Fitness tracker: How many steps should you take in a day and at what pace?
Fitness Tracker : Humans, once in constant motion as hunters and gatherers, are moving less than ever. At first, this trend seemed like progress: Transferring our heavy and dangerous work to animals, then machines, enabled more people to live longer. As recently as the 1950s, doctors considered exercise dangerous for people over age 40; for heart disease, which was then killing a record number of Americans, they prescribed bed rest. This was partly based on their concept of what “exercise” was: Early physiologists conducted studies on their (typically young, male) graduate students or on military servicemen — and in order to become more fit than they already were, these subjects needed to work out hard. “The mantra was, you have to go to a gym, you have to do high-intensity physical activity,” says Abby C King, a professor of health research and policy and medicine at Stanford University: “this sort of ‘no pain, no gain’ phenomenon.” That notion began to change with the 1968 ...
