Spending an extra hour a day watching TV, playing video games or using the internet in year 10 can lead to poorer grades at GCSE level.
Research by Cambridge University has uncovered the link between academic performance and spending too much time in front of digital screens, underlining how important it is for teenagers to focus on their studies.
The investigation also discovered that an extra hour of daily homework and reading can help pupils to perform significantly better than their peers, as they achieved on average 23.1 more GCSE points. But watching TV or online activity was still found to be damaging even if youngsters are putting in extra effort academically.
While the link between physical activity and health is well established, there is still not a huge amount known about the connection between physical activity and academic achievement.
Dr Kirsten Corder from the university's Centre for Diet and Activity Research said that although the research focused exclusively on year 10 pupils, she thinks this is "likely to be a reliable snapshot of participants' usual behaviour".
"We can reasonably suggest that screen time may be damaging to a teenager's grades. Further research is needed to confirm this effect conclusively, but parents who are concerned about their child's GCSE grades might consider limiting his or her screen time," she added.
Dr Esther van Sluijs believes the findings demonstrate just how important physical activity is and why it has to remain a public health priority. The study is published in the International Journal of Behavioural Nutrition and Physical Activity.
Posted by Tim Colman