The second you step out and have a brush with near-arctic winds, these tiny muscles flex.Įxercising that system is important: Cardiovascular diseases contribute to 31 percent of the world’s mortality. Tiny muscles line the arteries and veins and help push the blood through the body, which is critical for circulation and regulating blood pressure.
This blood superhighway is more than just a series of tubes it’s an active and responsive system. In a single day, roughly four to seven liters of blood travel thousands of miles. To explain why, you need to look at the human circulatory system, a complex network of arteries and veins that carry blood and oxygen to and from every tissue. Because stepping outside on a frigid day in only a T-shirt creates a cascade of physiological responses that deliver benefits similar to a workout. The bulk of us don’t see environmental stress in the same light as we do, say, jogging.īut we should. Take a plunge into cold water and not only will you trigger a number of processes to warm up the body, but those adjustments will help regulate blood sugar, exercise the circulatory system, and heighten mental awareness. And almost no environmental extreme induces as many changes in human physiology as the cold. Our muscles, organs, nerves, fat tissue, and hormones respond and adapt to changes or threats from the outside world. Human biology needs stress - and not the sort that damages muscle, gets us eaten by a bear, or degrades our physiques, but the environmental and physical fluctuations that invigorate our nervous system. In the past, comfort was almost indistinguishable from safety. There is a consensus among many scientists and athletes that humans were not built for constant homeostasis. It is almost as if our bodies have so little to struggle against that our stored energy instead wreaks havoc on our insides. Millions suffer from autoimmune diseases - arthritis, lupus, Crohn’s - in which the body literally attacks itself. Obesity, diabetes, chronic pain, arthritis, and hypertension are all at record highs. The last century saw an explosion of ”diseases of excess” in the developed world, or what happens when you have too much food and your lifestyle is sedentary. Compare your pasty-skinned office mate to one of our prehistoric ancestors, and bets are good that the modern-day man is fatter, lazier, and in worse health. But succeeding over the natural world hasn’t made our bodies stronger. Our modern-day struggles pale in comparison to the daily threats of death or deprivation that our forebears faced.
Variation and stress were the norm comfort, the exception. To get from then to now, we faced countless challenges as we fled predators, froze in snowstorms, sought shelter from rain, hunted and gathered our food, and continued to breathe despite suffocating heat. Which means your office mate 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. Humans have had the same anatomical makeup for nearly 200,000 years. So we jack up the heat on cold winter days, ratchet down the air-conditioning in the summer, and don sunglasses when it’s a little too bright outside.īut it hasn’t always been that way. The body craves homeostasis, the effortless state in which the environment meets our every physical need and the body can rest. If I had a spirit animal, it would probably be a jellyfish floating in an ocean of perpetual comfort. Nor do I particularly want to be cold, wet, or hungry. MORE: Laird Hamilton's Morning Ritual Read article I’m wearing boots, swim trunks, a wool cap, and a backpack containing emergency gear and water. Our goal is to reach the peak in 30 hours, with no acclimation to the altitude, on almost no food, on little sleep, and without any cold-weather gear. Usually they spend time adjusting to altitude and then embark on a five- or six-day climb, wearing the most advanced mountaineering apparel - waterproof down jackets, insulated trekking pants. Upwards of 35,000 tourists attempt to summit the mountain each year. It’s the first time our group of amateur climbers has seen it this close, and I can’t decide whether I’m excited or terrified. There, at nearly 20,000 feet, winds top 50 miles an hour and scour what is likely the only indigenous ice on the continent. Africa’s tallest mountain rises up out of the sun-drenched savanna to a place high above the clouds. Soon dawn sets the glacier ablaze like a beacon. At first it is only a dark purple absence of stars in a pinpricked sky.