Peggy Zoccola, assistant professor of psychology and team found that when their study participants were asked to dwell on a stressful experience, their C-reactive protein levels rose. C-reactive protein is a marker of tissue inflammation, i.e. the more C-reactive protein you have in your system, the more inflammation you will have.
The authors say this is the first study to directly measure the effects of ruminating on stressful events on inflammation in the body.
Other studies have demonstrated associations between certain mental states or behaviors and C-reactive protein levels. Scientist from Duke University Medical Center found that "healthy" people who are prone to mild to moderate depressive symptoms, anger and/or hostility tend to produce higher levels of C-reactive protein.
Professor Zoccola said:
"Much of the past work has looked at this in non-experimental designs. Researchers have asked people to report their tendency to ruminate, and then looked to see if it connected to physiological issues. It's been correlational for the most part."
Zoccola and team recruited 34 healthy young adult females. They were all asked to give a speech about their candidacy for a job to two interviewers. The interviewers wore white laboratory coats and listened to them with blank, stone-faced expressions - a stressful experience even for the best of us.
Afterwards, half of the participants were asked to think about what their performance was like in their public speaking tasks, while the other half were asked to think about neutral activities and pictures, including trips to the local shops and sailing ships.
Blood samples were taken from the 34 volunteers. The team found that C-reactive protein levels were considerably higher among those who were asked to dwell on their speech (a stressful event).
C-reactive protein - blood levels rise when we dwell on negative events
Among the ruminators of the stressful event, C-reactive protein levels continued to rise for at least one hour after their speech. However, among those who had to look at neutral images and talk about going down to the local shops, their levels of the inflammatory marker returned to their pre-stressful event levels rapidly.
Most of the human body's C-reactive protein is produced by the liver. It is the immune system's preliminary inflammatory response. Any exposure to high stress, injury, trauma or infection leads to a rise in C-reactive protein levels.
Doctors commonly measure C-reactive protein levels to determine whether a patient has an infection. It can also be an indication of disease risk later in life.
People with high levels of C-reactive protein tend to have a greater risk of developing heart disease. Researchers from University College London, England, explained in the journal Circulation: Cardiovascular Genetics that C-reactive protein levels vary according to each individual person's ancestry.
"More and more, chronic inflammation is being associated with various disorders and conditions. The immune system plays an important role in various cardiovascular disorders such as heart disease, as well as cancer, dementia and autoimmune diseases."
Written by Christian Nordqvist