By: Dr Ian C Dunican

Background

We know from many studies in the last ten years that elite athletes do not get enough sleep (<7hrs of sleep per night). However, most athletic research has been done with male athletes. To understand female athletes’ sleep, we partnered with an elite female basketball team in the Women’s National Basketball League (WNBL) to determine how they sleep during a season. Basketball players require good sleep to be ready for training sessions during the week and multiple games played in close succession (two days in a row) during a competitive season ¹.

There are many challenges for obtaining sleep in this group such as interstate travel (up to 5hrs and 3 time zones crossed), media, extra-curricular activities such as university education, additional work commitments and anxiety leading up to competitive games^{2 3}. The same can be said about coaches who are often overlooked in this work; they are no more immune to the deleterious effects of sleep loss than the players they train.

At the end of 2020, myself and fellow researchers had a paper accepted for publication in a scientific journal. The article is titled “An education intervention in a professional female basketball team and coaching staff improve sleep and alertness”. ⁴

Our hypothesis for this study was that a sleep-education program would improve sleep and alertness measures in elite female basketball players and their coaches. Before we commenced our education program, we had to collect a baseline of sleep measures to understand the current situation before we embarked on an education program for the group and individually. Therefore, our first aim was to quantify the sleep behaviours and alertness of players and coaches.

How did we collect the sleep and performance data?

We recruited 12 elite female basketball players and three male coaches. The coaches were aged 42±15 years, and their weight was 101±19 kg and a height of 186±10 cm with the players aged 25±2 years, and they weighed 70±8 kg. All wore actigraphy devices (Fatigue Science, Readiband) for 30 nights during the Women’s National Basketball League, Australia to assess sleep and completed questionnaires assessing daytime sleepiness, insomnia, and sleep apnoea. We recorded a combined 450 nights of sleep, resulting in >3,500 sleep and alertness measures. We generated a continuous measure of alertness over time using the biomathematical model known as SAFTE (Safety, Activity, Fatigue, Task, Effectiveness) to measure alertness.

The SAFTE algorithm incorporates a homeostatic sleep reservoir, circadian oscillator and a sleep inertia function ⁵ to generate a measure of alertness ⁶. These measures of alertness derived from the SAFTE algorithm have been validated against the psychomotor-vigilance test (R² = 0.88, p ≤ 0.001), such that the higher the alertness score the less the likelihood of lapses in reaction time. These alertness scores can also be related to the estimated reaction times at equivalent blood alcohol concentration and associated error risk. Ideally, individuals and teams should be training and competing when alertness is maximal >90%. We have used such an approach previously in Super Rugby⁷; the full paper can be accessed here.

So what did we find?

• No player or coach was at high risk for sleep apnea, or harmful levels of alcohol usage.
• Overall, the players have excellent sleep behaviours (>8hrs per night). The training schedule may explain this as no training was scheduled before 13:00 each day, allowing them an extended sleep opportunity.
• This training schedule design probably influenced the sleep measures by supporting an extended sleep opportunity each morning ⁸ in the present team-members, whereas in our other research in sports such as Rugby Union ⁷ and elite Judo athletes, the early training times tends to reduce sleep opportunities.
• The coaches sleep required improvement as they were getting <7 hrs per night. Their sleep may be reduced due to workload and stress associated with coaching ⁹. This can be seen with the main differences being the early time at wake each morning. They were getting up at 06:00, and the players were getting up at 07:10.

Conclusion

This data provides valuable information for the team and the coaches to assess where they are right now. However, more importantly, we now have a baseline to measure any differences. In part two of this story, we will look at how a sleep education program may improve sleep in this group.

References

1. Staunton C, Gordon B, Custovic E, et al. Sleep patterns and match performance in elite Australian basketball athletes. Journal of Science and Medicine in Sport 2017
2. Juliff LE, Halson SL, Peiffer JJ. Understanding sleep disturbance in athletes prior to important competitions. Journal of science and medicine in sport / Sports Medicine Australia 2015;18(1):13-8. doi: 10.1016/j.jsams.2014.02.007 [published Online First: 2014/03/19]
3. Gupta L, Morgan K, Gilchrist S. Does Elite Sport Degrade Sleep Quality? A Systematic Review. Sports medicine (Auckland, NZ) 2016 doi: 10.1007/s40279-016-0650-6
4. Dunican IC, Caldwell JA, Morgan D, et al. An education intervention in a professional female basketball team and coaching staff improves sleep and alertness. Translational Sports Medicine;n/a(n/a) doi: https://doi.org/10.1002/tsm2.218
5. Roma P HS, Mead A, Nesthus T. Flight Attendant Work/Rest Patterns, Alertness, and Performance Assessment: Field Validation of Biomathematical Fatigue Modeling. Office of Aerospace Medicine Federal Aviation Administration 800 Independence Ave., S.W. Washington, DC 20591: Office of Aerospace Medicine Federal Aviation Administration 800 Independence Ave., S.W. Washington, DC 20591, 2012.
6. Steven R. Hursh DPR, Michael L. Johnson, David R. Thorne, Gregory Belenky,Thomas J. Balkin, William F. Storm, James C. Miller and Douglas R. Eddy. Fatigue models for applied research in warfighting. Aviation Space Environmental Medicine 2004;75(Suppl 3 ):A44–53.
7. Dunican IC, Higgin CC, Murray K, et al. Sleep Patterns and Alertness in an Elite Super Rugby Team During a Game Week. J Hum Kinet 2019;67:111-21. doi: 10.2478/hukin-2018-0088
8. Sargent C, Lastella M, Halson SL, et al. The impact of training schedules on the sleep and fatigue of elite athletes. Chronobiol Int 2014;31(10):1160-8. doi: 10.3109/07420528.2014.957306 [published Online First: 2014/09/16]
9. Caia J, Scott TJ, Halson SL, et al. Do players and staff sleep more during the pre- or competitive season of elite rugby league? European journal of sport science 2017;17(8):964-72. doi: 10.1080/17461391.2017.1335348 [published Online First: 2017/06/07]