Smartphones remain a major part of the school day, despite the increase in public school policies meant to limit their use.A new study finds teens spend an average of 70 minutes on their phones when they’re supposed to be learning.Researchers analyzed data from 640 students, ages 13 to 18, using an app that tracked phone activity during school hours.Social media dominated overall phone use during school time, according to the results. Apps like Instagram, TikTok, and Snapchat accounted for nearly 30 minutes a day.Video apps, including YouTube, and gaming apps followed — at about 15 minutes each.The study showed high schoolers, ages 16 to 18, spent more time on their phones than younger students.The lead author says many schools assume phones stay mostly out of sight, “But objective data show that smartphones remain a significant part of students’ school-day experience.”As school phone policies evolve, the authors say objective tracking will be key to understanding their impact on learning and adolescent health.Source: JAMA Author Affiliations: University of California, San Francisco, Renaissance School of Medicine, Stony Brook University, SRI International, Seattle Children’s Hospital, University of Washington, Seattle.Sign up for our weekly HealthDay newsletter