Why you should never keep your mobile in your bedroom
The next time you can't sleep, your brain whirring over shopping lists, tomorrow's meetings and whether or not you locked the back door, the solution could be simple - move your mobile phone off the bedside table and out of your bedroom altogether.
Eight out of ten of us keep our mobiles on overnight according to Ofcom, and around half use our phone as an alarm clock, a survey found.
But experts are concerned about the effect this is having - at the very least it makes us 'hypervigilant' so our sleep is more likely to be disturbed and we end up not getting enough of the restorative sleep we need. But it might also trigger insomnia and other sleeping problems.
Most people will sleep better if the bedroom is kept free of mobile phones and other electronic devices, says Dr Guy Meadows, insomnia specialist at The Sleep School, London. Dr Meadows leaves his smartphone in the kitchen at night.
More controversially, there are suggestions that sleeping with your mobile by your bed may cause dizziness and headaches.
The main problem with mobile phones in the bedroom is light, particularly the kind produced by the bright, high-quality screen on modern phones.
It interferes with the body's natural rhythm, effectively tricking our bodies into believing it's daytime, according to Dr Charles Czeisler, a professor of sleep medicine at Harvard University.
This controls the release of the hormone melatonin, which makes you feel sleepy, and the waking hormone, cortisol.
All artificial light, whether from standard light bulbs or fluorescent strips, is thought to inhibit the release of melatonin, keeping us awake longer. But light from mobiles may have a greater effect.