The fight-or-flight reaction is something we are all aware of. It kicks into action with chemical messengers called epinephrine and norepinephrine, among others. Your heart beat increases, your blood pressure increases, your hands sweat, you feel anxiety, and the list goes on. The purpose of this reaction is for protection. This is a result of acute stress. So what happens if certain life events cause chronic stress?
Chronic stress is caused by life events. Life events include adjusting to a new marriage, losing a loved one, especially a spouse or a child, fear, social isolation, divorce, caregiving for an ill family member, becoming disabled as well as many other events in life. The chemical messengers released during the fight-or-flight reaction remain at higher levels, and this causes stress on the body. The body is ready for acute stressors, but it cannot handle chronic stressors. Chronic stress suppresses, dysregulates the adaptive immune responses, and depresses the function of certain immunoprotective cells (Dhabhar, 2013).
One research study identified the biological stress of baby piglets being weaned early. One of the most stressful life events in a pig's life is the weaning from the sow. This contributes not only to intestinal dysfunction, but it also contributes to a decreased immune system. The combination of these outcomes results in reduced pig health, growth, and feed intake, especially during the first week after the weaning (Campbell, Crenshaw, & Polo, 2013).
The same occurs in humans when life events become chronic stressors. Physiological stress causes decreased immunoprotection, resulting in acute infections such as pneumonia, sinus infections, and decreased capability of the body to accept the protective mechanisms of vaccinations. For example, only 50% of caregivers of patients with Alzheimer's disease responded to flu vaccinations, due to the chronic stress from the caregivine (Freeman, 2009). Other detrimental effects of decreased immunoprotection include problems with inflammatory disorders as well as autoimmune disorders (Dhabhar, 2013).
Campbell, J.M., Crenshaw, J.D., & Polo, J. (2013). The biological stress of early weaned piglets. Journal of Animal Science and Biotechnology, 4, 19-22. http://www.jasbsci.com/content/4/1/19
Dhabhar, F.S. (2013). Psychological stress and immunoprotection versus immunopathology in the skin. Clinics in Dermatology, 31, 18-30. http://www.dx.doi.org/10.1016/j.clindermtol.2011.11.003
Freeman, L. (2009). Complementary and alternative medicine (3rd ed.). St. Louis, MO: Mosby.