Letting children spend more than two hours a day on their phones or watching TV can damage their brain power, a major study has found.
Too much time playing computer games, going on social media and watching programmes leads to poorer brain development, scientists say.
Children who spent the most time on electronic devices or watching TV had around a 5 per cent lower cognitive function than other 8 to 11-year-olds.
Researchers believe screen time fails to stimulate the brain in the same way reading books and can lead to poorer quality sleep, which is essential for a child’s development.
Dr Jeremy Walsh, of the CHEO Research Institute, Ottawa, who led the study said it was important children get the right activity balance.
Letting children spend more than two hours a day on their phones could damage their brain power, a study has found. Stock photo
‘Behaviours and day-to-day activities contribute to brain and cognitive development in children and physical activity, sedentary behaviour, and sleep might independently and collectively affect cognition,’ he said.
‘We found that more than two hours of recreational screen time in children was associated with poorer cognitive development.’
The study of more than 4,500 children in the US looked at the amount of screen time, sleep and physical activity they were getting.
Children and parents completed questionnaires to estimate the child’s physical activity, sleep and screen time.
Only one in 20 children met the daily guidelines of nine to 11 hours of sleep, one hour of physical activity and limited screen-time.
Youngsters were then asked to complete a cognition test, which assessed language abilities, thinking skills, attention levels, working memory and processing speed.
Almost one in three children – 29 per cent – met none of the guidelines while four in ten – 41 per cent – met only one.
Children who used electronic devices or watched TV the most had about a 5 per cent lower cognitive function than others aged between eight and 11. File photo
A quarter of children (25 per cent) met two while just five per cent met all three recommendations by Canadian public health officials.
Only half of the children met the sleep recommendation while almost two-thirds (63 per cent) spent more than two hours watching TV or on devices.
The study found that US children spend an average of 3.6 hours a day engaged in recreational screen time.
Just 18 per cent met the physical activity recommendation of an hour’s exercise a day, with nearly a fifth (18 per cent) of kids classed as obese.
The more individual recommendations the child met, the better they performed on the cognition test, the findings published in The Lancet Child & Adolescent Health journal.
Meeting only the screen time recommendation or both the screen time and sleep recommendations had the strongest associations with cognitive development, Children’s Hospital of Eastern Ontario Research Institute researchers found.
Limited screen time and improved sleep were associated with the strongest links to improved cognition, while physical activity may be more important for physical health.
The study controlled for household income, parental and child education, ethnicity, pubertal development, body mass index and whether the child had had a traumatic brain injury.
Commenting on the findings, Dr Eduardo Esteban Bustamante, from the University of Illinois, USA, said: ‘Each minute spent on screens necessarily displaces a minute from sleep or cognitively challenging activities. In the case of evening screen use, this displacement may also be compounded by impairment of sleep quality.
‘The strong associations between global cognition and meeting the recreational screen time recommendation found by Walsh and colleagues potentially reflect the interruption of the stress-recovery cycle necessary for growth in children who do not meet this recommendation.’