During periods of adversity, the brain triggers release of cortisol, a hormone responsible for the fight - or - flight response. (discovermagazine.com)
In the presence of adrenal dysfunction, one may lose out on the morning release of cortisol to get them going. (holtorfmed.com)
A part of the autonomic nervous system, release of cortisol in the system is quick, unconscious and can be measured in saliva; therefore, measuring cortisol is a good indicator of stress in the body, said Mark V. Flinn, professor of biomedical anthropology and chair of the Department of Anthropology in the MU College of Arts and Science. (sciencedaily.com)