Circadian typology and implications for adolescent sleep health. Results from a large, cross-sectional, school-based study

Abstract Study objectives To investigate circadian typology in a large, representative sample of Norwegian adolescents, and its implications for sleep health. Methods The included 3920 1st year high school students aged 16–17 years. Respondents completed web-based survey, including the short version Horne-Ostberg Morningness-Eveningness Questionnaire (rMEQ), Munich Chronotype (MCTQ) items on sleep-related behaviors (eg electronic media usage bed, consumption caffeinated beverages), beliefs daytime sleepiness. Data were analyzed using one-way ANOVAs Chi-squared tests. Results In all, 7.8% categorized as morning, 52.3% intermediate 39.9% evening types, respectively. Evening types had later timing, longer latency, more social jetlag shorter day duration than morning with displaying pattern between these two extremes. None met minimum recommended amount nights (ie 8+ hours), only mean 7+ hours (7:19 h, nearly 1 h who slept 6:20 h, p  Conclusions from this study suggest that eveningness represents health challenge older adolescents.