Associations Between Weekday/Weekend Sleep Duration Differences, Chronotype, and Physical Activity in Female University Students

Objective: The abundance of digital devices has raised concerns about the impact of nighttime use of these devices on daily rhythms, especially for evening-type individuals. Therefore, a simple assessment method for chronotypes is required. This study investigated the associations between weekday-to-weekend sleep duration (WWD), chronotype, and physical activity level (PAL) in female university students.Methods: Participants were 201 female university students. PAL and sleep duration on weekdays and weekends were assessed from daily activity diary records. Chronotype was assessed using the Morningness–Eveningness Questionnaire (MEQ).Results: WWD exhibited weak negative and strong positive correlations with sleep duration on weekdays and weekends, respectively. Furthermore, the WWD had a moderate relationship with the MEQ score. These results indicate that individuals with the evening chronotype may compensate for the sleep deficit on weekdays by sleeping longer on weekends, which was reflected in the WWD. Further, although the WWD was not correlated with the PAL on weekdays, it was negatively correlated with the PAL on weekends. Therefore, sleeping for longer on the weekend indicates a shorter duration of other daytime activities, such as physical activity.Conclusion: The WWD can be assessed with a simple question and may be useful as a means of assessing approximate chronotypes without any notable burden on participants.