The Circadian Response to Evening Light Spectra in Early Childhood: Preliminary Insights

作者：Lauren E. Hartstein, Kenneth P. Wright, Cecilia Diniz Behn, Shelby R. Stowe, Monique K. LeBourgeois · 发表于：Journal of Biological Rhythms · 年份：2025 · DOI：10.1177/07487304241311652 · 被引用次数：6 · 研究领域：Circadian rhythm and melatonin、Spaceflight effects on biology、Sleep and related disorders

Although the sensitivity of the circadian system to the characteristics of light (e.g., biological timing, intensity, duration, spectrum) has been well studied in adults, data in early childhood remain limited. Utilizing a crossover, within-subjects design, we examined differences in the circadian response to evening light exposure at two different correlated color temperatures (CCT) in preschool-aged children. Healthy, good sleeping children ( n = 10, 3.0-5.9 years) completed two 10-day protocols. In each protocol, after maintaining a stable sleep schedule for 7 days, a 3-day in-home dim-light circadian assessment was performed. On the first and third evenings of the in-home protocol, dim-light melatonin onset (DLMO) was assessed. On the second evening, children received a 1-h light exposure of 20 lux from either 2700 K (low CCT) or 5000 K (high CCT) (~9 and ~16 melanopic equivalent daylight illuminance (mEDI lux), respectively) centered around their habitual bedtime. Children received the remaining light condition during their second protocol, with the order counterbalanced across participants. Salivary melatonin was collected to compute melatonin suppression and circadian phase shift resulting from each experimental light condition. Melatonin suppression across the 1-h light stimulus was significantly greater during exposure to the high CCT light ( M = 56.3%, SD = 19.25%) than during the low CCT light ( M = 23.90%, SD = 41.06%). Both light conditions resulted in marked del...