Children who have more physically active friends are more likely to engage in exercise themselves than kids whose friends are mostly sedentary, a US study says.

Sabina Gesell of the Vanderbilt School of Medicine and colleagues tracked groups of friends among 81 public school students aged 5 to 12 for a period of 12 weeks.

During the follow up, the researchers monitored participants’ physical activity level while they were taking part in 3 hours daily after-school programs.

The findings showed that children in peer groups that included others who were physically active were six times more likely to change their activity levels.

Children usually adjusted their activity levels to match those of their friends. However, active kids were no more likely to have a lot of friends than their more sedentary peers, the researchers wrote in the journal Pediatrics.

“We see evidence that the children are mirroring, emulating or adjusting to be similar to their friends,” said Gessell. “And that’s exciting because we saw meaningful changes in activity levels in 12 weeks.”

The researchers concluded that social networks can be used as a “novel” and “promising” means to promote healthy lifestyle and fight globally growing childhood obesity.

“We know that most obesity interventions do not work, which is why preventing obesity in the first place is so important,” noted Gesell. “This research suggests that if we consider friendship networks in our efforts to prevent childhood obesity, we are likely to see gains that we have not seen with other interventions.”

“We tend to think of teenagers as being very influential amongst their peers, but now we’re seeing this in a younger age group as well,” she added. “So with that influence, friends can bring each other up in their activity level or can bring them down to become more sedentary, depending on what they are doing themselves.”