Quick Returns - Sleep, Cognitive Functions and Individual Differences
Condition: Shift Work Schedule; Sleep Deprivation
MeSH terms: Sleep Deprivation
Study type: Interventional

Summary: 
      The project will contribute with new knowledge concerning how short rest periods between two
      consecutive shifts (<11h, often defined as a Quick Return (QR)) affects sleep and cognitive
      performance. The study will further examine whether individual differences in personality
      traits and genotypes may explain individual differences in performance and sleep. Data will
      be collected with a randomized cross-over design, in an experimental laboratory setting.
    

Detailed description: 
      Rotating shift workers may have a narrow time window to rest after an evening shift, before
      returning early to work for a day shift. In the literature, a rest opportunity of less than
      11 hours between two consecutive shifts, is defined as a Quick Return (QR). Most often, this
      is occurs when working an evening shift followed by a day shift. Survey- and longitudinal
      studies have found associations between QRs and an increased risk of being involved in
      occupational accidents. However, no studies have experimentally investigated how a QR
      scenario may affect performance at work and sleep between the two shifts. Thus, the project
      will experimentally simulate QRs, where a battery of cognitive tests will be administered in
      a laboratory to indicate performance. Objective and subjective sleep will be
      measured/reported at home where participants normally sleep. Additionally, genotype- and
      personality trait data will be collected and used as moderators in the analyses.

      A randomized cross-over design with two groups will be applied. In one condition,
      participants will work an evening shift (03:00PM-11:00PM) followed by a day shift
      (07:00AM-03:00PM, QR). In the other condition, participants work a day shift
      (07:00AM-03:00PM) followed by another day shift. Four weeks later after being in one of the
      conditions, the participants will return to the laboratory and work in the opposite
      condition. Sleep will be subjectively reported with a sleep diary and objectively measured
      using a low-powered ultra-wideband radar, two days before and between the two simulated
      shifts in each of the two conditions.
    

Intervention name(s): Short rest (8 hour) between two consecutive shifts.; 16 hour rest opportunity between to consecutive shifts.
Intervention type(s): Other; Other
Intervention description(s): Participants will have shortened rest opportunity (8 hours) between two consecutive shifts, due to the shift work schedule.; Participants will have a 16 hour rest opportunity between shifts, due to shift work schedule.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Participants are randomly assigned to the QR-condition (evening shift followed by a day shift) or a day shift followed by another day shift. After a four week wash-out, participants return to work in the opposite condition.
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Shift Work; Quick Return; Sleep; Cognitive Performance; Circadian Rhythm; Genotype; Shift Work Tolerance