Blood Pressure and Disease Increased by Stress

Summary
In a recent study in Pittsburgh, researchers examined the variations in blood levels of a chemical called interleukin-6 (IL-6) in an emotionally stressful situation, such as public speaking. IL-6 is a marker molecule that indicates an inflammatory response in the body. The present study has shown that people who feel more anger and more anxiety have significant changes in IL-6 levels and are prone to various immune-related diseases, such as Lou Gehrig’s disease, hepatitis or cancer. The study has also shown that there is significant increase in blood pressure and heart rate whenever people are exposed to emotional stress.

Introduction
Immune function can be a double-edged sword. This system normally helps us in fighting against microbes. But excessive or unwanted immunological response causes damage to the body by producing inflammation. In the present study, researchers evaluated the role of psychological stress in altering IL-6 levels. The study investigated whether psychological stress makes a person predisposed to developing immune-related diseases. A central purpose of the study was to identify whether there is any difference between individuals in the amount of IL-6 that is produced. The study additionally looked at cardiovascular changes in response to stress, which indicates activity of the sympathetic nervous system.

Methodology
* The study included 102 participants who were enrolled in the “Vaccination and Immunity Project.” Sixty percent were women. The mean age of participants was 50.
* At the beginning of the experiment participants were asked to completely relax for 30 minutes. Their blood sample was collected to measure baseline IL-6 level. Following this, participants were asked to give a three-minute simulated public speech after preparing for two minutes. The speech, which was videotaped, was about defending themselves against allegations. Two more blood samples were collected immediately after the task and 30 minutes after the task.
* Throughout the experiment blood pressure and heart rate of participants were measured.

Results
* After performing the task, there was a rise in blood pressure and heart rate, which returned to baseline after taking 30 minutes of rest.
* Mean IL-6 levels were 1.22pg/ml at baseline, 1.20 pg/ml immediately after the simulated public speaking task and 1.26 pg/ml after taking 30 minutes rest.
* Though the minor changes in IL-6 levels are not significant statistically, such minute increases may produce marked inflammatory response in the body.
* Individual responses varies markedly in the magnitude of their inflammatory response to the task.
* IL-6 levels raised markedly in men compared to women.

Next steps/Shortcomings
All the participants in the present study were healthy individuals. Results may prove to be different in individuals who already have some disease. A follow-up of more than 30 minutes is necessary to provide more reliable results.

Conclusion
This study once again highlights the role of emotional stress in producing inflammatory response, and thus, immune-related diseases. The study has also shown that there is a marked difference between individuals in the development of inflammatory response. It is thought that anger and anxiety stimulate the sympathetic nervous system that activates white cells and fat cells in the body. These cells, in turn, produce various pro-inflammatory molecules such as IL-6. “In conclusion, the present findings suggest that individual differences in affective responses to a mildly stressful speaking task are associated with the magnitude of change in circulating IL-6 levels, a marker of systemic inflammatory activity.”

For More Information:
Negative Emotions during a Simulated Public Speaking Task Induce Change in Interleukin-6 Levels
Brain, Behavior, and Immunity, October 2010
By Judith E. Carroll; Carissa A. Low; University of Pittsburgh, Philadelphia, and the University of Pittsburgh School of Medicine, Philadelphia

*FYI Living Lab Reports Are Summaries of the Original Research.