Research suggests teens' sleep patterns can be improved by reducing blue light exposure from extended screen time, even for just one week.

Recent studies have indicated that exposure to too much evening light, particularly the bluish 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 creates tiredness and poor concentration, but can also increase the risk of more serious long-term health issues such as obesity, diabetes and heart disease.

The new investigated the effects of blue light exposure on adolescents at home, finding 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.

A randomised controlled trial to assess the effects of blocking blue light with glasses and no screen time during the evening.

Both interventions 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 Dr Dirk Jan Stenvers from the department of Endocrinology and Metabolism of 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. 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.”