The Cortisol Awakening Response: Regulation and Functional Significance.
Level 5 - mechanism / opinion, no new human data
Narrative review and theoretical framework without systematic review methodology or new human data.
PubMed 39177247 · doi:10.1210/endrev/bnae024
What was done
Narrative review synthesizing existing literature on the regulation and functional significance of the cortisol awakening response (CAR)—the sharp rise in cortisol across the first 30 to 45 minutes after waking—to develop an integrative conceptual model of its physiological role.
What was found
The abstract reports no empirical numbers or quantitative findings. It outlines a proposed dual-control model wherein circadian, environmental, and neurocognitive factors regulate the CAR to drive both genomic (such as clock gene expression) and rapid nongenomic glucocorticoid actions. The authors propose two key adaptive functions: mobilizing metabolic, immunological, and neurocognitive resources for upcoming daily demands, and counterregulating adverse prior-day emotional experiences.
Why it matters
Provides an updated conceptual framework framing the cortisol awakening burst as an active, predictive physiological mechanism that prepares the organism for daytime activity and aids emotional recovery.
Limits
As a narrative review and theoretical model, no original data, sample sizes, or systematic effect estimates are provided. The functional hypotheses (including nongenomic signaling and prior-day emotional counterregulation) require prospective experimental validation.
Cited by
- supports Upon waking in the morning, circulating melatonin levels gradually decline while cortisol levels spike.