title: Effect of color temperature on melatonin production for illumination of working environments.
abstract: We studied the influence of correlated color temperature (CCT) of 7 polychromatic white light illuminations (1600 K-14,000 K, 200 lx) in two experiments. Visual performance was tested in 17 students (8 men) during daytime. Visual acuity, contrast sensitivity and sleepiness did not vary with illuminations but polychromatic white light of <2000 K impaired color discrimination. Melatonin synthesis was tested with weekly intervals in 8 trials from 10pm to 2am (7 polychromatic illuminations and a dim light reference (<0.1 lx)) in 16 students (9 men, semi-recumbent position). Melatonin suppression was almost negligible for CCT <2000 K but increased with increasing CCT.
  
  
  CONCLUSIONS
  CCTs <2000 K are not suitable for work places. Polychromatic white light with higher CCTs and significant melatonin suppression is expected to shift the circadian rhythm and to accelerate the adaptation to night work. This effect should be enhanced with elevation of luminance.
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors, University of Dortmund, Dortmund, Germany. Electronic address: kraneburg@ifado.de.
authors.forename: Anja
authors.initials: A
authors.lastname: Kraneburg
authors.affiliation: Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Franke
authors.affiliation: Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Methling
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors, University of Dortmund, Dortmund, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Griefahn
mesh_terms: D000328:Adult; D003116:Color; D005260:Female; D006801:Humans; D008027:Light; D008029:Lighting; D008297:Male; D008550:Melatonin / Q000032:analysis / Q000096:biosynthesis*; D012463:Saliva / Q000737:chemistry; D013696:Temperature; D014792:Visual Acuity; D017132:Workplace; D055815:Young Adult
chemical_list: D008550:Melatonin
keywords: Chronodisruption; Melatonin; Melatonin suppression; Night work; Phase shift; Polychromatic light; Shift work