The cortisol test measures your levels of the stress hormone cortisol in your blood. Cortisol is a hormone that is also called the body's stress hormone and is produced in the adrenal glands. By testing you, you find out if your body produces too much or too little cortisol, which in turn can give rise to possible symptoms.
When you are designated for physical or mental stress, the body's production of cortisol is affected in order for you to perform better both physically and mentally. Cortisol helps the body regulate the metabolism of fat, proteins and sugar in the body. Cortisol also inhibits inflammation and allergies. At too high levels of cortisol, it can cause, among other things, sleep problems, and at too low levels you can experience, for example, fatigue, anxiety, weight gain, weight loss and muscle weakness.