Sleep and light ecologies of parents with young infants: descriptive findings from the SUNSHINE project.

The interplay between sleep, light exposure, and circadian rhythms is critical for health, yet it remains inadequately described in the everyday lives of parents with young infants. Prior work has focused mainly on mothers, the early postpartum period, and short-term assessments, leaving a limited understanding of everyday parental ecologies. To address these gaps, we conducted a 2-week observation study in both mothers and fathers of infants aged 3-9 months, simultaneously measuring sleep and light exposure using wearable actigraphy and light sensors alongside sleep diaries. Our descriptive approach aimed to characterize real-life patterns of sleep and light, quantify their variability across nights and individuals, and explore differences by infant age, parental role, and contextual factors. We found that while sleep duration was generally adequate, nights were frequently fragmented, with multiple awakenings and substantial variability across individuals and nights. Light exposure during waking hours was predominantly dim, and brief exposures to light during sleep episodes were common. Seasonal variation, infant sleep location, and caregiving roles may have shaped sleep-light patterns. These findings highlight the complexity and heterogeneity of sleep and light ecologies in early parenthood, and underscore the value of wearable monitoring and descriptive profiling for informing circadian-aware interventions.