Taken directly from health.gov and exerciseismedicine.org
Children 3-5 years old
Children should be physically active throughout the day to promote growth and development. Adults should encourage children in active play with a variety of activities.
*Physical activity in children is heavily influenced by parent behavior so get out there and show your children was it's all about!
Children 6-17 years old
Cardiorespiratory Exercise:
Moderate or vigorous-intensity exercise should be performed for 60 minutes (or more)/day. Vigorous-intensity physical activity should be performed at least 3 days a week.
What classifies as moderate intensity exercise? A few different scoring systems exist to gauge exercise intensity but I like The Talk Test the most. The talk test is simple and well-proven. If you can only say 2-3 words while exercising you are participating in moderate intensity exercise. If you can utter 2 words or less, you are participating in vigorous intensity exercise.
Strength Training:
As part of these 60 active minutes (or more)/per day children and adolescents should include muscle-strengthening physical activity at least 3 days a week.
Bone Strengthening:
As part of these 60 active minutes/day children and adolescents should include bone strengthening activities on at least 3 days/week.
Exercise Guidelines for Kids