Jogging makes people angry and aggressive.
A new study suggests that going for a gentle run can trigger feelings of rage as the exercise is boring and monotonous.
US researchers - who took data from more than 10,000 people - have urged people to do yoga or aerobics if they want to stay calm.
Dr. Sophie Kjaervik, who led the study for Ohio State University, said: "The finding was something of a surprise. We expected activities like boxing to increase anger, but not jogging.
"Popular wisdom suggests that going for a run reduces anger and aggression, but it does not. Going for a run is good for your heart, but it is not good for managing anger. We found that jogging in particular elevated anger.
"This may be because it involves repetitive movements, which can be monotonous and lead to boredom or frustration, increasing the likelihood of experiencing anger.
"Some individuals may also feel like they have less control during jogging exercises, which may lead to feelings of anger."