A word of caution about him: I spent some time recently researching into his method, and there were too many red flags coming up.
These included not summiting and having to be evacuated in poor condition from mountains that he was claimed to have climbed (often the claims are not made by him directly, but also not contradicted by him). Having run a half-marathon distance while a full marathon is claimed. And acting evasive in interviews, while seemingly trying to hide it with excitement.
On the plus side he does hold documented world records in withstanding cold -- although his twin brother that has not trained is also reported to have higher than normal ability, but I didn't find details about it. He has also participated in a scientific study about his method, although the results of it are exaggerated by his followers.
The breathing method/trick itself is hyperventilation followed by long periods of holding the breath (a trick I suspect most kids will discover at some point). He claims that this somehow charges the body with oxygen and has various amazing health effects.
As far as I can tell (without medical training), the actual effect is to suppress the CO2 level in the blood. This disrupts the automatic breathing reflex which is driven by the blood CO2 levels, allowing you to hold your breath for extended periods. This is the same method used by free-divers, and many people have drowned after passing out due to lack of oxygen (including people specifically following the Wim Hof method).
I support skepticism about things like this, but I will say: Wim is not scamming people. He's showing them how to do something that works to lengthen his breath retention underwater and the regulation of his body heat. What he does is similar to pranayama, and dissimilar to hyperventilating in that he's pausing between the inhale and the exhale, a lot like the Navy SEALS.
Wim is not a great public speaker, and English is a second language to him, so what you see as evasion appears to me as a non-scientist trying to explain his experience in a language he hasn't mastered.
If you are going to claim that people have drowned by following his methods, you should link to it. Wim and his website are careful to say that this breathing technique should only be done in a safe place, sitting down. And if people go into ice water they should be supervised.
There is some scientific support, published in the Proceedings for the National Academy of Sciences (PNAS) for a breathing technique that can affect our autoimmune responses.
Briefly, sustained deep breathing mimics and breath retention stimulates the production of epinephrin/adrenalin and influences the autonomic nervous system.
When he came to the Bay, Andrew Huberman brought him into his neurobiology lab at Stanford to run some tests on him. Wim is doing something that deserves attention, and his breathing exercises can help change your mental and physical state. You don't take his word for, or mine. Just try it.
I did not say, nor do I think, that Wim Hof is scamming people. He appears genuine, although often evasive. And I do not think it has anything to do with English being his second language.
However, I do get a feeling that _someone_ is using him behind the scenes to make money, due to the false/exaggerated claims made about the results of his method and the related publications, and the method getting heavily commercialised and promoted.
As for the method itself, like I wrote before, it is nothing new. It is controlled hyperventilation (and cold showers). Like many kids, I discovered it when competing with friends in who could hold their breath the longest.
It has also been used by free-divers for a long time, and there is evidence that it may cause brain injury when done repeatedly (in addition to blacking out and drowning). Which is why I would not recommend anyone to "just try it".
Too many red flags for me personally, and I just wanted to share that since the topic came up.
Fair enough. Wim Hof and his organization have warnings on every single page of their tutorials telling people not to do the exercises in a swimming pool, like the guy did who died. Below is a screenshot of them. Saying that people die following his method, when they do the exact opposite of what he says, is inaccurate. Nobody should try it near water, or driving, or anywhere but sitting in a meditative position.
Wim's marketing is crap, and frankly, he's not making a lot of money off of this. No one is.
The method may not be new, but many old things are not known or popularized. Kids may discover it, but we are still learning about the effects of this technique on the body.
