Excerpt from "Born to Run"

"Humans are among the most communal and cooperative of all primates; our sole defense in a fang-filled world was our solidarity, and there's no reason to think we suddenly disbanded during our most crucial challenge, the hunt for food...

"'But there's a problem,' Dr. Bramble said. He tapped his forehead. 'And it's right up here.' Our greatest talent, he explained, also created the monster that could destroy us. 'Unlike any other organism in history, humans have a mind-body conflict: we have a body built for performance, but a brain that's always looking for efficiency.' We live or die by our endurance, but remember: endurance is all about conserving energy, and that's the brain's department. 'The reason some people use their genetic gift for running and others don't is because the brain is a bargain shopper.'"

"For millions of years, we lived in a world without cops, cabs, or Domino's Pizza; we relied on our legs for safety, food, and transportation, and it wasn't as if you could count on one job ending before the next one began. Look at []Nate's wild hunt with Louis; []Nate sure wasn't planning on a fast 10k immediately after a half-day hike and a high-speed hunt, but he still found the reserve energy to save Louis's life. Nor could his ancestors ever be sure that they wouldn't become food right after catching some; the antelope they'd chased since dawn could attract fiercer animals, forcing the hunters to drop lunch and run for their lives. The only way to survive was to leave something in the tank--and that's where the brain comes in."

"'The brain is always scheming to reduce costs, get more for less, store energy and have it ready for an emergency,' Bramble explained. 'You've got this fancy machine, and it's controlled by a pilot who's thinking, "Okay, how can I run this baby without using any fuel?" You and I know how good running feels because we've made a habit of it.' But lose the habit, and the loudest voice in your ear is your ancient survival instinct urging you to relax. And there's the bitter irony: our fantastic endurance gave our brain the food it needed to grow, and now our brain is undermining our endurance."

"'We live in a culture that sees extreme exercise as crazy,' Dr. Bramble says, 'because that's what our brain tells us: why fire up the machine if you don't' have to?'"

"To be fair, our brain knew what it was talking about for 99 percent of our history; sitting around was a luxury, so when you had the chance to rest and recover, you grabbed it. Only recently have we come up with the technology to turn lazing around into a way of life; we've taken our sinewy, durable, hunter-gatherer bodies and plunked them into an artificial world of leisure. And what happens when you drop a life-form into an alien environment? NASA scientists wondered the same thing before the first space flights. The human body had been built to thrive under the pressure of gravity, so maybe taking away that pressure would act as an escape-trajectory Fountain of Youth, leaving the astronauts feeling stronger, smarter, and healthier. After all, every calorie they ate would now go toward feeding their brains and bodies, instead of pushing up against that relentless downward pull--right?"

"Not by a long shot; by the time the astronauts returned to earth, they'd aged decades in a matter of days. Their bones were weaker and their muscles had atrophied; they had insomnia, depression, acute fatigue, and listlessness. Even their taste buds had decayed. If you've ever spent a long weekend watching TV on the sofa, you know the feeling, because down here on earth, we've created our own zero-gravity bubble; we've taken away the jobs our bodies were meant to do, and we're paying for it. Nearly every top killer in the Western world--heart disease, stroke, diabetes, depression, hypertension, and a dozen forms of cancer--was unknown to our ancestors. They didn't have medicine, but they did have a magic bullet--or maybe two, judging by the number of digits Dr. Bramble was holding up."

"'You could literally halt epidemics in their tracks with this one remedy' he said. He flashed two fingers up in a peace sign, then slowly rotated them downward till they were scissoring through space. The Running Man."

"'So simple,' he said. 'Just move your legs. Because if you don't think you were born to run, you're not only denying history. You're denying who you are.'"