title: Sleep inertia during a simulated 6-h on/6-h off fixed split duty schedule.
abstract: Sleep inertia is a safety concern for shift workers returning to work soon after waking up. Split duty schedules offer an alternative to longer shift periods, but introduce additional wake-ups and may therefore increase risk of sleep inertia. This study investigated sleep inertia across a split duty schedule. Sixteen participants (age range 21-36 years; 10 females) participated in a 9-day laboratory study with two baseline nights (10 h time in bed, [TIB]), four 24-h periods of a 6-h on/6-h off split duty schedule (5-h TIB in off period; 10-h TIB per 24 h) and two recovery nights. Two complementary rosters were evaluated, with the timing of sleep and wake alternating between the two rosters (2 am/2 pm wake-up roster versus 8 am/8 pm wake-up roster). At 2, 17, 32 and 47 min after scheduled awakening, participants completed an 8-min inertia test bout, which included a 3-min psychomotor vigilance test (PVT-B), a 3-min Digit-Symbol Substitution Task (DSST), the Karolinska Sleepiness Scale (KSS), and the Samn-Perelli Fatigue Scale (SP-Fatigue). Further testing occurred every 2 h during scheduled wakefulness. Performance was consistently degraded and subjective sleepiness/fatigue was consistently increased during the inertia testing period as compared to other testing times. Morning wake-ups (2 am and 8 am) were associated with higher levels of sleep inertia than later wake-ups (2 pm and 8 pm). These results suggest that split duty workers should recognise the potential for sleep inertia after waking, especially during the morning hours.
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.
authors.forename: Cassie J
authors.initials: CJ
authors.lastname: Hilditch
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.|b School of Psychology , Flinders University , Adelaide , South Australia , Australia.
authors.forename: Michelle
authors.initials: M
authors.lastname: Short
authors.affiliation: c Sleep and Performance Research Center , Washington State University , Spokane , WA , USA.|d Elson S. Floyd College of Medicine , Washington State University , Spokane , WA , USA.
authors.forename: Hans P A
authors.initials: HP
authors.lastname: Van Dongen
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Centofanti
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.
authors.forename: Jillian
authors.initials: J
authors.lastname: Dorrian
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Kohler
authors.affiliation: a Centre for Sleep Research , University of South Australia , Adelaide , South Australia , Australia.
authors.forename: Siobhan
authors.initials: S
authors.lastname: Banks
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000503:physiopathology; D020178:Sleep Disorders, Circadian Rhythm / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology*; D014940:Work Schedule Tolerance / Q000502:physiology*; D055815:Young Adult
keywords: Psychomotor vigilance test (PVT); shift work roster; split shifts; split sleep; subjective fatigue; subjective sleepiness