title: A unique, fast-forwards rotating schedule with 12-h long shifts prevents chronic sleep debt.
abstract: Sleep debt--together with circadian misalignment--is considered a central factor for adverse health outcomes associated with shift work. Here, we describe in detail sleep-wake behavior in a fast-forward rotating 12-h shift schedule, which involves at least 24 hours off after each shift and thus allows examining the role of immediate recovery after shift-specific sleep debt. Thirty-five participants at two chemical plants in Germany were chronotyped using the Munich ChronoType Questionnaire for Shift-Workers (MCTQ(Shift)) and wore actimeters throughout the two-week study period. From these actimetry recordings, we computed sleep and nap duration, social jetlag (a measure of circadian misalignment), and the daily timing of activity and sleep (center of gravity and mid-sleep, respectively). We observed that the long off-work periods between each shift create a fast alternation between shortened (mean ± standard deviation, 5h 17min ± 56min) and extended (8h 25min ± 72min) sleep episodes resulting in immanent reductions of sleep debt. Additionally, extensive napping of early chronotypes (up to 3 hours before the night shift) statistically compensated short sleep durations after the night shift. Partial rank correlations showed chronotype-dependent patterns of sleep and activity that were similar to those previously described in 8-h schedules; however, sleep before the day shift did not differ between chronotypes. Our findings indicate that schedules preventing a build-up of chronic sleep debt may reduce detrimental effects of shift work irrespective of shift duration. Prospective studies are needed to further elucidate the relationship between sleep, the circadian system, and health and safety hazards.
authors.affiliation: a Institute of Medical Psychology, Ludwig-Maximilian-University , Munich , Germany.|b Harvard T. H. Chan School of Public Health , Boston , MA , USA.|c Liberty Mutual Research Institute for Safety , Hopkinton , MA , USA.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Fischer
authors.affiliation: a Institute of Medical Psychology, Ludwig-Maximilian-University , Munich , Germany.|d Channing Division of Network Medicine , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA.
authors.forename: Céline
authors.initials: C
authors.lastname: Vetter
authors.affiliation: e Occupational Medical and Health Protection Department, BASF Societas Europaea , Ludwigshafen , Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Oberlinner
authors.affiliation: e Occupational Medical and Health Protection Department, BASF Societas Europaea , Ludwigshafen , Germany.|f Deutsche Gesellschaft für Internationale Zusammenarbeit , Eschborn , Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Wegener
authors.affiliation: a Institute of Medical Psychology, Ludwig-Maximilian-University , Munich , Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Roenneberg
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D020179:Jet Lag Syndrome / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*; D014940:Work Schedule Tolerance; D055815:Young Adult
keywords: MCTQ; Shift work; chronotype; circadian misalignment; napping; shift sequence; social jetlag