This is an invited research digest contributed by Dr. Viktoriya Maydych, Dr. Maren Claus, Dr. Thomas Kleinsorge, and Dr. Carsten Watzl at the Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund, Germany.
Almost everyone feels nervous or anxious when preparing for and taking an exam. Indeed, outcomes of exams are associated with consequences for career development, self-esteem, and judgement from others. Academic exams are one of many psychological sources of stress in everyday life which can increase susceptibility to a diverse set of diseases, influence their development and severity. Although the link between stress and negative health outcomes is a well-known fact, the underlying biological processes have not yet been completely understood. Immune dysregulation might be one of the core mechanisms behind stress-related health risks.
Psychologists and immunologists from the Leibniz Research Centre for Working Environment and Human Factors (Germany) have analyzed how academic stress affects immune function. The researchers also investigated whether personality traits influence the immune response to stress. 20 university students underwent immunological and psychological assessment five times during a period of 8 weeks. The first two assessments took place 4.5 weeks and 1.5 weeks before the exam period, the third session was scheduled for the first day of the exam period. The last two assessments took place directly after and one week after the exam period.
Blood and saliva samples were obtained from each study participant on each assessment session. Thus, researchers were able to analyze time-dependent changes of immunity using 45 different immunological parameters, such as subgroups of natural killer (NK) cells, monocytes or T cells. In order to draw conclusions on whether personality traits have a moderating influence on the effects of examination stress, the participants completed a series of standardized questionnaires on topics such as burnout, depression, mood, coping and others.
The results showed that the number of immune cells in the blood decreased during the observation period. This particularly affected NK cells and monocytes, i.e. cells of the innate immune system, which are important for early immune responses to infections. In addition to the reduced number of immune cells, another striking finding was a shift in the ratio of immature to mature subpopulations of NK and T cells. Until shortly before the start of the exam, the percentage of immature cells in the blood increased while that of the mature cells decreased. The reason for the redistribution might have been the migration of the mature cells from blood into the tissue. This would allow the body to prepare for infections or injuries that, from an evolutionary point of view, may be a result of a stressful situation.
With regard to the moderating influence of personality, the results showed that the immune system of individuals who were psychologically stressed before the exam period hardly responded to the acute stress from the upcoming exam. Chronically stressed persons had already fewer immune cells and this low number hardly changed during the exam period. Earlier stressors might have weakened the immune system to the extent that it was no longer able to adequately respond to brief stressors.
Follow-up studies with a larger number of participants as well as more standardized assessment situations such as final exams or driving tests are needed to substantiate the findings of the current study and to deepen the knowledge about the effects of stress and personality traits on the immune system.