Limiting exposure to blue-light emitting devices such as phones and laptops in the evening for just a week can help teenagers improve their sleep quality and reduce symptoms of fatigue, lack of concentration and bad mood, a study has found.
Recent studies have indicated that exposure to too much evening light, particularly the blue light emitted from screens on smartphones, tablets and computers can affect the brain's clock and the production of the sleep hormone melatonin, resulting in disrupted sleep time and quality.
The lack of sleep does not just cause immediate symptoms of tiredness and poor concentration but can also increase the risk of more serious long-term health issues such as obesity, diabetes and heart disease.
Other studies have suggested that sleep deprivation related to screen time may affect children and adolescents more than adults, but no studies have fully investigated how real-life exposure is affecting sleep in adolescents at home and whether it can be reversed.
Researchers from Netherlands Institute of Neuroscience, the Amsterdam UMC and the Dutch National Institute for Public Health and the Environment, investigated the effects of blue light exposure on adolescents at home.
Those who had more than four hours per day of screen time had on average 30 minutes later sleep onset and wake up times than those who recorded less than one hour per day of screen time, as well as more symptoms of sleep loss.
The team conducted a randomised controlled trial to assess the effects of blocking blue light with glasses and no screen time during the evening on the sleep pattern of 25 frequent users.
Both blocking blue light with glasses and screen abstinence resulted in sleep onset and wake up times occurring 20 minutes earlier, and a reduction in reported symptoms of sleep loss in participants, after just one week.
"Adolescents increasingly spend more time on devices with screens and sleep complaints are frequent in this age group," said Dirk Jan Stenvers from the Amsterdam UMC.
"Here we show very simply that these sleep complaints can be easily reversed by minimising evening screen use or exposure to blue light," Stenvers said.
"Based on our data, it is likely that adolescent sleep complaints and delayed sleep onset are at least partly mediated by blue light from screens," he said.
