Can Kids Exercise Too Much?

Although physical activity is crucial to children's development, there is such a thing as too much of a good thing. Get-Fit Guy explains the parameters of how much kids should exercise.

Ben Greenfield
4-minute read
Episode #207

Last year, I did an episode called How Much Should Kids Exercise?, in which I stated that although children don't need a lot of intense physical activity to get the health benefits of exercise, at least 7 minutes of exercise per day is the minimum necessary to prevent weight gain, obesity, and chronic health risks.

But two recent occurrences involving kids and exercise got me thinking.>

The first is that my friend Joe DeSena, the CEO of Spartan racing, told me that his 8-year-old boy had just completed a 50K race, and had also run the Boston Marathon along with a variety of other impressive and grueling feats of endurance. The second is a recently published magazine article in The Atlantic entitled “How Far Is Too Far for Kids to Run?”

Don’t get me wrong - I am a huge advocate of increasing physical activity in children. I’ve talked about this in a previous episode called How to Get Kids Fit and I recently spoke at The431Project about ways that we can combat childhood obesity and get kids more active.

But how much is too much? 

How Much Exercise Is Too Much?

While many children are still sitting around playing videos games, other children are now exercising in extremely high volumes with an increasing number of young athletes training for and competing in long-distance endurance events such as triathlons, obstacle races, adventure races, and marathons.  Injury and growth reduction potential risks aside, this may actually increase the propensity for those same active kids to eventually quit exercising.

The 2011 National Athletic Training Association’s position statement sums this up quite nicely:

“Athletes who sustain recurrent overuse injuries may stop participating in sports and recreational activities, thus potentially adding to the already increasing number of sedentary individuals and the obesity epidemic.”

Should Kids Run?

Running is a particular culprit, because, as this study shows, children’s bodies (particularly their bones, joints, and soft tissue) simply don’t absorb the impact of running as well as adults. Another study shows that children have different running biomechanics and a smaller legs to body size ratio, which can lower their body’s ability to absorb impact.

And although it has yet to be definitely proven by science (as there are obvious ethical issues with a controlled study that forces kids to pound the pavement) repeated impact to immature joints could potentially cause injuries to joint cartilage or separation of growth plates – which can lead to lifelong joint pain and stunted growth.

The Atlantic article I mentioned earlier sites the Clinical Journal of Sports Medicine as saying:

“Training to run in a marathon, which is more than eight times the usual cross-country competitive racing distance, is an inappropriate activity for children and adolescents.”

Perhaps this is one reason the Boston Marathon sets a minimum age limit of 18 for participation.


All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Ben Greenfield

Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.