Study on Stress

The cells that account for the immune system are white blood cells or leucocytes.  They circulate the body seeking out and destroying any organisms that may be harmful.  Lymphocytes remember and can recognize previous invaders.  There are B-cell lymphocytes and T-cell lymphocytes B-cells work to produce specific antibodies to neutralize infections and t-cells detect infected cells and kill them outright.  They are called Natural Killer (NK) cells.  Another type of leucocytes cell is macrophages, which engulf and then digests cell debris and pathogens.  The immediate (non specific) immune response just consists of NK cells and macrophages

There have been many studies that suggest that stress causes decreased immune system functioning.

One study looked at exam stress (acute stress).  T-cell activity was measured 3 months before the exam and during the exam period.  T-cell activity was always highest during the exam period.  Also those with the most stressful lives (determined by a questionnaire) had the lowest T-cell activity.  The rate of which wounds heal was also studied during and before exam time, and showed that wounds healed significantly slower during the exams.  Similar results were found with martial stress i.e. chronic stress.  More marital problems tend to correlate with increased chance of getting sick and slower to heal physical wounds (arm blisters took 40% longer with recently divorced adults).

These results could be explained by the pituitary adrenal system, and the effect of cortisol.  Cortisol is released as part of the stress response which suppresses the immune system.  When cortisol levels are consistently high the immune system is consistently suppressed and the body is much more vulnerable to infections and illnesses (and wounds).