Delayed school start times improve students' sleep, but little is known about its impact on teachers. The Austrian COVID-19 lockdown, enabling teachers to choose their working hours, created the unique opportunity to test the impact of a forced home office on Tyrolean teachers' sleep. From April to May 2020, a cross-sectional and complete online survey was implemented with 2,314 Tyrolean teachers participating. Bedtimes and wake times on workdays and on weekends were measured before the lockdown (retrospectively) and during the lockdown. Additional variables were calculated: time spent in bed on workdays/weekends, social jetlag, and sleep loss. During the lockdown, as compared to the period before it, the teachers reported later bedtimes and rise times, longer sleep duration on workdays, decreased workday sleep loss, and reduced social jetlag. These effects occurred predominantly due to a delay in rise times on workdays and were enhanced in younger teachers. Changing to a home office during lockdown induced a robust drift towards later hours on workdays, indicating that teachers benefit from delayed school start times by aligning their workday sleep habits to their biological sleep needs. In conclusion, not only adolescent students but also teachers benefit from a delayed school start.
Keywords: Teacher characteristics; distance education; educator effectiveness; quantitative research; sleep loss; social jetlag.