Fitness trackers are no good at counting calories, and other lessons ...

QuartzFitness trackers are no good at counting calories, and other lessons ...QuartzFor 10 days last month, I strapped on four fitness trackers for every waking hour—all in the name of science. I wore them to brunch. I wore them on my birthday. I wore them when I got sick and spent a full day in bed. For a week and a half, I was ...