CO2 Retention

[Darnold9999]

I find that a combination of things will get me. Weight belt or BCD too tight making it easier to take shallow breaths is often the start for me. You don't even notice that your breathing is very shallow. Then some other factor intrudes, chasing to get in front of something for a picture, chasing a buddy, overstress in current and all of a sudden you are in trouble. Focusing on a full breath fixes the problem pretty quickly, but until I figured out what was the underlying cause it was most disconcerting.

 

[TSandM]

The two places where CO2 has caught up with me is where I've been trying to do too much buoyancy control with my breathing, and where I've overexerted. I've taken a couple of very unpleasant CO2 hits in the Devil's system, swimming against flow, and what worries me the most is that I did not feel particularly short of breath or anxious at the time. I just had a horrible headache and nausea afterwards. I suspect I'm one of those people who adapts to CO2 quickly, and that's not necessarily a good thing in a diver.

 

[BlueC5Kitten]

Thanks for the insight here. On a recent river dive with about 8 others, one of the newer divers came out of the water and instantly felt nauseous. She was blaming her intake of sugar that morning, but perhaps it was her exertion against the current?

During our qualification dives, one of the group ended up with bad headaches afterward, dismissing them, citing he suffers migraines often. I do too, however, I am pretty sure that a CO2 headache is distinguishable from migraine headaches. My DM stated it was most likely that my classmate wasn't breathing properly. Thoughts?

 

[String]

CO2 headaches for me often appeared when i got onto my stop and as well as a terrible headache made me nauseous and quite often i was physically sick on the stop or getting back onto the boat. Tablets never seemed to help get rid of it and only a few hours of doing nothing helped.
Different from what i'm led to believe migraines are like.

It is very common amongst new divers who haven't got their buoyancy correct, maybe overweighted and therefore are exerting themselves a lot combined with not having adopted a proper breathing pattern yet.

I've seen a lot of it on try dives too.

Coming out of the water and feeling instantly sick if combined with a nasty headache i'd say is definite sign of CO2.

 

[TSandM]

It may be quite difficult to distinguish a CO2 headache from a "migraine", particularly if the word "migraine" is being applied to chronically recurring headache that does not fit the definition of classic migraine.

Some migraine sufferers have a clear syndrome of prodrome/aura, specific localization of the headache, photophobia and nausea, and response to certain medications that would render the headache fairly recognizable. Many other people report "migraines", when they are having tension or nonspecific headaches. These would be difficult to distinguish reliably from CO2 intoxication, although a pattern of headache post-diving might suggest CO2 problems.

I think a LOT of new divers get CO2 headaches, because they haven't developed an effective breathing pattern underwater, and their buoyancy tends to be erratic.

 

[mania]

CO2 retension is more of a problem with a snorkle than in Scuba, because of the much larger air space in the snorkle. (...)Full exhales ensure that depleted air is fully exhausted. Otherwise maintaining a natural breathing does the trick.

Trying to be nice I would simply suggest you go back to you OWD class and again read the materials carefully.
Mania

 

[dkatchalov]

Thanks everyone for the replies. Some excellent insights.

 

[Thalassamania]

... I suspect I'm one of those people who adapts to CO2 quickly, and that's not necessarily a good thing in a diver.

You and me both, that's why I consciously make an effort to keep my SAC rate up.

 

[scubaren]

Last year I dove with someone much younger than me. He has been diving practically his whole life, I've been diving about 3 years. We got into a very slight current towards the end of the dive. I could not keep up with him and then I started feeling starved for air. I tugged his fin and signaled for him to stop. He didn't realize what was happening to me. I couldn't catch my breath and wanted to bolt so bad but I didn't. I just hung out and slowed my breathing. I just started to catch my breath when he took off again. This time I GRABBED his fin and signaled STOP. I just hung out probably for less than a minute or so. Then we finished the dive without further incident. Upon surfacing he told me that I need to get in shape. While I am a bit overweight I get exercise up and down stairs at work. I also run at least once a week but not very fast. It takes me about 30 minutes to do a 5K. I have decided that I just need to dive with someone who is as much of a slug as I am.

 

[Seadeuce]

A few comments and tips based on this thread:

If someone has a migraine with aura, go have themselves checked out for a PFO (Patent Foramen Ovale), otherwise known as an Atrial Shunt. You may be able to kill two birds with one stone.

When kitting up on a boat before a dive it is better to put on your weightbelt so that it is just tight enough to remain on your midriff.
If you make your descent horizontally, i.e. skydive, you then can readjust your weightbelt on the way down.
This will allow you to breathe easier - less stress - and be in control of your dive.

If you find yourself overbreathing, i.e. beating your reg, through exertion or finning against a current, do the following:
LIGHTLY press on the purge button of your reg. This will allow you to breathe without having to overcome any resistance.
You will find your breathing rhythm will return to normal quite quickly, with less effort.
You may lose a few extra bubbles, but you will avoid the vicious circle that is CO2/rapid breathing/more CO2/more rapid breathing, etc.

I post this for those divers who are maybe new to the sport, or indeed some who, though experienced, have not yet found the least stressful way of diving.



Seadeuce