Poor night’s sleep linked to tablets

If you’re having trouble sleeping at night, the answer may be to close your iPad.

More and more people are taking their tablets to bed with them to surf the web and check Facebook or email before switching off the light.

Researchers at the Lighting Research Centre, at the Rensselaer Polytechnic Institute in New York, claim the blueish light from an iPad screen can mimic daylight, thereby convincing the brain it is still daytime.

The study, published in Applied Ergonomics, said that blue light stops the production of a brain chemical called melatonin, which helps us fall sleep.

However, light that is more orange or red in tone does not suppress melatonin production, because human brains recognise the colours as the sunset and “think” the day is ending.

Researchers said: “Although turning off devices at night is the ultimate solution, it is recommended that if these devices are used at night displays are dimmed as much as possible and time spent on them before bed should be limited.”

They measured melatonin levels in 13 volunteers, after they had spent time viewing iPads at full brightness at a distance of 25cm, for two hours. Melatonin levels were much lower than they were after the volunteers viewed their iPads while wearing orange glasses, which eliminated blue light.

Neurologists have known for years that staring at screens late in the evening can disrupt sleep. However, because mobiles and tablets are portable, more people are taking them into the bedroom.

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