Myocardial infarction is the most common cause of death in Sweden today and is responsible for approximately 30% of all deaths. The aim of this study was to obtain increased knowledge and understanding of what motive power is and how it affects the individual's rehabilitation and return to a functioning daily life. Thirteen patients, six females and seven males, who had experienced a myocardial infarction, aged between 39 and 72 years and with a minimum interval from myocardial infarction diagnosis of at least 12 months, were interviewed. Grounded theory was the method used for data collection and analysis, since the method is focusing on social processes and interaction. The analysis process identified motive power as a core category: zest for life. The participants expressed a desire and a longing to continue living. The participants' experiences of their disease as well as being discharged from hospital forced them to reorientation. Autonomy, the individual's own active decision-making, plays a significant role in this zest for life. Care for was identified as the support base for zest for life. As health-care professionals we must, at a very early stage on the ward, form an idea of what kind of patient we have in front of us.