question to the void: does anyone know much about breathing practices/breath holds for stress/anxiety management? most of the techniques I know focus on breathing itself- breath rate control, nasal breathing as a mental point of focus, etc.

these are really helpful, as it's one of a couple of places you can hook into your autonomous nervous system

but freedivers put a lot of emphasis on stress/arousal control during a breath hold, and that seems really interesting as well.