I disagree. The research on Wim Hof is only known what it will do to healthy individuals for about a day. While the long-term effects can be speculated about that is all it is from a scientific standpoint. I myself am quite strict about it since there's a lot of danger to go too occult on his method which in my experience is not helpful (I believed in a lot of occult stuff as a kid, got me in trouble a lot since the predictions were not always accurate). Of course, feel free to use the technique. I don't think the technique is harmful -- but also that has not been tested well enough, but one can infer from similar responses w.r.t. exercise. I do and it seems to help when I have a headache as a pain killer. But I use it mostly to feel happy regardless the weather and to feel like a boss and a caveman (under a cold shower), kind of like a drug five minutes per day :)

"If these researchers got more concrete about how patients can learn to do this"

Maybe I'm misinterpreting this, are you talking about the WHM, you can learn his method (next paragraph is an affiliate + Skype offer from my side). If you're talking about the researchers of the article, it's just classical conditioning. The procedure is very well known.

About learning WHM, like I said: can learn his method. He has an online course. You can find it here http://dealguardian.net/product/831/?hop=00melo00&trackingID... I have to disclaim it is an affiliate link. I've been teaching the WHM to my friends as a birthday gift and one of them told me I should make money from it. His (paraphrased) words were: "you were in his most important experiment and trained with him for 4 days that shows that you can learn this stuff. You have credibility from that." If HNers are interested in the course let me know. I'm making 20% ($40) for each sale and I'm willing to provide 30 to 60 minutes of Skype support (depends on my schedule / study).

The reason I signed up to be an affiliate is because I believe in his method. I didn't do the online course myself, I only know some capable video/web-dev guys edited it with him. I'll also be the first to say that you should take a real course, because in my experience you can get a lot more out of it when someone is physically present. Especially in The Netherlands, there are quite a few trainers who learned his method.

When I trained with him in the experiment I passed out a couple of times, so I was happy that someone was physically present (especially the doctors from The Radboud University with oxygen tanks if things got really bad, it never did fortunately). While this may sound dangerous, remember that we needed to train as hard as we could and there were no real medical risks IMO (note: I'm not a health professional, I'm a CS and graduated psy. student).

On another note, I read half of this article and while I want to know more about it, the WHM is not like this at all. I know that no one said this but I want to make it clear, because I'm noticing some people might read into it like that. What Wim Hof does is not classical conditioning, what he basically teaches is how to produce a stress response that suppresses the immune system indirectly (and give adrenaline and make you feel like a caveman ;) ). He formulates it perhaps a bit differently though but I always listened to the doctors during the experiment when we were talking about physiology.

If you want to know more about the WHM check out my stack exchange answer about it. It's the answer I would've wanted to read before I did his experiment. http://cogsci.stackexchange.com/questions/10651/does-wim-hof...

I hope this helped.