Using a mobile phone before going to bed can damage your health , according to a major study . It says that radiation from the mobile phone can cause insomnia (失眠症) and headaches as well as cutting the time spent in deep sleep . Failing to get enough sleep can lead to depression , lack of concentration and personality changes . In teenagers and young children , lack of sleep can result in attention disorders and poor grades . The research showed that using mobile phones before bed causes people to take longer to reach the deeper stages of sleep and to spend less time in them . Deep sleep is important as it is the time when the body rejuvenates (更新) cells and repairs damage suffered during the day . Scientists found that using mobile phones an hour before sleep affects it . In the study scientists examined the sleep patterns of 36 women and 35 men aged 18 to 45 . Some were exposed to radiation that is similar to what a person receives when using a mobile phone . The others received none . The results are as follows : The first group took longer to enter the first of the deeper stages of sleep and spent less time in the deepest one . However , the second group was opposite . The findings will shock many parents . Many parents are always worried about their children's health . But they didn't have a better way to persuade them not to use a mobile phone .