title: The 24-hour variation of mood differs between morning- and evening-type individuals.
abstract: This study investigated a 24-hour variation of subjective mood in 16 healthy Morning-type and 13 Evening-type subjects as defined by the time of day at which their oral temperature curve reached its maximum. The subjects were instructed to use a sleep-wake logbook, in which they kept daily records of the ratings of their mood and alertness for a period of two consecutive weeks. For mood as well as for alertness analysis of variance indicated significant interactions between Morning and Evening-types and time of day. It is concluded that a pronounced diurnal variation of mood can be observed in healthy individuals, which differs between Morning-type and Evening-type subjects.
authors.affiliation: Department of Physiology, University of Leiden, The Netherlands. kerkhof@rullf2.leidenuniv.nl
authors.forename: G A
authors.initials: GA
authors.lastname: Kerkhof
mesh_terms: D000328:Adult; D000339:Affect; D000704:Analysis of Variance; D001143:Arousal; D001831:Body Temperature; D002940:Circadian Rhythm; D004644:Emotions; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008499:Medical Records; D012890:Sleep; D014851:Wakefulness