Exposure to the blue light emitted by smartphones could be "toxic" for the body.
Smartphone light can be 'toxic' for the body
A study has found that being bombarded by blue-spectrum light throughout the day disrupts the body's regular functions and puts blood sugar levels out of balance.
Scientists at University College London say that the "red-starved" modern environment could be a public health "time bomb" that causes diabetes and shortens lives.
Professor Glen Jeffery said: "Sunlight has a balance between red and blue, but we now live in a world where blue light is dominant.
"Although we do not see it, LED lights are dominant in blue and have almost no red in them. Long-term exposure to blue light is potentially toxic without red.
"Blue light on its own impacts badly on physiology and can drive disrupted blood sugars that may in the long run contribute to diabetes and undermine health spans.
"This can partly be corrected by spending more time in sunlight."