This paper aims at contributing to the constantly growing literature on the dynamics of (self assessed) health. Using the eight waves of the Health and Retirement Study, targeting elderly Americans over the age of 50, we measure persistence in bad health using an index borrowed from the literature on persistent poverty. This new approach, which is totally non parametric in the way it defines the relationship (for each individual and along the time) among years of poor and not poor health, allows to catch some interesting links between the subjective health and several factors such as education, life styles and socioeconomic status that may have a long-lasting influence on an individual’s health.