Mood and the circadian system: Investigation of a circadian component in positive affect

Abstract

The aim of this study was to test if the pattern of human mood variation across the day is consistent with the hypothesis that self-reports of positive affect (PA) have a circadian component, and self-reports of negative affect (NA) do not. Data were collected under two protocols: normal ambulatory conditions of activity and rest and during a 27h constant routine (CR) procedure. Mood data were collected every 3 h during the wake span of the ambulatory protocol and hourly during the 27h CR. In both protocols, rectal temperature data were continuously recorded. In the ambulatory protocol, activity data were also collected to enable estimation of the unmasked (purified) temperature rhythm. Part..