# Longitudinal changes in screen time, sleep, and sports/exercise activity in early adolescence

## TL;DR

This study tracks how early adolescents in the U.S. spend their time on screens, sleep, and exercise over three years, finding that screen time increases while other activities decrease.

## Contribution

The study provides new longitudinal insights into how screen time displaces other daily activities during early adolescence using data from the ABCD Study.

## Key findings

- Screen time increased significantly over three years, with girls spending more time on digital socializing and boys on video games.
- Sleep duration slightly decreased, while sports/exercise activity initially dropped but later increased.
- Time spent on other activities decreased substantially as screen time increased.

## Abstract

This study aimed to examine longitudinal changes in screen time, sleep, and sports/exercise activity in early adolescents in the United States.

We examined data over four annual assessments collected from the Adolescent Brain Cognitive Development (ABCD) Study (N = 9,519) from baseline (2016–2018, ages 9–10) to Year 3 (2019–2021, ages 12–13). Trends in screen time, sleep, sports/exercise activity, and other activities in a 24-hour time-use paradigm were derived from compositional data analysis, incorporating isometric log-ratio transformations and mixed-effects modeling.

Screen time increased by 0.23 h/day from baseline to Year 1, 1.58 h/day from baseline to Year 2, and 3.28 h/day from baseline to Year 3. Video game playing increased more in boys, and digital socializing increased more in girls. Sleep duration slightly decreased from baseline to Year 3. Sports/exercise activity slightly decreased from baseline to Year 1, then increased until Year 3. Time spent on other activities decreased by 0.13 h/day from baseline to Year 1, 1.60 h/day from baseline to Year 2, and 3.38 h/day from baseline to Year 3.

Our findings indicate screen time may have increasingly displaced other activities as early adolescents age.

The online version contains supplementary material available at 10.1186/s12887-025-06368-z.