VANCOUVER — Children who spend most of their time sitting on the couch watching TV or playing on their mobile devices wind up developing “lazy bones,” compared to their more active counterparts, a new study finds.
Researchers as the University of British Columbia and the Vancouver Coastal Health Research Institute monitored 309 teens over a specific four-year period — girls from the ages of 10 to 14 and boys from the ages of 12 to 16 — viewed as the most crucial time for healthy bone development in children.
Using 3-D x-ray images, the team compared the bones of the children who enjoyed the recommended 60 minutes of moderate-to-vigorous physical activity in a day to those who totaled no more than 30 minutes.
The couch potatoes were determined to have a significant skeletal disadvantage.
“We found that teens who are less active had weaker bones, and bone strength is critical for preventing fractures,” says Leigh Gabel, lead author and PhD candidate in orthopedics at UBC, in a university news release. “Kids who are sitting around are not loading their bones in ways that promote bone strength.”
Gabel suggests that while participating in sports that involve plenty of running and jumping is a more obvious solution for children, even shorter activities like dancing in the house, playing tag with a sibling, or just chasing the dog are other ways kids can still enjoy important physical activity.
“The bottom line is that children and youth need to step away from their screens and move to build the foundation for lifelong bone health,” says co-author Heather McKay, a professor in orthopedics and family practice at the university and research institute.
The age window that the researchers selected for study is found to be a prime period for growth: as much as 36 percent of the skeleton is formed during these years and physical activity in particular greatly impacts that growth. McKay says parents of kids, especially of these ages, should consider programs in schools and within communities to encourage more kids to put down their devices and pick up a soccer ball or frisbee.
The study was published in the Journal of Bone and Mineral Research.