Stress is physiological response, whose purpose is to mobilize the reserves of the body.
This recruitment of bodily resources is mediated through different mechanisms including stress hormones. In chronic stress there is a perpetually increased level of stress hormones. The reason may be anxiety provoking psychological mechanisms or a life or work situation that is experienced as insecure demanding or overtaxing. Chronic stress leads sooner or later to so called burnout. It manifests as psychological and physiological disturbances and ultimately diseases.