Pervasive healthcare aims at applying mobile and ubiquitous computing technologies to address some of the major issues facing healthcare, such as the aging of the population, an increase in the prevalence of chronic diseases and escalating costs. One of the main characteristics of pervasive healthcare systems is their reliance on contextual information such as using the location of a nurse in a hospital ward to provide her with information relevant to the task at hand, or reminding a patient to take his medication when he returns home and his pillbox has not been opened during the day. Advances in activity recognition have made possible a second generation of pervasive healthcare solutions using activity-aware computing to identify the activities of daily living being performed by an elder and assist her with the task, or to monitor the intensity of the physical activity performed by a patient undergoing treatment. Moving forward this paper describes a new wave of pervasive healthcare applications, which are becoming possible due to progress in the estimation of user behavior. These behavior-aware systems can be used to measure the effects of medication in patients suffering from mental disorders, provide feedback in rehabilitation therapies or to perceive abnormal behaviors that provide early signs of an ailments such as Alzheimer's disease.