title: Associations between chronotype and salivary endocrinological stress markers.
abstract: OBJECTIVE
  To investigate the effect of chronotype on salivary cortisol or salivary α-amylase (sAA).
  
  
  METHODS
  From 108 male university students, saliva samples were collected in the afternoon (between 15:00 and 17:00). The salivary cortisol and sAA levels were determined with commercial kits. Chronotype was quantitatively evaluated using the Horne and Östberg Morningness-Eveningness Questionnaire. Subjects were categorized into morning types and evening types.
  
  
  RESULTS
  The sAA levels were lower in the morning types than in the evening types. We found no significant difference in salivary cortisol levels between the two groups.
  
  
  CONCLUSIONS
  These findings suggest that the sAA levels may be associated with chronotype.
authors.affiliation: Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. mt@envi.med.osaka-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Toda
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kawai
authors.forename: Keiko
authors.initials: K
authors.lastname: Takeo
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Rokutan
authors.forename: Kanehisa
authors.initials: K
authors.lastname: Morimoto
mesh_terms: D000293:Adolescent; D000328:Adult; D001244:Association; D002940:Circadian Rhythm / Q000502:physiology*; D005247:Feeding Behavior; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D012463:Saliva / Q000378:metabolism*; D055291:Salivary alpha-Amylases / Q000378:metabolism*; D011795:Surveys and Questionnaires
chemical_list: D055291:Salivary alpha-Amylases; D006854:Hydrocortisone