The Effect of Short Rest Periods Between Shifts (“Quick Returns”) on Sleep, Sleepiness, and Work-related Fatigue 

Employees in the European Union are entitled to at least 11 consecutive hours off between two work shifts. If shorter, it is referred to as a “quick return”. Despite this provision, approximately 23% of the European workforce regularly have quick returns in their work schedule. Quick returns typically occur in shift schedules when employees finish work late in the evening and start early the next morning. Studies show that quick returns are linked to an increased risk of accidents, sickness absence, fatigue, and sleep disturbances. These issues are thought to be caused by not getting enough time for sleep and recuperation between shifts. 

As part of the project; “Towards a sustainable work force in the healthcare sector for the 21st century: Health Promoting Work Scheduels” (funded by the Research Council of Norway, grant no: 303671), the Bergen Sleep and Chronobiology Network at the University of Bergen (www.BeSCN.no) has studied the effects of quick returns on sleep and fatigue in both a laboratory context and in the real-life setting among healthcare shift workers. Laboratory studies offer the advantage of controlling for variations in work load and tasks, thus eliminating common confounders of a regular workday. However, their applicability to real-world settings is uncertain, making field studies essential. Together, these approaches offer comprehensive and unique insights into the mechanisms and effects of quick returns. 

In the laboratory study, we explored the causal mechanism of short rest between shifts by simulating a quick return scenario. Participants were present in the laboratory for an evening shift from 15:00 to 23:00, followed by a day shift from 07:00 to 15:00 (8h rest period), and compared this to a control condition with two consecutive day shifts (16h rest period). Between shifts, the participants slept at home, where sleep was reported in a sleep diary and recorded with a sleep radar. In the field study we conducted the first large-scale cluster randomised controlled trial to determine the causal effects of quick returns among healthcare workers at a university hospital. The included 66 hospital units (1314 workers) were randomly assigned to a shift schedule with reduced quick returns (invervention) or to a schedule maintaining the usual number of quick returns (control) for six months. The workers reported symptoms of insomnia, daytime sleepiness and work-related fatigue in questionnaires before and towards the end of the intervention period.  

Although several field studies have shown that quick returns shorten sleep duration, results from the laboratory study indicates that this shortened sleep duration is causally determined by the amount of time shift workers have available between shifts. Additionally, the study also indicated that sleep quality and sleep stages are reduced in a quick return, which are important parameters in determining the health of shift workers. Furthermore, results from the randomised controlled trial demonstrated that halving the number of quick returns in the shift schedule had beneficial effects on insomnia and daytime sleepiness, but not work-related fatigue. Overall, the results emphasize the importance of adequate daily rest periods in shift schedules.