title: Photic resetting in night-shift work: impact on nurses' sleep.
abstract: The objective of this study was to quantify daytime sleep in night-shift workers with and without an intervention designed to recover the normal relationship between the endogenous circadian pacemaker and the sleep/wake cycle. Workers of the treatment group received intermittent exposure to full-spectrum bright light during night shifts and wore dark goggles during the morning commute home. All workers maintained stable 8-h daytime sleep/darkness schedules. The authors found that workers of the treatment group had daytime sleep episodes that lasted 7.1 ± .1 h (mean ± SEM) versus 6.6 ± .2 h for workers in the control group (p = .04). The increase in total sleep time co-occurred with a larger proportion of the melatonin secretory episode during daytime sleep in workers of the treatment group. The results of this study showed reestablishment of a phase angle that is comparable to that observed on a day-oriented schedule favors longer daytime sleep episodes in night-shift workers. (Author correspondence: diane.boivin@douglas.mcgill.ca ).
authors.affiliation: Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montréal, Québec, Canada. diane.boivin@douglas.mcgill.ca
authors.forename: Diane B
authors.initials: DB
authors.lastname: Boivin
authors.forename: Philippe
authors.initials: P
authors.lastname: Boudreau
authors.forename: Francine O
authors.initials: FO
authors.lastname: James
authors.forename: N M K Ng Ying
authors.initials: NM
authors.lastname: Kin
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D002940:Circadian Rhythm; D003624:Darkness; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D008875:Middle Aged; D009726:Nurses; D012890:Sleep / Q000502:physiology*; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D008550:Melatonin