What Keeps Night Owls Well During the Week? Circadian Preference, Sleep Timing, and Adolescent Wellbeing

• In Event: Sleep across the lifecourse

Abstract

Teenagers typically stay awake later than children and adults (Crowley et al., 2007). While this phenomenon is biologically driven and normative (Carskadon, 2011), it is accompanied by a related yet distinct sense of being more alert in evenings or mornings – one’s circadian preference – which varies across individuals (Tonetti et al., 2008). In adolescence, evening-types (so-called “night owls”) are more vulnerable to internalizing symptoms (Shimizu et al., 2019), externalizing problems (Merikanto et al., 2017), and poorer physical health (Randler et al., 2011). Sleep-timing consistency (going to bed and waking at approximately the same time each night) appears to be a protective factor against such risks among evening-type adolescents (Dong et al., 2019). Most studies, however, have relied on clinical samples and self-reported sleep measures (e.g., Harvey et al., 2018), and investigations using objective measures have been scarce. Further, most studies have included data from weekend nights (e.g., Bei et al., 2017); given that adolescents sleep later on weekends, combining weeknight and weekend data may create measurement bias by inflating night-to-night variability. Building on prior work, we examined objectively measured weeknight variability in sleep timing as a moderator of relations between circadian preference and adolescent adjustment and physical health. We hypothesized that the association between eveningness and diminished wellbeing would be strengthened by greater variability and attenuated by greater consistency in sleep timing.

We recruited 272 community-dwelling adolescents without sleep disorders (M age = 17.27, SD = 0.76 years; 49% female; 41% Black, 59% White) from semi-rural schools in the Southeastern U.S. Participants wore wrist actigraphs (Ambulatory Monitoring) at home for one week to record nighttime sleep, and visited a laboratory to complete questionnaires. Circadian preference was self-reported on a well-validated youth morningness–eveningness scale (Wolfson & Carskadon, 1998). Consistency of sleep timing on weeknights was assessed via actigraphs by computing a coefficient of variability (Snedecor & Cochran, 1967) in sleep midpoint (the minute halfway between sleep onset and wake). Mothers reported internalizing symptoms and externalizing problems (Wirt et al., 1990), and adolescents rated general physical health (Starfield et al., 1995).

Path analyses revealed that eveningness and greater variability in sleep timing were independently associated with more internalizing symptoms and externalizing problems and poorer ratings of physical health (Table 1). Significant interaction effects emerged with a similar pattern across models (Figure 1). Morningness was related to greater wellbeing regardless of sleep timing consistency. Importantly, evening-type adolescents who had less variability in sleep timing were more likely than those with greater variability to have fewer adjustment problems and better health.

Results suggest that, among teenage night owls, consistency in sleep timing on weeknights can mitigate risk for negative outcomes across multiple domains of development. Using objective sleep data, this study provides compelling evidence that sleep-timing consistency moderates the association between circadian preference and wellbeing in adolescence.

Authors

• Brian T. Gillis, Auburn University
  Presenting Author

• Mina Shimizu, Auburn University
  Non-Presenting Author

• Mona M El-Sheikh, Auburn University
  Non-Presenting Author