A British doctor has called on technology firms to develop an automatic bedtime mode for smartphones to stop them harming sleeping patterns.
The blue light emitted by smartphones, tablets and eReaders is disrupting body clocks, according to experts.
It mimics normal daylight and means users, particularly children, are kept awake.
As well as disrupting sleep, it means children are drowsy and tired during the day – harming their performance in school.
Professor Paul Gringras said screens need an automatic setting that triggers at the end of the day and filters out the blue light that delays the body clock.
As it gets darker, the body starts to produce the sleep hormone melatonin. However, certain wavelengths of light – those at the blue-green end of the spectrum – can disrupt the system. Professor Gringras, from Evelina Children’s Hospital in London, was part of a study published in journal Frontiers in Public Health that analysed the light emitted by devices.
It concluded there was a clear trend for devices to be bigger, brighter, have higher levels of contrast and emit more blue light.
The professor of children’s sleep medicine said: ‘That is great for use in the day, but awful for use at night. There is converging data to say if you are in front of one of these devices at night-time it could prevent you falling asleep by an extra hour.’
He told BBC News: ‘It’s not good enough to say “do less and accept this is the world we live in”, they’re fun devices but we do need some protection on what they do at night-time.’ – Daily Mail