New research shows that by limiting evening exposure to screens like those on smartphones and tablets for just one week, many sleep problems in teenagers can be reversed.
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 doesn’t 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.
In this collaborative study between the Netherlands Institute of Neuroscience, the Amsterdam UMC and the Dutch National Institute for Public Health and the Environment, researchers investigated the effects of blue light exposure on adolescents at home. Those who had more than 4 hours per day of screen time had on average 30 minutes later sleep onset and wake up times than those who recorded less than 1 hour per day of screen time, as well as more symptoms of sleep loss. The team conducted a randomized 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.
Dr Dirk Jan Stenvers from the Amsterdam UMC says, “Adolescents increasingly spend more time on devices with screens and sleep complaints are frequent in this age group. Here we show very simply that these sleep complaints can be easily reversed by minimizing evening screen use or exposure to blue light. 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”
Dr Stenvers and his colleagues are now interested in whether the relationship between reduced screen time and improved sleep has longer lasting effects, and whether the same effects can be detected in adults.