Acute Increases in Time in Bed Associated with Improved Competition Performance In Female Collegiate Swimmers

Abstract

Adequate sleep is vital for optimal athletic performance and health. A systematic review found that increasing time in bed or total sleep time significantly improved six performance outcomes [1]. However, these outcomes were mostly assessed through physical performance tests in controlled environments, with only two studies including female athletes. Previous works consistently demonstrate sex differences associated with objective and subjective sleep markers, highlighting female athletes have poorer sleep quality when compared to male athletes [2]. Moreover, the impact of sleep markers such as time in bed or sleep time on real-world competition outcomes in female athletes remains unclear. This study aimed to explore how acute sleep behavior affects swim race performance in female collegiate athletes. This retrospective study analyzed routine athlete monitoring data from 2022-2024 from the University’s athletic department and publicly available collegiate swim race results. 21 NCAA Division I female swimmers who wore a device (Ōura Health, Oulu, Finland) in-season on the eight nights leading up to a swim race and who competed in at least one race were included. Sleep quantity, measured as time in bed and sleep duration, was assessed from the device, while swim performance data were obtained from the SWIMS 3.0 database and evaluated using USA Swimming’s Power Point metric, which allows for comparing performances across sex, sprint type, and distance. Sleep metrics were converted into z-scores to compare the night before the swim race to the individual’s previous 7-day average. Linear mixed models were applied with fixed effects for Total Sleep Time 7-Day Z-Scores and Time in Bed 7-Day Z-Scores, and random effects for individual athletes to assess their impact on swimming performance. Significant main effects were found for Time in Bed 7-Day Z-Score (intercept, coefficient = 10.15 [1.61, 18.70], t = 2.33, p = 0.02) but not Sleep Time 7-Day Z-Score (intercept, coefficient = 4.74 [-4.33, 13.81], t = 1.03, p = 0.3) in predicting swimming performance. Time in bed is a significant predictor of improved swim race performance in female athletes. Practically, communicating the importance of time in bed, rather than sleep duration alone, may help reduce anxiety in female athletes who struggle to fall asleep before a meet. Emphasizing rest and recovery over sleep itself can shift focus away from stress about not sleeping, promoting a more relaxed pre-competition mindset and still providing benefits to performance. These results add the existing, albeit limited, literature about how sleep relates specifically to competition performance in female collegiate athletes. REFERENCES 1. Silva, A. C., Silva, A., Edwards, B. J., Tod, D., Souza Amaral, A., de Alcântara Borba, D., Grade, I., & Túlio de Mello, M. (2021). Sleep extension in athletes: What we know so far – A systematic review. Sleep Medicine, 77, 128–135. https://doi.org/10.1016/j.sleep.2020.11.028 2. Miles, K. H., Clark, B., Fowler, P. M., Miller, J., & Pumpa, K. L. (2022). What are the sleep characteristics of elite female athletes? A systematic review with meta-analysis. Biology of sport, 39(3), 751–763. https://doi-org.proxy.lib.ohio-state.edu/10.5114/biolsport.2022.108705

Emaly Vatne

Assistant Sport Scientist at The Ohio State University Department of Athletics and Human Performance Collaborative

My research interests include applied sport science, effects of recovery interventions, and data analysis, visualization, and engineering.