title: Sleep patterns in high school and university students: a longitudinal study.
abstract: We performed a longitudinal study to investigate whether changes in social zeitgebers and age alter sleep patterns in students during the transition from high school to university. Actimetry was performed on 24 high-school students (mean age+/-SD: 18.4+/-0.9 yrs; 12 females) for two weeks. Recordings were repeated in the same subjects 5 yrs later when they were university students. The sleep period duration and its center, the mid-sleep time, and total sleep time were estimated by actimetry. Actigraphic total sleep time was similar when in high school and at the university on school days (6.31+/-0.47 vs. 6.45+/-0.80 h, p = ns) and longer on leisure days by 1.10+/-1.10 h (p < 0.0001 vs. school days) when in high school, but not at the university. Compared to the high school situation, the mid-sleep time was delayed when at the university on school days (03:11+/-0.6 vs. 03:55+/-0.7 h, p < 0.0001), but not on leisure days. Individual mid-sleep times on school and leisure days when in high school were significantly correlated with the corresponding values 5 yrs later when at the university (r = 0.58 and r = 0.55, p < 0.05, respectively). The large differences in total sleep time between school and leisure days when students attended high school and the delayed mid-sleep time on school days when students attended university are consistent with a circadian phase shift due to changes in class schedules, other zeitgebers, and lifestyle preferences. Age-related changes may also have occurred, although some individuality of the sleep pattern was maintained during the 5 yr study span. These findings have important implications for optimizing school and work schedules in students of different age and level of education.
authors.affiliation: Sleep Disorders Center, Pulmonary Division, Department of Internal Medicine, University Hospital of Zurich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Urner
authors.forename: Jure
authors.initials: J
authors.lastname: Tornic
authors.forename: Konrad E
authors.initials: KE
authors.lastname: Bloch
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002940:Circadian Rhythm; D004493:Education; D005260:Female; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D055815:Young Adult