High and low use of electronic media during nighttime before going to sleep: A comparative study between adolescents attending a morning or afternoon school shift.

This study compared the effects of time spent on electronic media devices during nighttime before going to sleep on the sleep-wake cycle, daytime sleepiness, and chronotype in 568 Mexican students (288 girls, mean age = 14.08) attending a double school shift system (287 from morning shift and 281 from afternoon shift). Students completed anonymous self-report questionnaires. Results suggest that high exposure to an electronic media device may have an impact on their sleep-wake cycle, regardless of their school shift. Adolescents from the afternoon shift reported more time spent on devices. Those from the morning shift reported daytime sleepiness with the use of MP3 player, and from the afternoon shift with the use of computer, MP3 player, and television. Both school shifts reported an intermediate chronotype with all electronic media devices, but the afternoon shift with a tendency towards eveningness with the use of the computer, smartphone, and MP3 player.