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Cortisol Nadir Regulation

Meaning

Cortisol Nadir Regulation describes the precise physiological management of the lowest concentration point of the stress hormone cortisol, which normally occurs late in the evening or around midnight as part of the body’s diurnal rhythm. Proper regulation of this nadir is a critical indicator of a healthy hypothalamic-pituitary-adrenal (HPA) axis function and is essential for the subsequent robust morning cortisol awakening response (CAR). Clinically, a blunted or elevated nocturnal cortisol nadir can signal chronic HPA axis dysregulation, often associated with chronic stress, sleep pathology, or underlying adrenal fatigue, compromising metabolic and immune function.