement, anticipation, etc.

I’d hate to admit I was scared of this little wreck - I don’t know if I was, as I don’t remember much from that point - but that sounds reasonable.

 

[Lorenzoid]

What you felt could have been some combination of the narcotic effect of the breathing gas (see Meyer-Overton Hypothesis) and the narcotic effect of not ventilating your CO2 sufficiently. It's often difficult to tell. No matter what your depth, try to reduce your exertion and breathe fully so as to minimize the effects of CO2. Keep in mind that gas density increases with depth, so you are likely to work harder just to breathe, maybe even as relatively shallow as 80 feet. Our bodies behave differently as individuals. At 80 feet, I would often feel a little "off," despite concentrating on proper breathing technique and trying to minimize my exertion.

 

[freeflowigb]

What you felt could have been some combination of the narcotic effect of the breathing gas (see Meyer-Overton Hypothesis) and the narcotic effect of not ventilating your CO2 sufficiently. It's often difficult to tell. No matter what your depth, try to reduce your exertion and breathe fully so as to minimize the effects of CO2. Keep in mind that gas density increases with depth, so you are likely to work harder just to breathe, maybe even as relatively shallow as 80 feet. Our bodies behave differently as individuals. At 80 feet, I would often feel a little "off," despite concentrating on proper breathing technique and trying to minimize my exertion.

Thanks for the advice. My reg has this rotating thing that controls the ease of breathing and I do keep it on the harder level to reduce the risk of a free flow, so yeah - breathing took a bit of an effort.

 

[BoltSnap]

I do keep it on the harder level to reduce the risk of a free flow, so yeah - breathing took a bit of an effort.

That isn't proper, you shouldn't have to exert any effort to get air out of your regulator. Turn the knob all the way out and enjoy this feature. It is meant that you breathe from the regulator when the knob is in the easiest breathing setting, all the way out. If the second stage leaks air when the knob is all the way out, then it isn't adjusted properly and needs service. The knob should be set by the technician at at the edge of leaking air but doesn't leak air when open all the way out. You can turn it in just enough to stop any air leak but only just enough to stop the leak should it leak air when it is in your mouth (this also means that it needs service/tuning by a trained technician). You turn it all the way in if you are on the surface and the second stage is out of your mouth, using snorkel for example, to prevent free-flow but all the way out if you are breathing from the second stage. Exception will be when you are swimming against current where the current is causing pressure on the SS diaphragm making the second stage leak air (I never had to do this before myself).


At the end, your turning the knob to make it harder to breathe from the second stage may very well be the reason you were struggling and going through what you went through especially if you know and felt you had to exert an effort to breathe from the SS.

 

[Edward3c]

Research was done in the 1990s on the effects on N2, particularly when it starts to impair behaviour. The finding suggested some people were susceptible from an little as 15m (45ft).