A recently completed study ((PDF) Physical Activity Among Preadolescents Modifies the Long-Term Association Between Sedentary Time Spent Using Digital Media and the Increased Risk of Being Overweight (researchgate.net) showed that 6 hours of physical activity a week at age 11 could offset a weight gain by age 14 created by heavy digital media use.
Globally, obesity in children and teens is one of the most important health-related challenges we face. Knowing that physical activity can offset sedentary activity and prevent weight gain is a simple and important tool. Though further research is needed to determine how much activity is needed and at what intensity to prevent weight gain in preteens and teens, a good rule of thumb, for now, would be at least 60 minutes a day.
