Adolescents (13-18 years) who use screens daily in the hour before they go to bed have more sleep complaints. Examples of such complaints are that it takes them longer to fall asleep, their sleep is shorter and they tend to wake up more often during the night. They also have trouble staying awake during the day. These complaints diminish when adolescents do not use screens during the evening for one week or when they wear orange-tinted 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%). For adolescents (13-18 years) this was 83%. Adolescents 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. Although this coherency suggests a causal relationship, the evidence for this is lacking. The researchers therefore had young people not use screens for one week, and had them wear a pair of orange-tinted glasses, which block blue light, for another week. Sleep complaints were reduced in these adolescents.
People should thus be are conscious of the fact that they are using a computer, smartphone or tablet in the hour before bedtime. Previous research has shown that people with structural sleep deprivation have more trouble concentrating and perform less well. In addition, it could also cause health problems.
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 their wake up time remains the same, this means there is 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 could reduce the negative effects on sleep. In addition, further research should clarify the exact role of the possible underlying mechanisms.
This research was carried out by the RIVM National Institute for Public Health and the Environment in collaboration with the Amsterdam UMC, the Netherlands Institute for Neuroscience and Lifelines. The project was commissioned by the Dutch Food and Consumer Product Safety Authority.