The ageing population and the increase in sedentary lifestyles of knowledge workers has led to increasing concerns about the physical activity habits of the European population. Pervasive technologies and theories of behavioral change are being combined in an effort to promote physical activity. The Activity Coach is an example of one such system. Whereas the previous version of the Activity Coach set a fixed and permanent daily goal, in this work we describe the addition of an automatically adaptive goal-setting feature to this existing system. With the new feature, the daily goals for physical activity are set based on the user’s routine, contributing to the personalization of the system. A technical evaluation was performed to test the system’s adaptation to the user’s routine. Additionally, a conversion factor between a unit of energy expenditure and number of steps was determined. The evaluation indicates that our method of goal-setting provides more challenging but still attainable goals when compared to the previous version. Additional evaluations are recommended to evaluate the user’s perception and effects on physical activity behavior change of this new feature. The results of this research are implemented in the existing Activity Coach and will be used in future patient evaluations.