In this TEDxAmsterdam presentation, Wim Hof introduces his philosophy that nature is a teacher and that humans can gain control over their immune, nervous, and cardiovascular systems through specific breathing and cold‑exposure practices. He recounts his personal journey from childhood cold exposure to developing a method that claims to suppress inflammation via breath work. Professor Hopman then presents data from an 80‑minute ice immersion experiment conducted in Nijmegen, showing that Hof’s core body temperature remains virtually unchanged (37.7 °C → 37.4 °C) while skin temperatures drop to 5‑10 °C, heart rate and blood pressure rise only minimally, and metabolic rate doubles. Three possible mechanisms are discussed: (1) tummo‑like meditation‑generated heat, (2) long‑term training of autonomic control, and (3) potential genetic advantages. The audience engages in a light‑hearted Q&A where Hof explains that his mission is to demonstrate that every person can access an “inner doctor” – a self‑healing capacity often forgotten in modern medicine – by mastering breath and cold exposure. The talk blends scientific data, personal testimony, and a call for reconnection with nature.
Chapters
It's an honor to be here. Thank you for looking at me. Right here we got a box and I can do stuff like almost 2 hours stand in direct contact with the ice. But I learned it in hard nature. Hard nature is merciless but righteous. And he taught me to do things with my immune system, nervous system, the cardiovascular system, and my mind beyond my thinking, beyond belief. And it was tested by Professor Hopman, it was tested in New York, it was tested in Finland physiologically, with the immune system. All kinds of things came out because I exposed myself to the extreme, naturally, in hard nature. It's my teacher. He taught me, and I think we still got to learn a lot from nature because we are not in balance with nature anymore. It's gone. But for that, we are here. For that, you are there. And I'm going to do my utmost best to convey a message which I got since I was investigated by a blood research wherein I could suppress by thinking and respiratory exercises which I learned at HeartNature, suppress the inflammatory marks in my blood. So we can have power over the body by our mind, but for that we have to go back to be in balance with nature. Nature is our teacher. And I will try and share with you. Now Professor Hartmann is coming. She's going to explain data. Thank you.
Wim Hof. Thank you. Well, the big question, of course, here is, how is it possible for a human being to be exposed in an ice bath for 1 hour and 44 minutes? Well, in order to answer that question, we had to do an experiment, because there's no physiology textbook that tells you what happens to a human being in ice. And I'll show you a little bit of the atmosphere of the experiment in Nijmegen. You can see here, Wim came to Nijmegen and we exposed him for 80 minutes in ice, like it's now happening here. Okay, the big question that we all face in these days too with the cold weather is how to keep ourselves warm. Because our human body wants to stay at a core temperature of 37 degrees. In order to measure Wim Hof's core temperature, he swallowed a pill, the pill you see here, and that pill travels through his stomach and sits in his splenic area. And in that way, we can precisely measure his core body temperature. And what we expect when he's staying in the ice like this for 1 hour, 1.5 hours, that his core body temperature drops. And we know when it drops 10 degrees, up to 27 degrees, a person dies. But already under 35 degrees, we talk about hypothermia, and you really shiver and feel very badly. So the big question is, what happens to his core body temperature when he's standing in this ice? Well, that was the first big surprise. I show you the result here of the core body temperature. The blue shade is the area when he is 80 minutes in the ice, exactly like he's in the ice here in a few minutes. And what you see is that the core body temperature drops hardly. It goes from 37.7 to 37.4. Absolutely not important. So maybe there's a little layer of air between the ice and the skin which gives him a bit of isolation. But we measured a lot of skin temperatures too, and that's shown in this slide. And what you see here is many different skin temperatures. They're all around 30 degrees, which is very normal. And what you see is when he's in the ice, most of them drop to 5, to 10 degrees, and that's very, very cold. So there's no isolation from an air layer. His shell is very, very cold, gets extremely cold, whereas his core stays warm, and that's very exceptional. And here you see two temperatures that are— this is his head, and this is high up his shoulder. That were the areas that were above the ice. Another remarkable finding is that when we go in the ice or when we take a cold shower, your heart rate and blood pressure goes up tremendously. This is what happens when you go in a cold shower. Your heart rate goes up tremendously. And this is what happened with Wim. His heart rate and blood pressure hardly increased, only at the end of the experiment, so only after 45 minutes to an hour. One other remarkable finding that I would like to share with you is that he increases his metabolism. He can heat up his body by doubling his metabolism. During the whole procedure, while he was in the ice for 80 minutes, his energy expenditure was twice as high, and with that he produces extra heat, which, however, cannot explain the fact that his core body temperature does not decrease more. So what are possible explanations? And I have 3, and there may be others, but one explanation could be that Wim is very much into tummo meditation, And from the Tummo meditation, which is mostly done in Asia, we know that it produces heat. So maybe that's part of his heat production. Also, as Wim was telling a few minutes ago too, it creates for him a possibility to control his vessels, control his blood vessels. What we see is that he can separate his core very well from his shell. So this could be an explanation. Another explanation is that Wim Hof has been telling me that he's doing this for years and years. As a boy of 12 years old, he already jumped into cold water. So maybe it's more of a training effect, and we all could do it if we just expose ourselves gradually to cold and by that train our autonomic nervous system and control our circulation. A third explanation could be that he has some genetic advantage to do this, that he has some changes in his cold receptors or changes in his pain receptors that make it more easy for him to do those kind of experiments. We don't know yet. I just gave 3 explanations. We need to do more studies on Wim Hof. As you can see, It's really something exceptional. He was sitting 80 minutes in ice like this. His core body temperature did not drop. Physiologically, we call this a mystery, and we need to do more research to really understand how you can control processes in your body that we have thought so far that we were not able to control voluntarily. With this, I would like to finish my presentation, and I wish Wim good luck.
Wow. I think, Dr. Hamme, you've got to come up here and do it all again, because we were all watching this guy get buried alive in ice. So we're all going to pretend that this is normal and move forward. I know it, I know it, I know it, I know I can.
Sorry?
Okay. Okay, let me just repeat what was said. I don't know if you heard it. You don't have to do this to reap the benefits of a healthy cardiovascular system. That is good news for all of us that were thinking, "I need some work on my cardiovascular." Now, you know, when the clock goes off, we'll have to wheel poor Wim Hof. So one of the ideas worth sharing is— was made famous by a young fellow named Harry Houdini. Never get into a box that you can't get out of. Unless that box is headed up toward the world moon. But I have full confidence Wim's going to be out of there in no time. Again, this is like nothing for him. This is like watching TV. And if you're watching the Jydzynski right now, I mean, this is right here. It was right here in two dimensions like everything we've done today. I don't know if they're— it's like, "Are you sure you can't climb out? Because it would be pretty trouble if there's ice everywhere." The fake snow confetti was annoying. The real— the guys from the Stadtskalburg are going, "I really— I totally did not like the ice idea. We stand behind no ice on stage." And let me just say, you don't have to worry till I go over there and start helping pull. As long as I'm here just stalling, you know that Wim is safe and sound and there's nothing to worry about except the potential for a slightly shorter coffee break. Again, unless you run the StatsGauberg, then the risk— is a wet spot here that will make this red spot look like a nonexistent red spot. And now, uh— I'm still staying cool over here. So you know it's all okay. How about the guys who put this box together? This shit does not break apart. Here he comes. I got a good feeling. Here he comes. Fantastic.
Fantastic.
That is great. Well, we get a chance to ask Wim a couple of questions. Welcome back. How are you? One more time.
Wow.
He doesn't need the towel. He is not cold. That's the one problem he does not have. Uh, Wim, I have a couple of questions for you. Are you okay?
First of all, you all right?
I'm totally okay. Thank you very much for showing that, uh, I'm, I'm going into extreme and nobody needs to do this. This is my sport, you know. Football is, is healthy to do, you know. But if you want to be top player, you got to train. So I train to do this. And if you take just a little bit more, uh, you know, you're thinking, change it a little to work the cold, because the cold is a warm friend. It makes the cardiovascular system—
yeah, the cold, the cold, the cold is a warm friend.
Let me ask, it's a warm friend because it trains all the muscles in the, in the veins.
Let me ask, therefore I just want to ask you a question.
And blood is warm.
I know, it's a— Streaming better. Cold is warm, war is peace, love is hate. I know.
Yeah.
Um, Wim Hof.
You know something. Now you talked about the science, but why do you do this? Not a scientific reason, but what is it? Do you have a personal mission besides, you know, don't try this at home? I mean, what is the personal reason that you do this?
Um, I developed a method which is relatively easy to adopt, to learn. And it's about, you know, what I learned in the hard nature. I learned to use a different way of breathing which is able to make contact with the immune system and the nervous system to a very deep level.
But Wim, not how, but why?
Why?
What's your mission?
You said— why do you do it? My mission is to show that everybody by their mind can reach more depth within themselves and prevent— we got healing power, we really got it. But if we block it because we say, yeah, I cannot heal myself, I need to go to the doctor, be dependent, I need to take pills, I need to take that, then you won't be having this access towards your own healing power. The inner doctor of Paracelsus, 2,000 years ago, it was already known and said, and we forgot a little bit about this. We are dependent on outside forces while we have inner power. And by opening up our mind towards that, and be more conscious toward that, we can really feel this inner power, healing power, and prevent from disease.
