just had a quick look & came up with this article (
https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/coronavirus-recovery-breathing-exercises) that has lots of different ones that may be helpful for me. I have never read leaving your tongue on the roof of your mouth during breathing exercises, now humming on the exhale. Did you mean to strengthen my lung capacity?
It's funny though: the therapist in the video explains things well but when she
shows diaphragmatic breathing she's not moving her abdomen at all but rather her chest and shoulders, which is the opposite of what I have my patients do. You want to see/feel the hand on your abdomen move while the hand on your chest moves as little as possible. The humming creates more resistance for breathing out, which is kind of what a mask does as well. There are official gadgets out there you can breathe into to strengthen your muscles but you could also take a straw and try breathing out through that, maybe even into a tall glass of water. Or wear a tight, restrictive mask, now that we all have those. You want to practice breathing (out) against resistance while in a relaxed environment where you know you could just take off the mask or remove the straw at any time. When you do that for a couple of minutes every day it won't feel as restrictive once you really need it. If you practice with your "worst" mask you may even try doing some light activity (talking, singing, walking around, then maybe walking stairs or getting up and sitting back down) once you're used to breathing in it. On the bus you just have to sit quietly but you do have to get on the bus and they often have a couple of steps to get up. It really is a matter of practice and your diaphragm and intercostal muscles can build up just like any other muscles.
Also if you ever start hyperventilating from panicking in the mask, remember to completely exhale every inch of air. If you do that, you can't hyperventilate!
Completely exhale, and ideally do it somewhat slowly. That way it doesn't feel as restrictive and slowing down means you don't drop the CO2 levels in your blood so much (which is what triggers most of the unpleasant feelings that happen while hyperventilating).
Aaand... I should've read the second link as well before writing a novel here! Not removing it now though
I agree that most of the restricted feeling is psychological but with the N95 and firmer masks you do get some additional resistance. I wear my mask all shift long and if my ears don't hurt I'll forget to take it off during breaks. I even exercise in it with my patients. It doesn't make much of a difference now that I'm used to it
except when I'm genuinely out of breath. It does feel like it takes longer to recover then.