Fitness trackers are becoming increasingly popular when it comes to promoting a healthier lifestyle and more effective training. Ever more compact sensors that are worn on the body, so-called wearables, can record data such as step count, pulse, oxygen saturation, or skin conductance and thus provide indicators of physical and mental stress. In the working environment, too, wearables can help to reduce stress and physical overload or improve occupational safety. However, self-measurement must not violate privacy, but must respect the right to informational self-determination. In the joint project “WearPrivate”, an interdisciplinary team under the leadership of Fraunhofer IESE is investigating how wearables can be used in the work context for health protection in such a way that employees retain control over their data.