New shows that it is bad for children to watch TV, or mobile phone screens before bedtime. Researchers from the University of Colorado found that "screen time" before damages children's health. The researchers looked at over 60 studies on how screen time affects children. They said: "Of more than five studies looking at children aged from 5 to 17 around the , 90 per cent have found that more screen time is associated with bedtime, fewer hours of sleep, and poorer sleep ." Screens are becoming smaller and smaller, so children can look at them in . More than 75 per cent of children in the study had some of screen in their bedroom.
Children need a more sleep than adults. Pre-school children need 10 to 13 hours, pre-teens should get between nine and 12 , and teenagers should be getting between eight and 10 hours a . The researchers highlighted three main how screens affect children's sleep. First, the light from screens upsets a child's body clock. The light from screens getting into children's before they sleep tricks their body into thinking it is still . Second, children often watch of things that excite them or interest them. This keeps their active, so they take longer to sleep. Finally, when children are watching screens, they are not exercising. Children need activity to make them .