DO YOU sleep with your mobile phone beside you? Or worse, underneath your pillow?
Eight out of ten people keep their mobile phones on overnight and around half use it as an alarm clock, according to a new survey from UK communications regulator Ofcom.
But health experts warn this bad habit is ruining your sleep and could cause long term health problems such as insomnia.
The bright light from our mobile phone screens is the main thing keeping us from getting a decent night's sleep.
The light emitted from the screens of our phones, tablets and e-readers contains lots of blue, which has a more stimulating effect than regular light.
It stimulates the cells in our eyes that tell the brain what time it is, which then tricks our bodies into believing it's daytime, according Dr Guy Meadows, an insomnia specialist at The Sleep School in London.
And because of the way we sleep, if your phone wakes you up in the night you're more likely to stay awake.
"We sleep in cycles of 1½-2 hours, with brief moments of waking in between that normally go unnoticed," Dr Meadows told the Daily Mail.
"A flash of light or vibration of your phone from a text message at the wrong moment could make you fully conscious.
"This stems from our evolutionary past when, if we stayed fast asleep, there was a high chance we'd end up as a lion's midnight snack. So the brain wakes to check for danger."
Brightness, duration, time of day and distance from the light are also key factors that can impact upon your sleep.
This is why sleep experts recommend you avoid screen time 2-3 hours before going to bed. Reading a book is a much better alternative.
But the temptation caused by a Facebook notification or a text message is sometimes too much to resist. Four in every ten smartphone users say they check their phone if it goes off in the night.
"There's not always something new or interesting every time you check your messages - but there might be," said Tom Stafford, a lecturer in psychology and cognitive science at Sheffield University.
"So we want to check our phone more often than we rationally know we should - just in case.'
In order to get a good night's sleep, you need to feel safe and free from worry, said sleep expert Dr Neil Stanley.
"By having your phone close by at night, you're subconsciously saying you wish to attend to that phone.
"The brain will monitor the situation and your sleep will be lighter and more likely to be disturbed."
Most sleep experts recommend you leave your phone in a different room or turn it off overnight and avoid looking at your phone right before going to bed.
news.com.au 13 Mar 2014
While this article pertains specifically to mobile phones, it must also be noted that any background light, e.g. a television left on all night has the same effect.