Comparison of Sleep Onset Time According to Grade, Outdoor Time, and Screen-Based Media Device Use Time in Children and Adolescents in One District of Daegu, Korea

Objective: The purpose of this study is to identify the sleep onset time (SOT), outing activities, and screen-based media device (SBMD) use by grade and to evaluate the differences in SOT according to outing activities and SBMD use. Methods: A total of 10,080 students from one district in Daegu Metropolitan City completed Survey for Outing and Time Usage for Children, Adolescents, and Parents, among which SOT, outing activities, and mobile phone usage time and behavior were analyzed. Results: There was a significant difference in SOT on weekdays and weekends according to grade level. The SOT of high school seniors was 2 hours and 20 minutes later than that of elementary school seniors regardless of weekdays and weekends. There was a significant difference in SOT according to outing activity time, mobile game usage time, and video-watching time. Conclusion: The SOT is significantly delayed by grade, and the SOT of students who use a lot of SBMD is significantly delayed. It is possible that students’ sleep health deteriorates depending on the grade due to various factors. It is considered that personal, educational, and socio-environmental efforts are needed to improve students’ sleep health.