title: Toward optimizing lighting as a countermeasure to sleep and circadian disruption in space flight.
abstract: Light is being used as a pre-launch countermeasure to circadian and sleep disruption in astronauts. The effect of light on the circadian system is readily monitored by measurement of plasma melatonin. Our group has established an action spectrum for human melatonin regulation and determined the region of 446-477 nm to be the most potent for suppressing plasma melatonin. The aim of this study was to compare the efficacy of 460 and 555 nm for suppressing melatonin using a within-subjects design. Subjects (N=12) were exposed to equal photon densities (7.18 x 10(12) photons/cm2/s) at 460 and 555 nm. Melatonin suppression was significantly stronger at 460 nm (p<0.02). An extension to the action spectrum showed that 420 nm light at 16 and 32 microW/cm2 significantly suppressed melatonin (p<0.04 and p<0.002). These studies will help optimize lighting countermeasures to circadian and sleep disruption during spaceflight.
authors.affiliation: Thomas Jefferson University, Philadelphia, Pennsylvania, USA. Robert.Fucci@jefferson.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Fucci
authors.forename: James
authors.initials: J
authors.lastname: Gardner
authors.forename: John P
authors.initials: JP
authors.lastname: Hanifin
authors.forename: Samar
authors.initials: S
authors.lastname: Jasser
authors.forename: Brenda
authors.initials: B
authors.lastname: Byrne
authors.forename: Edward
authors.initials: E
authors.lastname: Gerner
authors.forename: Mark
authors.initials: M
authors.lastname: Rollag
authors.forename: George C
authors.initials: GC
authors.lastname: Brainard
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D018480:Astronauts / Q000523:psychology; D002940:Circadian Rhythm / Q000528:radiation effects; D003315:Cornea / Q000528:radiation effects; D006804:Ergonomics; D005118:Extraterrestrial Environment; D005260:Female; D006801:Humans; D008027:Light; D008029:Lighting / Q000379:methods*; D008297:Male; D008550:Melatonin / Q000097:blood* / Q000528:radiation effects*; D017299:Rod Opsins; D012890:Sleep / Q000528:radiation effects; D013026:Space Flight / Q000295:instrumentation; D018531:Spacecraft / Q000295:instrumentation; D014893:Weightlessness; D000099210:Melanopsin
chemical_list: D008550:Melatonin; D017299:Rod Opsins; D000099210:Melanopsin