Stress and Immune Functioning

The development of questionnaires to measure life stress has allowed researchers to look for correlations between stress and s variety of diseases. 

Found an association between life stress and the course of rheumatoid arthritis. 

Another study found an association between stressful life events and the emergence of lower back pain. 

Other researchers have connected stress to the occurrence of asthmatic reactions and periodontal disease. 

Studies have also found association between high stress and flare-ups of irritable bowel syndrome peptic ulcers.

These are just a handful of representative examples of research relating stress to physical diseases. Many of these stress illness connections are based on tentative are inconsistent findings, but the sheer length and diversity of the list is remarkable.

Why should stress increase the risk for so many kinds of illness? A partial answer may be the immune functioning.

The apparent link between stress and many types of illness probably reflects the fact that stress can undermine the body’s immune functioning. The immune response the body’s defensive reaction to invasion by bacteria, viral agents, or other foreign substances. The human immune response works to protect the body from many forms of disease. Immune reactions are remarkably complex and multifaceted. Hence there are a great many ways to measure immune function in an organism, and these multiple measures can sometimes produce conflicting, confusing results in research.

Nonetheless, a wealth of studies indicate that experimentally induced stress can impair immune functioning in animals. That is, stressors such as crowding, shock, food restriction, and restraint reduce various aspects of immune reactivity in laboratory animals.

Studies by Janice Kiecolt Glaser and her colleagues have also related stress to suppressed immune activity in humans. In one study medical students provided researchers with blood samples so that their immune response could be assessed at various points. The students provided the baseline sample a month before final exams and contributed the “high stress” samples on the first day of their finals. The subjects (the students) also responded to the Social Readjustment Rating Scale (SRRS) as a measure of recent stress. Reduced levels of immune activity were found during the extremely stressful finals week. Reduced immune activity was also correlated with higher scores on the SRRS.

Many other studies have also shown a link between stress and suppressed immune response. For example, when quarantined volunteers were exposed to respiratory viruses that cause the common cold, those under high stress were more likely to be infected by the viruses. Other studies have found evidence of reduced immune activity among people who scored relatively high on a stress scale measuring daily hassles among men who were recently divorced or separated among husbands and wives grappling with a high level of marital conflict among people recently traumatized by a hurricane and among men who recently experienced the death of an intimate partner.

Unfortunately, evidence suggests that susceptibility to immune suppression in the face of stress increases as people grow older. Scientists have assembled impressive evidence that stress can temporarily suppress human immune functioning, which can make people more vulnerable to infectious disease agents.

A wealth of evidence suggests that stress influences physical health. Moreover, critics of this research note that many of the studies used research design that may have inflated the apparent link between stress and illness.

Actually this fact should come as no surprise. Some people handle stress better than others. Furthermore, stress is one of the factors that undermine the body’s immune functioning.