Getty Images; raditya/iStock; Prykhodov/iStock; Tyler Le/BI Katie Anne Hayes felt like her Garmin watch was giving her a lot of valuable information, at least at first. She took particular interest in the "Body Battery" feature, which purports to tell users how much energy they've got left in the tank. Hayes says she started checking it "pretty religiously" to gauge whether she could handle a workout or weekend concert. If her battery was low, "that was usually a good predictor of how I'd feel