Exercising people are happy people.

Nonsense. Ever see someone’s face at mile 20 of a marathon? Do they look happy to you?

OK, maybe people aren’t happy while exercising, but evidence shows they’re better off, in general, after the fact. Physical activity has a positive effect on mood, and is considered a valid treatment strategy to battle anxiety disorders and even depression. Although most explanations are somewhat wishy-washy, researchers believe that hedonistic value of exercise is important in mental health. Exercise simply makes us feel good about ourselves. And this is not only true in humans, but in animals, as well. Rats and mice that are given free access to a running wheel will use it, and lab rodents typically won’t do anything that doesn’t provide them some sort of pleasure.

But what about anger -- can exercise prevent us from getting angry in the first place?

Gretchen Reynolds’ new post on the ‘NYT Well’ column discuss new evidence that shows exercise -- even a single, isolated session -- can alter how we respond to challenges that angered us in the past.

In one particular study, researchers showed a group of undergraduate students a series of images while recording EEG signals from their brains. Some of the images were pleasant, while others were meant to make the participants angry. After the students watched the videos, they rated their current anger on a scale from 0 to 9. At baseline, the electrical activity in the brains of students showed they were disturbed by the nastier images, and they all rated their anger on the high-side of the 0-9 scale.

The students were then divided into two groups. And on the days between the experiment, one group did some light/moderate exercise (like 30 minutes on a stationary bike), while the other group did not exercise at all. When re-tested, the electrical activity of the brains of all the students, regardless if they exercised or not, showed that they became angry while watching the videos. But the students that had exercised the day before were able to shake-off their anger, and at the end of the session, they just weren’t as upset as those in the physically-inactive group.

The results suggest that exercise may in fact be a preventive measure against the buildup of anger.

The rest of Reynolds’ post talks about the mechanism of how exercise could make us less like to boil over in anger. She provides some hand-waiving explanations, saying changes in serotonin levels in chronic exercisers make them less angry. While this may be true, exercise is a complex activity that changes so much in the body -- neurotransmitter levels, blood flow, hormone levels, just to name a few -- so I’d caution readers that it’s hard to pinpoint which physiological catalyst could be real the anger-fighting superhero. Or maybe it’s not one particular molecule, but the sum total that makes exercise so powerful.