Title

The Cortisol Awakening Response (CAR) in 2-to 4-year-old Children: Effects of Acute Nighttime Sleep Restriction, Wake Time, and Daytime Napping

Document Type

Article

Publication Date

5-1-2012

Department

Psychology

Abstract

The cortisol awakening response (CAR) is presumed critically important for healthy adaptation. The current literature, however, is hampered by systematic measurement difficulties relative to awakening, especially with young children. While reports suggest the CAR is smaller in children than adults, well-controlled research in early childhood is scarce. We examined whether robust CARs exist in 2- to 4-year-old children and if sleep restriction, wake timing, and napping influence the CAR (n?=?7). During a 25-day in-home protocol, researchers collected four salivary cortisol samples (0, 15, 30, 45?min post-wake) following five polysomnographic sleep recordings on nonconsecutive days after 4?hr (morning nap), 7?hr (afternoon nap), 10?hr (evening nap), 13?hr (baseline night), and 16?hr (sleep restriction night) of wakefulness (20 samples/child). The CAR was robust after nighttime sleep, diminished after sleep restriction, and smaller but distinct after morning and afternoon (not evening) naps. Cortisol remained elevated 45?min after morning and afternoon naps. (c) 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:412422, 2012.

Publication Title

Developmental Psychobiology

Volume

54

Issue

4

First Page

412

Last Page

422