The characteristics of sleep-wake rhythm in adolescents aged 15-20 years: A survey made at school during ten consecutive days.

Adolescents' fatigue is a worrying subject. Patients and method - A survey was carried out over a period of ten days (a school week between two weekends). Through a daily questionnaire, 386 adol escents aged 15-20 years were asked about sleep onset and offset, time dela y of sleep onset, quality of sleep, daytime sleepiness and naps. Results - The results confirmed that the length of sleep was lessened durin g weekdays. This duration was one hour shorter than on Saturday nights or d uring holidays. However, a significant delay occurs in sleep onset an Satur day nights and sleep offset on Sunday mornings, which represents the main i rregularity in the steep schedule. Poor quality of sleep is due to difficul ties in sleep onset (16%) and night awakenings (39%). Daytime sleepiness is reported by 38% of the adolescents, and many of them have a nap on Sundays , or other days of the week. Daytime activities (out-of-school sports, part icularly) and evening activities were studied as well as the use of hypnoti cs and stimulants. Conclusion. - This work stresses sleep insufficiency during the week at sch ool, changes in sleeping patterns during weekends, and sometimes poor quali ty of sleep. Similar facts have already been found in children, and this ma y explain the consequences on the life and behaviour of adolescents. The po pulation has to be informed about the effects of sleep on health. (C) 2000 Editions scientifiques et medicales Elsevier SAS.