Trends in sleep patterns among Czech adolescents and their current correlates of late bedtimes and social jet lag: HBSC study 2014-2022

Objectives: Sleep is vital for maintaining the health and wellbeing of people of all ages. However, for adolescents, sufficient sleep of adequate duration and quality is critical for profound mental, physical, social, and emotional development. This study aimed to describe trends in sleep duration and late bedtime during school and non-school days in representative cohorts of 11-, 13-, and 15-year-old adolescents from Czechia from 2014 to 2022, and to examine the current associations between late bedtimes/social jet lag and wellbeing indicators among adolescents in 2022. Methods: The analysed sample of 42,101 adolescents aged 10.5-16.5 years was drawn from three nationally representative cohorts of Czech schoolchildren from the last three cycles of the Health Behaviour in School-aged Children study, conducted between 2014 and 2022. Results: Mean sleep duration (hours:minutes) on school and non-school days significantly (p < 0.05) decreased for both boys (schooldays: 8:192014→7:592022; non-school days: 9:362018→9:232022) and girls (schooldays: 8:202014→7:552022; non-school days: 9:582018→9:412022) between 2014/2018 and 2022, while the prevalence of insufficient sleep significantly (p < 0.001) increased over the same period (boys schooldays: 35.4%2014→49.2%2022, boys non-school days: 14.9%2018→18.0%2022; girls schooldays: 35.1%2014→51.7%2022, girls non-school days: 9.8%2018→13.3%2022). Adolescents with late bedtimes or social jet lag (> 2 hours) had significantly higher odds (p < 0.001) of skipping breakfast daily, drinking energy drinks daily, being drunk at least twice in their lifetime, experiencing reduced psychological wellbeing and low life satisfaction, reporting irritability, and problematic social media use and internet gaming than those with earlier bedtimes or without social jet lag. Conclusions: It is highly desirable that families, in close cooperation with schools and professional representatives, make efforts to ensure adherence to the recommended length and quality of sleep, as the trend results indicate worsening sleep patterns, deepening social jet lag, and a disturbing increase in adolescent risk behaviours and health complaints related to insufficient sleep.