Stress A Factor In Infectious Disease

Researchers who have spent years studying the effects of stress on the body's immune system now believe they know enough to show that stress actually does weaken a person's health.

Dozens of studies have shown that stress can alter the levels of certain biochemical markers in the body -- key players in the human immune response. Still, scientists weren't sure those changes actually led to poorer health. Now, they seem convinced.

Reporting in the Journal of the American Medical Association (JAMA), a team of researchers from five universities argued that stress can lessen a person's immune response, and in turn make him or her more susceptible to infectious diseases.

"The evidence so far suggests that while the immune changes associated with psychological stress are generally small, they look like they're important enough to have biological consequences and increase health risks," explained Ronald Glaser, professor of medical microbiology and immunology at Ohio State University and lead author of the study.

The JAMA paper points to the important role that compounds known as cytokines play in regulating the immune response. In some cases, they stimulate the release of other compounds essential for inflammation. In other cases, they maintain the balance of other components of the human immune response.

Researchers know that psychological stress can alter the level of certain hormones. These alterations induced by stress are responsible for the changes in cytokine concentrations since stress hormones alter the synthesis and the release of the cytokines, the authors explained.

They said that enough is known now to show that certain changes in lifestyle can increase a person's resistance to some infectious diseases. Most of these changes -- gaining social support and companionship, maintaining a proper diet, regular exercise and enough sleep -- are not expensive, stated Prof. Glaser.