“Wearables are so common these days we rarely give them second thought. Yet packed into FitBits and Apple Watches are multiple tiny, sensitive sensors that monitor your steps, heart rate, sleep and—with your input—even menstrual cycles. Smart watches that “watch you” are accurate enough that Apple, for example, is teaming up with Stanford University in a massive clinical trial to see if data collected using the watch can identify abnormal heart rhythms, including those that lead to serious damage to the heart’s blood vessels…”
