The task of setting exercise limitations on children with aortic stenosis is fraught with difficulties. In particular, teenagers are difficult to manage because of the increasingly professional demands of adolescents sports; the rapid changes in somatic growth, which are often accompanied by an increase in the severity of aortic valve disease; and the natural tendency of teenagers to disregard advice from authoritarian sources like a medical team. This article describes our innovative approach of using a heart-rate monitor as a means of modulating physical activity in adolescents with mild to moderate aortic stenosis. This approach enabled the setting of clear, precise, observable, measureable limits on physical activity, and self-controling of an acceptable level of physical activity. This created a different negotiation between the patient, his parents, and the medical team, and eased the concern and anxiety of the mothers.