Children should not watch TV, or mobile phone screens before . Researchers found "screen time" before sleeping is for children's . The researchers looked at studies on how bad screen time is for . They said that 90 per cent of the found that screen time delays bedtime. It also leads to sleep, and poorer sleep . Screens are , so children look at them in . Most children have a screen in their bedroom.
Children need more sleep than . Pre-school children need up to 13 hours, pre-teens up to 12 , and teenagers up to ten hours a . There are three why screens affect children's sleep. First, the from screens upsets a child's body . It makes children think it is . Second, videos excite children and keep their brain , so they take to sleep. Finally, children are not exercising, so they are not .