Elizabeth Pantley explains that parents need to keep a careful watch on naps, because "the number of hours that your child sleeps is an incredibly important factor for his health and well-being. A sleep study completed by Dr. Avi Sadeh at Tel Aviv University demonstrates that even a one-hour shortage in appropriate sleep time will compromise a child’s alertness and brain functioning and increase fatigue." This means keeping track of how and when your child is sleeping. "The length of time that your child is awake from one sleep period to the next will also have a powerful impact on his temperament, mood and behavior, so it is one more important consideration," says Pantley. "The span of awake time is very, very short for a newborn baby and this gradually increases over time."