WHAT DOESN'T KILL US

A new theory promises to unlock your body’s full potential—and is actually scientifically sound

Today tens of thousands of people are discovering that the environment contains hidden tools for hacking the nervous system. But no matter what they might be able to accomplish, they’re not superhuman—the fortitude they find comes from within the body itself. When they forego a few creature comforts and delve more deeply into their own biology, they’re becoming more human.

For at least half a century, the conventional wisdom about maintaining good physical health has rested on the twin pillars of diet and exercise. While those are no doubt vital, there’s an equally important, but completely ignored, third pillar: environmental stimulation.

Anatomically, modern humans have lived on the planet for almost 200,000 years. That means your officemate who sits on a rolling chair beneath fluorescent lights all day has pretty much the same basic body as the prehistoric caveman who made spear points out of flint to hunt antelope. To get from there to here, humans faced countless challenges as we fled predators, froze in snowstorms, sought shelter from the rain, hunted and gathered our food, and continued breathing despite suffocating heat.

Until very recently, there was not a time when comfort could be taken for granted—there was always a balance between the effort we expended and the downtime we earned. For the bulk of that time, we managed these feats without even a shred of what anyone today would consider modern technology. Instead, we had to be strong to survive.

 Despite all of our technology, our bodies are just not ready for a world so completely tamed by our desire for comfort. Over the course of hundreds of thousands of years, humans invented some things that made life easier—fire, cooking, stone tools, fur skins, and foot bindings—but we were still largely at the mercy of nature. About 5,000 years ago, at the dawn of recorded history, things got a little easier still as we domesticated various animal species to do work for us, built better shelters, and carried more sophisticated gear. As human culture advanced, it all was getting incrementally easier. And then, sometime in the early 1900s, our technological prowess became so powerful that it broke our fundamental biological links to the world around us. Indoor plumbing, heating systems, grocery stores, cars, and electric lighting now let us control and fine-tune our environment so thoroughly that many of us can live in what amounts to a perpetual state of homeostasis.

We have a nervous system that is almost perfectly attenuated for homeostasis, which is the effortless state where the environment meets every physical need. Our nervous system automatically responds to challenges in the world around us—triggering muscle contractions, releasing hormones, modulating body temperature, and performing a million other tasks that give us an edge in a particular moment.

But barring an urgent need for survival, the human body is perfectly content to simply rest and do nothing. The programming that makes us gluttons for the easy life didn’t emerge out of nowhere: Almost every organism struggles against the environment that it inhabits. Every creature, whether it is an amoeba or a great ape, needs motivation to overcome the challenges of the world around it: Comfort and pleasure are the two most powerful and immediate rewards that exist.

What is comfort? It’s not really a feeling as much as it is an absence of things that aren’t comfortable. We sate our thirst, don layers of clothing on cold winter days, and clean our bodies because that yearning for comfort is hardwired into our brains. It’s what Freud called the “pleasure principle.”

 Effortless comfort has made us fat, lazy, and increasingly in ill health. It doesn’t matter what the weather is like outside—scorching heat, blizzards, thunderstorms, or just fine summer days—a person can now wake up long past when the sun rises, eat a breakfast chock-full of fruits flown in from a climate halfway across the globe, head to work in a temperature-controlled car, spend the day in an office, and come home without ever feeling the outside air for more than a few minutes. Modern humans are the very first species since the jellyfish that can almost completely ignore their natural obstacles to survival.

Yet comfort’s golden age has a hidden dark side. While we can imagine what a difficult environment might feel like, very few of us routinely experience the stresses of our forebears. With no challenge to overcome, frontier to press, or threat to flee from, the humans of this millennium are overstuffed, overheated, and under-stimulated. The struggles of us privileged denizens of the developed world—getting a job, funding a retirement, getting kids into a good school, posting the right social media update—pale in comparison to the daily threats of death or deprivation that our ancestors faced. Despite this apparent victory, success over the natural world hasn’t made our bodies stronger. Quite the opposite, in fact: Effortless comfort has made us fat, lazy, and increasingly in ill health.

The developed world no longer suffers from diseases of deficiency. Instead we get the diseases of excess. This century has seen an explosion of obesity, diabetes, chronic pain, hypertension, and even a resurgence of gout. Millions of people suffer from autoimmune ailments—from arthritis to allergies, and from lupus to Crohn’s and Parkinson’s disease—where the body literally attacks itself. It is almost as if there are so few external threats to contend with that all our stored energy instead wreaks havoc on our insides.

There is a growing consensus among many scientists and athletes that humans were not built for eternal and effortless homeostasis. Evolution made us seek comfort because comfort was never the norm. Human biology needs stress—not the sort of stress that damages muscle, gets us eaten by a bear, or degrades our physiques, but the sort of environmental and physical oscillations that invigorate our nervous systems.

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Author Scott Carney hiking shirtless in the snow. (Laura Krantz)

 There is a growing consensus among many scientists and athletes that humans were not built for eternal and effortless homeostasis. Muscles, organs, nerves, fat tissue, and hormones all respond and change because of input they get from the outside world. Critically, some external signals set off a cascade of physiological responses that skip the conscious parts of our brains and connect to a place that controls a well-spring of hidden physical reactions called collectively fight-or-flight responses. For example, a plunge into ice-cold water not only triggers a number of processes to warm the body, but also tweaks insulin production, tightens the circulatory system, and heightens mental awareness. A person actually has to get uncomfortable and experience that frigid cold if they want to initiate those systems. But who wants to do that? The bulk of us don’t see environmental stress in the same light as we do, say, exercise; there doesn’t seem to be an obvious reason to leave our shells of environmental bliss.

Maybe that’s not entirely fair. In recent years a counterculture has tried to push back against technological overzealousness to reclaim some of our animal nature. They’ve shucked fancy footwear for flat shoes (and some cases no shoes at all). They’ve turned away from climate-controlled exercise gyms in favor of rough obstacle courses and boot camps that force muscle groups to work in unison. They’re hacking their diets: eating tubers and meat and foregoing grains reminiscent of our Paleolithic ancestors. At least eight million people have bought a product called the Squatty Potty, a device for the toilet to help a person poop in a squatting stance like our pre-toileted forebears did.

Millions more sign up for obstacle course races that feature electrified grids, pools of freezing water, and grueling climbs over wooden barriers. They compete until they are so bone tired that their muscles shake. They puke in the mud with tears in their eyes. It’s not exhilaration they’re seeking: it’s suffering. Their pain is so much on the forefront of the experience that the industry of obstacle courses and boot camps are sometimes called “sufferfests.” Think about that for a second: There are companies out there that literally make fortunes by selling suffering. How did pain become a luxury good? Could it be that there is a specific sort of pain that might serve a hidden evolutionary function?

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Wim Hof, pioneer of environmental conditioning, hiking in the snow. (Scott Carney)

Advanced technology permeates everything we do, but the people who decide to abandon some of that comfort for the rawness of nature represent an indigenous ethos that has almost been wiped out by a societal desire for comfort. They’re learning that if they embrace the way their bodies respond to the natural world, they can unlock a hidden wellspring of animal strength.

For most of our evolutionary past, comfort was a rare treat and stress was a constant. The lower parts of our brain formed in environments where there were always physical challenges to overcome, and those challenges were part of what made us human in the first place. Despite all of our technology, our bodies are just not ready for a world so completely tamed by our desire for comfort. Without stimulation, the responses that were designed to fight environmental challenges don’t always lie dormant. Sometimes they turn inward and wreak havoc on our insides.

This book is largely about what happens when we reexamine our relationship with the environment and see ourselves as a part of something bigger than the comfortable spaces we mostly choose to live in. It explores how changing the environment around the body also fundamentally changes the body itself. More importantly, it shows how it is possible to manipulate our external environment to trigger autonomic responses in predictable ways. Once you realize that you can manipulate deep parts of your physiology by intentionally tweaking identifiable pre-programmed responses, you can begin to cede aspects of that automation to your consciousness.

It’s a strange claim to make for an investigative journalist who has spent much of his career trying to debunk false prophets and medical voodoo. For that matter, it’s an odd statement for a man whose spirit animal is still mostly made of “jelly.” But these findings are grounded in current science and the real lives of people around the globe who have taken control of their bodies to an extraordinary extent.

This is an edited excerpt from Scott’s book, What Doesn’t Kill Us: How Freezing Water, Extreme Altitude and Environmental Conditioning Will Renew Our Lost Evolutionary Strength. You can follow Scott on Twitter at @sgcarney. Learn how to write for Quartz Ideas. We welcome your comments at ideas@qz.com.

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