Cortisol is known as “the stress hormone” because it’s secreted by the adrenal glands in response to stress and prepares the body for “fight or flight.” Cortisol functions to regulate blood pressure, blood sugar, metabolism, and inflammation. Small increases of cortisol produce positive effects like improved memory, reduced sensitivity to pain, increased immunity, and increased energy. However, elevated cortisol levels from prolonged or chronic stress can cause decreases in thyroid function, bone density, muscle mass and cognition. In addition, it can also lead to increased blood pressure, abdominal fat, and blood sugar imbalances. High levels of cortisol can also lower immunity and inflammatory responses as well as slow down healing processes. Sustained high levels of cortisol will gradually tear down the body (called catabolism). Excessive acute or chronic stress can impair the functioning of the adrenal glands, eventually causing a decrease in the output of cortisol. This leads to adrenal fatigue or adrenal exhaustion. The main symptom of adrenal exhaustion is overwhelming fatigue that is not relieved with rest.