March 5th, 2012
New Insight Into Obesity and Physical Activity in Children
As obesity has increased among children, a clear link has been established between obesity and cardiovascular risk factors including high cholesterol, high blood pressure, and diabetes. However, less is known about whether being more physically active might protect children from developing these risk factors. Among adults, physical activity has been shown to reduce cardiovascular risk and prolong life regardless of whether a person is obese or non-obese. Less is known about how these factors work together in children.
A recent study in JAMA by Ekelund and colleagues is one of the first to directly address this question of whether physically active children have better cardiovascular health compared with less active children. It is a particularly powerful study because it analyzes the combined results of several studies to include over 6,000 children. The key findings are that moderate and vigorous physical activity (MVPA) is strongly linked to lower cardiovascular risk, that time spent sedentary is not directly linked to cardiovascular risk, and that relatively small differences in physical activity levels can have a profound impact on cardiovascular health. The study also found that physical activity and sedentariness interact in an interesting way. Specifically, children who were the most physically active and the least sedentary had lower cardiovascular risk compared with similarly active but more sedentary children.
This means that interventions that attempt to increase physical activity levels and to decrease sedentariness might have a greater effect on cardiovascular health than attempts to change either behavior alone. In addition, the results suggest that increasing children’s MVPA by only 20 minutes might significantly improve their health regardless of its impact on their weight. Thus, this study provides evidence of the urgent need to identify children who are less physically active and invest in large scale public health efforts to increase active play and reduce sedentariness.