As we have discussed earlier, psychological stress should be distinguished in accordance with its duration and intensity. The psycho-neuroimmunological community recognizes an acute stress and a chronic stress. Both types of stress have different impact on the functioning of the immune system. The sympathetic nervous system (SNS) and the hypothalamic–pituitary–adrenal (HPA) axis are activated by any psychological stress. The SNS is responsible for regulating the heart rate through secreting catecholomines, while the HPA axis controls the corticosteroids release from the adrenal glands (Brydon, Edwards et al., 2005). However, different types of stress differ in their roles in changing immunity. In case of an acute stress exposure, the organism activates the SNS functioning and the release of catechlomines, which influence the circulation of the natural killer (NK) cells. If the organism has to deal with a chronic stress, it decreases the HPA axis leading to inflammation caused by the alteration in the immune system (Ho, Neo et al., 2010).
In addition, we should talk about the stress-induced redistribution of immune cells. In particular, psychological and/or physiological stress might activate the leukocytes traffic in such a way that certain stress hormones are found in the right place and at the right time in order to be able to react to immune defiance caused by stress-induced agent (Dhabhar, Miller, McEwen & Spenser, 1996).
Personality and learned defense mechanisms constitute the individuality in perceiving stress and hence, in coping with it. Distinct emotional responses to chronic stress are more likely to be factors which contribute not only into the type of stress response, but also into particular changes in the immune system leading to its dysregulation (Epel, 2009). Several studies suggested that individual stress response might represent a major determining variable in susceptibility to a stress-induced disease (e.g., heart disease, cancer, allergy, asthma, and sleep disorder).
Brydon, L., Edwards, S., Jia, H., Mohamed-Ali, V., Zachary, I. et al. (2005). Psychological stress activates interleukin-1 gene expression in human mononuclear cells. Brain, Behaviour, and Immunity, 19, 540-546.
Dhabhar, F. S., Miller, A. H., McEwen, B. S., & Spencer, R. L. (1996). Stress-induced changes in blood leukocyte distribution – role of adrenal steroid hormones. Journal of Immunology, 157, 1638-1644.
Epel, E. (2009). Psychological and metabolic stress: A recipe for accelerated cellular aging? Hormones, 8(1), 7-22.
Ho, R., Neo, L. F., Chua, A. N. C., Cheak, A. A., & Mak, A. (2010). Research on psychoneuroimmunology: Does stress influence immunity and cause coronary artery disease? Psychoneuroimmunology and CAD, 39(3), 191-196.
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