…g workout-tracking apps last fall after recognizing that she was becoming obsessive about exercise. Those feelings came rushing back when she found herself in an interval training class that doled out heart rate monitors so attendees could monitor—and broadcast—how they were doing. “When there are screens displaying everyone’s statistics throughout the class, it basically singles out people who ‘aren’t working as hard,’” she says. “Everyone has different fitness levels, goals, and abilities, and it makes you feel either inferior …
