Everyone is built for running.

The words of the social critic Eric Hoffer were ringing true: "Every great cause begins as a movement, becomes a business, and turns into a racket."

The only way to truly conquer something, as every great philosopher and geneticist will tell you, is to love it.

You don't have to be fast. But you'd better be fearless.

The Tarahumara would party like this all night, then rouse themselves the next morning to face off in a running race that could last not two miles, not two hours, but two full days. According to the Mexican historian Francisco Almada, a Tarahumara champion once ran 435 miles, the equivalent of setting out for a jog in New York City and not stopping till you were closing in on Detroit.

If you can run six miles on a summer day, then you, my friend, are a lethal weapon in the animal kingdom.

Nearly all runners do their slow runs too fast, and their fast runs too slow." Ken Mierke says. "So they're just training their bodies to burn sugar, which is the last thing a distance runner wants. You've got enough fat stored to run to California, so the more you train your body to burn fat instead of sugar, the longer your limited sugar tank is going to last." -The way to activate your fat-burning furnace is by staying below your aerobic threshold--your hard-breathing point--during your endurance runs.