The role of objective sleep duration, continuity, and architecture for subjective sleep perception: Findings from an intensive longitudinal study using heart-rate variability to infer objective sleep indicators

This study investigates the relationship between objective sleep indicators derived from heart rate variability (HRV) and sleep perception in young adults using an intensive longitudinal design over 14 consecutive nights. The sample included 178 participants aged 18–29 years from two separate studies, who provided data via daily sleep diaries. Using a multi-resolution convolutional neural network model, heart rate variability measured via ambulatory electrocardiography was used for sleep stage classification. Within-subject analyses revealed that longer total sleep time, higher sleep efficiency, more slow-wave sleep, and more rapid-eye-movement sleep were associated with better sleep perception, while longer wake after sleep onset was linked to poorer sleep perception. Notably, no significant associations were found on the between-subject level. The objective sleep indicators explained nearly five times as much variance in sleep perception at the within-subject level than at the between-subject level. Additionally, gender, as well as depressive symptoms and insomnia symptoms measured at baseline did not moderate the within-subject associations between objective sleep indicators and sleep perception. These findings underscore the importance of sufficient sleep duration, quality of sleep architecture, and sleep continuity for individuals' perceptions of their sleep on a nightly basis. The study's use of HRV-derived sleep staging over multiple nights represents a methodological strength, providing detailed and less intrusive assessment compared to traditional polysomnography. Furthermore, these results are particularly important for clinical applications, as they can be basis for individualized interventions to improve sleep perception.