Circadian adaptation to night shift work is associated with higher REM sleep duration

On average, bedtime occurred 2.16 hours before the acrophase of aMT6s in the partially adapted group.

• Individuals in the partially adapted group had more sleep in the week prior to the simulated night shift compared to the unadapted group (6.47 vs. 5.26 hours).
• Total sleep time after the simulated night shift was similar between both groups (6.68 hours in partially adapted vs. 6.63 hours in unadapted).
• The partially adapted group experienced longer durations of rapid eye movement sleep compared to the unadapted group (106.79 vs. 77.90 minutes).
• Rapid eye movement sleep accumulation was significantly higher in the partially adapted group after 5 hours compared to the unadapted group.
• Circadian adaptation did not affect sleep latency or other sleep stages.

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