The human brain has a complex and reliable response to stressful and life threatening situations. This mechanism, however, can have untoward consequences for the organism if it is triggered too frequently. In contemporary living, humans are constantly exposed to stressors that engage this system. In order to fully understand this process, the nature of the brain's natural "alarm system" is more fully described below.
When faced with what the brain regards as a dangerous situation, a well orchestrated sequence of chemical events is set in motion that can lead ultimately to a "flight or fight" response. The chain of events begins when the brain signals the hypothalamus, situated deep within the brain, to secrete corticotrophin-releasing hormone (CRH) that signals the nearby pituitary gland to subsequently release adrenocorticotropin hormone (ACTH) into the bloodstream. ACTH binds to specific receptors on the adrenal glands, located near the kidneys. This binding triggers a cascade of chemical events within the cells of the adrenal gland that ultimately produce cortisol that is released into the bloodstream. Cortisol is a hormone that elicits a wide range of responses throughout the body that heightens the organism's ability to respond to challenging situations. But the persistent release of this hormone can result in lasting damage.
In order to mitigate the potency of this mechanism, the body has countermeasures at its disposal. One of these, Neuropeptide Y dampens the effects of CRH in various regions of the brain. Another is dehydoepiandosterone (DHEA) that counteracts the role of the hormone cortisol. It is believed that certain drugs and psychotherapy might be effective in stimulating the release of these natural agents. This ability to cope with stress is referred to as resilience. From the above description, it becomes quite evident that resilience is important in the maintenance of good health.