01544nas a2200229   4500000000100000008004100001260007600042653002200118653001100140653001800151653001600169100002200185700002900207700003000236700003200266245006700298300001200365490000700377520090200384022001401286020001401300       2010                            d  c06/2010bSociedad Española para el Estudio de la Ansiedad y el Estrés10acircadian rhythms10aHealth10alight therapy10aperformance1 aJulio Lillo Jover1 aLeticia Álvaro Llorente1 aHumberto Moreira Villegas1 aM. del Carmen Durán Pulido00aCircadian rhythms and light: Effects on health and performance  a259-2690 v163 aA general view on circadian system structure and performance is provided for a better understanding of the problems derived from its malfunction and the ways to compensate for the negative effects using light therapy. The relevance of exposure to light-darkness cycles, in order to synchronize the circadian system, is highlighted and the reasons behind night-shift workers  ill health are explained. Differences between circadian and visual stimulation are given which relates to the reasons why standard photometry does not provide accurate measurements for the optimum stimulation of the circadian system. Finally, the philosophy of light therapy and its efficacy in avoiding/eliminating problems associated with inaccurate circadian system functioning in reference to (1) its transitory activation, (2) biological and chronological clocks mismatches and (3) seasonal depression, are described.  a1134-7937  a2174-0437