Sleep Characteristics of Elite Female Soccer Players Competing in the National Women's Soccer League Across a Competitive Season.

Purpose

Sleep supports recovery and readiness in professional sport, yet season-long objective data in women's professional soccer are limited. This study aimed to provide a longitudinal, objective description of sleep across a competitive season and to compare sleep characteristics between preseason and in-season phases.

Methods

Twenty-seven professional athletes were monitored from January to November 2024 using a finger-worn wearable. Nightly total sleep time (TST), sleep efficiency, sleep onset latency (SOL), and sleep stage durations were extracted. Preseason versus in-season differences were examined using linear mixed-effects models and reported as estimated marginal mean differences with 95% CIs.

Results

During the in-season, TST averaged 7.8 (1.2) hours (median: 7.9 h), sleep efficiency 89.1% (5.4%), and SOL 15.6 (12.6) minutes. Mean sleep stage durations were 262.8 (52.8) minutes (light), 96.6 (31.8) minutes (deep), and 106.8 (34.2) minutes (Rapid Eye Movement). Notable night-to-night variability was observed, particularly for TST (within-player coefficients of variation: 10%-18%) and SOL (50%-114%). Compared with preseason, in-season sleep was characterized by lower REM sleep (-4.8 min, 95% CI -6.9 to -2.8; P < .001), reduced sleep efficiency (-0.37%, 95% CI -0.71 to -0.02; P = .036), and shorter SOL (-1.1 min, 95% CI -2.0 to -0.2; P = .020). TST did not differ between phases (P = .287), and deep and light sleep remained unchanged. Effect sizes were small (Cohen d ≤ 0.15).

Conclusions

Group averages of sleep parameters might mask individual and seasonal changes in sleep, highlighting the need for longitudinal, athlete-specific monitoring to guide proactive sleep monitoring strategies.