The body starts to produce the sleep hormone melatonin as it starts getting darker in the evening. This helps people nod off. However, certain wavelengths of light, those at the blue-green end of the spectrum, can disrupt the circadian rhythm. A new study has revealed that people with smartphones and tablets should have 'bed mode' to protect sleep as their blue-light emission can keep them up at night.
Evelina Children's Hospital's Paul Gringras said, "Since every new model was 'bluer and brighter', the setting should filter out the blue light that delays the body clock and keeps people awake later into the evening. Manufacturers need to show more responsibility."
The researchers concluded that there was a clear trend for new devices to be bigger, brighter, have higher levels of contrast and emit more blue light.