June 8, 2010 -- If you're about to have a meeting with your boss that you just know will tick you off, go out and take a quick jog first.
The findings need to be replicated in much larger numbers of people before any firm recommendations can be made, says Nathaniel Thom, PhD, a contractor to the Naval Health Research Center in San Diego, who performed the study while at the University of Georgia.
The findings were presented at the annual meeting of the American College of Sports Medicine in Baltimore.
Slideshows Evoke Anger
The study involved 16 high-strung college-age men who were easily angered.
Before and after 30 minutes of moderate-intensity cycling, participants viewed a slideshow of pictures known to evoke anger (Ku Klux Klan, Hitler, malnourished children) mixed with images designed to induce fear, pleasantness, or no emotions.
Then, before and after 30 minutes of quietly resting, they watched the slideshows again.
At various points in the study, the men were asked to rate how angry they felt on a 20-point scale, where higher numbers equal more anger.
Exercise Helps to Mitigate Anger
After exercising, the men's average anger rating after viewing the slides went up slightly, to about 7 points compared with about 6.3 points before viewing the slides, but the difference was so small it could have been due to chance.
But after resting, scores jumped from about 8 points before the slideshow to about 10 points after the slideshow, a significant difference.
"After exercising, watching the pictures didn't make the men more angry, while after rest, they did," Thom says.
However, some of the findings were not consistent. Exercise did not reduce the intensity of anger. When they rated their anger on a standardized 0 to 9 point scale, where higher numbers equal more intense anger, the men had an average score of about 4.2 points before exercise, compared with about 3.9 points afterward, a difference was so small it could have been due to chance.
Also, there were no changes in brain activity when the men viewed the violent pictures after exercise.
Exercise May Boost Serotonin Levels
Although the study was not designed to determine how exercise might mitigate anger, Thom notes that anger and aggression are associated with low levels of the calming mood chemical serotonin.
The selective serotonin reuptake inhibitors (SSRIs) commonly used to treat mood disorders, which boost serotonin levels in the brain, decrease aggressive behavior, he notes, and animal studies suggest exercise may increase serotonin levels in the brain.
Sports physiologist Michael R. Bracko, EdD, director of the Institute for Hockey Research in Calgary, Canada, tells WebMD that just the distraction offered by exercise can have a calming effect.
"A group exercise class or weight lifting can take your mind off things," thereby relieving angry emotions, he says.
Thom acknowledges that much more work is needed. But if it does pan out, "there's a huge public health benefit," he says.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.