The effect of α-lactalbumin consumption on sleep quality and quantity in female rugby union athletes: a field-based study.

This double-blind randomised placebo-controlled trial aimed to investigate the effects of α-lactalbumin consumption on sleep quality and quantity in female rugby union athletes during a competition season. Eighteen semi-professional female rugby union players (age 23.8 ± 5.2 y; mean ± SD) wore wrist actigraphy watches for four seven-day blocks corresponding to the pre-season, a home game, a bye week (i.e. no competition game scheduled) and an away game. Participants consumed either an α-lactalbumin (α-LAC), or placebo drink (PLA) every night two hours before bed for the duration of the season. Generalised linear mixed models were used to investigate the effects of the nutritional intervention on sleep variables (total sleep time, sleep efficiency (SE), sleep onset latency (SOL) and wake after sleep onset) over the duration of the season. There was a significant condition by period interaction effect on SOL (p = 0.01). While similar at baseline (23.3 ± 16.3 and 23.2 ± 18.9 min α-LAC and placebo respectively) and for the home game (22.4 ± 17.6 and 19.3 ± 14.9 min α-LAC and placebo respectively), SOL was reduced in the α-LAC group for the bye (11.6 ± 13.4 min) and away game (17.0 ± 11.5 min; p = 0.045). In comparison, SOL remained unchanged in the PLA group (bye 21.2 ± 17.3 and away 22.5 ± 18.5 min). Pre-sleep α-lactalbumin consumption improved SOL in a semi-professional female team-sport cohort. Thus, α-lactalbumin could be utilised by athletes to support sleep during a competitive season.

What are the sleep characteristics of elite female athletes? A systematic review with meta-analysis.

With the recent growth in female sport, practitioners need to be able to provide specific support to female athletes to ensure their sleep, health and athletic performance are optimised. Examine the patterns, duration and quality of sleep among elite female athletes, and consider the impact of situational challenges and their effects on the sleep of elite female athletes. Data was located through a search of SPORTDiscus, MEDLINE and Scopus from inception up to May 2021. Studies needed to be peer-reviewed research reporting quantitative sleep outcomes for female athletes ≥ 18 years of age and competing at a predefined elite level. A meta-analysis was performed on habitual sleep outcomes (e.g. total sleep time [TST] and sleep efficiency [SE]) measured with actigraphy. A total of 38 studies were included. Meta-analysis showed habitual TST (n = 14) was 7.8 h [7.4, 8.2] (mean [95% CI]), and SE was 86.7% [84.7, 88.6], with high variability among studies (I2 = 97.8-98.2%). Subjective sleep complaints are common before a competition, as do post-training sleep disturbances (63% studies report TST decrease), and post-competition sleep disturbances (75% studies report TST decrease). Female athletes achieve satisfactory objective sleep quantity and quality during habitual periods, but experience sleep disturbances pre- and post-situational challenges. There is high variability of objective sleep outcomes, demonstrating the individual nature of habitual female athlete sleep. Overall, future research must focus on optimising the sleep appraisal methods and creating high-quality study designs in a broader number of sports.

Facial feature tracking: a psychophysiological measure to assess exercise intensity?

The primary aim of this study was to determine whether facial feature tracking reliably measures changes in facial movement across varying exercise intensities. Fifteen cyclists completed three, incremental intensity, cycling trials to exhaustion while their faces were recorded with video cameras. Facial feature tracking was found to be a moderately reliable measure of facial movement during incremental intensity cycling (intra-class correlation coefficient = 0.65-0.68). Facial movement (whole face (WF), upper face (UF), lower face (LF) and head movement (HM)) increased with exercise intensity, from lactate threshold one (LT1) until attainment of maximal aerobic power (MAP) (WF 3464 ± 3364mm, P < 0.005; UF 1961 ± 1779mm, P = 0.002; LF 1608 ± 1404mm, P = 0.002; HM 849 ± 642mm, P < 0.001). UF movement was greater than LF movement at all exercise intensities (UF minus LF at: LT1, 1048 ± 383mm; LT2, 1208 ± 611mm; MAP, 1401 ± 712mm; P < 0.001). Significant medium to large non-linear relationships were found between facial movement and power output (r2 = 0.24-0.31), HR (r2 = 0.26-0.33), [La-] (r2 = 0.33-0.44) and RPE (r2 = 0.38-0.45). The findings demonstrate the potential utility of facial feature tracking as a non-invasive, psychophysiological measure to potentially assess exercise intensity.

How Do the Habitual Sleep Patterns of Elite Female Basketball and Soccer Athletes Compare With the General Population?

PURPOSE: To compare the habitual sleep of female basketball and soccer athletes to age- and sex-matched controls and to characterize the sleep of basketball and soccer athletes at different competition locations and on the days surrounding competition. METHODS: Using an observational case-control design, 41 female participants were recruited to participate, consisting of 11 basketball athletes (mean [SD]: age = 24.1 [4.9] y), 10 soccer athletes (24.8 [6.4] y), and 20 nonathletic controls (24.2 [2.8] y). Sleep was monitored using actigraphy for four 7-day periods throughout the preseason and subsequent competition season. Generalized linear models were used to analyze the effect of group and competition situation (eg, Home or Away) on sleep. RESULTS: During habitual conditions, basketball athletes had longer sleep durations (7.4 [1.5] h) than soccer athletes (7.0 [1.2] h, P < .001) and controls (7.3 [1.2] h, P = .002). During competition, basketball and soccer athletes had longer sleep durations following home (7.7 [1.7] and 7.2 ± 1.3 h) compared with away games (6.8 [1.8] and 7.0 [1.3] h). In addition, basketballers went to bed earlier (23:49 [01:25]) and woke earlier (07:22 [01:59]) following away games compared with soccer athletes (00:10 [01:45] and 08:13 [01:45]). CONCLUSIONS: Basketballers had longer habitual sleep durations compared with soccer athletes and nonathletic controls. During competition, basketballers had earlier bed and wake times compared with soccer athletes following away games, highlighting the need for individualized sleep strategies.

Reply to Dunican, I.C.; Walsh, J.H. Comment on "Gratwicke et al. Nutritional Interventions to Improve Sleep in Team-Sport Athletes: A Narrative Review. Nutrients 2021, 13, 1586".

We thank Dunican and Walsh [...].

Nutritional Interventions to Improve Sleep in Team-Sport Athletes: A Narrative Review.

Athletes often experience sleep disturbances and poor sleep as a consequence of extended travel, the timing of training and competition (i.e., early morning or evening), and muscle soreness. Nutrition plays a vital role in sports performance and recovery, and a variety of foods, beverages, and supplements purportedly have the capacity to improve sleep quality and quantity. Here, we review and discuss relevant studies regarding nutrition, foods, supplements, and beverages that may improve sleep quality and quantity. Our narrative review was supported by a semi-systematic approach to article searching, and specific inclusion and exclusion criteria, such that articles reviewed were relevant to athletes and sporting environments. Six databases-PubMed, Scopus, CINAHL, EMBASE, SPORTDiscus, and Google Scholar-were searched for initial studies of interest from inception to November 2020. Given the paucity of sleep nutrition research in the athlete population, we expanded our inclusion criteria to include studies that reported the outcomes of nutritional interventions to improve sleep in otherwise healthy adults. Carbohydrate ingestion to improve sleep parameters is inconclusive, although high glycemic index foods appear to have small benefits. Tart cherry juice can promote sleep quantity, herbal supplements can enhance sleep quality, while kiwifruit and protein interventions have been shown to improve both sleep quality and quantity. Nutritional interventions are an effective way to improve sleep quality and quantity, although further research is needed to determine the appropriate dose, source, and timing in relation to training, travel, and competition requirements.

ɑ-Lactalbumin Improves Sleep and Recovery after Simulated Evening Competition in Female Athletes.

PURPOSE: This study aimed to determine the efficacy of α-lactalbumin (A-LAC) supplementation for improving sleep and performance recovery after simulated evening competition in female athletes. METHODS: Sixteen trained women (mean ± SD: age, 27 ± 7 yr; mass, 62 ± 10 kg; stature, 167 ± 8 cm) participated in this randomized double-blind three-arm crossover study. Participants completed a simulated evening competition before consuming either an A-LAC whey protein, whey protein placebo (PLA), or water control (CON) beverage. Sleep was monitored via polysomnography, and participants completed a series of physical, cognitive, and perceptual assessments before, and 14 and 24 h after simulated competition. RESULTS: Non-rapid eye movement stage 2 sleep increased after competition in A-LAC (pre, 199 ± 44 min; post, 212 ± 37 min) but decreased in CON (pre, 228 ± 43 min; post, 195 ± 40 min) and PLA (pre, 224 ± 25 min; post, 211 ± 35 min; P = 0.012). In addition, Yo-Yo Intermittent Recovery Test Level 1 distance improved over time in A-LAC (baseline, 664 ± 332 m; 14 h post, 667 ± 326 m; 24 h post, 781 ± 427 m) compared with CON (baseline, 741 ± 366 m; 14 h post, 648 ± 351 m; 24 h post, 720 ± 407 m) and PLA (baseline, 763 ± 394 m; 14 h post, 636 ± 366 m; 24 h post, 720 ± 396 m; P < 0.001). CONCLUSIONS: The findings indicate that A-LAC supplementation may be useful for retaining some sleep characteristics after evening competition, leading to improved physical performance in female athletes.

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.

Sleep practices implemented by team sport coaches and sports science support staff: A potential avenue to improve athlete sleep?

OBJECTIVES: The primary aims of the present study were to assess the sleep hygiene knowledge of high performance team sport coaches and sports science support staff; the sleep practices these individuals implement with athletes; and the barriers to the more frequent use of these practices. DESIGN: Cross-sectional observational study. METHODS: A sample of 86 Australian coaches and sports science support staff working within high performance team sport volunteered to complete a four-part questionnaire, including the Sleep Beliefs Survey used to assess sleep hygiene knowledge. RESULTS: Overall sleep hygiene knowledge was adequate (15.3±2.9, score range 0-20; mean±SD), however knowledge of sleep-wake cycle behaviours (score 4.9±1.6 out of 7) and thoughts and attitudes about sleep (3.6±1.0 out of 5) were inadequate. Over half (56%) of coaches and support staff had monitored athlete sleep, while 43% had promoted sleep hygiene. Lack of resources (response range 44-60%) and knowledge (16-41%) were the two main barriers to the implementation of sleep monitoring and sleep hygiene practices. CONCLUSIONS: Team sport coaches and sports science support staff have adequate overall sleep hygiene knowledge, yet some specific areas (e.g. sleep-wake cycle behaviours) warrant improvement. There appear to be limited sleep practices implemented with athletes, particularly regarding the promotion of sleep hygiene. The development of educational sleep resources for coaches and support staff to implement with athletes may help address the identified barriers and improve sleep knowledge.