Children with more-active friends tend to raise their own levels of physical activity, according to a new study.
Experts say the finding could help create interventions to curb the growing rates of childhood obesity.
To conduct the study, researchers interviewed 81 children ages 5 to 12, who were enrolled in after-school programs, and asked about their friendships. The kids also wore devices called accelerometers to monitor their activity at three points in time over the course of the 12-week study.
"By far, the greatest influence on how active kids are is what their friends are doing," said study author Sabina Gesell, a research assistant professor of pediatrics at Vanderbilt University School of Medicine. "In our study, they were six times more likely to adjust their behavior to be like their friends than they were not to."
Children in the study typically adjusted their amount of physical activity by 10 percent or more, to be more like their friends.
Gesell noted the change went in both directions, with more-active and less-active kids both moving toward the group's average activity level.
"The existing friendship network had a tremendous influence on how active kids were," she told MyHealthNewsDaily. "It can help kids, and it can harm them."
Gesell cautioned against being overly concerned with peer pressure and weight in this age group.
"If your kid has only inactive friends, that should be a red flag," she said. "If he has one inactive friend among many friends, that shouldn't be a concern."
The fight against childhood obesity
Childhood obesity rates have received increased attention from researchers in recent years. According to a 2010 study in the Journal of the American Medical Association, 19.6 percent of children between ages 6 and 11 are considered obese. That number was 7 percent in 1980.
Gesell said the next step in her group's research will involve figuring out whether kids' activity levels are more effectively raised by efforts to help kids build friendships with more-active children, or efforts to encourage the peer leader in a given group to become more active, in the hope that friends will follow suit.
"The next step is to leverage these influences. How do we get these kids to get active and stay active?" she said.
In the study, the researchers suggested that groups of inactive students might exercise more if they were introduced to groups who engage in a lot of physical activity. One of the study's findings was that within this age group, children did not appear to discriminate based on physical activity levels when choosing their friends.
But, Gesell said, if the kids aren't happy, and don't maintain their friendships, the interventions will fail.
For that reason, there is another step needed to create effective interventions, said Ray Browning, a physiologist at Colorado State University who studies social networks in health interventions, and was not involved in the new study.
"I'd like to understand what it is that causes those friendships to form, and potentially, what causes them to dissolve," Browning said.
Simply putting inactive and active kids together won't work, he said. In order to help children to find more active friends, researchers need a better sense of what values children might share that could help them form a bond.
In his experience with his own children as well as in studies, younger children tend to form and end friendships rapidly, he said. This means the potential to promote an active lifestyle via social networks is there, but researchers first need a better understanding of why and how the friendships form.
"Friendship selection, in at least this limited window of time, is not due to any sort of bias around body weight or obesity status," which is encouraging, Browning said.
Browning also noted that school-related friendships may have more influence on children than the after-school friendships analyzed in the study.
Research in this area will help explain how our friendships at different ages affect us – and how they might be used to develop better habits, Browning said.
"If we can take this and develop or start to think about how these social connections can influence health promoting behaviors, then we're all going to benefit," he said.
The study appears online today (May 28) in the journal Pediatrics.
Pass it on: Kids with more-active friends may raise their activity level, a new study finds.