North Gas, South Gas.
The reality is, it’s coming out somewhere.
The north side
Most of our dive related gas exchange happens from the north end… our mouth.
It doesn’t happen all the time, but it can build up over time. After a particularly long dive, or repetative deep dives nitrogen has already invaded the lining of your stomach. Depending on how quickly you come up from one stage of your dive to the next, those bubbles could count out in your lungs, where we expect, or your stomach, where you will naturally burp them off.
What’s in a squeeze
All divers are familiar with the squeeze. We equalize our ears the instant we start to descend, and most of us let a little air out of our nose to prevent the mask from getting too tight. The opposite of this is also possible.
A reverse squeeze (that’s what it’s called when you’re on the way our of your dive [decreasing pressure outside compared to the higher pressure inside]) in your tooth, for example, sucks, and is fairly rare. But what happens when it’s another air space?
Well, depending on how deep you are, they’re just that… tiny. The problem is what happens on your way up. As the ambient pressure decreases the air spaces inside our bodies start to let bubbles out. If they’re in your sinuses it happens automatically: very few of us have to equalize on the way out of a dive.
The south side
To start off with some science, your digestive system (aka butthole) can withstand about 1% of one atmosphere of pressure, or 0.147 psi. After that, you can’t keep the within from coming out. So what happens at depth when that “south of the border” meal starts to bubble up and creat tiny flavor crystals of air in your colon?
Well, the reality is, you’re probably safe. The moment that intestinal SMB feels like it needs to blast off you’ll be in an environment where both no one else will notice and no one else will care. There’s already lots of bubbles to provide your flatulary camouflage, and only the fish have an olfactory sense of your offense!
At 0.147psi the butt-rocket you re building up may not even become a thing until the pressure on the outside is less of an issue. BUT, if your tummy starts to hurt on the way up and out of a dive, remember the golden rule: stop, change your depth (up or down, depending on your direction of travel), wait for the symptoms to subside (or let one off the chain), and continue on your way!
In other words, cut and run! Let that beautiful beast bubble forth and enjoy your abdominal pain-free dive.
The reality is…
Gas happens. Up or down it’s going to be a thing in your life you have to contend with. If you’re a bubble chaser like me, then at some point you’re going to have to contend with off gassing, both up and down.
Get used to it!
There’s more
I’ve got more to say on this subject, but it’s not really scuba relevant. Click here to check it out!
