Trackers can cause people to “fixate on a number”—whether that’s calories, steps, or minutes of sleep, reports New York magazine.
Unlike other quantified-self offshoots, sleep is much harder to control. Walking 10,000 steps a day is pretty much in your hands. Getting eight hours of sleep, however, is not. And this fixation on getting the best possible sleep can also encourage problematic sleep behaviors, Baron says.