Sleep Behaviors and Nutritional Knowledge in Amateur and Professional Combat Sport Athletes.

ABSTRACT: Dunican, IC, Galpin, A, Turner, M, and Reale, R. Sleep behaviors and nutritional knowledge in amateur and professional combat sport athletes. J Strength Cond Res XX(X): 000-000, 2024-Combat sports is a term applied to various competitive contact sports involving 2 competitors engaging in a bout or contest under a specific ruleset. Little is known about combat sports athletes' sleep and nutritional knowledge. This study aimed to assess (a) sleep behaviors, (b) alcohol and shiftwork disorders, and (c) the nutritional knowledge of combat sports athletes. Subjects completed various demographic questions and estimations of their weight management practices and validated surveys, including the Athlete Sleep Behavior Questionnaire, Shiftwork Disorder (SWD) Screening Questionnaire, Alcohol Use Disorders Identification Test, and the Abridged Nutrition for Sports Knowledge Questionnaire. A total of 844 combat sports athletes completed the survey, 79% male, height of 177 ± 10 (cm), and body mass of 79 ± 15 (kg). Subjects were categorized into their specific combat sport type (e.g., boxing or Brazilian jiu-jitsu [BJJ]) and by their level (professional or amateur). Sleep quality was average for all combat sport types and risk prevalence of shiftwork disorder at 11%. Mann-Whitney U tests revealed that amateurs, compared with professional strikers (p = 0.046, CLES = 0.80), boxers (p = 0.01, CLES = 0.78), and BJJ (p = 0.046, CLES = 0.61) athletes, consumed significantly more alcohol. A Friedman test showed significant (p < 0.001, W = 0.51) differences in weight between time points, with most combat sports athletes reducing weight for competition. An overall nutritional knowledge average of 55% was reported. This study highlights a critical gap in the knowledge and practices of combat sports athletes in relation to sleep behaviors and disorders, alcohol consumption, and nutritional knowledge, emphasizing the need for targeted educational interventions.

Around the world in 16 days: the effect of long-distance transmeridian travel on the sleep habits and behaviours of a professional Super Rugby team.

There is a scarcity of research examining the effects of long-distance transmeridian travel (LDTT) on the sleep and match performance of team sport players. To address this, 37 elite male rugby union players from a Super Rugby team undertaking LDTT were recruited. The participants completed validated sleep questionnaires and wore a wrist-worn activity monitor (Readiband™) during a Super Rugby season (including during periods of LDTT crossing 5, 6, and 13 time-zones) to ascertain objective measures of sleep. Sleep measures were compared using mixed model analysis to ascertain the effects of competition and LDTT on sleep. Total sleep time (TST) increased in the days prior to matches, and decreased following matches (accompanied by a later time at sleep onset), particularly when next-day early-morning flights were required. TST was decreased when sleep was attempted during LDTT, except for in the last travel bout where players napped in addition to achieving night-time sleep. TST was also reduced for the night immediately following LDTT, except for in Condition 3 where players delayed wake time and also achieved naps. This study exemplifies the challenges that team-sport athletes face in obtaining regular sleep when LDTT is required.

Influence of Electronic Devices on Sleep and Cognitive Performance During Athlete Training Camps.

ABSTRACT: Jones, MJ, Dawson, B, Eastwood, PR, Halson, SL, Miller, J, Murray, K, Dunican, IC, Landers, GJ, and Peeling, P. Influence of electronic devices on sleep and cognitive performance during athlete training camps. J Strength Cond Res 35(6): 1620-1627, 2021-This study investigated the effects of removing athletes' electronic devices in the evening on sleep and performance during training camps. Water polo athletes (n = 26) attending a 7-night training camp (study 1) and triathletes (n = 23) attending a 4-night training camp (study 2) were randomly allocated to a no-device group (no electronic devices could be used after dinner or overnight; ND) or control group (unrestricted electronic device use; CON). Sleep was monitored through wrist actigraphy. The ND group completed a questionnaire measuring anxiety related to being unable to use electronic devices ("nomophobia"). Triathletes also completed a psychomotor vigilance test (PVT) at the start and end of camp. Water polo ND athletes went to bed earlier and spent longer time in bed than CON on the first night, but not on other nights. In triathletes, sleep quantity was not different between groups on any night. No statistically significant differences were observed for changes in nomophobia from the first to the last night of camp. No differences in PVT performance were observed between ND and CON triathletes. In conclusion, removal of evening electronic devices does not improve sleep quantity or cognitive performance in athletes during short-duration (4-7 nights) training camps.

No familiarization or 'first-night effect' evident when monitoring sleep using wrist actigraphy.

Anecdotal reports suggest that the first night of sleep monitoring using a wrist-actigraphy monitor may result in impaired sleep when compared to subsequent nights, due to increased levels of anxiety and awareness of being monitored. This phenomenon has been seen in sleep laboratories with polysomnographic monitoring. However, this is yet to be established for wrist actigraphy monitoring in the research literature. A total of 240 healthy adult participants (177 male, 63 female; age range, 18-35 years) had their sleep monitored using wrist actigraphy over a period of five nights of 'normal' sleep (1,200 nights of data). Sleep variables including sleep latency, wake episodes, wake after sleep onset, awakenings per hour, time in bed, total sleep time and sleep efficiency % were evaluated across all nights of sleep. Comparisons were made using repeated measures ANOVAs, mean differences, range of mean differences, intraclass correlation coefficients (ICC) and Cohen's d effect sizes. There were no significant differences between the first night and subsequent nights for any of the measured sleep variables (p < .05) and all differences were associated with trivial effect sizes (d < 0.2). ICCs ranged from 0.35 to 0.62 (low to moderate). Despite claims of impaired sleep during the first night of sleep monitoring, our results indicate that a familiarization period may not be necessary when monitoring sleep in healthy participants using wrist actigraphy. However, the response is highly individual and further research is required to assess personality traits and responses to sleep monitoring.

Evening electronic device use and sleep patterns in athletes.

The present study aimed to investigate pre-sleep behaviours (including evening electronic device use) and sleep quantity in well-trained athletes. Seventy well-trained athletes (44 females, 26 males) aged 21 ± 4 y from a range of team and individual sports were asked to complete an online sleep diary for 7 days. The sleep diary included questions about pre-sleep behaviours (e.g. napping, caffeine intake), electronic device use in the 2 h prior to bedtime (e.g. type of device and duration of use) and sleep (e.g. time in bed, sleep onset latency). On average, athletes spent 8:20 ± 1:21 h in bed each night. Associations between age, time in bed and sleepiness suggested that younger athletes spent more time in bed (B = -0.05, p = 0.001) but felt sleepier (r = -0.32, p < 0.01) than older athletes. On average, athletes mostly used electronic devices for 0-30 min prior to sleep. The use of multiple devices in the evening was associated with more perceived difficulty in falling asleep (B = 0.22, p = 0.03), but no associations existed with other sleep variables. In summary, younger athletes may require later start times or improved sleep quality to resolve excessive sleepiness.

Prevalence of sleep disorders and sleep problems in an elite super rugby union team.

The aim of this study was to determine the prevalence of sleep disorders in an elite rugby union team using in-laboratory polysomnography (PSG) and sleep questionnaires. Twenty-five elite rugby union players underwent a night of PSG during the "off-season" of the Super Rugby competition to assess their sleep. Of interest were measurements that detected the presence of obstructive sleep apnea (OSA; apnea-hypopnea index ≥5 events/hr) and the presence of moderate-severe periodic leg movements during sleep (PLMs; ≥15 events/hr). Players completed sleep-related questionnaires to assess daytime sleepiness, perception of insomnia, risk of OSA, and the presence of restless legs syndrome (RLS) and underwent basic anthropometric assessments including body mass index and neck circumference. OSA was present in 24% (n=6) of players and PLMs ≥15 events/hr in 12% (n=3). Questionnaire responses showed that all players had insomnia defined subthreshold insomnia and excessive daytime sleepiness, two players were identified as being at risk for OSA and none were classified as having RLS. In conclusion, sleep disorders and excessive sleepiness are common in elite rugby union players. A process to identify and manage sleep disorders should be considered by teams to optimise their physical recovery, athletic performance and to safeguard their health.

The psychomotor vigilance test: a comparison of different test durations in elite athletes.

The 10-min Psychomotor Vigilance Test (PVT-10) is regarded as the gold-standard for assessing vigilant attention following sleep loss; however, other studies have investigated whether shorter versions of the test elicit similar results to the PVT-10. The present study compared the PVT-10 with 3-min (PVT-3) and 5-min (PVT-5) versions of the test in elite female basketball players. Athletes performed all three tests in the morning and evening for seven consecutive days. Response speed (mean reciprocal reaction time; mean 1/RT), number of errors and number of lapses were determined for each test and time point. The PVT-3 elicited significantly faster response speeds than the other two tests (p < 0.01), while the PVT-5 and PVT-10 were not different. The PVT-10 resulted in more lapses than the PVT-5, followed by the PVT-3, with all tests being significantly different to each other (p < 0.01). In conclusion, while the PVT-5 and PVT-10 were generally similar for response speed, the PVT-3 did not produce results comparable with the PVT-10 for response speed, lapses or errors, and should therefore not be used interchangeably. Further research is required to determine whether the shorter tests are a suitable replacement for the PVT-10 in professional basketball players.

The Effect of Water Loading on Acute Weight Loss Following Fluid Restriction in Combat Sports Athletes.

Novel methods of acute weight loss practiced by combat sport athletes include "water loading," the consumption of large fluid volumes for several days prior to restriction. We examined claims that this technique increases total body water losses, while also assessing the risk of hyponatremia. Male athletes were separated into control (n = 10) and water loading (n = 11) groups and fed a standardized energy-matched diet for 6 days. Days 1-3 fluid intake was 40 and 100 ml/kg for control and water loading groups, respectively, with both groups consuming 15 ml/kg on Day 4 and following the same rehydration protocol on Days 5 and 6. We tracked body mass (BM), urine sodium, urine specific gravity and volume, training-related sweat losses and blood concentrations of renal hormones, and urea and electrolytes throughout. Physical performance was assessed preintervention and postintervention. Following fluid restriction, there were substantial differences between groups in the ratio of fluid input/output (39%, p < .01, effect size = 1.2) and BM loss (0.6% BM, p = .02, effect size = 0.82). Changes in urine specific gravity, urea and electrolytes, and renal hormones occurred over time (p < .05), with an interaction of time and intervention on blood sodium, potassium, chloride, urea, creatinine, urine specific gravity, and vasopressin (p < .05). Measurements of urea and electrolyte remained within reference ranges, and no differences in physical performance were detected over time or between groups. Water loading appears to be a safe and effective method of acute BM loss under the conditions of this study. Vasopressin-regulated changes in aquaporin channels may potentially partially explain the mechanism of increased body water loss with water loading.

The Effects of the Removal of Electronic Devices for 48 Hours on Sleep in Elite Judo Athletes.

This study examined the effects of evening use of electronic devices (i.e., smartphones, etc.) on sleep quality and next-day athletic and cognitive performance in elite judo athletes. Over 6 consecutive days and nights, 23 elite Australian judo athletes were monitored while attending a camp at the Australian Institute of Sport (AIS). In 14 athletes, all electronic devices were removed on days 3 and 4 (i.e., for 48 hours: the "device-restricted group"), whereas 9 were permitted to use their devices throughout the camp (the "control group"). All athletes wore an activity monitor (Readiband) continuously to provide measures of sleep quantity and quality. Other self-reported (diary) measures included time in bed, electronic device use, and rate of perceived exertion during training periods. Cognitive performance (Cogstate) and physical performance (single leg triple hop test) were also measured. When considering night 2 as a "baseline" for each group, removal of electronic devices on nights 3 and 4 (device-restricted group) resulted in no significant differences in any sleep-related measure between the groups. When comparing actigraphy-based measures of sleep to subjective measures, all athletes significantly overestimated sleep duration by 58 ± 85 minutes (p = 0.001) per night and underestimated time of sleep onset by 37 ± 72 minutes (p = 0.001) per night. No differences in physical or cognitive function were observed between the groups. CONCLUSION: This study has shown that the removal of electronic devices for a period of two nights (48 hours) during a judo camp does not affect sleep quality or quantity or influence athletic or cognitive performance.

Pyjamas, Polysomnography and Professional Athletes: The Role of Sleep Tracking Technology in Sport.

Technological advances in sleep monitoring have seen an explosion of devices used to gather important sleep metrics. These devices range from instrumented 'smart pyjamas' through to at-home polysomnography devices. Alongside these developments in sleep technologies, there have been concomitant increases in sleep monitoring in athletic populations, both in the research and in practical settings. The increase in sleep monitoring in sport is likely due to the increased knowledge of the importance of sleep in the recovery process and performance of an athlete, as well as the well-reported challenges that athletes can face with their sleep. This narrative review will discuss: (1) the importance of sleep to athletes; (2) the various wearable tools and technologies being used to monitor sleep in the sport setting; (3) the role that sleep tracking devices may play in gathering information about sleep; (4) the reliability and validity of sleep tracking devices; (5) the limitations and cautions associated with sleep trackers; and, (6) the use of sleep trackers to guide behaviour change in athletes. We also provide some practical recommendations for practitioners working with athletes to ensure that the selection of such devices and technology will meet the goals and requirements of the athlete.

Fatigue Risk Management Systems Diagnostic Tool: Validation of an Organizational Assessment Tool for Shift Work Organizations.

Background: This study aimed to determine and define the elements of an Fatigue Risk Management System (FRMS) diagnostic tool to assist an organization in systematically assessing its level of implementation of an FRMS. Methods: A modified Delphi process was used involving 16 participants with expertise in sleep science, chronobiology, and fatigue risk management within occupational settings. The study was undertaken in two stages 1) review of elements and definitions; 2) review of statements for each element. Each stage involved an iterative process, and a consensus rule of ≥ 60% was applied to arrive at a final list of elements, definitions, and statements. Results: Stage 1: a review of elements (n = 12) and definitions resulted in a final list of 14 elements and definitions with a consensus of ≥ 60% achieved after 2 Delphi rounds. Stage 2: a review of statements (n = 131) resulted in a final list of 119 statements with a consensus of ≥ 60% achieved after 2 Delphi rounds. Conclusion: The final FRMS diagnostic tool will enable an organization to systematically assess the level of implementation of their current FRMS and identify gaps and opportunities to reduce risk.

Digging for data: How sleep is losing out to roster design, sleep disorders, and lifestyle factors.

Shift workers employed at a remote mining operation may experience sleep loss, impaired alertness, and consequently negative health and safety outcomes. This study determined the sleep behaviors and prevalence of risk for sleep disorders among shift workers; and quantified alertness for a roster cycle. Sleep duration was significantly less following; night shift by 77 ± 7 min and day shift by 30 ± 7 min. The wake after sleep onset was less by 23 ± 3 min for night shifts and 22 ± 3 min for day shifts (p < 0.05 for all). The prevalence of risk for sleep apnea was 31%, insomnia was 8%, and shiftwork disorder was 44%. Average alertness for all working hours was 75%. Shiftwork in remote mining operations is a significant factor that leads to sleep loss and reduced alertness, which is exacerbated by the high prevalence of risk for sleep disorders.

Evaluation of a Brief Sleep Intervention Designed to Improve the Sleep, Mood, and Cognitive Performance of Esports Athletes.

This study evaluated a brief sleep intervention designed to improve the sleep, mood, and cognitive performance of professional electronic sports (esports) athletes from three major esports regions (i.e., Asia, North America, and Oceania). Fifty-six esports athletes from South Korea (N = 34), the United States (N = 7), and Australia (N = 15) completed the study. Participants completed an initial 2-week pre-intervention phase to establish a baseline, followed by a 2-week intervention phase that involved a group sleep education class, 1:1 session with a trained clinical psychologist, and daily biofeedback. A wrist activity monitor and daily sleep diary were used to monitor sleep during both phases, while at pre- and post-intervention, participants completed a battery of sleep and mood questionnaires and underwent cognitive performance testing. Sleep knowledge increased from pre- to post-intervention (d = 0.83 [95% CI −1.21, −0.43], p =< 0.001), while there were modest improvements in sleep diary estimates (i.e., sleep onset latency (Mdiff = −2.9 min, p = 0.02), sleep onset time (Mdiff = −12 min, p = 0.03), and sleep efficiency (Mdiff = 1.1%, p = 0.004)) and wrist activity monitor estimates (i.e., sleep onset time (Mdiff = −18 min, p = 0.01)). Insomnia severity scores decreased significantly (d = 0.47 [95% CI 0.08, 0.84], p = 0.001), while sleepiness scores increased but not meaningfully (d = 0.23 [95% CI −0.61, 0.14], p = 0.025). However, there was no significant change in mood (i.e., depression and anxiety) or cognitive performance scores (i.e., mean reaction time or lapses). Sleep interventions for esports athletes require further investigation. Future research should examine whether a stepped-care model, whereby increasing therapeutic input is provided as needed, can optimize sleep, mood, and cognitive performance outcomes.

Comment on Gratwicke et al. Nutritional Interventions to Improve Sleep in Team-Sport Athletes: A Narrative Review. Nutrients 2021, 13, 1586.

We recently read with great interest the recent paper by Gratwicke, M et al. (2021) [...].

Dietary Fibre Intervention for Gut Microbiota, Sleep, and Mental Health in Adults with Irritable Bowel Syndrome: A Scoping Review.

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder affecting 4-5% of the global population. This disorder is associated with gut microbiota, diet, sleep, and mental health. This scoping review therefore aims to map existing research that has administrated fibre-related dietary intervention to IBS individuals and reported outcomes on at least two of the three following themes: gut microbiota, sleep, and mental health. Five digital databases were searched to identify and select papers as per the inclusion and exclusion criteria. Five articles were included in the assessment, where none reported on all three themes or the combination of gut microbiota and sleep. Two studies identified alterations in gut microbiota and mental health with fibre supplementation. The other three studies reported on mental health and sleep outcomes using subjective questionnaires. IBS-related research lacks system biology-type studies targeting gut microbiota, sleep, and mental health in patients undergoing diet intervention. Further IBS research is required to explore how human gut microbiota functions (such as short-chain fatty acids) in sleep and mental health, following the implementation of dietary pattern alteration or component supplementation. Additionally, the application of objective sleep assessments is required in order to detect sleep change with more accuracy and less bias.

Sleep and Performance during a Preseason in Elite Rugby Union Athletes.

BACKGROUND: Preseason training optimises adaptations in the physical qualities required in rugby union athletes. Sleep can be compromised during periods of intensified training. Therefore, we investigated the relationship between sleep quantity and changes in physical performance over a preseason phase in professional rugby union athletes. METHODS: Twenty-nine professional rugby union athletes (Mean ± SD, age: 23 ± 3 years) had their sleep duration monitored for 3 weeks using wrist actigraphy. Strength and speed were assessed at baseline and at week 3. Aerobic capacity and body composition were assessed at baseline, at week 3 and at week 5. Participants were stratified into 2 groups for analysis: <7 h 30 min sleep per night (LOW, n = 15) and >7 h 30 min sleep per night (HIGH, n = 14). RESULTS: A significant group x time interaction was determined for aerobic capacity (p = 0.02, d = 1.25) at week 3 and for skinfolds at week 3 (p < 0.01, d = 0.58) and at week 5 (p = 0.02, d = 0.92), in favour of the HIGH sleep group. No differences were evident between groups for strength or speed measures (p ≥ 0.05). CONCLUSION: This study highlights that longer sleep duration during the preseason may assist in enhancing physical qualities including aerobic capacity and body composition in elite rugby union athletes.

Sleep Characteristics and Mood of Professional Esports Athletes: A Multi-National Study.

Esports is becoming increasingly professionalized, yet research on performance management is remarkably lacking. The present study aimed to investigate the sleep and mood of professional esports athletes. Participants were 17 professional esports athletes from South Korea (N = 8), Australia (N = 4), and the United States (N = 5) who played first person shooter games (mean age 20 ± 3.5 years, 100% male). All participants wore a wrist-activity monitor for 7-14 days and completed subjective sleep and mood questionnaires. Participants had a median total sleep time of 6.8 h and a sleep efficiency of 86.4% per night. All participants had significantly delayed sleep patterns (median sleep onset 3:43 a.m. and wake time 11:24 a.m.). Participants had a median sleep onset latency of 20.4 min and prolonged wake after sleep onset of 47.9 min. Korean players had significantly higher depression scores compared to the other groups (p < 0.01) and trained longer per day than the Australian or United States teams (13.4 vs. 4.8 vs. 6.1 h, respectively). Depression scores were strongly correlated with number of awakenings, wake after sleep onset, and daily training time (p < 0.05). As the first pilot sleep study in the esports field, this study indicates that esports athletes show delayed sleep patterns and have prolonged wake after sleep onset. These sleep patterns may be associated with mood (depression) and training time. Sleep interventions designed specifically for esports athletes appear warranted.

The effect of sleep restriction on cognitive performance in elite cognitive performers: a systematic review.

STUDY OBJECTIVES: To synthesize original articles exploring the effects of sleep restriction on cognitive performance specifically for Elite Cognitive Performers, i.e. those who engage in cognitively demanding tasks with critical or safety-critical outcomes in their occupation or area of expertise. METHODS: Backward snowballing techniques, gray literature searches, and traditional database searches (Embase, MEDLINE, Web of Science, Google Scholar, PSYCinfo, and SportDiscus) were used to obtain relevant articles. A quality assessment was performed, and the risk of training effects was considered. Results were narratively synthesized. Fourteen articles fit the criteria. Cognitive outcomes were divided into three categories defined by whether cognitive demands were "low-salience," "high-salience stable," or "high-salience flexible." RESULTS: Low-salience tests (i.e. psychomotor vigilance tasks & serial reaction tests), mainly requiring vigilance and rudimentary attentional capacities, were sensitive to sleep restriction, however, this did not necessarily translate to significant performance deficits on low-salience occupation-specific task performance. High-salience cognitive outcomes were typically unaffected unless when cognitive flexibility was required. CONCLUSIONS: Sleep restriction is of particular concern to occupations whereby individuals perform (1) simple, low-salience tasks or (2) high-salience tasks with demands on the flexible allocation of attention and working memory, with critical or safety-critical outcomes.

Managing Travel Fatigue and Jet Lag in Athletes: A Review and Consensus Statement.

Athletes are increasingly required to travel domestically and internationally, often resulting in travel fatigue and jet lag. Despite considerable agreement that travel fatigue and jet lag can be a real and impactful issue for athletes regarding performance and risk of illness and injury, evidence on optimal assessment and management is lacking. Therefore 26 researchers and/or clinicians with knowledge in travel fatigue, jet lag and sleep in the sports setting, formed an expert panel to formalise a review and consensus document. This manuscript includes definitions of terminology commonly used in the field of circadian physiology, outlines basic information on the human circadian system and how it is affected by time-givers, discusses the causes and consequences of travel fatigue and jet lag, and provides consensus on recommendations for managing travel fatigue and jet lag in athletes. The lack of evidence restricts the strength of recommendations that are possible but the consensus group identified the fundamental principles and interventions to consider for both the assessment and management of travel fatigue and jet lag. These are summarised in travel toolboxes including strategies for pre-flight, during flight and post-flight. The consensus group also outlined specific steps to advance theory and practice in these areas.