NBC News - There's another good reason for kids to get out and exercise... besides staying in shape.
A new study shows it also helps them deal with stress.
Researchers asked more than 200 eight-year olds to tell stories and work on math problems, which are potential stressful situations for children.
They found that those who were most active had the lowest levels of the stress hormone "cortisol" while performing the tasks.
Their determination: Exercise can improve mental health by regulating stress hormones.