ArticleThe Journal of school health2025
Effect of Delaying High School Start Time on Teen Physical Activity, Screen Use, and Sports and Extracurricular Activity Participation: Results From START.
Article in The Journal of school health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
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Who cites it
2 citing papers in PubMed.
- Temporal trends of no moderate to vigorous physical activity in adolescents: a 16-year trend analysis of 115,926 participants.The international journal of behavioral nutrition and physical activity · 2025Article
- Effect of Delaying High School Start Time on Teen Physical Activity, Screen Use, and Sports and Extracurricular Activity Participation: Results From START.The Journal of school health · 2025Article
Corrections and comments
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Authors and funding
7 authors.
Funding
Abstract
backgroundWe aimed to characterize relationships between delayed high school start time policy, which is known to lengthen school night sleep duration, and patterns in activity outcomes: physical activity, non-school electronic screen time (non-schoolwork), and sports and extracurricular activity among adolescents.
methodsWe used data from the START study, a multi-site evaluation of a natural experiment, assessing the effects of a school start time policy change in high schools in the Minneapolis, Minnesota metropolitan area. The study follows students in 2 schools that shifted to a later start time (8:20 or 8:50 am) after baseline year and 3 schools that maintained a consistent, early start time (7:30 am) over the 3-year study period. Activity was measured by participant self-report on an in-school survey. The analysis used a difference-in-differences estimator, in which the changes in each outcome observed in the comparison schools estimate the changes in each outcome that would have been observed in the late-start adopting schools had they not delayed their start times after baseline.
resultsOver 2 years of follow-up, no changes emerged to suggest that later school start times either interfered with, or promoted, any activity-related outcome that was measured. IMPLICATIONS: Communities interested in promoting sleep by delaying start times may do so knowing that there are unlikely to be adverse effects on adolescent physical activity, electronic screen time, or organized sports and activity participation.
conclusionsA shift to later school start times does not appear to enhance or detract from the healthfulness of students' activity level.
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