Do infants show a cortisol awakening response?

Melissa A Bright1, Douglas A Granger, Janet E Frick

  • 1Department of Psychology, University of Georgia, Athens, GA 30602, USA. mbright@uga.edu

Insights

The cortisol awakening response (CAR) differs in infants compared to adults. Infant cortisol levels decreased after waking, unlike the typical adult CAR increase.

Area of Science:

  • Endocrinology
  • Developmental Psychology
  • Neuroscience

Background:

  • The cortisol awakening response (CAR) is a well-documented phenomenon in adults, reflecting hypothalamic-pituitary-adrenal axis activity upon waking.
  • Previous research has primarily focused on the CAR in adult populations, with limited understanding in infants.

Purpose of the Study:

  • To investigate the cortisol awakening response (CAR) in infants for the first time.
  • To compare infant CAR patterns with established adult CAR responses.

Main Methods:

  • Saliva samples were collected from 32 mothers and their infants (aged 7.8–17.4 months) upon waking and 30 minutes later.
  • Cortisol levels were measured following morning waking and the infant's first nap.

Main Results:

  • Infant cortisol levels showed a decline from waking to 30 minutes post-waking, contrasting with the adult CAR.
  • No significant cortisol changes were observed following infant naps.
  • Mother-infant cortisol levels were associated at both group and dyadic levels.

Conclusions:

  • The cortisol awakening response (CAR) in infants appears distinct from that observed in adults.
  • Infant sleep-wake cycles and associated hormonal responses warrant further investigation.
  • Maternal and infant cortisol levels exhibit interconnectedness.

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