I briefly got into breath holding. It's impressive how long you can go with simple techniques; slow stretches with lungs full of air, packing, and iterating animal names.

But I started to question the brain damage and couldn't find good science to confirm it either way.

Did you ever try wearing a pulseox and seeing what your sat looked like? As long as sats aren't ever dipping below (NOT medical advice, but I'm being conservative here), say, 90%, brain damage is very remote. Plenty of COPD patients walking around with sats in the 80s, or even 70s.

But as someone with bad lungs...yeah, you only get one set and most meds/treatments are partial symptom relief at best.

Hey, I happened to try this recently when I was holding my breath for another reason! It hit 70% or a little lower by the end*, but that was after having exhaled for a while. I do wonder what effect that kind of thing can have, even minor.

* sensor accuracy not guaranteed

Were you engaging in a highly scientific study of the deco song whip it?

Close! Avoiding wildfire smoke.

Not the OP but I used to do breathe hold training for surfing and bought a pulse oximeter. I don’t think I ever got below 90%.

What do you mean by “iterating animal names”?

I read an article years ago on this. It was interesting. There'a a big psychological component to holding your breath. If I remember correctly, you go through the alphabet and think of an animal that corresponds to each letter. You can also try to think of a person you know for each letter. It's to help you stay calm and focused. The fear and accompanying response will have you out of the water fast. I suspect it's also dangerous. If you start freaking out underwater you're in trouble. I tried applying it while doing Wim Hoff exercises and it helped a lot.

Again I read this in an article. I'm just some guy on the internet. Please don't try without investigating how it's actually done and about any associated dangers.

I assume a mental strategy to distract yourself from the pain