Chronic stress is the response to emotional pressure suffered for a prolonged period over which an individual perceives he or she has no control. It involves an endocrine system response in which occurs a release of corticosteroids. While the immediate effects of stress hormones are beneficial in a particular situation, long-term exposure to stress creates a high level of these hormones that remains constant. This may lead to high blood pressure (and subsequently heart disease), damage to muscle tissue, inhibition of growth, suppression of the immune system, and damage to mental health.
Linked to impairment of the medial prefrontal cortex are deficits in the part of the striatum with which it is linked. This can bias decision-making strategies, as affected individuals shift from flexible behavior to one dominated by habit. Changes also occur to dopaminergic activity in the prefrontal cortex.
Stress has a role in humans as a method of reacting to difficult and possibly dangerous situations. The "fight or flight" response when one perceives a threat helps the body exert energy to fight or run away to live another day. This response is noticeable when the adrenal glands release epinephrine, causing the blood vessels to constrict and heart rate to increase. In addition, cortisol is another hormone that is released under stress and its purpose is to raise the glucose level in the blood. Glucose is the main energy source for human cells and its increase during time of stress is for the purpose of having energy readily available for over active cells.
The release of these hormones is evolved to be temporary. If someone is under stress for long periods of time they may have adverse health effects later on, such as hypertension and increased risk of cardiovascular disease.
Chronic stress is also known to be associated with an accelerated loss of telomeres in most but not all studies.
Different factors may prolong this "fight or flight" reaction in the body. Chronic stress can be rooted in prolonged psychological stressors. For example, some studies have looked at the health effects of social discrimination in African Americans. This demographic has markedly higher hypertension levels that are attributed to higher levels of social discrimination. This phenomenon has been coined John Henryism by sociologist James Sherman.
^Sousa N, Lukoyanov NV, Madeira MD, Almeida OF, Paula-Barbosa MM (2000). "Reorganization of the morphology of hippocampal neurites and synapses after stress-induced damage correlates with behavioral improvement". Neuroscience. 97 (2): 253–266. doi:10.1016/S0306-4522(00)00050-6. PMID10799757.
^ abDias-Ferreira E, Sousa JC, Melo I, Morgado P, Mesquita AR, Cerqueira JJ, Costa RM, Sousa N (2009). "Chronic Stress Causes Frontostriatal Reorganization and Affects Decision-Making". Science. 325 (5940): 621–625. doi:10.1126/science.1171203. PMID19644122.
^Tsigos C.; Chrousos G.P. (2002). "Hypothalamic-pituitary-adrenal axis, neuroendocrine factors, and stress". Journal of Psychosomatic Research. 53 (4): 865–871. doi:10.1016/s0022-3999(02)00429-4.
^Blascovich J.; Spencer S. J.; Quinn D. M.; Steele C. M. (2001). "African Americans and high blood pressure: The role of stereotype threat". Psychological Science. 12 (3): 225–229. doi:10.1111/1467-9280.00340. PMID11437305.
^Notterman DA, Mitchell C (2015). "Epigenetics and Understanding the Impact of Social Determinants of Health". Pediatric Clinics of North America (Review). 62 (5): 1227–40. doi:10.1016/j.pcl.2015.05.012. PMID26318949.
^Quinlan J, Tu MT, Langlois EV, Kapoor M, Ziegler D, Fahmi H, Zunzunegui MV (2014). "Protocol for a systematic review of the association between chronic stress during the life course and telomere length". Syst Rev (Review). 3 (40). doi:10.1186/2046-4053-3-40. PMID24886862.
^James S. A.; Hartnett S. A.; Kalsbeek W. D (1983). "John Henryism and blood pressure differences among black men". Journal of Behavioral Medicine. 6 (3): 259–278. doi:10.1007/bf01315113.
^Miller, Gregory E.; Chen, Edith; Zhou, Eric S. (January 2007). "If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans". Psychological Bulletin. 133 (1): 25–45. doi:10.1037/0033-2909.133.1.25. PMID17201569.