Journal of Physiological Anthropology

The relationship between weekday sleep duration and chronotype differences in students aged 15–17 and sleep satisfaction, breakfast consumption, and regular exercise.

Kazushige Oshita, Yujiro Ishihara, Takeshi Horai, Tadashi Uno, Satoki Murai

Background The importance of ensuring quantity and quality of sleep for the maintenance of good health is commonly known. This study investigated the relationship between differences in sleep duration and chronotype in students aged 15–17, sleep satisfaction, and the frequency of breakfast consumption and exercise. Methods A total of 498 students who attended classes at 08:50 on weekdays completed a self-administered questionnaire assessing bedtime and wake-up times on weekdays and weekends, Morningness-Eveningness Questionnaire (MEQ) scores, and how often the participants achieved sleep satisfaction, consumed breakfast, and participated in exercise/sports activities. Results Around 90% of non-evening-types reported being satisfied with their sleep ≥ 4 days/week, compared to around 60% of evening-types. Similar results were obtained when the analysis was restricted to those who slept ≥ 7 h on weekdays. Logistic regression analysis showed that lower sleep satisfaction was significantly associated with lower MEQ scores, regardless of whether students slept ≥ 7 h on weekdays. Furthermore, lower frequencies of consuming breakfast and participating in exercises were also significantly associated with lower MEQ scores. Conclusion These results suggest that many evening-type students living in a morning-oriented society do not experience sleep satisfaction, even if they sleep ≥ 7 h on weekday nights, and that these individuals may be less likely to adopt healthy lifestyle habits, such as eating breakfast and exercising regularly.