I suspect you’re missing something important- not surprising since Wim is a really unclear teacher. The low oxygen and/or high co2 causes your body to panic and you are supposed to use that as a stimulus to gradually train conscious control of your heart rate and stress response and calm yourself down. This is where the benefit comes from, not the short term physiological panic itself, whose symptoms you are describing. In fact, those symptoms should go away entirely when you learn to calm the panic and consciously control your autonomic nervous system. This then also primes you mentally to be able to go into ice water, which is also a large stimulus to learn to calm, plus trains your brain to more easily jump into anything difficult. All of this takes months or years of consistent practice to gradually develop a relatively permanent sense of calm and internal strength among other things, and is really just a simplified form of tantric tummo meditation.
I'm not sure. I figured out most of that from taking Wims online class, and through years of personal practice and experimentation. I found that I was able to pick up a lot more by watching Wims body language and actions in videos, that he never directly explains, but I am not sure everyone could pick those up.
Ultimately, Wim's stuff is mostly based on tummo and other Vajrayana/Tantra yoga practices, and you can find both books and in person teaching locally in most places that cover these things. Wim never even explicitly mentions this, but effectively what he is is a yoga master that has developed yet another new system of yoga. Before the 'Ice Man' stuff he had even developed and written about other yoga innovations he had come up with.
Another thing worth mentioning is that while Wim is truly a master at his own method, he tries to rationalize everything with a scientific backing, but he has absolutely zero understanding of what he is talking about, and it's all nonsense. I have a biomedical background, and have developed some of my own theories about how his stuff is actually working physiologically and psychologically, plus there is some academic research out there you can read both on his methods and Tummo itself- but ignore everything he says about that, he doesn't even understand the basics.
Also, ignore everything he says about putting breath pressure up in your head/ears- absolutely never do that, as it can cause tinnitus, and the methods work fine without it.
