Book review: The science behind the Wim Hof Method

“What Doesn’t Kill Us: How freezing water, extreme altitude, and environmental conditioning will renew our lost evolutionary strength” by Scott Carney

This is a phenomenal book. It is the story of our long-lost superhuman capability that we once possess, and the science behind the ability to consciously control our immune system and body temperature. It is also a book largely about Wim Hof, and his unorthodox method that surely will change the way we practice medicine and could even save humanity in the future.

So, who is Wim Hof? the Dutchman holds 26 official Guinness Book of Records, he climbed pass the death zone altitude at mount Everest (around 7500 metres) wearing nothing but shorts and shoes, he dipped into ice bath for nearly 2 hours and his body temperature didn’t plunge, and he can hold his breath under water for 10 long minutes.

Moreover, the “iceman” can also run at a high altitude without suffering from altitude sickness, he completed a full marathon above the Arctic Circle in Finland wearing, again, nothing but shorts and shoes despite the temperature was close to -20 degree Celsius (-4 degree Fahrenheit), he ran another full marathon in the scorching hot Namib desert without training and without water (and like a badass re-hydrated afterwards with a beer). And all of this are achievable thanks to his method.

Perhaps the best part of this insane achievements is, despite looking like a hippie and behave like a funny madman, he routinely asks scientists to measure and validate his “crazy” method. Method that are continuously verified to be legitimate, including by the MIT lab. Method that is not genetically available to his “normal” twin brother without practice. Method that is teachable and trainable to anyone, including you and me. And this is where this book excels.

Now, while the book is not about Wim Hof per se, it is a testament on Wim as the absolute superstar in this particular bio-hacking subject. Thus, it has Wim at the cover, Wim for the foreword, Wim for the first few chapters, and Wim again at the last few concluding chapters. But the space in between? It’s the juicy science stuff.

At the core of the book lies Brown Adipose Tissue, an inactive “brown fat” deposit within our body that plays an important role in insulin sensitivity and packed with mitochondria that acts as the power generator for the cells (the ATP). It is a “hidden function” in our body that Harvard researcher Aaron Cypess discovered can be ignited to instantly keep our body warm (the thermogenesis process).

Previously, scientists used to believe that only babies had brown fat since birth (to protect the body from the outside-world cold exposure), but the fat disappears by the time most people reached adulthood. However, recent studies suggest that adults have small reserves of brown fat (usually stored in small deposits around the neck and shoulders), and more importantly some brown fat can be “recruitable” by converting white fat (the normal fat that we have) into brown fat, which can be done most effectively by exposing our body to cold water. And this is where Wim Hof breathing method come in play.

So how does it work? First you inhale deeply through your mouth or nose, filling your belly and chest with as much oxygen as you can, then exhale gently through your mouth. And repeat the sequence 29 more times in short and powerful bursts. On the 30th sequence inhale deeply, then exhale all the way (let all the air out), and then hold your breath for 1 minute or until you have the urge to breathe again. Then take one big gulp of inhale, and stop breathing again for 15 seconds. And exhale, release all. Repeat this whole sequence 1 more time. The breathing method brilliantly trigger both sympathetic and parasympathetic responds in our body (more on that shortly).

Note that you should do this breathing method sitting down in a safe place (not while driving, for example), and in the middle of the 30 sequences you could start feeling light-headed, tingling sensations in your body, or erupted by a sudden emotion (several people even burst out crying for no reason) and that’s normal, it’s the body reaction that we can instantly feel from the method.

And here’s the scientific explanation. Neuroscientists have found that every inhale that we take nudges our sympathetic nervous system (which will increase our heart rate, dilating our pupils slightly, heighten our alertness), and every exhale prods our parasympathetic nervous system (which will slow down our heart rate, constricting our pupils, and calming us down). While normally every inhale is matched with an exhale, by spending more time exhaling and less time inhaling we can produce a net change towards our parasympathetic nervous system (like the 2nd part of the Wim Hof Method, where we hold our breath for 1 minute after we exhale all the way).

And conversely, if we inhale more than we exhale (like in the first 30x rapid breathing in Wim Hof Method) we’ll create a fight-or-flight condition within our body, where the sympathetic nervous system is activated by the hypothalamus by sending signal through the autonomic nerves to the adrenal glands. These glands will then respond by pumping epinephrine (or more commonly known as adrenaline) into the bloodstream, which will prop up our immune system, produce anti-inflammatory effect, give us the boost of energy, and trigger the redistribution of blood to the muscles that will keep us warm.

In other words, by net-inhaling in rapid successions the Wim Hof Method fooled our brain to think that we’re in a danger, and trigger it to produce the adrenaline that normally appears when we are chased by a tiger, or have to lift a very heavy falling wall during a fire, and in any other life and death situation. And the 2nd part of the method then relaxes our body to calm state, in order to prevent a prolonged adrenaline rush.

This same adrenaline is what protected Wim during a lab experiment where he was injected with a bacterial endotoxin, which should normally affect our immune response. But through the breathing method, Wim demonstrated that he can voluntarily influence his autonomic nervous system, and thus he can consciously control his immune system and treat it as a barrier against the disease. To show that he is not the anomaly, Wim then teach this to 12 other people, and all of them also didn’t get any body reaction when injected by endotoxin.

The Wim Hof Method is not a new phenomenon, however. It is a similar method used by the Tibetans to adapt their body in high altitude, the same approach implemented by the Inuits to withstand the freezing cold, similar like the aborigines and the Kalahari bushmen that use a method to remain warm in plunging temperatures at night without clothes on, and interestingly archaeological findings suggest that it’s even the same technique used by the Neanderthals to survive in the cold.

It is also similar like a long tradition of semi-mystic practices such as Tummo breathing and Prāṇāyāma yoga, although these two have the opposite objection to Wim Hof Method where it relies on parasympathetic deep breathing to induce a “hypometabolic state” where autonomic and mental arousal are minimal.

And true to his superhero-like narrative, Wim did not initially discover his method through science or training, but through pain after his wife committed suicide and left him alone with his 4 kids and little money to get by. This is when the ice cold water of the nearby lake became his sanctuary, the saviour that healed his pain. And in time, through trial and error the superior combination of the cold and his breathing method turned him into a superhuman capable of breaking various limitations that were thought humanly impossible. And it didn’t kill him.