Adolescents (13-18 years) who use screens daily in the hour before going to sleep have more sleep complaints. Examples of such complaints are a longer latency to fall asleep, shorter sleep duration and more frequent waking up during the night. They also have trouble staying awake during the day. These complaints are reduced when adolescents do not use screens during the evening for one week or when they wear orange glasses that block blue light.
For the first time in the Netherlands, researchers looked at the effects of evening screen use on sleep in children and adolescents (8-18 years). More than one in five children (8-13 years) use a luminous screen every day in the evening (22%), compared to 83% among adolescents (13-18 years). They often use screens in the evening for more than two hours.
The group that uses screens more frequently or for longer periods sleeps up to half an hour shorter. This coherency suggests a causal relationship, but there is no evidence for that yet. The researchers therefore let young people use no screens for a week, and wear an orange pair of glasses that blocks blue light for another week. Sleep complaints were reduced in these adolescents.
For this reason, it is important that people are aware of the use of a computer, smartphone or tablet in the hour before bedtime. Previous research showed that people with structural sleep deprivation have more trouble concentrating and perform less well. In addition, health problems can arise.
In recent years, more and more luminous screens – not only televisions but also computers, laptops, tablets and smartphones – have been developed. The recently developed screens use LED technology, which emits relatively more blue light than traditional displays. It is known that blue light affects our biological clock, and can thus disturb sleep.
This research shows that blue light does indeed have an effect on sleep. In addition, the cognitive load of the activities performed on the devices with luminous screens may play a role. It is also possible that people go to sleep later as a result of screen use. If the time they have to wake up at remains the same, they have less time to sleep.
The study confirms results from previous research among adults. This research showed that frequent or prolonged screen use in the evening is associated with sleep complaints. Follow-up research should determine whether available (built-in) blue light filters on devices can reduce the negative effects on sleep. In addition, further research should clarify the exact role of the possible underlying mechanisms.
The RIVM National Institute for Public Health and the Environment performed this research together with the Amsterdam UMC, the Netherlands Institute for Neuroscience and Lifelines. The project was commissioned by the Dutch Food and Consumer Product Safety Authority.