What impact does cortisol have on the immune system when excessive?

Cortisol is a glucocorticoid hormone produced by the adrenal glands, and its primary role in the body includes regulating metabolism, immune response, and stress reactions. When cortisol levels are excessive, especially during periods of chronic stress or when corticosteroid medications are overused, it exerts a suppressive effect on the immune system.

The suppression of immune response occurs because cortisol inhibits the production and action of various immune cells, including lymphocytes and macrophages. This leads to a reduction in the body’s ability to fight off infections and reduces inflammation, which is a natural defense mechanism. While this anti-inflammatory action can be beneficial in preventing excessive damage during immune responses, it becomes harmful when the immune system is too suppressed, potentially leading to increased susceptibility to infections and illnesses.

In contrast, choices that suggest enhancement of immune function, stimulation of antibody production, or acceleration of healing processes do not align with the known effects of high cortisol levels. Elevated cortisol does not promote these functions; instead, it diminishes the immune capabilities, making the option that addresses immune suppression the accurate understanding of cortisol's impact when present in excess.