Are you referring to the hyperventilation technique? I ended up at one of his workshops randomly and tried that. It’s actually an old technique to increase the

Are you referring to the hyperventilation technique? I ended up at one of his workshops randomly and tried that. It’s actually an old technique to increase the ability to hold the breath. The hyperventilation clears carbon dioxide from the system (hypocapnia). That’s what the buzz is. Never ever ever ever ever do this underwater or you have a serious risk of death: https://en.wikipedia.org/wiki/Freediving_blackout#Shallow_water_blackout https://en.wikipedia.org/wiki/Freediving_blackout#Shallow_wa... Hof did not warn of this at the time, though I believe he does now after someone died using the technique while swimming. As for the cold resistance, Hof’s twin brother Andre displayed the same physiological traits that Hof has, despite not having undergone the same training: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0101653 https://journals.plos.org/plosone/article?id=10.1371/journal... The one interesting thing I have seen related to Hof is that he apparently was able to suppress the immune response to an endotoxin. Though it would be interesting to see that same study done on his twin. This is a reasonably good article: https://www.pepijnvanerp.nl/2016/01/wim-hof-method/#andre https://www.pepijnvanerp.nl/2016/01/wim-hof-method/#andre I think Hof is well intentioned, sincere, a poor communicator, and prone to both mystical thinking but also interested in scientific verification.