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Longitudinal changes in sedentary time and physical activity during adolescence.
Sarah K Harding1, Angie S Page2, Catherine Falconer3
1Centre for Exercise, Nutrition and Health Sciences, University of Bristol, Bristol, UK. sarah.harding@bristol.ac.uk.
Summary
Adolescent sedentary time significantly increased across all daily periods, including school, after-school, and weekends, between ages 12 and 15. Interventions are crucial to mitigate these unhealthy sedentary behavior changes during adolescence.
Area of Science:
- Adolescent Health
- Behavioral Science
- Public Health
Background:
- Adolescence is a critical period for declining physical activity and increasing sedentary time.
- These changes are linked to adverse health outcomes, but differences across daily contexts are unclear.
Purpose of the Study:
- To examine changes in sedentary time, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) during school, after-school, and weekend periods in adolescents.
- To determine if the magnitude of these changes differs across these time contexts.
Main Methods:
- Utilized accelerometer data from 363 adolescents (PEACH project) at ages 12 and 15.
- Categorized time into sedentary (<100 cpm), LPA (100–2295 cpm), and MVPA (≥2296 cpm).
- Analyzed activity patterns during school-time, after-school, and weekend periods based on school schedules.
Main Results:
- Significant increases in sedentary time were observed during school (+8.23%), after-school (+6.99%), and weekends (+6.86%).
- A corresponding decrease in LPA occurred across all periods: school (-7.62%), after-school (-7.01%), and weekends (-6.72%).
- MVPA levels remained relatively stable across all time contexts.
Conclusions:
- Objectively measured sedentary time increases significantly between ages 12 and 15 in all daily contexts.
- Interventions are needed to reduce age-associated increases in sedentary time during school, after-school, and weekends.
- Further research should identify specific sedentary activities to inform targeted interventions.
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