What is the Origin of Morning Cortisol Response?

This is a well-established phenomenon in neuroendocrinology, focusing on the rhythmic secretion of cortisol, the primary glucocorticoid. Response emphasizes the rapid, predictable hormonal change following the transition from sleep to wakefulness. Morning denotes the time of day for this specific peak.

What is the Mechanism of Morning Cortisol Response?

The morning cortisol response is initiated by the suprachiasmatic nucleus signaling the hypothalamus, which activates the HPA axis. This cascade leads to the adrenal glands secreting a pulse of cortisol, peaking approximately 30-45 minutes after waking. Cortisol then acts to promote gluconeogenesis in the liver and increase circulating glucose, providing the necessary fuel to support cognitive and physical activity throughout the day.

Morning Cortisol Response

Meaning

The characteristic, sharp increase in circulating cortisol concentration that occurs immediately upon awakening, known clinically as the Cortisol Awakening Response, or CAR. This physiological surge is a key marker of HPA axis function and serves to mobilize energy reserves, enhance alertness, and prepare the body for the metabolic demands of the active phase. A healthy, robust response is indicative of a well-regulated stress system and metabolic readiness.