By: Amy Fleming | The truth about blue light: does it really cause insomnia and increased risk of cancer? | Neuroscience | The Guardian
The light emitted from our LED screens is blamed for everything from bleary eyes to much more serious health issues. So just how worried should we be?
Long attached to visions of clear skies and calm seas, the colour blue historically could not be more welcome, refreshing and natural. Yet, because of the proliferation of blue-emitting LEDs in our artificially lit lives, blue light has come to represent bleary eyes, sleeplessness and the poor health associated with disruption of the circadian rhythm.
Of the spectrum of lightwaves emitted by the sun that our eyes can detect, it is the shorter “blue” ones that get reflected and bounced around most by the molecules in the Earth’s atmosphere. They are the reason the sky is blue. So why is blue light apparently so bad for us? Earlier this month, a study published in The Lancet Psychiatry looked at data from 91,105 middle-aged people and found that those with disrupted sleep patterns were more likely to have depression or bipolar disorder. The worst affected were described by one of the authors of the paper, Professor Daniel Smith at the University of Glasgow, as those with “very poor sleep hygiene – people on their mobile phones at midnight checking Facebook or getting up to make a cup of tea in the middle of the night”. He reiterated the now common advice from sleep experts: switch off electronic devices an hour before bedtime.