Study Finds Some Kinds of Stress Harm Immune System

MONITOR News Services

The conclusion is based on a study that was designed to draw out the different effects that active and passive coping might have on the body's defenses. It presents some of the strongest evidence yet that certain kinds of stress can promote good health.

"Our findings lend scientific truth to the idea that a hassle a day keeps the doctor away," said Jos A. Bosch, postdoctoral fellow in oral biology at Ohio State and lead author of the study.

Bosch and his colleagues conducted their experiments on a group of 34 volunteers, who were exposed to two different stressful experiences. The first was a timed memory task that required the students to memorize some given material and take a 12-minute test. In the second activity, the subjects were shown a gruesome 12-minute video on surgical procedures.

The difference between the two kinds of stresses -- both of which are considered acute, rather than chronic, stress -- was that participants were actively engaged in the memory task, but the video had to be watched passively.

To examine the effect of these stresses on the immune system, the researchers studied the concentration of certain defense proteins in the saliva of the subjects. These proteins -- known as immunoglobulins -- are also contained in body fluids that make up the protective outer film of organs such as the lungs. The deployment of these immune factors inside the human body constitutes what biologists call the secretory immune system -- the first line of defense that pathogens have to cross before invading tissues.

Bosch and his colleagues found that the memory task caused an increase in the salivary concentration of a major immune factor -- the SIgA or secretory immunuglobulin A. The video had the opposite effect, lowering levels in the saliva.

"It appears that the stress from engaging in the memory task activated the subjects' immune system, whereas the stress from watching the video caused a downregulation (or weakening) of immunity," Bosch said.

The results suggest that deadlines and challenges at work could be a good thing. "Even being annoyed about something, particularly if it is for a short time, could help strengthen the body's defenses," Bosch said.

Being exposed to violent scenes on television, on the other hand, may suppress the immune system. The continuous replays of the World Trade Center towers' collapse on September 11, Bosch said, were a likely example.

As a next step, Bosch intends to investigate the mechanisms underlying the immunological effects of active and passive coping. The work was published in a recent issue of the journal Psychophysiology.