 We previously evidenced in both animal models and patients that a short duration ambulatory anesthesia impacts the circadian rest-activity biological rhythm, at least during the first 3 days. The light is the main, natural synchronisateur, of the biological cerebral clock, and is used as therapeutics in chronic disturbances of the circadian rest activity rhythm and of the sleep Alzheimer disease for example. We would like to test for a simple and safe strategy to prevent such a long-lasting effect of anesthesia on biological clock:the increase of the light intensity at a still physiological level during the initial phase of recovery from anesthesia by using a particular artificial light of color spectrum similar to natural sun daylight. 