Research has revealed that less than 10% of British adolescents meet the recommended guidelines for sleep, exercise and screen time.
Second Guidelines for 24-hour movement developed by Canadian researchers, children between the ages of 5 and 17 should spend an hour a day doing moderate to vigorous exercise, no more than two hours a day in front of the screen and sleeping at least eight hours a night .
But a new study suggests that only 9.7% of 14-year-olds in the UK handle all three recommendations, with over three-quarters of teenagers spending more than two hours a day interacting with screens.
"Time on the screen was the main factor of non-compliance with all three recommendations," the authors noted.
However the idea of time on the screen is controversial: many experts say that there is not enough evidence to recommend a threshold for children, with the recent guidelines of the Royal College of Pediatrics and Child Health stating: "We are not able to recommend a cut for the total time of the children's screen". Instead they advise parents to focus on whether the use of the screen interferes with other activities such as sleep and family time.
Other research supports the idea that it is not the duration of the screen that counts in itself, but more nuanced considerations, such as when and how screens are used.
Mark Hamer, professor of sports medicine and exercise at University College London and co-author of the new research, said the evidence suggests that physical activity levels are the three most important health behaviors . But, he added, increasing the exercise time it was necessary to observe how time was dedicated to other activities.
He said: "Basically these behaviors are strongly correlated since the 24-hour day is over and increasing the time in one behavior tends to decrease the time in another, [for example to decide] to play soccer instead of watching TV. "
The last study, published in the journal Jama Pediatrics, is based on data collected between January 2015 and March 2016 by fourteen-year-olds in the United Kingdom in the context of a wider research effort.
Each participant independently reported their average daily time on the screen – including the use of TVs, tablets and computers – and the time to lie down and wake up during an average school night. The exercise levels were monitored through an activity tracker worn both on weekdays and weekdays. Other data were collected through questionnaires and measurements. In total, data from nearly 4,000 adolescents were analyzed.
The results reveal that almost 90% of the participants said they had slept for more than eight hours during a school night, but only 23% said they spent two hours or less a day interacting with the screens. Activity tracker data revealed that approximately 41% of adolescents reached the recommended level of moderate to vigorous physical activity. Only 9.7% of participants received recommendations for all three behaviors.
The team found that adolescents with symptoms of depression were less likely to meet all three recommendations. Even overweight girls and obese boys were less likely to meet all three.
However, the study has limitations, including screen time and sleep duration based on auto-reports, which can be unreliable.
Professor Russell Viner, president of the Royal College of Pediatrics and Child Health, and who was not involved in the research, stated that the study examined the behavior only at a certain time, and therefore could not clear cause and effect, for example depression. Furthermore, UK guidelines recommend that adolescents sleep at least 10 hours per night, more than Canadian guidelines suggest.
He said: "Other research has suggested that the use of the screen could have an impact on mental health and well-being by interfering with healthy activities like physical activity and sleep. Although this study cannot demonstrate such a connection, it confirms that we need to focus on ensuring that young people get enough sleep and physical activity during the day ".