Cortisol, synthesized from cholesterol, is a hormone produced in the adrenal gland in response to stress. Its primary functions are to increase blood sugar, suppress the immune system, and aid in fat, protein and carbohydrate metabolism.
Cortisol works with epinephrine (adrenaline) to create memories of short-term emotional events; this is the proposed mechanism for storage of flash bulb memories, and may originate as a means to remember what to avoid in the future. However, long-term exposure to cortisol damages cells in the hippocampus; this damage results in impaired learning. Furthermore, it has been shown that cortisol inhibits memory retrieval of already stored information.
In addition, cortisol has anti-inflammatory properties, reducing histamine secretion and stabilizing lysosomal membranes. Stabilization of lysosomal membranes prevents their rupture, preventing damage to healthy tissues.
Factors Which Can Reduce Cortisol Levels
- sexual intercourse
- black tea
- crying: William H. Frey II, a biochemist at the University of Minnesota, proposed that people feel “better” after crying, due to the elimination of hormones associated with stress, specifically adrenocorticotropic hormone. This, paired with increased mucosal secretion during crying, could lead to a theory that crying is a mechanism developed in humans to dispose of this stress hormone when levels grow too high.
Factors Which Can Increase Cortisol Levels
- sleep deprivation
- anorexia nervosa
Many high-stress lifestyels cause people to live in constant upregulation of cortisol. Because cortisol suppresses the immune system, it can keep one from becoming sick during the stressful period. However, once the work load goes back to normal, the immune system will return to full speed and cause symptoms of sickness to occur. In people with extremely stressful jobs, such as business CEO’s and military generals, a sudden retirement can create a drastic change in cortisol levels the immune system, and can cause them to become fatally ill.