Personal health wearable devices used to monitor heart rates, sleep patterns, calories, and even stress levels raise new privacy and security risks, according to a report released today by researchers at American University and the Center for Digital Democracy. Watches, fitness bands, and so-called “smart” clothing, linked to apps and mobile devices, are part of a growing “connected-health” system in the U.S., promising to provide people with more efficient ways to manage their own health.