Effects of school start time and its interaction with the solar clock on adolescents' chronotype and sleep: A systematic review and meta-analysis.

Adolescents' late chronotypes colliding with early school start times (SSTs) are associated with students' unhealthy sleep habits. Most studies comparing different SSTs associate later SSTs with longer sleep duration and lower social jetlag. However, the magnitude of the effect varies between studies and the effect of different SSTs on chronotype is not well established.