New U.S. guidelines on exercise advise starting sooner to get children active to avoid health problems later in life.
Physical activity guidelines used to start at age 6, but now they recommend involving kids as young as 3 in active play throughout the day.
For adults, the advice remains to get at least two and a half hours of exercise in a week, including aerobic exercise and lifting weights or other muscle-strengthening work.
Exercise doesn't have to be all at once or very hard. Even little things like taking the stairs instead of an elevator help.
The guidelines were released Monday at an American Heart Association conference in Chicago and published in the Journal of the American Medical Association.