Running is what made us human... It defined a large part of our genetic makeup: our (relative) lack of body hair, the way we sweat, our bone structure, the fun

Running is what made us human... It defined a large part of our genetic makeup: our (relative) lack of body hair, the way we sweat, our bone structure, the function of our leg muscles in pumping blood back to the heart, a cardiovascular system with more endurance than any other land mammal.