Short daily rest periods (SDRPs) are particularly common when a morning shift on the next day follows an evening shift. They occur across many occupational categories, with 23% of workers in the European Union and 45-50% of U.S. retail workers experiencing them at least once a month. In Scandinavian healthcare, the prevalence is even higher, ranging from 60% to 83%, although the European Working Time Directive requires a minimum of 11 continuous hours of rest within every 24 hours. The Accreditation Council for Graduate Medical Education requires a minimum of 10 hours off for U.S. medical residents; however, no similar federal rules apply to other healthcare professionals. Employees consistently report SDRPs as one of the most undesirable work arrangements. They are associated with fatigue, sleep disturbance, stress, poor work-life balance, depressive symptoms, elevated risk of injury, and sickness absence.
This randomized clinical trial examined the effects of decreasing SDRPs to fewer than 11 hours between consecutive work shifts on disease-related absence and economic outcomes in healthcare workers.
In this study, a total of 811 participants who were working at least 80% of a full-time position were enrolled from multiple Norwegian healthcare institutions. However, the initial target sample size was 2,028 participants. Clusters of employees were randomized to either an intervention group, where SDRPs were reduced by half, or a control group, which maintained standard scheduling practices with usual SDRP frequency. The primary outcome was sickness-related absence, objectively measured using registry-based payroll data to minimize subjectivity or recall bias. Secondary outcomes included cost-benefit analyses, self-reported sleep quality, and perceived flexibility. Adherence to the intervention and potential unintended changes in scheduling, such as an increase in consecutive evening shifts, were carefully monitored and ruled out.
Statistical analyses included regression models with cluster adjustments to account for the randomized design. Sensitivity analyses tested robustness, and cost-benefit estimates were calculated using the human capital approach.
The study involved 66 hospitals with 811 participants (626 females [77.5%], mean standard deviation [SD] age: 29.8 years [12.8]) working at least 80 % or above of a full-time position. Of these, 31 clusters (344 workers) were assigned to the intervention group and 35 clusters (467 workers) to the control group. In the intervention group, the mean SD of SDRPs decreased to half during the intervention period, from 18 (8.4) to 9.2 (6.2). The frequency was the same in the control group (intervention period: 17.5 [8.4] days, reference time: 18.3 [8.3] days). The intervention groups revealed a small elevation in the sickness-related absence days (95% confidence interval [CI]: 0.41 to 0.79, incidence rate ratio [IRR]: 0.56, p < 0.001) and absence periods (95% CI: 0.61 to 0.86, IRR: 0.73, P < 0.001) compared with the control group. The impact on disease-related absence days in intervention units resulted in a positive projected net economic return of about NOK 1,174,620 ($213,600 USD) over 5 months.
This study found that decreasing SDRPs may improve the workforce health and decrease costs. However, concerns about type II error were raised due to the smaller-than-planned sample size and potential differences in baseline sickness rates, absence rates, and sex distribution between groups. Access to extended pre-intervention data could allow for a more robust evaluation of underlying trends. The natural environment and cluster design also limited precise estimation of baseline participant numbers.
The findings do not justify a complete ban on SDRPs. Instead, they suggest that SDRPs should be applied more judiciously and restrictively, balancing operational needs with workers’ well-being. Determining the ideal frequency of SDRPs requires weighing the health risks, employee preferences, and operational efficiency.
References: Djupedal ILR, Harris A, Svensen E, et al. Shift Schedule With Fewer Short Daily Rest Periods and Sickness Absence Among Health Care Workers: A Cluster Randomized Clinical Trial. JAMA Netw Open. 2025;8(9):e2531568. doi:10.1001/jamanetworkopen.2025.31568
