Terrible night's sleep? Blame your mobile phone: How exposure to artificial light 'fools' the brain into staying awake

  • Laptop and smartphone screens disrupt sleep and make us drink caffeine
  • Britons uses 4 times more artificial light today compared to the 1950s
  • Poor sleep associated with obesity, diabetes, heart disease and depression

Electric lights, including those which illuminate laptop computers, smartphones and tablets, often play a key role in causing people to sleep badly, a leading expert has warned.


Writing today in the journal Nature, the professor of sleep medicine at Harvard Medical School called for research to help develop 'behavioural and technical' ways of counteracting the ill effects of artificial light on modern sleeping patterns.

Screen breaks: Illuminated screens have been found to affect the body's circadian clock - the genetic mechanism which helps regulate sleep - 'more powerfully than any drug'


While all electric light affected circadian rhythms - 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.


'But the precipitating factor is an often unappreciated, technological breakthrough: the electric light.


Poor sleep has been linked with health problems including obesity, heart disease and depression



It fools the brain into delaying its 'second wind', which kicked in during the afternoon to see people through to sunset before electric light was invented, until much later in the day.

He said that as a result of modern technology 'many people are still checking email, doing homework or watching TV at midnight, with hardly a clue that it is the middle of the solar night'.

In a study, 30 per cent of all working adults in the United States and 44 per cent of night workers reported getting less than six hours sleep a night on average.

Fifty years ago less than 3 per cent of the US adult population slept so little. And around the world, children are sleeping 1.2 hours less on school nights than a century ago, he said.

'Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later,' he said.


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