Zept once bubbled...
How do you tell the difference? I've read several comments like this, but I have no idea whether I'm holding my breath with my diaphragm or my throat (note: I am trying this at my desk, not in the water).
Z
Your glottis is at the back of your mouth, where you swallow. You can close it off against your soft palate so no air can pass through and then you can have big problems.
Try this. Take a deep breath and "hold" it, meaning keeping your lungs and diaphragm expanded. Now try puffing small amounts of air in/out with slight movements of your diaphragm. If you can, your glottis is open, if you can't, it's closed. If closed, you'll feel your diaphragm moving and you'll also feel right where the air is pressing in your throat at the very back of your mouth near the soft palate. You'll figure it out in about 1 and a half seconds, tops.
Keeping your glottis open means that your lungs and airway are "open" and if you rise a little bit when diving and keeping your lungs expanded, the expanding gas in your lungs will simply blow right through your second stage out the exhaust ports. It's pretty easy for you to get to feel this closed glottis condition. When you do,
don't ever do it underwater because then, if you rise a little bit, the expanding gas in your lungs won't go out the exhaust port on your second stage, it will blow right through your lungs into your chest cavity, and that will ruin your
whole damn day, guaranteed. As you say, practicing at your desk is better than practicing when diving
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Roakey, Pugg, et all, what a great thread! Enough here to keep anyone busy practicing for a while. Preesh!