When I tried Wim Hof techniques it was extremely painful, which shouldn't be a symptom. After blood clot resolution (multiple PE), I did this yoga thing where I wrapped my elbows around a straight object like a broom handle and breathed. It was more comfortable and I still do that. It can be found in the Iyengar book which is probably my favorite yoga book. (It's a big heavy textbook type of book, and not very user friendly but it has great stuff in it). Thanks for pulling together all these methods in one place. Very helpful!