Wouter van Marken Lichtenbelt writes this about Wim Hof:
There is, however, a string attached to the Wim Hof Method, that is the risk that people may think the method is scientifically valid. Wim is a wholehearted speaker, but his scientific vocabulary is galimatias. With conviction, he mixes in a non-sensical way scientific terms as irrefutable evidence. Many less scientifically literate people believe what he says and several seriously diseased people have used his method as the final straw. Stories of believers circulate on the Internet, in popular magazines and are broadcasted as well. The scientific investigations are often presented with a biased view.
When practicing the Wim Hof Method with a good dose of common sense (for instance, not hyperventilating before submerging in water) and without excessive expectations: it doesn't hurt to try. Although the effects on our health wait to be proven, people may feel healthier.
When you're a Cat, You're a Cat all the way From your first catnip mouse To your ninth dyin' day.