Rivkees Scott A
Yale Child Health Research Center, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Pediatrics. 2003 Aug;112(2):373-81. doi: 10.1542/peds.112.2.373.
Circadian rhythms are endogenously generated rhythms with a period length of approximately 24 hours. Evidence gathered during the past decade indicates that the circadian timing system develops prenatally and the suprachiasmatic nuclei, the site of a circadian clock, is present by midgestation in primates. Recent evidence also shows that the circadian system of primate infants is responsive to light at very premature stages and that low-intensity lighting can regulate the developing clock. After birth, there is progressive maturation of the circadian system outputs, with pronounced rhythms in sleep-wake and hormone secretion generally developing after 2 months of age. Showing the importance of photic regulation of circadian phase in infants, exposure of premature infants to low-intensity cycled lighting results in the early establishment of rest-activity patterns that are in phase with the 24-hour light-dark cycle. With the continued elucidation of circadian system development and influences on human physiology and illness, it is anticipated that consideration of circadian biology will become an increasingly important component of neonatal care.
昼夜节律是内源性产生的节律，周期长度约为24小时。过去十年收集的证据表明，昼夜节律计时系统在出生前就已发育，灵长类动物在妊娠中期时，昼夜节律钟所在的视交叉上核就已存在。最近的证据还表明，灵长类婴儿的昼夜节律系统在非常早产的阶段就对光有反应，而且低强度光照可以调节发育中的生物钟。出生后，昼夜节律系统的输出逐渐成熟，睡眠-觉醒和激素分泌的明显节律通常在2个月大后形成。早产婴儿暴露于低强度循环光照下会导致与24小时明暗周期同步的休息-活动模式的早期建立，这表明了光对婴儿昼夜节律相位调节的重要性。随着对昼夜节律系统发育及其对人体生理和疾病影响的不断阐明，预计昼夜生物学的考量将成为新生儿护理中越来越重要的组成部分。
