Sleep architecture in healthy 5-year-old preschool children: associations between sleep schedule and quality variables

Aim: Although disturbed sleep quality such as night awakenings and difficulties in falling asleep are common symptoms during sleep in preschool children, relationships between sleep quality and sleep schedule are mostly unknown. This study aimed to evaluate the relationships between sleep schedule and quality variables in preschool children. Methods: Sleep-wake patterns of 48 healthy 5-year-old children were assessed over 7 consecutive days using actigraphy. Results: Children with longer sleep latency had a lower sleep quality, a later bedtime, a later sleep onset time, a shorter nocturnal sleep period and a longer daytime nap. Children with a longer nocturnal sleep period on weekends compared with weekdays had longer sleep latency and a later sleep onset time on weekdays, resulting in a lower sleep quality on weekends. An irregular bedtime on weekdays was associated with a later sleep onset time and a shorter sleep period on weekends. Conclusion: Sleep quality and schedule were linked with each other, which may explain why sleep problems tend to aggregate and form a wider syndrome of disturbed sleep even in young children. Strategies solely targeting the improvement of sleep quantity may not promote ideal sleep; simultaneous considerations for the sleep rhythm and quality may be required.