0172 Scrolling Past Bedtime: How Smartphone Use Limits Sleep in Elite Adolescent Athletes

Abstract Introduction Elite adolescent athletes typically experience insufficient sleep. Demanding schedules limit sleep by imposing early morning wakes, and late bedtimes. In addition, increasing evening screen use, particularly on smartphones, may further restrict sleep by delaying bedtime. Our objective was to examine these behaviours more closely by investigating how adolescent athletes used their smartphones and how this affected their sleep. Methods Twenty-nine male rugby athletes (16.4 ± 0.7 years) were followed for two and a half months. Sleep was assessed daily using actigraphy. Smartphone use was monitored objectively through daily screenshots of their "screen usage", allowing the quantification of total screen time, type of use (social media, entertainment, video games), and timing of use throughout the day. Each athlete also underwent two polysomnography recordings spaced three weeks apart to assess sleep architecture. Results Athletes spent an average of 5.88 ± 2.17 h/day on their phones, ranging from 3.91 ± 1.03 h to 8.16 ± 2.33 h. Weekday use (5.66 ± 2.04 h) was lower than weekend use (7.47 ± 2.36 h, p < 0.001). The majority of screen time was dedicated to social media (80.9%), followed by entertainment (9.1%), video games (4.5%), and other applications (5.5%). Each additional hour of smartphone use was associated with a delayed bedtime (+5.7 min/h, p < 0.001). This association was much stronger when use occurred in the late evening (20:00–03:00), producing a delay of +34.4 min/h (p < 0.001). Late use was also associated with a reduction in total sleep time (−35.8 min/h, p = 0.0017) and a higher proportion of deep slow-wave sleep (N3) (+3.35%, p = 0.028). Conclusion Adolescent elite athletes spend substantial amounts of time on their smartphones, primarily on social media. The most significant effects concern late-evening use, which is associated with delayed sleep onset, reduced sleep duration and changes in sleep architecture, highlighting the increased sleep-debt. These findings indicate that the timing of use matters more than total use, and highlight the importance of limiting late-night screen exposure to preserve sleep rhythms and recovery in young athletes. Support (if any)