Cortisol and sleep in infancy and early childhood

Introduction. Cortisol release is often associated with physiological arousal or perceived stress. Findings in adults as well as in older children and adolescents show that cortisol is also connected to sleep. Furthermore, it is assumed that high-quality sleep is a predictor of regular cortisol release throughout the day. Objective. This review summarizes the current literature on how sleep and cortisol levels are associated in early childhood. Methods. In order to identify studies on sleep and cortisol in young children, a structured literature search was performed in the PsychINFO, PsycARTICLES, PSYNDEX, and Google Scholar databases. Results. A total of 14 studies could be included this review. According to the results of the reviewed publications, daily cortisol release patterns develop within the first 6 months of life. In addition, young children display a cortisol awakening response (CAR) and cortisol levels are influenced by taking naps during the day as well as by the quality of nighttime sleep. Conclusion. After reviewing the recent findings in the literature concerning children from birth up to the age of 5 years, it can be assumed that sleep patterns and sleep are associated with cortisol secretion in early childhood. This finding could be included in the creation and further development of interventional sleep training programs.