Can exercise moderate anger?

A study presented at the most recent annual conference of the American College of Sports Medicine provides some provocative if ambiguous answers. For the study,hundreds of undergraduates at the University of Georgia filled out questionnaires about their moods. From that group,the researchers chose 16 young men with high trait anger or,in less technical terms,a very short fuse. They were,their questionnaires indicated,habitually touchy.

During the two days of the study,the men were each fitted with high-tech hairnets containing multiple sensors that could read electrical activity in the brain. Next,researchers flashed a series of slides across viewing screens set up in front of each young man.

The slides,intended to induce anger,depicted upsetting events like Ku Klux Klan rallies and children under fire from soldiers,which were interspersed with more pleasant images. Electrical activity in the mens brains indicated that they were growing angry during the display. For confirmation,they described to researchers how angry they felt,using a numerical scale.

On alternate days,after viewing the slides again,the men either sat quietly or rode a stationary bike for 30 minutes while their brain patterns and verbal estimations of anger were recorded. Afterward,the researchers examined how angry the volunteers became during each session.

The results showed that when the volunteers hadnt exercised,their second viewing of the slides aroused significantly more anger than the first. After exercise,conversely,the mens anger reached a plateau. They still became upset during the slide show exercise didnt inure them to what they saw but the exercise allowed them to end the session no angrier than they began it. What the results suggest is that exercise,even a single bout of it,can have a robust prophylactic effect against the buildup of anger,said Nathaniel Thom,a stress physiologist who was the studys lead researcher.

Its like taking aspirin to combat heart disease, he said. You reduce your risk.

When the men did not exercise,they had considerable difficulty controlling their racing emotion. But after exercise,they handled what they saw with more aplomb. Their moods were under firmer control.

The question of just how,physiologically,exercise blunts anger remains open. Thom and his colleagues did not test levels of stress hormones or brain chemicals in the test subjects. But earlier work by other scientists suggests that serotonin,a neurotransmitter in the brain,probably played a role,Thom said.

Animal studies have found that low levels of serotonin are associated with aggression,which is our best analogue of anger in animals, he said. Exercise increases serotonin levels in the rat brain. Low serotonin levels in humans are also thought to contribute to mood disorders.

Changes in the activity of certain genes within the brain may also have an impact. In a 2007 experiment at Yale University,researchers found that prolonged running altered the expression of almost three dozen genes associated with mood in the brains of laboratory mice. Thom says he hopes that future studies by himself and others will help to determine the specific underlying mechanisms that link exercise and a reduction of anger.

But for now,the lesson of his preliminary work,he said,is that if you know that youre going to be entering into a situation that is likely to make you angry,go for a run first.