Too Much Stress Hinders Immune System

Chronic Stress Makes Body Less Able to Control Inflammation

Nov. 4, 2002 -- Being stressed out may not only increase your chances of getting sick, but it could also hinder your immune system's ability to fight off infection and disease. New research shows that chronic stress can affect how well the immune system is able to respond to its own signals.

The study shows that constant stress impairs the immune system's capacity to respond to the normal hormonal cues that signal the end of an inflammatory attack after an infection or injury. Those hormones, known as glucocorticoids, are responsible for turning off the production of compounds from the immune system that trigger inflammation.

Researchers say the findings suggest that this interference could increase the risks associated with a variety of conditions, such as heart, allergic, and immune diseases. Their study appears in the November issue of Health Psychology.

Although psychological stress has been linked to a variety of health problems, researchers say it's not clear exactly how stress affects the immune system. In addition, the effect of chronic stress is difficult to quantify due to the variety of stressors people experience.

But in this study, researchers attempted to examine what happens to people's immune systems during an ongoing stressful experience. They compared blood samples from 25 healthy parents who had a child undergoing treatment for cancer with samples taken from 25 healthy parents with healthy children. Investigators also measured the parent's mental health, levels of social support, and levels of stress hormones obtained from saliva samples.

They found that the parents of cancer patients had more psychological stress than the other parents. They also found that blood samples from these parents had less of a decrease of inflammatory compounds after treatment with glucocorticoids than the blood samples of parents without stress. Stress, the researchers say, lowered the parents' sensitivity to glucocorticoids. This lowered sensitivity means that inflammation may go unchecked, leading to an increased risk for stress-related ailments.

But social support also seemed to play an important role in countering these negative effects of stress. Study author Gregory Miller, PhD, of Washington University, and colleagues found less immune impairment among parents of cancer patients that reported having a strong support network.