REVIEW

 

Sleep interventions in elite sport - a systematic review

 

 

SC Bilgoe^{I, II}; S den Hollander^{III, IV}; DC Janse van Rensberg^V; S Hendricks^{IV, VI}; G Kerkhoffs^{VII, VIII, IX, X}; V Gouttebarge^{VII, VIII, III, XI, VII, VIII}

^IBSc; Amsterdam UMC, location University of Amsterdam, Department of Orthopedic Surgery and Sports Medicine, Meibergdreef 9, Amsterdam, the Netherlands
^IIBSc; Amsterdam Collaboration on Health & Safety in Sports (ACHSS), IOC Research Center of Excellence, Amsterdam, the Netherlands
^IIIPhD; Football Players Worldwide (FIFPRO), Hoofddorp, the Netherlands
^IVPhD; Division of Physiological Sciences and Health through Physical Activity, Lifestyle and Sport Research Centre, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
^VMD; Section Sports Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
^VIPhD; Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
^VIIPhD; BSc; Amsterdam UMC, location University of Amsterdam, Department of Orthopedic Surgery and Sports Medicine, Meibergdreef 9, Amsterdam, the Netherlands
^VIIIPhD; BSc; Amsterdam Collaboration on Health & Safety in Sports (ACHSS), IOC Research Center of Excellence, Amsterdam, the Netherlands
^IXPhD; Academic Center for Evidence-based Sports Medicine (ACES), Amsterdam, the Netherlands
^XPhD; Amsterdam Movement Sciences, Aging & Vitality, Musculoskeletal Health, Sports, Amsterdam, the Netherlands
^XIPhD; Section Sports Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa

Correspondence

 

 

---

ABSTRACT

BACKGROUND: Elite athletes encounter various situations and conditions that may disrupt their sleep, a crucial factor for optimal performance and well-being.
OBJECTIVES: The aim of this study was to synthesise existing research on the effect of sleep interventions on sleep quantity and quality in elite sports and to provide evidence-based guidance for athletes, coaches, and other stakeholders in elite sports who seek to enhance sleep quantity and quality.
METHODS: This review followed the PRISMA guidelines, whereas the search was executed in September 2023 utilising the electronic databases SCOPUS, PubMed and Web of Science. Studies were included if they met the inclusion criteria.
RESULTS: A total of 1014 studies were retrieved from the databases, and data extraction was performed on 32 studies. The included studies evaluated sleep hygiene education/strategies, acute cold exposure, light therapies, supplementation, neurostimulation/neurofeedback, and other (mindfulness and massage therapy) strategies. Sleep hygiene education was the most effective intervention to improve sleep quantity. Supplementation and light therapy interventions showed improved sleep quality and quantity. Additionally, cold water immersion and mindfulness showed improved sleep quality, but further studies are required for confirmation.
CONCLUSION: Future research should use reliable and valid methods to improve the quality of evidence and ensure conclusive findings.

Keywords: sleep quality, elite athletes, sports medicine

---

 

 

Sleep plays an important role in improving performance, promoting health, and ensuring the overall well-being of elite athletes.^[1]Reportedly, rnost elite athletes do not get the daily recommended hours of sleep per night (7-9 hours),^[2] and, on average, get less sleep than the general population.^[3] Various factors, including training schedules,^[4] frequent travel,^[5] competition demands,^[6,7] and caffeine consumption,^[8] have been shown to disrupt the sleep patterns of elite athletes. Sleep disruption can have a significant impact on elite athletes as sleep deficiency has been associated with impaired physical performance,^[9] impaired neurocognitive performance,^[10] and an increased risk for injuries and illnesses.^[11,12]

Various sleep interventions have been implemented in elite sports to address sleep-related challenges and reduce the risks associated with sleep deprivation. These interventions include napping,^[13] sleep hygiene education,^[14] and post-exercise recovery strategies.^[15] Nevertheless, the efficacy and effectiveness of these available interventions in elite sports settings remain uncertain. Some studies have explored the impact of sleep interventions on sleep, recovery and athletic performance.^[16,17] However, no study has specifically focused on the effectiveness of sleep interventions on sleep quality and quantity among elite athletes.

This systematic review synthesised the existing research on sleep interventions in elite sports. It addressed the following key research question: What sleep interventions effectively improved the quantity and quality of sleep among elite athletes? The objective was to provide evidence-based guidance for athletes, coaches, and other stakeholders in elite sports who seek to enhance sleep quality and quantity.

 

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.^[18]

Data sources and search strategy

Three databases [SCOPUS, PubMed and Web of Science (MEDLINE)] were searched for relevant studies in September 2023. The search queries for each database, detailed in Table 1, included ten queries related to sleep interventions in elite or professional sports. No filters were set.

Eligibility criteria

The eligibility criteria were as follows:

• An original research study published in a peer-reviewed journal.

• Studies published in the English language.

• The sample consisted of elite athletes, defined as collegiate, Olympic, or professional athletes (Tiers 3 and

• The study assessed either the quantity or quality of sleep.

• The study analysed the effectiveness of an intervention to improve the quantity and/or quality of sleep.

Data selection

After duplicate removal, two reviewers (SB and SDH) independently screened all titles and abstracts using the eligibility criteria. Subsequently, all potentially eligible full-text articles were screened. The reference lists of the papers that met the eligibility criteria and the retrieved reviews were searched, and the full texts of any relevant papers were screened for eligibility. At any stage of eligibility, disagreements were resolved by consensus between the two reviewers.

Data extraction

The following data were extracted and recorded onto a data extraction table: publication details (title, author, year of publication), details of the sample (level of competition, country, sport, age, sex, sample size), methods (study design, intervention, sleep measurements, outcome measures), and results (summary of key findings).

Methodological quality

The methodological quality of the included studies was assessed using a modified version of a quality assessment scale by Abernethy and Bleakley (Table 2).^[20] Hereby, the quality of the study design, participant descriptions, interventions, outcome measures, assessor blinding, and measurement duration were assessed. Two authors (SB and SDH) independently conducted the assessment and were aware of the study authors, place of publication, results, and they were not blinded to this information. In uncertainty, a third researcher (VG) was consulted to obtain consensus. The included studies could obtain a score of 0, 1 or 2 for each item on the scale, resulting in a maximum possible total score of 16 points (Quality score key detailed in Table 2). The overall quality scores were converted into a percentage value and then rated (0-49%=poor, 50-89%=moderate, and >90%=good). Studies that rated as poor were subsequently excluded.

 

Results

Study selection

From 1014 studies retrieved from the databases, 643 duplicates were removed, and a further 333 were excluded (Figure 1). Ultimately, 49 studies were screened for eligibility, resulting in 32 studies for data extraction. Figure 1 represents the detailed flow chart of the study selection.

Study characteristics

The Table 3 presents detailed information about the reviewed articles. The studies encompassed athletes from 13 countries participating in 16 different sports,^{[14,15,21-49]} with 16 involving only male participants (Table 3);^{[14,15,21,24-26,29-35,40,41,49]} Furthermore, the quality scores of the included studies ranged from 8 to 14, with seven of the studies rated as 'good' and 25 as 'moderate' (Table 4).

 

 

Sleep interventions

Among the various sleep interventions, sleep hygiene education^[14,21-26] and strategy^[27-32] followed by supplementation^[40-44] were mostly used in the included studies (Table 5). Each study assessed sleep quality and sleep quantity using different measurements. The most common quality assessments were sleep latency, sleep efficiency, wake after sleep onset, and subjective sleep measurements (questionnaires). The most common quantity assessments included time in bed and total sleep time. Seven studies^{[14, 21-26]} examined the effect of sleep hygiene education on several sleep parameters, where improvements in these parameters ranged from 29 % for sleep latency to 75 % for total sleep time. Among sleep hygiene strategies, six studies were included evaluating various strategies such as removal of electronic devices at night,^{[27, 28]} a 10-minute shower at ~40°C before lights out,^[29] sleeping on a high heat capacity mattress,^[30] napping,^[31] and a sleep extension intervention^[32] where improved sleep parameters ranged from 17 % for sleep latency to 40 % for time in bed. Furthermore, five studies^[40-44] observed various supplementation interventions where improvements in wake after sleep onset and time in bed reached 33%.

Three studies ^[15,33,34] on cold water immersion were included in which sleep latency, sleep efficiency, time in bed, and total sleep time measurements were observed. Two three-day cold water immersion sessions (10 minutes each session) improved sleep latency. In contrast, a combination of 15-minute cold water immersion, compression garments and sleep hygiene recommendations improved time in bed and total sleep time.^[15,33]

Three studies evaluated the effect of cryostimulation (partial body exposure and whole-body exposure), whereas no improvements in sleep parameters were observed.^[30,35,36]

As for light therapy, three studies were included that evaluated either bright light therapy or red light therapy, where improved sleep quality ranged from 0% for sleep efficiency to 100% for subjective sleep measurements.^[37-39]

Three studies evaluated the impact of neurostimulation/ neurofeedback on elite athletes during training periods.^[45-47] Auditory brainwave entrainment improved subjective sleep measurements, time in bed, and total sleep time.^[45] The other sleep interventions included in our study, an eight-week mindfulness-based stress reduction course and massage therapy, also improved subjective sleep measurements.^[48]

 

Discussion

Thirty-two studies evaluating various sleep interventions across different elite sports were analysed. The interventions retrieved from the literature included sleep hygiene education and strategies, cold water immersion, cryostimulation, light therapies, supplementation, neurostimulation/neurofeedback, and other (mindfulness-based stress reduction and massage therapy) strategies. Based on the reviewed studies, sleep hygiene education was the most effective intervention to improve sleep quantity. Supplementation and light therapy interventions showed improvements in both sleep quality and quantity. Furthermore, cold water immersion and mindfulness-based stress reduction showed improved sleep quality.

However, these findings are based on a limited number of studies; thus, further research is needed to confirm these results.

Sleep hygiene

Sleep hygiene has been suggested as a potential solution for promoting optimal sleep in athletes, although its effectiveness is limited when implemented as a standalone treatment.^[15,26,50] The effects may be influenced by individual differences among athletes, such as their motivation to incorporate sleep hygiene into their long-term routine.^[16,17] The reviewed studies indicate that sleep hygiene education in elite athletes can lead to improved sleep quantity.^[14,21-26] Our results also indicate the necessity for educating elite athletes about sleep hygiene, enabling them to optimise their sleep patterns effectively. Caia et al.(2018) highlighted the advantages and limitations of a sleep hygiene intervention among professional rugby league athletes.^[14] Implementing a sleep hygiene intervention initially led to notable improvements in time in bed and total sleep time.^[14] However, at the 1-month follow-up, the favourable impacts on time in bed were not sustained, and a decreased sleep efficiency was observed, implying the limited long-term effectiveness of time in bed as a standalone treatment.^[14] The results have conflicted regarding sleep hygiene strategies focused on sleep extension, whether through 40-minute naps or a 3-week sleep extension intervention.^[31,32] A 40-minute napping intervention observed no differences in sleep parameters post-intervention. In contrast, a 3-week sleep extension intervention aiming for 10 hours per night showed improved Pittsburgh Sleep Quality Index (PSQI) scores, time in bed and total sleep time in elite athletes.^[31,32] Another strategy, namely removing electronic devices, reported no improvements in sleep parameters.^[27,28] Furthermore, a study evaluating showering at ~40°C before bed and another study evaluating the use of high-heat capacity mattresses reported positive sleep results in elite athletes.^[29,30] The ability to assess and compare the effectiveness of sleep hygiene is limited, as these studies evaluated different strategies across various sports. Hence, it remains difficult to conclude which sleep hygiene strategies are most effective as this effect may differ across sport types due to contextual and individual differences.

Cold exposure

Elite athletes increasingly use acute cold exposure as a recovery strategy, whether through cold water immersion or cryostimulation.^[51,52] Our reviewed articles included two types of cryotherapy: whole-body, where the entire body is exposed, and partial-body, where specific areas are targeted, excluding the head.^[36] Partial-body cryostimulation at -180°C for 180 seconds among professional soccer players showed significant reductions in the number of movements during the night post-intervention.^[35] Furthermore, whole-body cryostimulation among elite rugby athletes and synchronised swimmers did not show differences in sleep parameters post-intervention.^[30,36] The existing literature regarding cryostimulation is still limited, and it shows varied results on sleep quality among elite athletes. Therefore, additional research is necessary to understand the effectiveness before recommending the implementation of cryostimulation as a strategy to promote sleep. Another cold exposure intervention we reviewed in our study was cold water immersion,^[15,33,34] where Robey et al. (2013) did not observe any effects on sleep after 15-minute sessions among elite cyclists and triathletes post-exercise.^[34] However, Lastella et al.(2019) observed shorter sleep latency in the intervention condition compared to the control condition.^[33] Furthermore, 15-minute cold water immersion combined with other strategies such as three hours of wearing full-body compression garments and sleep hygiene recommendations (incl. establishing a cool temperature (19±2°C) and low-light environment, avoiding the use of electronic devices and excessive light 30 minutes before 9.30pm) after daily on-court tennis training and match-play sessions resulted in improvements in sleep quantity.^[15]

Light therapy

Existing literature suggests that artificial light exposure can shift the circadian rhythm, playing a crucial role in our daily hormonal and behavioural patterns of melatonin secretion, sleepiness, alertness, and performance.^[53] Bright light therapy may impact melatonin suppression, affect the body clock, and increase evening alertness when it usually starts to drop.^[54] Rosa et al.(2018) reported a delayed sleep/wake cycle after bright light therapy in the evening. Thompson et al.(2012) reported that bright light therapy did not substantially reduce jet lag symptoms in athletes after travelling.^[37,38] As for red light therapy, which does not impact melatonin suppression, Zhao et al.(2012) reported increased PSQI scores following red light treatment in the evening.^[39,55] These results should be interpreted cautiously as the assessment tool (PSQI) is not validated in an athletic population and may be unreliable in examining sleep quality over a short-term period.^[56,57]

Supplementation

Our findings indicate that probiotic supplementation may improve objective and subjective sleep parameters among professional soccer and rugby athletes.^[40,41] These results should be interpreted cautiously as these two studies also contain limitations. In the study among professional rugby players, an additional probiotic was used to prevent diarrhoea, possibly influencing the outcome.^[40] Moreover, sleep among soccer players who received probiotic strains for 30 days was measured using actigraphy.^[41] However, this method may not be sensitive enough to detect changes in sleep latency in players without sleep problems, potentially leading to underreported sleep latency values.^[58] Nonetheless, probiotic supplementation has been shown to improve subjective sleep quality in non-athlete populations.^[59] Recent literature suggests that probiotics may improve athletes' sleep by reducing muscle soreness and influencing the sleep/wake cycle through melatonin synthesis.^[40,60] While recent studies showed promising results regarding the relationship between probiotics and athletes' sleep, future research that uses more thorough methods for assessing sleep (e.g., polysomnography) and implements stricter control of confounding variables is necessary to accurately evaluate the true effect of probiotic supplementation on athletes' sleep.

Other nutritional strategies have positively affected sleep indices in an elite athlete population, including kiwifruit and tart cherry juice consumption.^[43,44] Kiwifruit consumption for four weeks improved PSQI scores among elite sailing and track and field athletes.^[43] Additionally, tart cherry juice intake among female hockey players improved time in bed, sleep efficiency and wake after sleep onset.^[44] Both of these nutrient supplementation strategies have shown positive effects on sleep indices in the general population due to their level of melatonin and serotonin.^[61-63] Furthermore, kiwifruit contains a substantial amount of folate, potentially improving sleep quality, as a folate deficiency is associated with insomnia.^[62,64] However, most studies exploring the use of tart cherry juice in athletic populations have focused on its impact on various aspects of recovery, such as muscle soreness,^[61,65,66] thus emphasising the need for future studies focusing on its impact on sleep parameters among elite athletes. Further on the nutrient supplementation evaluation, consuming pre-sleep α-lactalbumin in a semi-professional female rugby team during a competition season led to improved sleep latency.^[42] In recent literature, α-lactalbumin has been identified as containing the highest levels of tryptophan, an amino acid serving as a precursor to the sleep-promoting hormones melatonin and serotonin.^[67,68]

Neurostimulation/neurofeedback

The electroencephalogram cortical oscillations can be categorised into specific frequencies linked to different states of brain functioning (delta [1.5-6 Hz], theta [6.5-8 Hz], alpha [8.5-12 Hz], beta [8.5-30 Hz]).^[69] Brainwave entrainment requires stimulating the brain during sleep with frequencies between 1 and 9 Hz, supporting the healthy human sleep cycle.^[70,71] Abeln et al.(2013) reported improvements in subjective sleep quality after eight weeks of auditory brainwave entrainment among high-level soccer players.^[45] Furthermore, eyes-open alpha training among elite gymnasts and mental coaching in combination with alpha power feedback among elite athletes did not significantly improve sleep parameters.^[46,47]

Other

The other strategies we evaluated, specifically eight weeks of mindfulness-based stress reduction for elite rowing athletes and massage therapy for elite para-cyclists, both enhanced subjective sleep parameters.

Limitations

While our systematic review suggests that many of the interventions positively affect sleep, these findings are based on a limited number of studies. Furthermore, most of the studies presented a substantial risk of bias, also mentioned in a recent consensus statement on sleep among athletes.^[57] The statement emphasises the necessity for more consistent, reliable, and valid research methods in studies on athlete's sleep, given the poor quality of current research on this topic.^[57] Moreover, each study assessed sleep quality and quantity using different outcome measures. The variability in the assessment of sleep quality and sleep quantity between the studies made it difficult to synthesise and compare the results.

Recommendations

Recommendations for practice

Athletes, coaches, and other stakeholders involved in elite sports should receive sleep education to raise awareness about the importance of sleep and offer insights into different strategies that can be implemented. Sleep education should cover information on the appropriate night-time sleep quantity, daytime sleep quantity (naps), good sleep hygiene, and the potential impact of late-night or early-morning training on sleep health as recommended in the recent consensus statement.^[57] Additionally, practitioners should regularly screen athletes for sleep problems and refer them to a sleep specialist for clinical diagnosis. As a result, the proper treatment can be provided, as some sleep interventions may be ineffective in the presence of a sleeping disorder. Notably, caution is necessary when using sleep monitors, as athletes can become concerned about the data, leading to reduced sleep quality due to increased anxiety.^[57]

Recommendations for researchers

Empirical studies regarding sleep health among elite athletes are still limited. Therefore, future researchers and clinicians should collaborate with elite athletes, teams, and organisations across different sports types to increase the quantity and quality of current studies in this area. To improve the quality of these studies, researchers should design longitudinal studies to assess the long-term effectiveness of sleep interventions by using validated measurement tools to objectively and subjectively assess sleep parameters. Additionally, researchers should investigate how sport-specific factors, individual differences (e.g., sex, age, race/ethnicity, and chronotype), and other factors (e.g., training, travel, and competition schedules) can influence the effectiveness of sleep interventions. Furthermore, sleep measurements show major heterogeneity among studies in elite athletes, highlighting the need to develop standardised guidelines for measuring sleep parameters in this population. This review's findings should also contribute to future research to identify and develop effective evidence-based sleep interventions for elite athletes.

 

Conclusion

Our systematic review suggests that sleep hygiene education improves sleep quantity in elite athletes. The remaining strategies, such as supplementation, light therapy, mindfulness-based stress reduction, and cold water immersion, positively affect elite athletes' sleep health. Still, more studies are needed to confirm these results. The variability in the assessment of sleep quality and sleep quantity between the studies made it difficult to synthesise and compare the results. Future research should implement consistent, reliable, and valid methods, thereby enhancing the quality of evidence and allowing for more conclusive findings.

Conflict of interest and source of funding: These authors report no conflict of interest in this project. There were no sources of funding.

Author contributions: All authors conceptualised the need for a review. SB and SDH conducted the literature search, analysed the data, and drafted the manuscript. Each author contributed critical feedback and approved the final version.

 

References

1. Halson SL. Sleep monitoring in athletes: motivation, methods, miscalculations and why it matters. Sports Med 2019;49(10):1487-1497. [doi: 10.1007/s40279-019-01119-4] [PMID:31093921].         [ Links ]

2. Lastella M, Roach GD, Halson SL, Sargent C. Sleep/wake behaviours of elite athletes from individual and team sports. Eur J Sport Sci 2015;15(2):94-100. [doi: 10.1080/17461391.2014.932016] [PMID:24993935].         [ Links ]

3. Leeder J, Glaister M, Pizzoferro K, Dawson J, Pedlar C. Sleep duration and quality in elite athletes measured using wristwatch actigraphy. J Sports Sci 2012;30(6):541-545. [doi: 10.1080/02640414.2012.660188] [PMID:22329779].         [ Links ]

4. Sargent C, Halson S, Roach GD. Sleep or swim? Early-morning training severely restricts the amount of sleep obtained by elite swimmers. Eur J Sport Sci 2014;14 Suppl 1:S310-S315. [doi: 10.1080/17461391.2012.696711] [PMID:24444223].         [ Links ]

5. Richmond LK, Dawson B, Stewart G, Cormack S, Hillman DR, Eastwood PR. The effect of interstate travel on the sleep patterns and performance of elite Australian Rules footballers. J Sci Med Sport 2007;10(4):252-258. [doi: 10.1016/j.jsams.2007.03.002] [PMID: 17524795].         [ Links ]

6. Sargent C, Roach GD. Sleep duration is reduced in elite athletes following night-time competition. Chronobiol Int 2016;33(6):667-670. [doi: 10.3109/07420528.2016.1167715] [PMID: 27097227].         [ Links ]

7. Juliff LE, Peiffer JJ, Halson SL. Night Games and Sleep: Physiological, Neuroendocrine, and Psychometric Mechanisms. Int J Sports Physiol Perform 2018;13(7):867-873. [doi: 10.1123/ijspp.2016-0809] [PMID:29252066].         [ Links ]

8. Dunican IC, Higgins CC, Jones MJ, Clarke MW, Murray K, Dawson B, et al. Caffeine use in a Super Rugby game and its relationship to post-game sleep. Eur J Sport Sci 2018;18(4):513-523. [doi: 10.1080/17461391.2018.1433238] [PMID: 29431593].         [ Links ]

9. Reilly T, Piercy M. The effect of partial sleep deprivation on weight-lifting performance. Ergonomics 1994;37(1):107-115. [doi: 10.1080/00140139408963628] [PMID: 8112265].         [ Links ]

10. Simpson Simpson NS, Gibbs EL, Matheson GO. Optimizing sleep to maximize performance: implications and recommendations for elite athletes. Scand J Med Sci Sports 2017;27(3):266-274. [doi: 10.1111/sms.12703] [PMID: 27367265].         [ Links ]

11. Milewski MD, Skaggs DL, Bishop GA, Pace JL, Ibrahim DA, Wren TA, Barzdukas A. Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. J Pediatr Orthop 2014;34(2):129-133. [doi: 10.1097/BPO.0000000000000151] [PMID: 25028798].         [ Links ]

12. Horgan BG, Drew MK, Halson SL, Piromalli LE, Drinkwater EJ, Chapman DW, Haff GG. Impaired recovery is associated with increased injury and illness: A retrospective study of 536 female netball athletes. Scand J Med Sci Sports 2021;31(3):691-701. [doi: 10.1111/sms.13866] [PMID: 33124056].         [ Links ]

13. Daaloul H, Souissi N, Davenne D. Effects of Napping on Alertness, Cognitive, and Physical Outcomes of Karate Athletes. Med Sci Sports Exerc 2019;51(2):338-345. [doi: 10.1249/MSS.0000000000001786] [PMID: 30239491].         [ Links ]

14. Caia J, Scott TJ, Halson SL, Kelly VG. The influence of sleep hygiene education on sleep in professional rugby league athletes. Sleep Health 2018;4(4):364-368. [doi: 10.1016/j.sleh.2018.05.002] [PMID: 30031530]        [ Links ]

15. Duffield R, Murphy A, Kellett A, Reid M. Recovery from repeated on-court tennis sessions: combining cold-water immersion, compression, and sleep recovery interventions. Int J Sports Physiol Perform 2014;9(2):273-282. [doi: 10.1123/ijspp.2012-0359] [PMID: 23799825].         [ Links ]

16. Song Bonnar D, Bartel K, Kakoschke N, Lang C. Sleep interventions designed to improve athletic performance and recovery: A systematic review of current approaches. Sports Med 2018;48(3):683-703. [doi: 10.1007/s40279-017-0832-x] [PMID: 29352373].         [ Links ]

17. Cunha LA, Costa JA, Marques EA, Brito J, Lastella M, Figueiredo P. The impact of sleep interventions on athletic performance: A systematic review. Sports Med - Open 2023;9(1):58. [doi: 10.1186/s40798-023-00599-z] [PMID: 37462808].         [ Links ]

18. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. [doi: 10.1136/bmj.n71] [PMID: 33782057].         [ Links ]

19. McKay AKA, Stellingwerff T, Smith ES, Martin DT, Mujika I, Goosey-Tolfrey VL, et al. Defining training and performance caliber: A participant classification framework. Int J Sports Physiol Perform 2022;17(2):317-331. [doi: 10.1123/ijspp.2021-0451] [PMID: 34965513].         [ Links ]

20. Abernethy L, Bleakley C. Strategies to prevent injury in adolescent sport: a systematic review. Br J Sports Med 2007;41(10):627-638. [doi: 10.1136/bjsm.2007.035691] [PMID: 17496070].         [ Links ]

21. Driller MW, Lastella M, Sharp AP. Individualized sleep education improves subjective and objective sleep indices in elite cricket athletes: A pilot study. J Sports Sci 2019;37(17):2121-2125. [doi: 10.1080/02640414.2019.1616900] [PMID: 31076021].         [ Links ]

22. Dunican IC, Caldwell JA, Morgan D, Stewart A, Eastwood PR. An education intervention in a professional female basketball team and coaching staff improves sleep and alertness. Transleep latency Sports Med. 2021; 4: 419^27. [doi: 10.1002/tsm2.218].         [ Links ]

23. O'Donnell S, Driller M. Sleep-hygiene Education improves Sleep Indices in Elite Female Athletes. Int J Exerc Sci 2017;10:522-530. [doi: 10.70252/DNOL2901] [PMID: 28674597].         [ Links ]

24. Sargent C, Lastella M, Schwerdt S, Roach GD. An individualized intervention increases sleep duration in professional athletes. J Strength Cond Res 2021;35(12):3407-3413. [doi: 10.1519/jsc.0000000000004138] [PMID: 34570054].         [ Links ]

25. Tuomilehto H, Vuorinen VP, Penttilä E, et al. Sleep of professional athletes: Underexploited potential to improve health and performance. J Sports Sci 2017;35(7):704-710. [doi: 10.1080/02640414.2016.1184300] [PMID:27173843].         [ Links ]

26. Van Ryswyk E, Weeks R, Bandick L, et al. A novel sleep optimisation programme to improve athletes' well-being and performance. Eur J Sport Sci 2017;17(2):144-151. [doi: 10.1080/17461391.2016.1221470] [PMID:27574901].         [ Links ]

27. Jones MJ, Dawson B, Eastwood PR, et al. Influence of electronic devices on sleep and cognitive performance during athlete training camps. J Strength Cond Res 2021;35(6):1620-1627. [doi: 10.1519/jsc.0000000000002991] [PMID:30741866].         [ Links ]

28. Dunican IC, Martin D, Halson S, et al. The effects of the removal of electronic devices for 48 hours on sleep in elite Judo athletes. J Strength Cond Res 2017;31(10):2832-2839. [doi: 10.1519/JSC.0000000000001697] [PMID: 28081034].         [ Links ]

29. Whitworth-Turner C, Di Michele R, Muir I, Gregson W, Drust B. A shower before bedtime may improve the sleep onset latency of youth soccer players. Eur J Sport Sci 2017;17(9):1119-1128. [doi:10.1080/17461391.2017.1346147] [PMID:28691581].         [ Links ]

30. Aloulou A, Leduc C, Duforez F, et al. Effect of an innovative mattress and cryotherapy on sleep after an elite rugby match. Med Sci Sports Exerc 2020;52(12):2655-2662. [doi: 10.1249/mss.0000000000002403] [PMID:32472928].         [ Links ]

31. Souabni M, Hammouda O, Souabni M,et al. Nap improved game-related technical performance and physiological response during small-sided basketball game in professional players. Biol Sport 2023;40(2):389-397. [doi: 10.5114/biolsport.2023.116004] [PMID: 37077801].         [ Links ]

32. Swinbourne R, Miller J, Smart D, Dulson DK, Gill N. The Effects of Sleep Extension on Sleep, Performance, Immunity and Physical Stress in Rugby Players. Sports (Basel, Switzerland) 2018; 6(2), 42. [doi: 10.3390/sports6020042] [PMID: 29910346].         [ Links ]

33. Lastella M, Roach GD, Halson SL, Sargent C. The effects of cold water immersion on the amount and quality of sleep obtained by elite cyclists during a simulated hill climbing tour. Sport Sci Health 2019;15(1):223-228. [doi: 10.1007/s11332-018-0522-6].         [ Links ]

34. Robey E, Dawson B, Halson S,et al. Effect of evening postexercise cold water immersion on subsequent sleep. Med Sci Sports Exerc 2013;45(7):1394-1402. [doi: 10.1249/MSS.0b013e318287f321] [PMID:23377833].         [ Links ]

35. Douzi W, Dupuy O, Theurot D, Boucard G, Dugué B. Partial-body cryostimulation after training improves sleep quality in professional soccer players. BMC Res Notes 2019;12(1):141. [doi: 10.1186/s13104-019-4172-9] [PMID:30876470].         [ Links ]

36. Schaal K, Y Le Meur, Louis J, et al. Whole-body cryostimulation limits overreaching in elite synchronized swimmers. Med Sci Sports Exerc 2015;47(7):1416-1425. [doi: 10.1249/mss.0000000000000546] [PMID:25314578].         [ Links ]

37. Rosa JPP, Silva A, Rodrigues DF, et al. Effect of bright light therapy on delayed sleep/wake cycle and reaction time of athletes participating in the Rio 2016 Olympic Games. Chronobiol Int 2018;35(8):1095-1103. [doi: 10.1080/07420528.2018.1459660] [PMID:29658807].         [ Links ]

38. Thompson A, Batterham AM, Jones H, Gregson W, Scott D, Atkinson G. The practicality and effectiveness of supplementary bright light for reducing jet-lag in elite female athletes. Int J Sports Med 2013;34(7):582-589. [doi: 10.1055/s-0032-1331160] [PMID:23258609].         [ Links ]

39. Zhao J, Tian Y, Nie J, Xu J, Liu D. Red light and the sleep quality and endurance performance of Chinese female basketball players. J Athl Train 2012;47(6):673-678. [doi: 10.4085/1062-6050-47.6.08] [PMID:23182016].         [ Links ]

40. Harnett JE, Pyne DB, McKune AJ, Penm J, Pumpa KL. Probiotic supplementation elicits favourable changes in muscle soreness and sleep quality in rugby players. J Sci Med Sport 2021;24(2):195-199. [doi: 10.1016/j.jsams.2020.08.005] [PMID: 32847731].         [ Links ]

41. Quero CD, Manonelles P, Fernández M, et al. Differential health effects on inflammatory, immunological and stress parameters in professional soccer players and sedentary individuals after consuming a synbiotic. A triple-blinded, randomized, placebo-controlled pilot study. Nutrients 2021; 13(4), 1321. [doi: 10.3390/nu13041321] [PMID: 33923663].         [ Links ]

42. Gratwicke M, Miles KH, Clark B, Pumpa KL. The effect of α-lactalbumin consumption on sleep quality and quantity in female rugby union athletes: a field-based study. Biol Sport 2023;40(2):449-455. [doi: 10.5114/biolsport.2023.116002] [PMID:37077794].         [ Links ]

43. Doherty R, Madigan S, Nevill A, Warrington G, Ellis JG. The impact of kiwifruit consumption on the sleep and recovery of elite athletes. Nutrients 2023;15(10):2274. [doi: 10.3390/nu15102274] [PMID: 37242157].         [ Links ]

44. Chung J, Choi M, Lee K. Effects of short-term intake of Montmorency tart Cherry Juice on sleep quality after intermittent exercise in elite female field hockey players: A randomized controlled trial. Int J Environ Res Public Health 2022;19(16), 10272. [doi: 10.3390/ijerph191610272][PMID:36011907].         [ Links ]

45. Abeln V, Kleinert J, Strüder HK, Schneider S. Brainwave entrainment for better sleep and post-sleep state of young elite soccer players - a pilot study. Eur J Sport Sci 2014;14(5):393-402. [doi: 10.1080/17461391.2013.819384] [PMID: 23862643].         [ Links ]

46. Dekker MK, van den Berg BR, Denissen AJ, Sitskoorn MM, van Boxtel GJ. Feasibility of eyes open alpha power training for mental enhancement in elite gymnasts. J Sports Sci 2014;32(16):1550-1560. [doi: 10.1080/02640414.2014.906044] [PMID: 24784756].         [ Links ]

47. Rijken NH, Soer R, de Maar E,et al. Increasing performance of professional soccer players and elite track and field athletes with peak performance training and biofeedback: A pilot study. Appl Psychophysiol Biofeedback 2016;41(4):421-430. [doi: 10.1007/s10484-016-9344-y] [PMID:27761664].         [ Links ]

48. Jones BJ, Kaur S, Miller M, Spencer RMC. Mindfulness-based stress reduction benefits psychological well-being, sleep quality, and athletic performance in female collegiate rowers. Front Psychol 2020;11. [doi: 10.3389/fpsyg.2020.572980] [PMID:33071908].         [ Links ]

49. Kennedy AB, Patil N, Trilk JL. 'Recover quicker, train harder, and increase flexibility': massage therapy for elite paracyclists, a mixed-methods study. BMJ Open Sport Exerc Med 2018;4(1):e000319. [doi: 10.1136/bmjsem-2017-000319] [PMID: 29387449].         [ Links ]

50. Nédélec M, Halson S, Delecroix B, Abaidia AE, Ahmaidi S, Dupont G. Sleep hygiene and recovery strategies in elite soccer players. Sports Med 2015;45(11):1547-1559. [doi: 10.1007/s40279-015-0377-9] [PMID: 26275673].         [ Links ]

51. Al Haddad H, Laursen P, Didier C, Lemaître F, Ahmaidi S, Buchheit M. Effect of cold or thermoneutral water immersion on post-exercise heart rate recovery and heart rate variability indices. Auton Neurosci 2010;156:111-116. [doi: 10.1016/j.autneu.2010.03.017] [PMID:20403733].         [ Links ]

52. Al Haddad H, Parouty J, Buchheit M. Effect of daily cold water immersion on heart rate variability and subjective ratings of well-being in highly trained swimmers. Int J Sports Physiol Perform 2012;7(1):33-38. [doi: 10.1123/ijspp.7.1.33] [PMID:21941017].         [ Links ]

53. Lovato N, Lack L. Circadian phase delay using the newly developed re-timer portable light device. Sleep Biol Rhythms 2016;14(2):157-164. [doi: 10.1007/s41105-015-0034-6].         [ Links ]

54. Touitou Y, Reinberg A, Touitou D. Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption. Life Sci 2017;173:94-106. [doi: 10.1016/j.lfs.2017.02.008] [PMID:28214594]        [ Links ]

55. Yeager RL, Oleske DA, Sanders RA, Watkins JB, 3rd, Eells JT, Henshel DS. Melatonin as a principal component of red light therapy. Med Hypotheses 2007;69(2):372-376. [doi: 10.1016/j.mehy.2006.12.041] [PMID:17321060].         [ Links ]

56. Buysse DJ, Reynolds CF, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh sleep quality index: A new instrument for psychiatric practice and research. Psychiatry Res 1989;28(2):193-213. [doi: 10.1016/0165-1781(89)90047-4] [PMID:2748771].         [ Links ]

57. Walsh NP, Halson SL, Sargent C, Roach GD, Nédélec M, Gupta L, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med 2021;55:356-368. [doi: 10.1136/bjsports-2020-102025] [PMID:33144349].         [ Links ]

58. Fuller KL, Juliff L, Gore CJ, Peiffer JJ, Halson SL. Software thresholds alter the bias of actigraphy for monitoring sleep in team-sport athletes. JSAMS 2017;20(8):756-760. [doi: 10.1016/j.jsams.2016.11.021] [PMID:28189461].         [ Links ]

59. Irwin C, McCartney D, Desbrow B, Khalesi S. Effects of probiotics and paraprobiotics on subjective and objective sleep metrics: a systematic review and meta-analysis. Eur J Clin Nutr 2020;74(11):1536-1549. [doi: 10.1038/s41430-020-0656-x] [PMID:32433598].         [ Links ]

60. Wong RK, Yang C, Song G-H, Wong J, Ho K-Y. Melatonin regulation as a possible mechanism for probiotic (VSL#3) in irritable bowel syndrome: A randomized double-blinded placebo study. Dig Dis Sci 2015;60(1):186-194. [doi: 10.1007/s10620-014-3299-8] [PMID:25092036].         [ Links ]

61. Howatson G, McHugh MP, Hill J, Brouner J, Jewell A, Van Someren KA, et al. Influence of tart cherry juice on indices of recovery following marathon running. Scand J Med Sci Sports 2010;20(6):843-852. [doi: 10.1111/j.1600-0838.2009.01005.x][PMID:19883392].         [ Links ]

62. Lin HH, Tsai PS, Fang SC, Liu JF. Effect of kiwifruit consumption on sleep quality in adults with sleep problems. Asia Pac J Clin Nutr 2011;20(2):169-174. [PMID:21669584].         [ Links ]

63. Pigeon WR, Carr M, Gorman C, Perlis ML. Effects of a tart cherry juice beverage on the sleep of older adults with insomnia: a pilot study. J Med Food 2010;13(3):579-583. [doi: 10.1089/jmf.2009.0096] [PMID:20438325].         [ Links ]

64. Kelly G. Folates: supplemental forms and therapeutic applications. Altern Med Rev 1998;3(3):208-220. [PMID:9630738].         [ Links ]

65. Connolly D, Mc Hugh M, Padilla-Zakour O. The efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. Br J Sports Med, 40(8): 679-683. [doi: 10.1136/bjsm.2005.025429][PMID:16790484].         [ Links ]

66. McCormick R, Peeling P, Binnie M, Dawson B, Sim M. Effect of tart cherry juice on recovery and next day performance in well-trained Water Polo players. J Int Soc Sports Nutr 2016; 13(1). [doi: 10.1186/s12970-016-0151-x] [PMID:27895542].         [ Links ]

67. Thompson Markus CR, Olivier B, Panhuysen GE, Van der Gugten J, Alles MS, Tuiten A, et al. The bovine protein α-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress. Am J Clin Nutr 2000;71(6):1536-1544. [doi: 10.1093/ajcn/71.6.1536][PMID:10837296].         [ Links ]

68. J Halson SL. Sleep in elite athletes and nutritional interventions to enhance sleep. Sports Med 2014;44(Suppl 1):13-23. [doi: 10.1007/s40279-014-0147-0] [PMID:24791913].         [ Links ]

69. De Pauw K, Roelands B, Marusic U, Tellez HF, Knaepen K, Meeusen R. Brain mapping after prolonged cycling and during recovery in the heat. J Appl Physiol 2013;115(9):1324-3131. [doi: 10.1152/japplphysiol.00633.2013] [PMID:23990240].         [ Links ]

70. Wilson E. Preliminary study of the Hemi-Sync sleep processor. Colorado Association for Psychophysiologic Research 1990.         [ Links ]

71. Rhodes L. Use of the Hemi-Sync super sleep tape with a preschool-aged child. Hemi-Sync Journal 1993;11(4):4-5.         [ Links ]

72. Beaven CM, Cook C, Gray D, Downes P, Murphy I, Drawer S, et al. Electrostimulation's enhancement of recovery during a rugby preseason. Int J Sports Physiol Perform 2013; 8(1): 92-98. [doi: 10.1123/ijspp.8.1.92] [PMID:23302142].         [ Links ]

 

 

Correspondence:
Sharaisha Bilgoe
s.c.bilgoe@amsterdamumc.nl