Sleep timing, physical activity and school strain among Finnish adolescents

Background

Schools are key settings for adolescent health promotion, but sleep, physical activity and learning-related strain are often considered separately. We examined whether sleep timing and vigorous physical activity were associated with school strain among Finnish adolescents, and whether academic difficulty marked students for whom these behaviours mattered most.

Methods

Data were from the 2019 Finnish School Health Promotion Study, including 70,580 students in grades 8-9. Weekday sleep duration was calculated from bedtime and wake-up time, and social jetlag from the difference in sleep midpoints between school days and free days. Vigorous physical activity was measured as weekly hours of leisure-time exercise. Linear regression estimated associations of sleep duration, social jetlag and physical activity with school burnout and daytime fatigue, tested academic difficulty as a moderator, and adjusted for grade, gender, parental education, immigrant background, family economic situation and breakfast regularity.

Results

Shorter sleep duration and greater social jetlag were linked to higher burnout and fatigue; social jetlag remained associated with both outcomes after sleep duration was considered. Physical activity was more clearly related to lower fatigue than to burnout. Academic difficulty was the dominant correlate, accounting for 15.9% additional variance in burnout and 7.4% in fatigue, while statistically significant interactions explained less than 0.1%. Thus, behavioural associations were detectable, but academic difficulty carried greater practical weight.

Conclusions

Sleep timing and physical activity are relevant to school health, but academic difficulty is a stronger marker of burnout and fatigue. Health promotion in schools should combine support for sleep and physical activity with learning-related support for students experiencing academic difficulty.

Key messages

• Academic difficulty explained more variance in school burnout and fatigue than sleep or physical activity interactions.

• School health promotion should combine sleep and physical activity support with learning-related support.