Jeff Newman

“When my colleague Dr. Aaron Baggish attached accelerometers (tiny devices, like Fitbits, that measure steps per day) to more than twenty Tarahumara men, he discovered they walked on average ten miles a day. In other words, the training that enables them to run back-to-back marathons is the physical work that is part and parcel of their everyday life.”
― Daniel E. Lieberman, Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding