children runningHealth professionals are promoting exercise to help curb rising childhood obesity rates but results from a new study show that getting too much exercise might actually be bad for a child’s health.

Currently the U.S. Department of Health and Human Services recommends children and adolescents engage in one hour of physical activity each day for a total of about seven hours each week. The new study, published in the BMJ journal Archives of Disease in Childhood, suggests the optimal amount of physical activity may actually be 14 hours per week. The study also suggests that exercising more than 14 hours each week may actually have negative health consequences for a child.

Researchers from Canada and Switzerland surveyed more than 1,245 Swiss teenagers aged 16 to 20 years, gathering information about the participants’ demographics, height and weight, socioeconomic status, sports practice, and sports injuries. The scientists also measure well-being using World Health Organization (WHO) Well-Being Index. This index provides scores between 0 and 25, where a score of 13 or lower indicates poor well-being.

The researchers categorized sports participation into four groups. People in the low activity group exercised zero to 3.5 hours each week while those in the average group exercised 3.6 to 10.5 hours every week. Participants in the high activity group exercised 10.6-17.5 hours per week while those in the very high group were physically active more than 17.5 hours weekly.

The overall score for well-being was 17, showing most participants were relatively happy and healthy. However, the researchers found that participants in the low and very high activity groups were more than twice as likely to score below 13 as were those in the average group. The scientists also found that participants who exercised 14 hours weekly scored the highest in the WHO Well-Being Index.

The researchers reaffirm the association between physical activity and positive emotional well-being, reduced depression and anxiety disorders, and improved self-esteem; however, they noted that exercise stopped being a protective factor when the child exceeds the recommended weekly limit by at least twofold. The scientists recommend physicians caring for adolescents monitor the level of activity and assess the well-being of young patients who are very active in sports or other forms of exercise.


  1. Arnaud Merglen, Aline Flatz, et al. Weekly Sport Practice and Adolescent Well-being. Archives of Disease in Childhood. 20 Nov 2013. Web. Retrieved 3 Dec 2013.
  2. Physical Activity Guidelines for Americans, Chapter 3: Active Children and Adolescents. Department of Health and Human Services. 16 Oct 2008. Web. Retrieved 3 Dec 2013.
  3. Too much sport 'may be bad' for teens' health'. Medical News Today. 21 Nov 2013. Web. Retrieved 3 Dec 2013.