Sleep Regularity and Predictors of Sleep Efficiency and Sleep Duration in Elite Team Sport Athletes

Abstract

Background Many elite athletes have suboptimal sleep duration and efficiency, potentially due to factors that may impact sleep onset and offset times. Variability in sleep onset and offset may negatively influence sleep. The sleep regularity index (SRI) is a novel metric for sleep regularity, however there are no published descriptions of SRI in elite athletes. Further, contributors to sleep efficiency and duration in elite athletes using objective measures have not been explored. Methods Sleep was monitored over a minimum of seven consecutive days (7 to 43)—in 203 elite team sport athletes (age range = 19–36 years; female, n = 79; male, n = 124, total sleep nights = 1975) using activity monitoring and sleep diaries. The sleep regularity index (SRI) was calculated to reflect the night-to-night shifts in sleep by accounting for changes in sleep onset and sleep offset. Sleep characteristics were compared between regular and irregular sleepers and important contributors to sleep efficiency and total sleep time were assessed using multiple linear regression models. Results The median sleep regularity index and interquartile range were 85.1 (81.4 to 88.8). When compared to irregular sleepers, regular sleepers demonstrated (1) significantly greater sleep efficiency (p = 0.006; 0.31 medium effect size [ES]), (2) significantly less variability in total sleep time (− p ≤ 0.001; − 0.69, large ES) and sleep efficiency (− 0.34, small ES), (3) similar total sleep time and (4) significantly less variation in sleep onset (p ≤ 0.001; − 0.73, large ES) and offset (p ≤ 0.001; − 0.74, large ES) times. Sleep characteristics explained 73% and 22% of the variance in total sleep time and sleep efficiency, respectively. The most important contributor to total sleep time was a later sleep offset time, while the most important contributors to sleep efficiency were an earlier bedtime and less variable sleep onset times. Conclusions Bedtime and a consistent sleep onset time are important factors associated with sleep efficiency in athletes, while sleep offset is an important factor for total sleep time. Coaches and staff can assist their athletes by providing training schedules that allow for both regularity and sufficiency of time in bed where possible.

Intraindividual variability in sleep among athletes: A systematic review of definitions, operationalizations, and key correlates

“…Among rugby league players, elite juniors demonstrated greater variability in sleep onset time, time in bed, and sleep duration than both elite seniors and subelite seniors, as well as greater variability in sleep efficiency and subjective sleep quality than elite seniors 18 . Regarding differences among elite team sport athletes, regular sleeper displayed less variability in total sleep time, sleep efficiency, and sleep onset and offset 5 …”

“…18 Regarding differences among elite team sport athletes, regular sleeper displayed less variability in total sleep time, sleep efficiency, and sleep onset and offset. 5…”

“…It is generally accepted among the sport science community that many elite athletes accrue insufficient amounts of sleep 4 and the quality of their sleep is suboptimal. 5 Much of the available work prioritizes evidence on differences in mean levels of sleep metrics between individuals (interindividual variability) for interventions or strategies, [6][7][8] with little consideration of intraindividual variability for optimizing sleep health. This gap in knowledge limits our potential to generate innovative tactics that might optimize sleep health, that is, multidimensional sleep patterns (e.g., duration, efficiency, and quality) contextualized to personal and contextual factors, which give rise to positive health and well-being.…”

“…The extent to which these recommendations generalize to elite athletes remains unknown 4 and is likely challenging to pinpoint because of the diverse, often multifactorial physical and psychological conditioning programs required for certain sports. It is generally accepted among the sport science community that many elite athletes accrue insufficient amounts of sleep 4 and the quality of their sleep is suboptimal 5 . Much of the available work prioritizes evidence on differences in mean levels of sleep metrics between individuals (interindividual variability) for interventions or strategies, 6–8 with little consideration of intraindividual variability for optimizing sleep health.…”

Sleep and its importance in sport: a concise systematic review

“…The scientific explanation for this phenomenon is the action of the hippocampus while we sleep, as it reactivates itself to produce some activities similar to those when we are awake. The hippocampus directly sends data to the cortex, which response and results in the "delta wave" and then the "dream axis" [14].…”