What Doesn't Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength

by Scott Carney

humans in industrial countries generally lacked the conditions that would spark the body to start building BAT. It’s not that the levels of BAT naturally decline as humans get older, it’s just that the body learns that it doesn’t need to invest energy into building BAT when it lives in perpetual summerlike conditions indoors.

In broad strokes, however, thermogenic research has showed four main strategies that the body can use to resist the cold: Humans can increase their metabolic rate by shivering; they can stay warm through some passive metabolic mechanism; or they can shunt blood to their core by closing off the arteries in their extremities. Lastly, as in most cases of people who live in colder climates, the human body can also accumulate higher levels of ordinary white fat as an insulation to help stem heat loss in the first place. Anthropologists credited the different strategies to genetic adaptations that evolved from people reproducing in diverse environments and not necessarily a sign of evolutionary abilities shared among all humans.

Cypess deduced that the very examination rooms where the PET/CT scans happened were ideal for activating BAT. They were abnormally cold, and patients wore only thin hospital gowns when they were in the confines of the machine. Under these conditions BAT was simply doing its job to keep people warm: sucking up fats and sugars from the bloodstream and producing enough heat to light up the PET/CT readouts. More important, the discovery showed that BAT wasn’t a vestigial tissue at all, but that even adult humans might reap benefits from its presence. And thus, BAT might not only help explain the mysteries of how Neanderthals survived through ice age winters, but also how modern humans could use it to get through their own winters as well. Oncologists now note that PET/CT scans taken in the winter months have more instances of BAT than in the summer, suggesting that it comes and goes with the seasons.

The Wampanoag seemed to understand intuitively that resistance to the elements wasn’t an innate power. Instead, they recognized that their bodies already had all the tools necessary to survive in the environment if they made a conscious effort to adapt.

“We’re overlit, overfed, and overstimulated, and in terms of how long we’ve been on Earth, that’s all new,” he says to me while summer is settling in Alabama. We’re missing out on what he calls “metabolic winter,” a time when the body adjusts to discomfort and scarcity between times of plenty. As he writes in his opus article on the subject, “Our 7-million-year evolutionary path was dominated by two seasonal challenges—calorie scarcity and mild cold stress. In the last 0.9 inches of our evolutionary path we solved both.” The inevitable result of losing seasonal variation is obesity and chronic disease. As proof, he doesn’t point only to the population of his home state, which ranks at #5 of the most obese states in the nation, but also to the fact that our pets are fat, too. “The only two animals in the world that suffer chronic obesity are humans and the pets we keep at home,” he says. “There’s a connection.”

The key to fixing the problem, according to Cronise, is to artificially reintroduce seasons back into our lives. Drawing on the growing literature on brown fat and metabolic analysis, he prescribed himself daily hour-long walks in sub-60 degree temperatures along with moderate exercise and calorie restriction. In the course of just 6 months, from June to November, he dropped almost 40 pounds.

Cronise’s research isn’t just about losing weight, though. He’s trying to correct what biological anthropologists call evolutionary mismatch diseases, or, in layman’s terms, what happens to the body when the...

One day his professor mentioned a metabolic process called the bicarbonate buffer system that regulates the amount of carbon dioxide and hydrogen in the blood stream. This complex system dictates that when the body works harder, acidity builds in the muscles. We experience this as fatigue.

From the gasses that left my lungs he can tell that I burn mostly carbohydrates, indicating that I’m definitely not a world-class endurance runner. Top athletes that compete in ultramarathons run mostly on slow burning fat for a reliable source of energy.

So training starts with one of the most fundamental human reflexes: the urge to breathe. When the Buddha first taught meditation to his followers, he recommended that they start by watching their breath move in and out of their body. Breathwork is a staple of every yoga class, as students move their bodies in sync with their lungs. The Wim Hof Method tasks students to hold their breath until they can’t take it anymore. And then hold it just a little longer. This is the quickest and probably safest way to build your own wedge.

The urge to gasp for air is not directly linked to the amount of oxygen in the bloodstream. That’s because, for some reason that has been lost in the convoluted process of evolution, the body cannot sense oxygen, only its byproduct. Breathing is a two-part process—inhaling to bring oxygen to the lungs and exhaling to expel carbon dioxide (CO2). When the brain senses too much CO2 in the bloodstream, the chest tightens, vision blurs, and just about every muscle from the abdomen to the forehead clenches down hard. When we talk about this sensation we usually say that we need to take a breath. However, on a physiological level your body wants to expel CO2. It sounds counterintuitive but it’s easy enough to test. Take a deep breath in and hold it until you feel the urge to breathe. Then release a little bit of air. With less CO2 in your lungs you will feel like you can hold your breath a little bit longer. That’s because you’ve removed a potentially poisonous waste product from your body and your nervous system has turned off the alarm bells.

The first goal is to prepare your body by blowing CO2 out of your system. Start by sitting down on a couch or lying on the floor and taking 30 fast breaths. Each inhale should take about a second, but you should not force the exhale. Instead let it flow out naturally. Your breath should sound like you’re at the peak of a sprint just a few seconds shy of having to slow down. Pretty soon you’re going to feel a little dizzy; this is normal. You might also feel tingling in your hands and feet. You might also feel cold. Or experience ringing in your ears. After about 30 breaths you will have radically increased your blood oxygen saturation and cleared out most of the CO2 in your system. Now, finish the hyperventilating1 with a big gulp of air and hold it with a full chest. Time yourself to see how long it takes you to reach the point where you feel the need to gasp. Hold on as long as you can and clench the muscles in your chest, arms, and legs. You’re probably making a pretty crazy face as you struggle against the urge to breathe. But when you can’t stand it anymore, slowly let the air out of your lungs. This gives you a little boost of time before you take any more air in. The first time you try this probably won’t produce any dramatic results, but you should find that you can hold your breath a little bit longer than your baseline. Before starting the next round of breathing, fill your lungs with a half-breath of air and hold it for about 15 seconds. This is the recovery bre...

Of course, this is a pretty well-understood body hack. When you clear your lungs of CO2 and fill them with air, there’s enough stored oxygen to do a fair amount of physical exertion. However, your brain doesn’t intrinsically know how you’ve changed the oxygen baseline to perform a little bit better. Every time you do this you effectively grow a slightly stronger wedge.

Some medical literature has also shown that it’s possible to have a stroke or even a heart attack from hyperventilation so, again, people with serious heart conditions or advanced circulatory problems should take extra care.

The autonomic nervous system divides itself into two interrelated components. First is the sympathetic nervous system, which controls the so-called fight-or-flight response. If you were a car, the sympathetic system would be the gas pedal. It gives you short-term boosts in energy, activates the adrenal gland, and triggers dilation and vasoconstriction. The parasympathetic nervous system controls the opposite responses, sometimes called the “feed-and-breed” actions. This is the equivalent of a car’s brake pedal. The parasympathetic nerves act on digestion, salivation, sexual arousal, and tears. Both systems are involved in breathing, and the right techniques can help strengthen both sides of the nervous system. In the same way that someone at a gym can focus on particular muscle groups during exercise, different breathing routines target different aspects of the nervous system. The basic breathing technique of holding your breath after hyperventilating acts mostly on parasympathetic nerves. The sympathetic system only starts to kick in closer to the moment when you are struggling to stop yourself from gasping, and it is often best to train with breath-out holds. Breath-in holds are better for getting to your absolute maximum number of pushups or retention duration, but are less efficient at cracking into your nervous system.

In order to prime your body to get to the gasp point earlier (and thus build a stronger wedge and activate the sympathetic nervous system), start with the basic breathing method for approximately 30 quick, deep breaths. Keep your eyes closed and breathe hard enough that you begin to feel light-headed. Now, instead of taking in a deep breath and holding it, let most of the air out of your lungs like you would at the end of a normal breath (by which I mean, don’t force it) and hold your breath with mostly empty lungs. Your body will quickly deplete the oxygen stores available in the lungs and have to rely solely on what is available in the bloodstream. When you get close to needing to gasp, you can extend your limits in two ways. The first is the same as with basic breathing, slowly letting out what is left of the air in your lungs.

The process is as follows: Relax your body and clench the muscles in your feet. Then clench your calves, then thighs. Work the contractions up your body until every part of you is tight from the bottom to the top. Clench your stomach, your chest, fingers, biceps, and jaw. Tighten the muscles behind your ears and imagine all of this pressure that you’ve built up going out the top of your head like you were rolling out pizza dough. Whenever I do this I end up making all sorts of grunting noises and squint my face into awkward contortions. It feels like I’m going to pop. But I never have. Once you finally have to breathe, take in a half lungful of air and hold it for about 10 to 15 seconds. This is the recovery breath, and it feels awesome. Now start over from the beginning. Since your lungs start near empty, it won’t be possible to hold your breath as long as with the basic breathing technique. Aim to increase the amount that you hold your breath with each repetition.

There are many explanations of what happens during meditation visualizations. Monks, yogis, and Chinese meditation practitioners say that the colors correspond to a system of spinning chakras (wheel-like torrents of energy) that make up a human’s spiritual anatomy. Others argue that the colors indicate the metabolic functions of specific organs. Most scientists say there is no proof that the shapes a person sees are anything more than just the meaningless static of the brain. Whatever the truth of the matter, the visualizations are real experiences.

But your goal here is to command your nervous system to submit to your will. If your body can’t shiver itself warm again or rely on the insulating properties of your white fat, its only remaining option is to start ramping up your metabolism. This is to say, you will begin passively generating brown fat and building up your stores of mitochondria if you can suppress your shiver response.

The first time you experience the cold will be the worst. Every nerve will fire like it is raw and has never been used before. Your heart will race and you’ll want to do anything you can to retreat into warmth. Unless you are in weather where frostbite is likely, you’re not in any serious danger, even though your mind will tell you that you are. The arteries in your hands and feet will clench with the force that it reserves for severing a limb. If you are jumping into a cold body of water, go with a friend just in case one of you runs into trouble. Nonetheless, if you last just 5 minutes your entire body will probably be screaming for relief. Go inside and warm up. Most likely, the sensation of vasodilation, when the arteries loosen and let warm blood back inside, will hurt even more. For some, the process of rewarming is more painful than the initial exposure. Think of the pain as a sort of baptism. When you try it again the next day, it will be much more manageable.

For Hamilton, using the cold makes sense. He grew up swimming in the tropical waters in Oahu, hypothermia was always a present danger. Even warm Pacific waters slowly leach away heat from submerged swimmers, and for people waiting around on a surfboard for just the right set without a wetsuit, it’s easy for them to end up shivering uncontrollably. Hypothermia is far from unknown to warm water surfers. Yet Hamilton can spend half a day in the water and says controlling his temperature is half the reason he has any success riding big waves.

Exhaustion is just the inevitable result of what happens when breathing hits its maximum rate and the body can’t get enough energy into the system. This is what physical trainers call VO2 max. When you hit this moment of peak performance it’s simply not possible for you to push any further. We’ve all been at this point some time or another. Your face is flushed red and your chest is heaving, but try as you might you know that in a second or two you’re going to crash. Peak performance at VO2 max is partly based on genetics, as everyone has a slightly different ability to metabolize oxygen.

“If you have to stop to catch your breath, then you probably started the race all wrong in the first place,” he tells me. “Instead, if you lead with a breathing pattern like you are already at your maximum load, then you won’t have to work so hard later.”

He tells me to think of it this way: The body has an internal program that automatically evaluates and responds to the conditions it is working in, but it doesn’t have any way to know on its own what sort of oxygen load it is going to need in the future. It responds to the workload of the moment. When a sudden spike in heavy exertion happens, the body has to play catch-up. When you don’t plan for breathing in a workout, it’s easy to end up with an oxygen deficit.

The solution is to start breathing hard long before you actually feel the need to. The most obvious application for this technique is with running. A typical adult takes about 15 breaths every minute when they are at rest, but will start breathing 40 to 50 breath...

VO2 max. An untrained runner will breathe faster as they reach their limit, but they typically draw shallow breaths that don’t give their lungs a chance to maximize oxygen absorption. By anticipating what the body is going to do, Hamilto...

His lips bulge stiffly outward and his eyes narrow to slits as he sucks air in coarsely through his nose. Waiting just long enough for his lungs to fully draft, he exhales with a growl reminiscent of Maori warriors as they perform a haka. Taking a breath every second makes him sound like he is under heavy labor. His face flushes with exertion but his eyes have the serene gaze of a mind focusing only on the action of its lungs. After 50 breaths he inhales deeply and is ready to run. The process scrubs carbon dioxide from his lungs, allowing his body to run more efficiently for a short sprint in the same way the Hof breathing method allows

someone to do more pushups than they expect, or, if he were to keep it up, throughout the duration of a longer exertion.

In India and China, yogis who use similar breathing techniques, called pranayama in Sanskrit, or qi

breathing in Mandarin, frequently report experiencing visions. In fact, most Eastern traditions believe that breath control can engender profound spiritual insights.

“You ride a wave, you don’t conquer it,” Hamilton says. “The trick to surviving is knowing when you’re out-matched.” In part, he credits his achievements as a surfer to what is for him a humble connection to nature and the realization that he is not just the rider of a wave, but indeed, that a surfer is part of the wave. “There’s no beginning and no end of a wave,” Hamilton says. “Instead there is a sort of timeless aspect to surfing where every wave you’re ever on is part of the same eternal wave. Really good surfers have a connection to the ocean where the great waves simply come to them. Surfers who fight the ocean and try to defeat it never connect and aren’t given good waves.”

In the split second that he realizes that he’s lost control, he thinks about what the crash might be like and then plans to minimize the damage. Whether this means rolling into a ball, diving off the board, or whatever else opportunity puts on his

doorstep, he believes that there will always be a moment when he will have a semblance of control again. The trick is waiting for it to happen.

The four rules to his formula—commitment, crash, submission, and escape—provide a blueprint for every failure in his life, he says. It has allowed him to survive the unsurvivable and has given him a guiding philosophy for every venture he gets into outside of the water. “It’s the attitude I go into before I start a new business, or a new training regimen,” he says. Together they form a wedge that he crams between his consciousness and the autopilot of his own nervous system. It’s the division between his own natural limits and the control he can express over the world around him. Hamilton’s philosophy mixes spirituality with exercise and environmental conditioning. An outsider might call it holism.

Then, in 2011, scientists at Harvard discovered that brown fat wasn’t just a vestigial tissue locked away in our evolutionary past, but was something that just about every human has the potential to build and use. It was a ray of hope amidst a bleak and unrelenting epidemic.

An extremely overweight person with a surplus layer of insulating white fat doesn’t necessarily need to ramp up their metabolism to fight against the cold. The layer of fat alone suffices to protect

respond much more quickly to cold temperatures, forcing their bodies to generate BAT in order to stay alive.

In what might just be the most profoundly lucky occurrences of happenstance for a researcher investigating Hof’s method, it turns out that Hof has a genetically identical twin brother, André. Previous examinations of Wim Hof’s physiology had shown that the Iceman himself possesses much more BAT than other people his age. He has about the same amount that a typical 20-year-old does. While Wim Hof is incredibly active, his twin brother isn’t. As a truck driver who spends most of his time inside a heated cab, André lives a mostly sedentary lifestyle. Though they look the same, van Marken Lichtenbelt figured that Wim’s near-constant exposure to the cold would result in his having a much greater amount of BAT than his twin would.

But when the professor put both Wim and André into a PET/CT scan, he found that they—remarkably—had very similar (high) levels of BAT. Even so, despite their similar biology, Wim’s ability to withstand the cold is undoubtedly stronger than his brother’s. While BAT likely plays a part in his metabolic robustness, defining the exact underlying mechanisms proves to be a deceptively difficult task.

Even after such a short training program the active group showed positive levels of epinephrine as well as an increased amount of anti-inflammatory molecules in their blood. They had fewer fever-like symptoms than the control group experienced, and their cortisol levels returned to normal much quicker. To quote the subsequent journal article from the Proceedings of the National Academy of Sciences: “Hitherto, both the autonomic nervous system and innate immune system were regarded as systems that cannot be voluntarily influenced. The present study demonstrates that, through practicing techniques learned in a short-term training program, the sympathetic nervous systems and immune system can indeed be voluntarily influenced.” This short declarative statement forced the scientific community to completely reevaluate their understanding of the immune system. The article earned a mention on the journal Nature’s website and caught fire across

the internet, lending scientific credibility to Wim Hof’s program. If the finding continues to hold up to scientific scrutiny, then it would seem to have potential implications for a huge variety of illnesses—from autoimmune conditions to diabetes to bacterial infections to food allergies to, well, anything. If not an actual cure for any of these, environmental stimulation adds an important dynamic to the overall picture for treating human illness. A year later a related but unaffiliated anatomical discovery helped shed light on how conscious control of the immune system might work. For the most part, the immune system has a standard operating procedure for uncovering and destroying foreign invaders. Once it locates a virus, tumor, bacteria, or, in the past 60 years, transplanted organs, it sends out white blood cells to eat the pathogens or explode the sick cells. The process is essentially the same in every part of the body except for the brain. If an infection breaches the blood-brain barrier (think meningitis), the body has no defense against invading bacteria.

It turns out that many cases of Parkinson’s begin in a similar way. A small but intense trauma initiates a cascade of stiffness that slowly propagates through the entire body, ultimately leading to progressive and irreversible neurological impairment. Over time the disease can all but stop the interaction between the peripheral body and the central nervous system

“I found that as soon as I started doing difficult things that everything else in life got easier,”

He would need surgery, complete with screws. The doctor told him it would be a long recovery. Furthermore, a large purple horseshoe-shaped bruise stretched over his kidney. A nurse offered him an opium-based pain medication while he waited for surgery, but he turned it down. For him, the broken bone was an opportunity for him to practice pain control. The nurse was shocked. She’d never had anyone in his position refuse morphine, but he did. So, long after adrenaline had blunted his pain, van der Meulen breathed consciously for hours and visualized light moving from his lungs to his arm in lieu of a much easier path to painlessness. The doctors fitted him with a temporary cast and scheduled a surgery for 4 days later. He spent the evening meditating on his injuries, and when he came in for a follow-up appointment the next day the bruises on his ribs and kidneys were gone. The nurse wondered why van der Meulen wasn’t healing like a normal person.

When he finally was admitted to the operating room a few days later, he turned down the drugs again. Doctors gave him only a local anesthetic as they opened up

his flesh to set the bone. A few hours later, when he emerged from surgery, a yellowish incision spanned from his wrist halfway to his elbow with broad, inelegant sutures. A nurse told him that he would have to wait for 2 weeks before they could be removed, but asked him to come back the next day so the doctors could have a look at how the surgery took. Van der Meulen spent the next 4 hours breathing and focusing on his arm. When he tells me this story, I have trouble wrapping my mind around the amount of concentration it must have taken. The effort was constant, but he tells me that it seemed to pay off. When he finally grew tired and went to bed that night...

Under his program athletes getting ready for 100-plus-mile ultra-marathons don’t run increasingly long distances until they hit their target; instead they train in 1-minute ultra bursts of activity followed by short cool downs. His routines bring a person up to the threshold of their VO2 max—the very point of exhaustion—and can transform a sprinter into an endurance athlete. The method is called high-intensity interval training, or HIIT, and breaks 50 years of running orthodoxy.

By 2016 researchers at Canada’s McMaster University in Hamilton, Ontario, showed that just 1 minute of all-out interval training was more effective at getting people into shape than a moderate, 45-minute run.

“The beauty of the ice is that it forces you back to your center,”

“This trip is not about just testing out limits,” he begins. “It’s about leaving our egos behind and delving deep into our physiologies.” He pauses for a moment and smiles at a pun forming in his inspirational ether. “There is no ego on this mountain. Just we go.”