The term allostasis denotes long-term adaptation processes, by which the organism maintains homeostasis in the context of chronic stressor load. This ensures survival, but also increases waste and ageing (allostatic load). Allostasis results from a directed change in the parameters of affected information processing structures. Consequently, beneficial alterations in the behaviour of the respective system ensue, but in the long-term also setpoint diseases. The term was first coined by Sterling and Eyer in order to sharpen the concept of stress response. Examples for allostatic reactions are