For years, researchers have known that exercise can affect certain moods. Running, bike riding and other exercise programs have repeatedly been found to combat clinical depression. Similarly, a study from Germany published in April found that light-duty activity like walking or gardening made participants “happy,” in the estimation of the scientists. Even laboratory rats and mice respond emotionally to exercise; although their precise “moods” are hard to parse, their behavior indicates that exercise makes them more relaxed and confident. But what about anger, one of the more universal and, in its way, destructive moods? Can exercise influence how angry you become in certain situations?