A study from the University of Houston has found that lack of sleep affects children’s emotional health. Researchers studied 53 children between the ages of 7-11 years old, for over a week. The kids' emotional health was tested twice, once after a night of healthy sleep, and again after two nights of restricted sleep. Changes were seen in the way the children experienced, regulated, and expressed their emotions. The biggest change was found in the children’s response to positive and negative stimuli. The children viewed a series of pictures and video clips to stimulate positive and negative emotions . This assessment showed some children having irregular heartbeats and disinterested facial expressions. Kids with symptoms of anxiety had the most dramatic emotional responses to sleeping less. The experience and expression of positive emotions are essential for children's friendships, healthy social interactions and effective coping, Candice Alfano, Professor of Psychology at the University of Houston. The findings of this study could explain why kids who get less-sleep than needed have more problems with their peers