Circadian Preference and Sleep-Wake Regularity: Associations With Self-Report Sleep Parameters in Daytime-Working Adults

Abstract

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23–48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were assessed using the STQ separately for work-week nights (Sunday–Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: [email protected])

Keywords:

• Chronotype
• Human
• Regularity
• Sleep

ACKNOWLEDGMENTS

Primary support for data collection was provided by NASA grants NAG9 1036, NAG9 1234, and NNJ04HF76G awarded to T.H.M. Additional support was provided by National Institute on Aging grants R01 AG13396 and P01 AG020677 awarded to T.H.M., as well as National Institute of Mental Health grant T32MH089919 − 1A1 awarded to A.M.S. The authors sincerely thank Lynda Rose, Jean DeGrazia, Mary Fletcher, and Jean Miewald for data management, the University of Pittsburgh Alumni Association for their help, and the kind subjects for their gracious cooperation.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.