Final answer:
Stress increases cortisol, which can decrease immune system functioning.
Step-by-step explanation:
Stress increases the stress hormone cortisol, which can decrease immune system functioning if it is overly secreted.
Cortisol, often referred to as the "stress hormone," is released by the adrenal glands. While cortisol is essential for various bodily functions, such as regulating metabolism and managing inflammation, excessive or prolonged secretion, as seen in chronic stress, can have negative effects.
One significant impact of prolonged elevated cortisol levels is its potential to suppress the immune system. Cortisol works by inhibiting certain aspects of immune function, making the body more susceptible to infections and impairing its ability to respond effectively to pathogens. This is why chronic stress has been associated with increased vulnerability to illnesses.