Prevalence of insufficient, borderline, and optimal hours of sleep among high school students - United States, 2007.

We describe the prevalence of insufficient, borderline, and optimal sleep hours among U.S. high school students on an average school night. Most students (68.9%) reported insufficient sleep, whereas few (7.6%) reported optimal sleep. The prevalence of insufficient sleep was highest among female and black students, and students in grades 11 and 12. [ABSTRACT FROM AUTHOR]