Influences of Recovery Time and Time of Day on Sleep Duration Prior Work Shifts: Analysing Diary and Actigraphy Data From 14 Studies

Introduction: Flexible working hours are common and recovery times between shifts vary extensively. It seems obvious that shorter recovery times curtail sleep duration, but there is a poor understanding of how time of day affects this relationship.

Methods: The analyses were based on diary and actigraphy data from 328 subjects in 14 data collections at 11 work sites in Sweden, Finland and Australia, totally rendering data on 4000 sleep episodes. The recovery times between shifts were used to predict sleep duration before morning, evening and night shifts using multilevel mixed effects modeling.

Results: Sleep duration was strongly associated with recovery times between shifts, particularly before evening and night shifts (b=+.31 hours of total sleep time for each hour of recovery time, p=.012; and b=+.34 hours, p < .001, respectively). More recovery time before morning shifts was also a significant predictor of sleep duration (b=+.12 hours, p < .001), but this amount of sleep seemed more affected by schedule specific factors, e.g., the starting time of the morning shift. In addition, sleep duration was strongly affected by work site and individual differences.

Conclusion: Sleep duration prior shifts are curtailed by several factors including 1) short recovery times between shifts, 2) circadian influences (most dramatically shortened prior evening and night shifts), 3) shift specific aspects (e.g., change-over times), and 4) individual differences. It is recommended to avoid recovery times shorter than 12 hours off between shifts, since it drastically increases the number of workers having curtailed sleep.

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Artikel online veröffentlicht:
08. Oktober 2025