About 10% of Americans say they have chronic insomnia^[1], and millions of others report poor sleep quality. Ongoing research^[2] has found that bad sleep could lead to numerous health problems, including heart disease^[3].

Dr. Julio Fernandez-Mendoza^[4] is a professor of psychiatry and behavioral health, neuroscience and public health sciences at Penn State College of Medicine. He discusses the need for sleep, why teenagers require...