title: Adaptation of the circadian rhythm of 6-sulphatoxymelatonin to a shift schedule of seven nights followed by seven days in offshore oil installation workers.
abstract: This study evaluated circadian adaptation in a 'swing shift' schedule (seven nights, 18:00-06:00 h; then 7 days, 06:00-18:00 h) on North Sea oil installations. Eleven healthy men provided sequential urine collections for the study period offshore. The urinary melatonin metabolite 6-sulphatoxymelatonin (aMT6s) was used as an index of circadian phase. A significant difference (P=0.0004) was found between the mean aMT6s acrophase (calculated peak time) at the start (+/-SD: 05:34+/-2.42 h) and end (+/-SD: 10.95+/-3.34 h) of the night shift week, but not between the start (+/-SD: 11:04+/-4.03 h) and end (+/-SD: 12:59+/-8.83 h) of the day shift week. As a group, the subjects adapted to the night shift but very large individual variations were seen during the day shift. These individual differences clearly require further study.
authors.affiliation: Neuroendocrinology Research Group, Centre for Chronobiology, School of Biomedical and Life Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
authors.forename: M
authors.initials: M
authors.lastname: Gibbs
authors.forename: S
authors.initials: S
authors.lastname: Hampton
authors.forename: L
authors.initials: L
authors.lastname: Morgan
authors.forename: J
authors.initials: J
authors.lastname: Arendt
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives* / Q000652:urine*; D008875:Middle Aged; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: C054513:6-sulfatoxymelatonin; D008550:Melatonin