A lightbulb moment for sleep professor …

ELECTRIC lights, including those on laptops and tablets, play a key role in causing people to sleep badly, a leading expert has said.

Charles Czeisler, professor of sleep medicine at Harvard Medical School, says artificial lights disrupt the body’s natural rhythm, affect the brain and make people use stimulants such as caffeine to stay awake.

Writing in the journal Nature, he called for research to find ways of counteracting the ill-effects of artificial light on sleep.

A study found 30% of working adults in the US and 44% of night workers got fewer than six hours of sleep a night. Fifty years ago fewer than 3% of US adults slept so little.

Mr Czeisler said a drop in sleep hours raises the risk of obesity, diabetes, heart disease, depression and stroke in adults and gives children concentration problems.

While all electric light affected the natural body clock and sleep, night-time exposure to LED lights like those in phones and computers was “typically more disruptive” than standard electric light bulbs, he said.

He wrote: “There are many reasons why people get insufficient sleep … But the precipitating factor is an often unappreciated technological breakthrough – the electric light.

“Without it, few people would use caffeine to stay awake at night. And light affects our circadian rhythms more powerfully than any drug.”