Abstract
Background: Bedtime routines are widely recommended for children’s sleep. Despite abundant advice on what activities to include or avoid, research has mainly examined ‘routineness’ (bedtime routine presence, frequency, or consistency), and evidence for how activities relate to sleep is sparse beyond electronic screen use. Most research on activity-sleep and routineness-sleep associations has relied on subjective reports of ‘usual’ practices and sleep, which are prone to inaccuracy and bias, particularly given night-to-night variability in activities and sleep. Actigraphy has occasionally measured sleep in bedtime routine research, yet objective measures of evening activities remain rare, and bedtime routineness has not been objectively assessed. Most bedtime routine research also originates from the United States, with limited evidence on young children’s evening practices in Aotearoa (New Zealand).
Objectives: To comprehensively describe the pre-bedtime activities of young children through objective measurement of evening activities in a community sample from Aotearoa; to explore associations between these activities and subsequent objective sleep measures; and to develop preliminary objective bedtime routineness measures and examine how these, alongside subjective routineness measures, relate to objective sleep outcomes.
Methods: The Preschool Cam Study recruited 70 preschool-aged tamariki (children) from Ōtepoti (Dunedin), Aotearoa. Tamariki wore AX3 actigraphs for seven consecutive nights and GoPro cameras during the two hours before bedtime over five of those evenings. Caregivers completed questionnaires on usual sleep practices and sleep diaries. Camera footage was coded for screen exposure, stories, eating/drinking, self-care, and other comfort/connection activities using a reliable coding scheme (κ ≥ 0.8). Routineness was measured objectively, via seven novel measures from camera-derived activity data over at least three evenings (mean 4.6 evenings) per participant, and subjectively, via caregiver-reported bedtime routine frequency. Descriptive analyses examined activities within two windows, starting from one and two hours before bedtime to 30 minutes post-bedtime, with bedtime determined from cameras, diaries, or indirect measures. Exploratory inferential analyses used mixed and fixed effects Bayesian linear and Poisson regression models and the one hour pre- to 30 minutes post-bedtime window. Associations were estimated for each activity and that night’s sleep, and for routineness with participants’ mean sleep metrics. Sleep quantity, quality, and timing were examined.
Results: In the one hour pre- to 30 minutes post-bedtime window, common activities included connection activities with a caregiver (at least one of: comforting physical contact, lullaby/waiata, prayer/karakia, being read to, or oral storytelling; 79% of each participant’s evenings), screen exposure (62%), and brushing teeth (69%). Other story and comfort activities near bedtime (e.g., audiobooks or lullaby/waiata) were uncommon overall (3-11% of each participant’s evenings, on average) but semi-regular among children who experienced them at least once (approximately half of these children’s evenings, on average). When tamariki experienced a connection activity, their total sleep time (TST) was 16 minutes longer [Bayesian 95% credible interval (95% CrI) -11, 43] with an 88% chance of a positive association, though being read to was not associated with sleep when measured separately. Bathing was also associated with more sleep (TST 15 min longer [95% CrI -9, 38]; 89% chance of a positive association), and patterns varied for other activities. Screen exposure did not show evidence of a relationship with sleep (TST <1 min shorter per 10 min of exposure [95% CrI -6, 5]). Audiobook use was uncommon, so credible intervals were wide, but overall findings suggested less sleep (TST 42 min shorter [95% CrI -97, 15]; 93% chance of a negative association). Estimates were similar when sociodemographic factors and other activities were adjusted for. Higher objectively measured routineness was generally associated with lower objective sleep quantity, although evidence of directionality and estimated effect magnitudes varied across the seven camera-derived routineness measures. Findings for subjective routineness (grouped as seldom, often, and frequently) suggested a non-linear association: TST was similar for tamariki who seldom or frequently had a bedtime routine, whereas children who often had a routine averaged 26 minutes less TST [95% CrI -67, 16] than the seldom group. Higher routineness was associated with earlier sleep timing across objective and subjective routineness measures.
Conclusion: This study highlights how important caregiver connection may be for young children’s sleep. Findings also indicate that two common areas of paediatric sleep guidance, screen exposure and bedtime routines (normally found to be associated with poorer and better sleep, respectively) might have more complex connections to sleep than previously thought. Further research is needed to confirm and extend these preliminary findings, particularly those using the novel, objective routineness measures. Subjective measures convey information available to caregivers, which can be limited. Nightly, objective measures of sleep-related behaviours combined with actigraphy could offer nuanced insights that complement, or at times, challenge findings based on subjective measures, and ultimately help advance our understanding of children’s sleep health.