> I do assume many modern breathing practices stem from something like pranayama

Yes, I think this is almost certainly true with respect to Wim Hof (who I'm also a fan of)

arrivederci

Thanks for the link! Will definitely read some of these recommended books! Yeah, I have taken yoga briefly before and took a full class in community college so I've practiced certain forms of pranayama, just never dove into breathing from that angle. Although, I do assume many modern breathing practices stem from something like pranayama, and I'm sure the breathing techniques I practice are mentioned within the texts of pranayama. 

BTCFC

health

Optimal Breathing

A little suprised to find no mention of pranayama (प्राणायाम) here, which are yogic breathing practices.

[This page](https://www.prana-sutra.com/post/best-books-to-learn-pranayama) has 5 book recommendations for learning about pranayama and, on the basis of it having the book I've read and found insightful as the 2nd recommendation, I think it's probably a good list.