Which physiological system may experience decreased activity as a response to stress?

The immune system may experience decreased activity as a response to stress due to the body's adaptive mechanisms in high-stress situations. When an individual encounters stress, the body initiates the "fight or flight" response, primarily regulated by the autonomic nervous system and hormonal changes, specifically the release of stress hormones like cortisol and adrenaline.

Cortisol, while useful in managing short-term stress, can suppress certain functions of the immune system. This suppression can lead to a temporary decrease in the immune response, making the body more vulnerable to infections and reducing the effectiveness of the immune system's ability to combat pathogens. This physiological response is essentially a prioritization mechanism; the body focuses its energy on immediate survival rather than long-term health maintenance.

Understanding this relationship is crucial for recognizing how chronic stress can lead to a weakened immune system, increasing susceptibility to illness over time.