Alerting effects of light.
Light exerts powerful non-visual effects on a wide range of biological functions and behavior. In humans, light is intuitively linked with an alert or wakeful state. Compared to the effects of light on human circadian rhythms, little attention has been paid to its acute alerting action. Here I summarize studies from the past two decades, which have defined and quantified the dose (illuminance levels), exposure duration, timing and wavelength of light needed to evoke alerting responses in humans, as well as their temporal relationship to light-induced changes in endocrinological and electrophysiological sequelae of alertness. Furthermore, neuroanatomical and neurophysiological findings from animal studies elucidating a potential role of light in the regulation of sleep/wake states are discussed. A brief outlook of promising clinical and non-clinical applications of lights' alerting properties will be given, and its involvement in the design of more effective lighting at home and in the workplace will be considered.
Cajochen
Christian
C
Centre for Chronobiology, Psychiatric University Clinics, Wilhelm Kleinstr. 27, CH-4025 Basel, Switzerland. christian.cajochen@unibas.ch
D000818:Animals; D001143:Arousal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008029:Lighting; D010789:Phototherapy / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D016574:Seasonal Affective Disorder / Q000628:therapy; D013647:Task Performance and Analysis; D014851:Wakefulness / Q000502:physiology