What is the Origin of Cortisol Rhythm Damping?

The concept is derived from endocrinology and chronobiology, focusing on the rhythmic secretion of cortisol, which is typically high upon waking, the Cortisol Awakening Response or CAR, and low before sleep. Damping is an engineering term applied to biological systems, signifying a reduction in the oscillation's magnitude. It highlights a common pattern observed in chronic stress states that disrupt the hypothalamic-pituitary-adrenal, HPA, axis.

What is the Mechanism of Cortisol Rhythm Damping?

Damping occurs when chronic psychological or physiological stress leads to sustained over-activation and eventual desensitization of the HPA axis feedback loops. Continuous high levels of circulating ACTH or persistent sympathetic nervous system output can alter adrenal gland responsiveness. The resultant blunted rhythm compromises the body's ability to mount an appropriate stress response and interferes with the natural nocturnal shift toward restorative processes.

Cortisol Rhythm Damping ∞ Area

Cortisol Rhythm Damping

Meaning

A physiological or clinically induced reduction in the normal, pronounced amplitude of the diurnal cortisol curve, specifically a blunting of the sharp morning peak and an elevated level in the evening. This flattening of the rhythm is often indicative of chronic stress adaptation or HPA axis dysregulation, rather than frank adrenal insufficiency. Clinically, damping is associated with fatigue, sleep disturbances, and altered immune function.