Sufficient sleep is critically important for children's physical, emotional, and cognitive development. Without sufficient sleep, children have difficulty concentrating at school, and may become hyperactive. Proper sleep contributes to neurological development, and help children to maintain emotional control. Poor sleep habits of children in this age range can lead to learning problems in school, and behavior problems as a lack of sleep can make children more impulsive. It is important to note that lack of sufficient sleep causes a sleep deficit, and over time, causes the child's body to require more sleep to catch up.