Cortisol is a steroid hormone, produced by the adrenal glands. Cortisol's role in stress is well known. More is released during the body's fight or flight response to danger and leads to changes in the body as it prepares to deal with the perceived threat. Modern lives with constant stimulation, work, and social pressures can lead to persistently high cortisol. </p><p>Although cortisol is associated with stress, it is also important for many other functions including your immune function, blood pressure regulation, and controlling insulin to maintain blood sugar levels.