Cardiovascular diseases are the leading cause of death and disability worldwide. They are mainly caused by lifestyle risk factors, such as physical inactivity, which is also the fourth leading risk factor for mortality. Regular physical activity is crucial for the prevention and treatment of cardiovascular diseases. Nevertheless, success in achieving long-term adherence to physical activity recommendations after an acute cardiac event or even after exercise-based cardiac rehabilitation is rather low. Furthermore, even though most research has focused on physical activity, engaging in reduced amounts of sedentary behavior is also crucial, as it represents an important cardiovascular risk even after adjusting for physical activity. Health behavior change theories, such as the transtheoretical model, and empirical evidence highlight the importance of motivation and motivational factors in the behavior maintenance or change process. Thus, the main goal of the present study is to assess preliminary effectiveness of an intervention mostly based on the transtheoretical model to promote cardiovascular patients' motivation to be physically active and to engage in reduced amounts of sedentary behavior. Most intervention components will be delivered digitally to the participants' smartphones via a study specific app. Furthermore, weekly questionnaires allow the investigators' to individualize the intervention components and investigate associations not only between-subjects, but also within-subjects over time, which is essential and has been neglected in the literature. The primary objective is to assess study feasibility.
This study investigates the feasibility of an app based intervention, which uses questionnaires and personalized motivational messages to achieve change in physical activity and sedentary behaviour of cardiovascular patients. The questionnaires and messages are based on behaviour change theories, such as the transtheoretical model. The intervention will take place over eight weeks. One week before and during the last week, physical activity will be measured via accelerometers. A comprehensive questionnaire will be given before and at the end of the intervention and Feasibility measures will be evaluated at the end as well, including an optional qualitative interview with the participants.