Actually "Radiation" is not just a false excuse.. see the article below...
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Experts now warn that sleeping next to a charging phone could be very bad for us.
Our nervous system operates on very low voltage electricity – meaning the brain uses electricity to send signals to our muscles.
For some, the man-made alternating current that powers our homes can interfere with these processes. This might be why some people may find it difficult to sleep near a charging phone.
Because batteries heat up when charging, it's also a major fire risk charging your phone on your bed or under your pillows while you sleep – forget about those brain cells, you’ll burn down the house!
Try placing your phone in a saucer while it charges to avoid starting any inadvertent fires. It’ll protect you… at least until you wake up and smell the smoke, right?
Though it does make sense to recharge our phones while we in fact recharge our own battery with sleep - charging your phone overnight just isn't worth the mental and physical health risks to you, and the technical risks for your handheld best friend.