Comparative study on circadian typology of Japanese and Italian students aged 12-18 years

Current bedtime fixation made the students (both Japanese and Italian) aged 12–15 years more morning-typed, while it had no effects on the M-E scores of students 16–18 years.

Abstract

The average bedtime and sleep duration of Japanese students aged 12–18 years was later and shorter, respectively, by 1 h compared with those of Italian students. Japanese students aged 12–15 years were predominantly more evening-typed than Italian students, while there were no significant differences in the morningness-eveningness (M-E) scores between students aged 16–18 years in the two countries. The bedtime of approximately 70% of Italian students was fixed by parents during their childhood, whereas the bedtime of only 40% of Japanese students was fixed by their parents. Current bedtime fixation made the students (both Japanese and Italian) aged 12–15 years more morning-typed, while it had no effects on the M-E scores of students 16–18 years.