My attempts to kick my comfort dependence came at a personal low point, back in July 2012. I had been sitting in front of my computer for almost eight hours straight, with a sinking feeling that I was getting past my prime. My legs throbbed from underuse and my back ached. But I told myself that as I was now approaching my mid-thirties, it was perfectly normal for my stomach to sag over my belt.
Then I stumbled across a picture online of a nearly naked man sitting on a glacier somewhere north of the Arctic Circle. It was as if this bearded gentleman, 20 years my senior, had travelled through time from Ancient Sparta, when the warriors would pit their bodies against the elements to defy the gods. Whatever he was into, it wasn’t comfort. Yet he projected something vital that I’d recently noticed was missing from my own life.
A Google search revealed him to be Wim Hof, a Dutch guru dubbed “The Iceman” for his apparent ability to control his body temperature in extreme cold, which has sparked a whirlwind of scientific study.
He ran a training camp in the snowy wilderness of Poland, teaching a male clientele willing to wage war on their bodies (and pay upward of ??1,500 for the privilege) how to stay warm without clothes in sub-zero temperatures. Doing so, he believes, allows you to consciously control your autoimmune system; ramping it up against sicknesses, improving your moods and increasing your energy.
Hof’s promises sounded crazy to a 33-year-old journalist raised on a diet of processed foods and little exercise. I don’t like to suffer. Nor do I want to be cold, wet or hungry. The human body craves homeostasis, the effortless state in which the environment meets our physical needs and the body can rest.
Indoor plumbing, central heating, supermarkets, cars and artificial lighting now let us finetune our environment so thoroughly that many of us can live in what amounts to a perpetual state of homeostasis. We can wake long past sunrise, eat a breakfast full of fruits flown in from a climate halfway around the world, head to work in a heated car, spend the day in an air-conditioned office and come home without ever feeling the outside air for more than a few minutes.
Yet comfort’s golden age has a dark side. If we came up against one of our prehistoric ancestors, we would undoubtedly be fatter, lazier and in worse health. The developed world no longer suffers from diseases of deficiency, but 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 allergies to arthritis, lupus and 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 that humans were not built for eternal, 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 or gets us eaten by a bear, but the sort of environmental and physical oscillations that invigorate our nervous systems, setting off a cascade of physiological responses that skip the conscious parts of our brains.
No environmental extreme induces as many changes in human physiology as the cold: a plunge into icy temperatures not only triggers a number of processes to warm the body, but heightens mental awareness, tweaks insulin production and tightens the circulatory system.
Weak circulatory muscles are a side-effect of living in a very narrow band of temperature variation. The majority of us, spending the bulk of our time indoors and only venturing into the cold while wearing state-of-the-art outdoor gear, never exercise this critical system. Even those with chiselled abs might be secretly hiding weak circulatory muscles beneath. And the stakes are huge: circulatory diseases contribute to almost 30 per cent of the world’s mortality.
It’s also possible to see the twin epidemics of diabetes and obesity through a thermodynamic lens. In 2015, Wouter van Marken Lichtenbelt, a professor of energetics and health at Maastricht University in the Netherlands, found eight overweight men in their late fifties suffering from type 2 diabetes and decided to see how short-term cold exposure would alter their bodies.
The men dressed in shorts and sat in a chilly, 14C room, the temperature just above the point where they would begin to shiver uncontrollably. They spent six hours a day in the cold for 10 straight days as their insulin production and blood levels were monitored. At the end of the study, their bodies metabolised sugar from their blood 43 per cent more efficiently than when they started. In other words, in just under two weeks, cold exposure began to reverse the symptoms of diabetes.
It seems experiencing cold can spur your body to activate mitochondria-rich brown adipose tissue (BAT), known as brown fat. Its primary purpose is to pull white fat from storage and burn it to keep you warm. So, counterintuitive as it sounds, the more brown fat you have, the higher your capacity to stay lean.
Everyone is born with about 5 per cent of their body mass as brown fat – it’s what allows infants not to succumb to cold in their earliest months. But thanks in part to the perpetual summer-like conditions of central heating, most of us have almost no active brown fat left by the time we reach adulthood.
Which brings us back to Wim Hof. Scientific interest in him really snowballed in 2008, when researchers at Maastricht University learnt that the then 51-year-old had built up so much brown fat that he could produce five times more heat energy than the typical 20-year-old – most likely because of his repeated exposure to cold. Though I was sceptical of his superhuman claims, I flew to Hof’s training centre in Przesieka, Poland, to put his body-hacking methods to the test.
First, he taught a breathing routine that alternated between controlled hyperventilation and breath-holds with empty lungs that, with a little practice, allowed me to hold my breath for three minutes at a stretch. This apparently reprogrammes the way the nervous system responds to the stress of not breathing, helping you to withstand environmental stressors and stay warm – even get hot – in very low temperatures.
The brutally simple second half of his method: get used to being cold, and suppress the urge to shiver. Shivering is an autonomic method the body uses to warm up, but relaxing and taking calm breaths helps quell this impulse, forcing our bodies to switch from using muscle movement for heat to generating brown fat and burning white fat for energy.
Hof’s relatively simple exercises made undeniable changes in my endurance levels, seemingly overnight. I hadn’t gone on the trip with the intention of losing weight, but at the end of seven days I had shed 7lb of fat. After another six months of training, I reached the peak of Kilimanjaro with him in less than 30 hours – most of them spent not wearing a shirt.
You don’t have to mount summits, bare-chested, to reap the benefits. The good news is that placing yourself in even moderately cold temperatures, for instance by setting your thermostat to less than 15C [more than a third of Britons keep theirs at 25C] for a few weeks – and not wearing lots of layers to insulate yourself from it – can reinvigorate our evolutionary programming, improve our circulation, activate brown fat and kick our metabolism into high gear.
Try taking 30-second cold showers and build up from there – turn the knob as low as it will go and let the cold water cascade over your head, back, chest and legs. The immediate sensations are rarely pleasant. You’ll start breathing fast, your pupils will dilate, and you’ll want to start moving to keep warm.
While you’re in this moment of shock and pain, you have two basic goals. First, to control your breathing and keep calm. The burning sensations will dissipate if you focus your mind on the pain and relax, instead of tightly clenching up every muscle. Once you feel reasonably calm, the second thing you need to master is suppressing your impulse to shiver yourself warm, so that your body generates brown fat.
I also find shirtless runs (while other brave souls are clad in fleece) one of the most comfortable ways to practice the Wim Hof method, because your core temperature spikes as soon as you get moving.
Part of the reason humans have become weaker is because we’ve insulated ourselves from experiencing variety in our daily lives. Make yourself a little uncomfortable, and you might not just reap the benefits, but discover it isn’t nearly as bad as you imagined.
WARNING: Prolonged breath holding and cold exposure can have inherent health risks. Consult a doctor before beginning any practice.
What Doesn’t Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength by Scott Carney is published by Scribe (£14.99).
The Telegraph, London