CO2 retention, Overexertion, and Panic

[northernone]

Thanks all for the responses so far. I’m slightly intrigued by the science and mechanism of CO2 retention and panic now. Nitrogen narcosis is often talked about in cert classes but not CO2.

Yes, I have access to lots of those easy sites thankfully. I know I need to get “back on the horse” sooner rather than later, but ease back in.

For further reading the terms Hypercapnia and/or "dark narced" probably would be interesting.

Careful "full" breaths help me, both flushing out the bottom of my lungs (increasing tidal volume of my breaths) and to mentally calm (similar to helping with on land panic).

It's unfortunately easy to get co2 buildup and start feeling crazy/panicky. My brain goes irrational. Just takes a 2 minute breath hold at moderate depth to start wondering/feeling/frightened if a sea monster is behind me, my equipment is defective or I'm having a medical emergency. Horrible things mentally, all imaginary.

(Not a recommended test... I use it to see how co2 buildup effects me. Symptoms and severity varies against my own subjective baseline).

Never had a land based panic/anxiety and I'm a calm person (former first responder)... underwater "dark narced", my brain goes crazy with fears I didn't know anywhere else. It's remarkable.

Thanks for the post, it's something sometimes that isn't talked about much I think in training.

Also, glad you're planning to "get back on the horse" soon enough.

 

[PoolsOpen]

Thank you for sharing this episode.

With terms such as “out of breath and shortness of breath” it sounds more like hyperventilating due to overexertion. Hyperventilating would cause blowing off excess CO2 not retaining it. As a 1st responder this is a common occurrence and also very real. Some symptoms are feeling of doom, feeling of pins and needles in hands and lips, and cramping of the hands. To the bystanders it sometimes looks like they're having a stroke. Since you were diving and using a regulator my guess is that you overbreathed the regulator which in turn started the hyperventilation episode. I don't think by breathing fast in open circuit SCUBA you retained CO2. This is just an opinion, there are real doctors on this board that can probably contribute a more informed opinion.

I agree with the other comments that taking deep breaths and slowing down will help.
Good luck and see you underwater soon...

 

[Dish]

@Lopez116 back in the 70’s when I was getting certified, the instructor tasked us to swim in SCUBA back and forth in the pool as hard as we could swim. This was a 50 meter pool, so 100 meters swimming hard. I believe that the intent was to demonstrate that swimming hard was a bad idea. Which we all learned. Whether it was hypercapnia or hyperventilating, was not discussed. I just learned that you probably shouldn’t do that. That said, deep, slow breathing should mitigate both hypercapnia or hyperventilating symptoms. I have noticed dark narc symptoms on occasion, and that has always helped.

I applaud you for keeping your wits about you. Probably saved your own life.

 

[Lopez116]

Thank you for sharing this episode.

With terms such as “out of breath and shortness of breath” it sounds more like hyperventilating due to overexertion. Hyperventilating would cause blowing off excess CO2 not retaining it. As a 1st responder this is a common occurrence and also very real. Some symptoms are feeling of doom, feeling of pins and needles in hands and lips, and cramping of the hands. To the bystanders it sometimes looks like they're having a stroke. Since you were diving and using a regulator my guess is that you overbreathed the regulator which in turn started the hyperventilation episode. I don't think by breathing fast in open circuit SCUBA you retained CO2. This is just an opinion, there are real doctors on this board that can probably contribute a more informed opinion.

I agree with the other comments that taking deep breaths and slowing down will help.
Good luck and see you underwater soon...

It’s somewhat reassuring to know that even an IDC instructor gets those feelings - even if purposely induced.

 

[Lopez116]

Thank you for sharing this episode.

With terms such as “out of breath and shortness of breath” it sounds more like hyperventilating due to overexertion. Hyperventilating would cause blowing off excess CO2 not retaining it. As a 1st responder this is a common occurrence and also very real. Some symptoms are feeling of doom, feeling of pins and needles in hands and lips, and cramping of the hands. To the bystanders it sometimes looks like they're having a stroke. Since you were diving and using a regulator my guess is that you overbreathed the regulator which in turn started the hyperventilation episode. I don't think by breathing fast in open circuit SCUBA you retained CO2. This is just an opinion, there are real doctors on this board that can probably contribute a more informed opinion.

I agree with the other comments that taking deep breaths and slowing down will help.
Good luck and see you underwater soon...

Yes, I had the pins and needles feeling running down my arms and hands, I felt hot flashes, and of course, the racing/irrational thoughts. Maybe it was hyperventilation.

That brings up another question I had - I thought it was not possible to “overbreathe” a modern regulator (I was diving with an Aqualung Legend).

 

[Lopez116]

I found this post reply by the late TS&M and I think it’s apropos. Apparently, hyperventilating does cause a retention of CO2?

The term "overbreathing your regulator" is supposed to refer to reaching a respiratory rate that the regulator simply can't provide. In practice, this is all but impossible. What DOES happen is that, as a result of overexertion or anxiety, the diver raises his respiratory rate. Given that regulators -- even the best ones -- increase work of breathing, as the diver reaches a less efficient ventilatory pattern, CO2 climbs. The diver feels anxious and short of breath because the increased CO2 causes an increased ventilatory drive. The obvious conclusion is that the regulator isn't delivering enough air, when in fact, it's delivering everything that is asked for.

Heavy exertion is always something to be avoided on scuba. If you ever get the feeling that you just aren't getting enough air, STOP and rest. If that means grabbing a rock to stabilize yourself, do it. High CO2 heightens narcosis, causes anxiety, and predisposes to panic. Stopping, breathing quietly, and thinking can prevent accidents.

 

[doctormike]

I don't think by breathing fast in open circuit SCUBA you retained CO2. This is just an opinion, there are real doctors on this board that can probably contribute a more informed opinion..

I'm not a hyperbaric doc, or even a GP, I just dig out earwax for a living. But I can tell you that hyperventilation can cause hypercapnea. It seems illogical, because CO2 buildup comes from underventilation, but breathing fast usually means smaller tidal volumes, which means more dead space ventilation. That is, you are using a lot of effort to move gas in and out of your trachea and larger airways, but no gas exchange takes place there (so not very efficient CO2 offloading).

Hypercapnea can also result from overproduction of CO2, which correlates with physical work, so taking it easy can help with both the inefficient offloading and the excessive production.

Mr. Chatterton explains it a lot better than I can...

 

[Divingblueberry]

Thanks for sharing this.

I got myself in the same kind of situation during my trip to Cozumel (my only one actually).

It was my 5th dive ever (I think) and, being a newbie and wanting to improve my air consumption, I tried to breathe like I was sipping the air through a straw (inhale and exhale)

After probably 15 to 20 minutes into the dive, we were in a swim-through (probably 35 to 40 feet long) and I was the last one of the 4 divers.I suddenly started to get serious dizzy spells and feeling "off". I really didn't know what was happening since it started really suddenly. Then I felt my heart starting to pound and things weren't getting better with the "confusion". The diver in front of me was swimming away and I had no way of letting her know what was happening. I was in that passage and I felt very stuck. I clearly remember feeling the panic setting in and the urge that you are talking about to spit out the reg.

Through this confused mind of mine, I remembered what I read here : stop, breathe, think. So I looked at my gauges and focused on the fact that I had lots of air. That was my only though, and I repeated it like a mentra, "I have plenty of air". That calmed me down a lot and I started taking many deep breaths and the dizzy spells and confusion quite rapidly went away. It was followed by a very painful headache and I aborted the dive.

Reading your post reminded me of that crazy feeling and how quickly it can take over.

Thanks again for sharing

 

[happy-diver]

Hey!

So you go for a walk around the house breathing only through your nose

you will conk out sooner than if you were breathing through your mouth.

The resistance breathing through a regulator falls somewhere in between


When you've had enough house walking there is the option to stop

In current you no can stop so your increasing respiration continues


So you hug a rock and pray, unlike when you come off a surfboard

hopefully with no rocks


and the moral simply is don't do currents and always carry a rock

and maybe a ship to hold on to too

 

[helodriver87]

Sounds like a CO2 narc from overexertion/hyperventilation. I had one in Ginnie once just after getting cave certified. It was back near the keyhole. Fairly close to the entrance in the grand scheme of things, not nearly close enough when something like this happens. It happened the exact same way too. I had a more experienced buddy who was moving pretty quickly, but I hadn't quite figured out how to avoid the flow, so I was working my ass off to keep up. I got the exact same sensation you wrote about. Feeling like you can't get enough to breathe, desperately wanting the reg out of your mouth, etc... I felt that same sense of panic and doom set in. If I'd been in open water, I would've immediately headed for the surface. It was that bad. I was pretty close to full on panic. Not exactly proud to admit that, but it happened. But I remembered reading something about CO2 narc and overexertion at depth, specifically in the cave environment. The only thing you can do is stop moving and focus completely on restoring a normal breathing pattern. So I signaled my buddy and gave him the stop signal. In reality, we only sat there for about 2 minutes (I checked the dive log). In my head, it felt like about 20. It took pretty much all of my willpower to convince my brain that I wasn't dying and I needed to calm down. Once it cleared up, I thumbed the dive. We talked about it on the surface, figured out what had happened, waited for my killer headache to clear up a bit, and I took the lead on the next dive to set pacing and avoid overexertion. Since then, I've learned to monitor my workload much closer and maintain a pace that isn't strenuous. A bit of helium doesn't hurt either. It shook me up for a bit, but I found that going back after a couple weeks and doing a few dives focused purely on pacing and monitoring effort level did a lot to rebuild my confidence.