Which of the following is a potentially negative effect of excess cortisol production in response to exercise or stress?

Excess cortisol production in response to exercise or stress can lead to suppressed immune function, which is a significant concern. Cortisol, often referred to as the "stress hormone," is released by the adrenal glands and plays a crucial role in the body's response to stress. While it helps manage various functions, including metabolism and blood sugar regulation, elevated cortisol levels over prolonged periods can negatively impact the immune system.

When cortisol levels are high, it can inhibit the production of certain immune cells and cytokines, which are vital for a strong immune response. This suppression can make the body more susceptible to infections and diseases, as the immune system is less effective in identifying and combating pathogens. Therefore, while cortisol has important functions, excessive amounts can lead to compromised immune capabilities, highlighting the potentially negative effects of chronic stress or prolonged exercise without adequate recovery.

The other options, such as increased muscle mass, enhanced fat metabolism, and improved insulin sensitivity, are typically associated with healthy cortisol levels and appropriate exercise responses, rather than excessive cortisol production. Excess cortisol is more associated with negative health outcomes rather than beneficial effects in these areas.