Yes, sorta. Just like boxers train themselves not to flinch when punched, you can teach yourself to tolerate cold better. As to boosting your immune system an

Yes, sorta. Just like boxers train themselves not to flinch when punched, you can teach yourself to tolerate cold better. As to boosting your immune system and the other claims, no one can prove that at home and is probably due to other changes in their personal lives. But I will say I did the Wim Hot method for 1000 days straight, and considering the cost of admission (free), my resistance to cold increased. I am that weirdo that walks around barefooted in the winter anyways, and it just allowed me to go a bit longer in colder conditions. I used to teach people to survive extreme situations, and only used the WHM to teach them how to endure cold a bit better, but some people are just wired to be able to do so or not. It is no magic bullet.