The role of daytime napping on salivary cortisol in children aged 0–5 years: a systematic review and meta-analysis

Abstract

Daytime napping plays a minor role in the fluctuation of salivary cortisol levels during the day. The conditions of the home or the childcare environment under which napping occurs might have a greater influence on cortisol levels than daytime napping itself in early childhood. PROSPEROIdentifier: CRD42020212249. • The regulation of sleep involves circadian rhythmicity of cortisol secretion via activation of the HPA axis and a subsequent release of cortisol upon morning awakening followed by a decline throughout the day. • The available evidence supports the occurrence of a cortisol awakening response after a daytime nap. • A small decrease in cortisol after napping was observed when the nap occurred at home but not at childcare. • The conditions of the home or childcare environment under which the nap occurs and the activities before and after napping may have a greater influence on cortisol levels than napping itself.