Are adolescents chronically sleep-deprived? An investigation of sleep habits of adolescents in the Southwest of Germany.

BACKGROUND: Adolescent sleep receives increasing attention. Several studies have shown that adolescents generally do not sleep enough. This survey assessed adolescents' sleep patterns, and results were compared with sleep logs.

METHODS: A total of 818 students aged 12-18 attending three different school types were asked to complete a questionnaire, adapted from the 'School Sleep Habits Survey', and filled in a sleep protocol over 2 weeks. Information on sleep patterns and demographic data were obtained additionally.

RESULTS: A total of 601 students completed the questionnaire (i.e. 73.5% return rate), 55.1% female and 44.9% male. Average sleep duration during the week amounted to 8.04+/-0.89 h and 9.51+/-1.65 h on weekends. Sleep duration times on school days decreased from an average 8.64+/-0.83 h for the age category 12-13 years to 7.83+/-0.72 h for students above 16 years. 91.6% of all students slept less than 9.2 h per night during the week. Data from the 153 returned sleep logs showed even lower sleep times (7.75+/-0.82 h for school nights).

CONCLUSIONS: The main hypothesis that students sleep on average considerably less than the recommended 9 h during weekdays was confirmed. Bedtimes changed throughout the week with the latest on Friday and Saturday nights and the least sleep around midweek. There were no significant group differences regarding school type and environment (rural vs. urban). Interestingly, the majority reported only little daytime sleepiness and no impaired performance. Results regarding the consequences of chronic sleep deprivation in the literature are inconclusive. The impact on physiological parameters, especially metabolic functions, requires further investigations.