Screen Time Linked to Weaker Bones in Teenage Boys
Teenage boys who spend more time in front of screens as opposed to doing any kind of weight training exercises are more likely to have weaker bones as they age, a small study by Norwegian researchers concludes. A team from the University Hospital of North Norway found that while it’s most likely not a direct cause and effect, higher screen time is related to lower bone density.
The researchers analyzed 316 boys and 372 girls for the study, all who had either two to four hours, or more than six hours of daily screen time. The teenagers were asked to log how many hours a day they spent in front of a computer or watching TV and movies on weekends, as well as how much time they spent being sedentary, walking, biking or participating in sports.
The team found that boys with a higher screen time tended to have lower boner mineral density (BMD). Researchers say that their most important discovery was that this relationship between a sedentary lifestyle and bone density was also present two years later. BMD is the amount of mineral in a square centimeter of bone, and can be a strong predictor of a person's bone fracture risk. To collect these values, the researchers used bone density scans at the hip, thigh bone and other areas. Girls with heavy screen time were shown to have higher BMD, but researchers said both boys and girls with heavy screen time tended to weigh slightly more than those with less screen time.
Experts say these results present a real concern regarding the lifestyle of many young adults. Between childhood and your early 20’s they say you’re, “setting up the scaffolding of life.” Engaging in more sedentary lifestyles during younger years may put young people more at risk for weaker bones and complications later on in life.
However, researchers did add that this study focused mainly on older teens, whereas lifestyle choices may have the most impact for those between nine and 15 years old. They also noted that since girls mature faster than boys do, the boys have have been more “malleable” which may also explain the difference in results.
But to stay healthy, the American College of Sports Medicine recommends 10 to 20 minutes of gymnastics or running, jumping, or other weight-bearing exercise at least three days a week for children and adolescents.