Testing Self-Control as a Behavior Change Mechanism to Increase Physical Activity

It is widely known that being physically active is beneficial for one's health and well-being, yet only a small percentage of adults engage in the recommended amounts of physical activity. Research has shown that health-damaging behaviors such as a sedentary lifestyle can be attributed in part to a lack of self-control. There is some evidence that self-control strategies can be improved with targeted interventions. The overall aim of the proposed study is to test self-control as a behavior change mechanism for physical activity and to investigate whether a smartphone-based self-control intervention can increase physical activity among sedentary middle-aged and older adults. To test the effect of this self-control intervention, participants will be randomized into two conditions: The self-control treatment group and the control group. Both groups will track their daily physical activity using a Fitbit step counter over eight weeks. Additionally, the self-control intervention group will receive a 7-week smartphone-based self-control intervention to learn strategies how to potentiate desirable impulses or weaken undesirable ones. It is expected that the self-control treatment group will show greater increases in physical activity and that changes will last longer compared to the control group. Self-control is expected to mediate the relationship between condition and physical activity. It is predicted that the self-control treatment group will show greater changes in self-control compared to the control group and that people who increase more in self-control also increase more in their physical activity. Two versions of the MindHike smartphone application will be used to communicate with all participants. The self-control treatment group will receive a version delivering a self-control intervention. The control group will receive a minimal version without the interventional components. Both groups are matched in terms of contact frequency.