title: Gender differences in the sleep habits of 11-13 year olds.
abstract: OBJECTIVE
  Sleep plays an important role in the physical and emotional development of adolescents. The aim of this study was to examine gender differences in sleep habits in a sample of 11-13 year olds.
  
  
  METHODS
  The study was carried out in the city of Patos de Minas, Brazil. The study cohort was composed of 200 students (96 boys and 104 girls) attending (in the morning or in the afternoon) the 5th, 6th or 7th grades, with ages ranging from 11 to 13 years. A Sleep Questionnaire developed at the Federal University of São Paulo was used in order to evaluate student sleep habits and schedules, as well as the overall quality of sleep.
  
  
  RESULTS
  For the period between Friday night and Sunday morning, girls displayed longer sleep duration than did boys. During the week, students attending only afternoon classes woke up later than did students attending only morning classes. In addition, morning-class students showed more adverse effects on sleep, including irregular sleep/wakefulness circadian rhythms, when compared with afternoon-class students.
  
  
  CONCLUSIONS
  Sleep habits are affected by gender and school schedule.
authors.affiliation: Faculdades COC, Ribeirão Preto, SP, Brazil.
authors.forename: César L
authors.initials: CL
authors.lastname: Natal
authors.forename: Tânia J
authors.initials: TJ
authors.lastname: Lourenço
authors.forename: Luana A
authors.initials: LA
authors.lastname: Silva
authors.forename: Rita A
authors.initials: RA
authors.lastname: Boscolo
authors.forename: Andressa
authors.initials: A
authors.lastname: Silva
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Marco Túlio de
authors.initials: MT
authors.lastname: Mello
mesh_terms: D000293:Adolescent; D001938:Brazil; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006184:Habits; D006801:Humans; D008297:Male; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires