1280 Influence of Competition on Nighttime Sleep and Heart Rate Metrics: A Longitudinal Study in NCAA Division 1 Women’s Volleyball Athletes

Abstract Introduction The physical, psychological, and logistical aspects of competition can negatively affect the sleep health of athletes. Despite a growing body of research in this area, women collegiate athletes are underrepresented and understudied. This investigation was designed to examine how competition affects sleep (duration, continuity, and timing) in National Collegiate Athletic Association (NCAA) Division 1 women’s volleyball athletes, leveraging objective data collected longitudinally across a calendar season. Methods The Oura Ring measured nighttime sleep duration, continuity (sleep onset latency and efficiency), and timing (bedtime and waketime) continuously across a competitive season in Division 1 women’s volleyball athletes. Sleep episodes were classified based on competition status (no match [NM], night before [NB], or night following [NF]). Linear mixed-effects models examined differences in sleep between NM, NB, and NF, with post-hoc pairwise comparisons conducted when appropriate. Secondary analyses explored the influence of match timing (before 17:00 vs. ≥ 17:00) and location (home vs. away) on NB and NF sleep. Results 656 nights of sleep from 10 athletes were analyzed, including data collected over 22 matches. Significant variance was observed across NM, NB, and NF conditions for sleep duration (F(2,644.7) = 22.5, p < 0.0001), bedtime (F(2,644.3) = 69.7, p < 0.0001), and waketime (F(2,644.5) = 24.7, p < 0.0001 ), but not for continuity variables. Athletes had significantly shorter sleep duration during NF (6.95 ± 0.15 hours), relative to NM (7.34 ± 0.13 hours, p < 0.0001) and NB (7.82 ± 0.15 hours, p < 0.0001), while sleep duration was significantly longer during NB compared to NM (p < 0.0001). Bedtimes and waketimes were significantly delayed during NF, relative to NM and NB, with waketimes significantly later in NB compared to NM. For match timing, significantly shorter sleep duration occurred prior to earlier matches and following later matches. For match location, significantly shorter sleep duration occurred prior to home matches and following away matches. Conclusion NCAA Division 1 women’s volleyball athletes were vulnerable to shortened and delayed sleep following competition. Athletes showed extended sleep on the night prior to competition, perhaps reflecting an intentional prioritization and protection of sleep to enhance performance. Support (if any) None.