What is the Origin of Cortisol Curves?

This diagnostic tool is firmly situated within clinical endocrinology and chronobiology, emerging from early research on the diurnal rhythm of adrenal steroid secretion. The methodology requires multiple timed measurements, often via saliva or dried urine, to capture the distinct peak and trough pattern accurately. Understanding this rhythm is fundamental to assessing adrenal function and stress physiology.

What is the Mechanism of Cortisol Curves?

The mechanism reflects the body's central clock, the suprachiasmatic nucleus, signaling the HPA axis to release cortisol in a distinct pattern. The curve typically shows a sharp rise upon waking, known as the Cortisol Awakening Response, followed by a gradual, steady decline throughout the day, reaching its nadir around midnight. Deviations, such as a flattened curve or elevated nocturnal levels, indicate HPA axis dysregulation impacting sleep, metabolism, and immune function.

Cortisol Curves ∞ Area

Cortisol Curves

Meaning

Cortisol Curves are precise graphical representations illustrating the quantitative fluctuations of the glucocorticoid hormone cortisol in systemic circulation over a full 24-hour period. These curves map the dynamic, circadian rhythm of cortisol release, which is orchestrated by the hypothalamic-pituitary-adrenal (HPA) axis. Clinical analysis of the curve’s shape and amplitude provides essential insights into an individual’s stress adaptation and neuroendocrine health.