Do not keep a mobile phone beside the bed at night switched on, because even when on standby it is in contact with the nearest phone mast and emits radiation at regular intervals. Only use your cell phone to establish contact or for conversations lasting a few minutes as the biological effects are directly related to the duration of exposure. For longer conversations, use a land line with a corded phone, not a cordless phone, which uses electromagnetic emitting technology similar to that of cell phones.