Based on an ethnographic study in a functional rehabilitation center for patients suffering a heart attack, the article focuses on the social conditions of formation of self in the context of prevention of cardiovascular diseases. We study the medical activities aimed at inculcating the patient, following the heart attack, to self monitor their disease and control their lifestyle, contractually establishing a figure of a “self carer.” In the context of the center, this results in a working agreement between professionals and patients concerning what to do for the long term management of the illness. This work is the articulation of two social worlds: The care that establishes the principles or the structure of the contract for securing the trajectory of the disease; and the patient, as well as his lifestyle, who attempts to transform these principles into personal reasons. We show the extent to which rehabilitation can be seen as a series of medical knowledge legitimation trials, and how, within caregiver patient interactions, it spreads as a practical knowledge. The learning of the self carer profession takes place as a transition from one of these action plans to another and permits, among others, to awaken the patient to new bodily limitations caused by the accident, as well as to the knowledge and expertise required to manage the disease in the long term.