Cortisol is a hormone produced by the adrenal gland. It is often called a stress hormone, because the body makes more of it in the face of acute, or chronic (ongoing), stress.Levels of cortisol in the blood fluctuate over a 24-hour period, with highest levels typically in the morning (6-8am), and lower levels around midnight. Doctors can test for increased or decreased cortisol levels using a serum (blood) or urinary cortisol test. While cortisol plays a valuable role in the day to day functioning of the body, chronically-elevated cortisol has been linked to reduced longevity because of its detrimental effects on the cardiovascular, metabolic, and immune systems.
Cortisol Level. US National Institutes of Health Medline Public Information Sheet. Accessed June 26, 2012.
Cortisol: Urine. US National Institutes of Health Medline Public Information Sheet. Accessed June 26, 2012.