Exploring Sleep and Nocturnal Physiology in Elite and Recreational Female Athletes

To describe objective sleep quantity and quality and nocturnal physiological measures in elite and recreational female athletes and compare between and within groups on weekdays and weekends.

Sleep was assessed over 4 to 8 nights (mean [SD]: 7 [1] nights) in 21 elite and 27 recreational athletes using partial polysomnography in their home environment. Linear mixed models compared measures between groups and day (weekends: Friday and Saturday night, weekdays: Sunday to Thursday night).

Sleep variables were similar between groups. Elite athletes obtained a lower minimum heart rate (estimate ± SE: -5 ± 2 beats/min, Cohen effect size: d = -0.3 ± 0.3, significance: P = .03) and blood oxygen saturation (-1.4 ± 0.7%, d = -0.3 ± 0.3, P = .045) than recreational athletes. On weekdays, elite athletes obtained a greater percentage of nonrapid eye movement stages 1 and 2 sleep (light sleep: 4 ± 1.2%, d = 0.2 ± 0.1, P = .001) and a lower percentage of rapid eye movement sleep (-2.4 ± 1.2%, d = -0.1 ± 0.1, P = .04) than on weekends. On weekdays, both elite and recreational athletes obtained earlier sleep onset time than on weekends (elite mean ± SD: 22:38 [1:03] hh:mm vs 22:52 [1:45] hh:mm, d = -0.24 ± 0.12, P ≤ .001; recreational 22:11 [0:59] hh:mm vs 22:41 [1:16] hh:mm, d = -0.19 ± 0.12, P = .002). Only recreational athletes obtained earlier sleep offset times (5:37 [1:27] hh:mm vs 6:23 [1:10] hh:mm, d = -0.19 ± 0.12, P = .002) on weekdays than on weekends.

Sleep outcomes did not vary by athlete level, but nocturnal physiological measures did. Sleep outcomes also differed within each group between weekends and weekdays, suggesting strategies may be required to minimize sleep irregularity.