Active kids appear to be "happier".

A new study suggests that kids who exercise aren’t only in better physical shape; they’re happier, too.

Canadian researcher Mark Holder and colleagues asked 375 children, ages 8-12, about what they did for fun, paying special attention to the amount of time the kids said they spent in “active” leisure activities—physical activities such as sports and exercise—or “passive” activities, such as watching TV, talking on the phone, or playing on the computer or with videogames.

Holder found that the more kids engaged in active leisure, and the more important active leisure was to them, the happier they were and the more positive they felt about themselves.

Even though the study does not necessarily prove that active leisure directly increases kids’ happiness, Holder and his colleagues theorize that physical activity may make kids happier because it provides opportunities both to boost self-confidence and to develop stronger social relationships, which are key to happiness.