The stress response system evolved early in mammalian evolution as a response to acute stressors. Two physiological systems, the sympathetic adrenal medullary system and the hypothalamic pituitary adrenal axis, respond to stress; collectively these systems serve to increase mental alertness and provide energy to allow an organism to respond rapidly to an emergent situation. While the response is adaptive for short-term and infrequent stressors, modern human life presents more persistent stressors which can have a negative impact on health. Psychosocial stress has a variety of emotional, behavioral, and physiological consequences. Biological anthropologists have demonstrated that environmental changes, cultural transitions, and every day stressors result in elevated stress markers and negative health consequences across the lifespan.