Physical Activity for Kids

We often hear about the importance of physical activity for kids from different perspectives: the increase of childhood obesity; how increasing screen time has led to decreases in physical activity; and fond retellings of the good old days, when children would play outside. There is also study1 after study2 providing evidence that physical activity provides benefits in a wide variety of aspects, from cognitive benefits (sharper focus and better grades in school) to emotional benefits (better moods) to biological benefits (better sleep) and beyond.

Boy playing in sprinkler
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A crucial part of physical development is when we have the majority of our gains in bone mass during the years just before and during puberty. To improve bone health and avoid excess fat, the Center for Disease Control and Prevention (CDC) recommends the following:3

  • For preschoolers (ages 3 through 5 years), physical activity throughout the day should add up to at least 3 hours per day of activity of all intensities: light, moderate, or vigorous intensity
  • For school-aged youth (ages 6 through 17 years), physical activity throughout the day should add up to at least 60 minutes per day of moderate- and vigorous-intensity activities

School-aged children should also include aerobic and muscle-strengthening activities. For all ages, it is important that children have many opportunities to engage in a variety of enjoyable physical activities, and are encouraged to do so by the important people in their lives.

We know all of this information, but what are we supposed to do with it? 

Intensity Levels: What Do They Mean?

Part of the problem is interpretation: one person’s “light-intensity” activity could be another person’s “vigorous-intensity.” This is also called “relative intensity,” when a person’s level of cardiorespiratory fitness is used to assess the level of effort for a particular activity. In contrast, there is also “absolute intensity,” which is the amount of energy expended during the activity, without considering a person’s cardiorespiratory fitness. These are usually measured on a scale from 0 to 10, where 0 is the lowest amount of effort (for example, sitting or reclining) while 10 is the highest amount of effort.

Moderate-intensity activity registers around a 5 or 6, while vigorous-intensity activity begins around a 7 or 8. The heart will beat faster than normal, and breathing will be harder than normal. You can also use the “talk test”: During moderate-intensity activity you can talk but not sing, while during vigorous-intensity activity you will not be able to say more than a few words without taking a breath.4

As the caretaker, it will be easier for you to determine the level of intensity by gauging it based off of what you see and what you know about the child’s health and abilities.

IntensityActivity Examples
LightWalking slowly
Sitting at the computer
Making the bed
Eating and preparing food
Folding laundry
Reading a book
Stacking blocks
ModerateWalking briskly
Sweeping the floor
Slow dancing
Washing windows
Playing catch or tag
Gymnastics or tumbling
VigorousRunning (at more than 5 mph)
Jumping rope
Carrying heavy loads
Playing on a playground
Martial arts

Key Points

  • Physical activity benefits all aspects of development, from cognitive benefits (sharper focus and better grades in school) to emotional benefits (better moods) to biological benefits (better sleep) and beyond.
  • Preschoolers need at least three hours of physical activity per day; school-age children need at least 60 minutes per day.
  • Children should be provided with many opportunities for a variety of enjoyable activities of varying intensity levels, and should be encouraged to take those opportunities.
Young boy playing in autumn leaves
Photo by Thgusstavo Santana from Pexels

References and Additional Resources

1 Claudia Crova, Ilaria Struzzolino, Rosalba Marchetti, Ilaria Masci, Giuseppe Vannozzi, Roberta Forte & Caterina Pesce (2014) Cognitively challenging physical activity benefits executive function in overweight children, Journal of Sports Sciences, 32:3, 201-211, DOI: 10.1080/02640414.2013.828849

2 Janssen, I. & LeBlanc, A.G. Int J Behav Nutr Phys Act (2010) 7: 40.

3 U.S. Department of Health and Human Services. (2018). Chapter 3. Active Children and Adolescents. In Physical Activity Guidelines for Americans, 2nd Edition (pp. 46-54). Retrieved from

4 Prosch, N. (2018, December 19). Light, Moderate, And Vigorous Activity [Blog Post]. Retrieved from

Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion. (2019, September 11). Physical Activity. Retrieved from

U.S. Department of Health and Human Services. (2019, September 30). For Parents: Get your kids moving. Retrieved from

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