I honestly don't know if the book targets a broad audience or not but everything it has claimed so far seems to be factual from my own quick searches. It's really opened my eyes to breathing techniques and how effective they are. With the techniques helping with autoimmune diseases and more, I can only hope it'll help with the stutter as it helps with the mind and organs. I can't really explain it too well from memory tbh but the book is a good read and I do recommend it. It doesn't talk just about Wim Hof but others too and other studies, even the author went through a study themselves with a team behind it. I know people here practice breathing techniques and meditation but I was hoping someone would have tried any of these specific techniques which seem to be most effective at everything else the body seems to struggle with.