To Nap or Not to Nap? A Systematic Review Evaluating Napping Behavior in Athletes and the Impact on Various Measures of Athletic Performance

The acute effects of nonsleep deep rest on perceptual responses, physical, and cognitive performance in physically active participants

This study aimed to examine the effect of nonsleep deep rest (NSDR) on physical and cognitive performance, as well as sleepiness, acute readiness, recovery, stress, and mood state in physically active participants. A total of 65 physically active participants (42 male, 23 female) were randomly assigned into two groups: an experimental group (NSDR, n = 34), in which participants completed a 10-min NSDR intervention, and a control group (CON, n = 31), whereby participants sat passively for 10 min. Testing measures were assessed immediately pre and 10 min post each condition and comprised completing a hand grip strength dynamometer test and a countermovement jump test on force plates, cognitive function measures via a psychomotor vigilance task (PVT-B), and a Simon task test, along with four questionnaires to assess sleep, recovery, and mood state. A significant Group × Time interaction favored the NSDR condition for handgrip strength, median reaction time during the PVT-B, and accuracy percentage during the Simon task. Questionnaire responses demonstrated NSDR to be associated with significant benefits to physical readiness, emotional balance, overall recovery, negative emotional state, overall stress, and tension in comparison to CON (p < .05). The NSDR intervention could be a valuable strategy for acutely enhancing overall well-being and readiness.

Benefits of napping habits in healthy adults: Maintaining alerting performance and cortisol levels change within 90 min of habitual napping time

BACKGROUND

Napping is garnering increased attention as a strategy for adults to sustain alertness and alleviate stress in contemporary society. The nuances of napping habits are emerging as an independent factor influencing the extent of individual benefits. This study aimed to demonstrate the long-term benefits of napping and explore the impact of napping habits on individual alertness, as well as whether this effect was correlated with cortisol levels.

METHODS

The study involved 80 healthy adults categorized into two groups based on self-reported napping habits: habitual nappers (n = 49) and non-habitual nappers (n = 31). Karolinska Sleepiness Scale (KSS), psychomotor vigilance task (PVT), and saliva collection were performed every 30 min within 90 min in the absence of napping during the afternoon dip. The measurements were analyzed using repeated measures ANOVA and Pearson correlation analyses.

RESULTS

There was an interaction between groups and time in reaction speed and lapse number of PVT and cortisol (all p < 0.05). Post hoc analysis found that habitual nappers maintained higher objective alertness and experienced more significant increases in cortisol over time (all p < 0.05). The cortisol levels at sleepiness time were negatively associated with the slowest 10 % reaction speed of PVT in non-habitual nappers (r = -0.409, p = 0.022).

CONCLUSION

Under the premise of mitigating the impacts of acute nap deprivation on sleep homeostasis and rhythm, napping habits emerge as a potential factor influencing the ability of individuals to sustain heightened alertness.

Napping and heart rate variability in elite athletes

Sleep and autonomic nervous system (ANS) influence each other in a bidirectional fashion. Importantly, it has been proposed that sleep has a beneficial regulatory influence over cardiovascular activity, which is mostly controlled by autonomic regulation through the activity of sympathetic and parasympathetic pathways of the ANS. A well-established method to non-invasively assess cardiac autonomic activity is heart rate variability (HRV) analysis. We aimed to investigate the effect of a 40-min nap opportunity on HRV. Twelve professional basketball players randomly accomplished two conditions: 40-min nap (NAP) and control (CON). Nocturnal sleep and naps were monitored by actigraphic recording and sleep diaries. Total sleep time (TST), time in bed (TIB), sleep efficiency (SE), sleep onset latency (SOL), and wake after sleep onset (WASO) were analyzed. HRV was analyzed in 5-min segments during quiet wake before and after each condition with controlled breathing. Were analysed high (HF) and low frequency (LF) bands, the standard deviation of NN interval (SDNN), HRV index and stress index (SI). Wellness Hooper index and Epworth Sleepiness Scale (ESS) were assessed before and after both conditions. There was no significant difference in TIB, TST, SE, WASO, and VAS between NAP and CON. A significant increase in SDNN, HRV index, and LF and a significant decrease in HF, SI, ESS, and Hooper's stress and fatigue scores were observed from pre- to post-nap. In conclusion, napping reduces sleepiness, stress and fatigue, and might provide an advantage by preparing the body for a much-required sympathetic comeback following peaceful rest.

Habitual Nocturnal Sleep, Napping Behavior, and Recovery Following Training and Competition in Elite Water Polo: Sex-Related Effects

PURPOSE

To examine nocturnal sleep patterns, napping behaviors, and subjective wellness responses of elite water polo players within an in-season week and to identify whether sleeping patterns differ between men and women.

METHODS

Sleep characteristics of 10 male and 17 female professional water polo players were objectively assessed during 1 week of the in-season period, including 5 training days, 1 match day, and 1 day of rest. Internal load (rating of perceived exertion × duration of training or match) was assessed 30 minutes posttraining or postmatch, and the total quality of recovery was recorded every morning. A series of multilevel models were used to analyze the data.

RESULTS

Time in bed and wake-up time were earlier on both training (P < .001) and rest days (P < .001) than on the day of the match. Internal workload did not predict any of the players' sleeping patterns. Midday naps predicted less time in bed (P = .03) and likely less sleep time (P = .08). The total quality of recovery was predicted only by the total sleep time (P < .01). Women exhibited higher sleep efficiency (P < .001), less waking after sleep onset (P = .01), and a lower number of awakenings (P = .02) than men.

CONCLUSIONS

The current results indicate that the nocturnal sleep patterns of elite water polo players are not associated with internal load and that women display better nocturnal sleep quality compared with men. As long naps interfere with nocturnal sleep, and total nocturnal sleep time predicts total quality of recovery, we suggest that athletes follow hygiene sleep strategies to facilitate adequate nocturnal sleep and next-day recovery.

The impact of strategic napping on peak expiratory flow and respiratory function in young elite athletes

Respiratory health is a critical determinant of athletic performance, and the utilization of restorative strategies, such as strategic napping, may offer a competitive edge to athletes. This study investigates the effects of nap duration on the respiratory function of young elite athletes who have achieved top rankings national competitions. Participants engage in three test sessions with varying nap durations: no nap (N0), a 25-minute nap (N25), and a 45-minute nap (N45), with a minimum 72-hour interval between sessions. Respiratory parameters including Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1/FVC ratio, Peak Expiratory Flow rate (PEF), Forced Expiratory Flow at 25-75% of FVC (FEF25-75%), and Forced Expiratory Time (FET) are assessed. Results reveal a significant enhancement in PEF values following a 45-minute nap (N45) compared to the no-nap control (N0) [F1 - 11=7.356, p =.004, ηp2 = 0.401, (95% CI for difference: -1.56 to - 0.056)], indicating a potential positive influence of napping on maximum expiratory flow rate and, consequently, athletes' respiratory performance. While no significant changes are observed in other respiratory parameters across different nap durations, these findings underscore the potential benefits of strategic napping in optimizing respiratory health in young elite athletes.

The Negative Effects of Travel on Student Athletes Through Sleep and Circadian Disruption

Collegiate athletes must satisfy the academic obligations common to all undergraduates, but they have the additional structural and social stressors of extensive practice time, competition schedules, and frequent travel away from their home campus. Clearly such stressors can have negative impacts on both their academic and athletic performances as well as on their health. These concerns are made more acute by recent proposals and decisions to reorganize major collegiate athletic conferences. These rearrangements will require more multi-day travel that interferes with the academic work and personal schedules of athletes. Of particular concern is additional east-west travel that results in circadian rhythm disruptions commonly called jet lag that contribute to the loss of amount as well as quality of sleep. Circadian misalignment and sleep deprivation and/or sleep disturbances have profound effects on physical and mental health and performance. We, as concerned scientists and physicians with relevant expertise, developed this white paper to raise awareness of these challenges to the wellbeing of our student-athletes and their co-travelers. We also offer practical steps to mitigate the negative consequences of collegiate travel schedules. We discuss the importance of bedtime protocols, the availability of early afternoon naps, and adherence to scheduled lighting exposure protocols before, during, and after travel, with support from wearables and apps. We call upon departments of athletics to engage with sleep and circadian experts to advise and help design tailored implementation of these mitigating practices that could contribute to the current and long-term health and wellbeing of their students and their staff members.

The Impact of Daytime Napping Following Normal Night-Time Sleep on Physical Performance: A Systematic Review, Meta-analysis and Meta-regression

BACKGROUND

Daytime napping is used by athletes as a strategy to supplement night time sleep and aid physical performance. However, no meta-analytical overview regarding the impact of napping following a night of normal sleep (7-9 h) on physical performance is available.

OBJECTIVE

The aim of this study was to evaluate the effect of daytime napping following normal night-time sleep on physical performance in physically active individuals and athletes.

METHODS

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seven electronic databases (i.e., PubMed, Web of Science, Scopus, SPORTDiscus, CINAHL, SCIELO, and EBSCOhost) were used to search for relevant studies that investigated the impact of daytime napping, following normal night-time sleep, on physical performance in physically active individuals and athletes, published in any language, and available before September 01, 2022. Studies that included assessments of any physical performance measures were included. QualSyst was used to assess the methodological quality of the studies.

RESULTS

Of 18 selected articles, 15 were of strong quality and 3 were of moderate quality. Compared with no-nap conditions, physically active individuals and athletes who napped experienced an increase in highest distance (effect size [ES] 1.026; p < 0.001) and total distance (ES 0.737; p < 0.001), and a decrease in fatigue index (ES 0.839, p = 0.008) during the 5-m shuttle run test (5MSRT). However, napping yielded no effect on muscle force (ES 0.175; p = 0.267). No effect of napping was found in one study that measured sprint performance and in two studies that measured performance during the 30-s Wingate test. Two of three studies reported an increase in jump performance after napping. Two of three studies reported an increase in repeated sprints after napping. One study reported an increase in upper-body power performance after napping, and napping was beneficial for endurance performance in one of two studies.

CONCLUSION

Following normal sleep, napping is beneficial for the performance of the 5MSRT, with no significant effect on muscle force. No firm conclusions can be drawn regarding other physical performance measures due to the limited number of studies.

Circadian rhythm in sportspersons and athletic performance: A mini review

Circadian rhythms in the physiological and behavioral processes of humans play a crucial role in the quality of living and also in the magnitude of success and failure in various endeavors including competitive sports. The rhythmic activities of the body and performance in sportspersons do have a massive impact on their every cutthroat competition. It is essential to schedule sports activities and training of players according to their circadian typology and time of peak performance for improved performance and achievement. In this review, the focus is on circadian rhythms and diurnal variations in peak athletic performance in sportspersons. Accuracy and temporal variability in peak performance in an individual could be attributed to various factors, namely chronotype, time of the day, body temperature, jetlag, hormones, and prior light exposure. Circadian rhythm of mood, alertness, T-core, and ultimately athletic performance is not only affected by sleep but also by circadian variations in hormones, such as cortisol, testosterone, and melatonin. There are, however, a few reports that are not consistent with the conclusions drawn in this review. Nevertheless, circadian rhythm and performance among sportspersons and athletes are important areas of research. This review might be useful to the managers and policymakers associated with competitive sports and athletic events.

The impact of a 40-min nap on neuromuscular fatigue profile and recovery following the 5-m shuttle run test

This study aims to investigate the impact of a 40-min nap opportunity on perceived recovery, exertion, and maximal voluntary isometric contraction (MVIC) following the 5-m shuttle run test (5SRT), after 1 night of normal sleep. In a randomised, counterbalanced, cross-over design, 17 trained men (mean [SD] age 20 [3] years, height 173 [6] cm, body mass 68 [6] kg) performed a 5SRT under two conditions: a 40-min nap opportunity and no-nap condition. After both conditions, electromyography signals during a 5-s isometric knee extension were recorded before and immediately after the 5SRT. Two electrical nerve stimulations at the femoral nerve were measured during and after the MVIC. Force, voluntary activation level, M-wave amplitudes, potentiated twitch, and electromyography signals (root mean square) were measured during each MVIC. Perceived exertion was recorded after each repetition of the test and perceived recovery was determined after the end of the MVIC. Compared to the no-nap condition, the 40-min nap resulted in significant enhancements in both the highest distance (p < 0.01, Δ = +7.6%) and total distance (p < 0.01, Δ = +7.5%). Before and after exercise, values for MVIC, root mean square, M-wave amplitudes, and voluntary activation level were improved after the 40-min nap opportunity compared to no-nap condition (all p ≤ 0.01). Values for perceived exertion and recovery were improved after the 40-min nap opportunity in comparison with no-nap condition (p ≤ 0.01). A 40-min nap opportunity improved repeated high-intensity short-term maximal performance, perceived recovery, associated neuromuscular responses, and reduced perceived fatigue. Therefore, our findings suggest that central and peripheral processes are involved in the improvements of 5SRT performance after napping.

Daytime naps improve afternoon power and perceptual measures in elite rugby union athletes-a randomized cross-over trial

Daytime naps are used by elite athletes in both training and match-day settings. Currently, there are limited interventional studies on the efficacy of napping on physical performance in elite team-sport athletes. Therefore, the objective was to investigate the effect of a daytime nap (<1 hour) on afternoon performance of peak power, reaction time, self-reported wellness, and aerobic performance in professional rugby union athletes. A randomized cross-over design was carried out among 15 professional rugby union athletes. Athletes performed nap (NAP) and no nap (CON) conditions on two occasions, separated by 1 week. Baseline testing of reaction time, self-reported wellness, and a 6-second peak power test on a cycle ergometer were completed in the morning, followed by 2 × 45-minute training sessions, after which athletes completed the NAP or CON condition at 1200 hours. Following the nap period, baseline measures were retested in addition to a 30-minute fixed-intensity interval cycle and a 4-minute maximal effort cycling test. A significant group × time interaction was determined for 6-second peak power output (+157.6 W, p < 0.01, d = 1.53), perceived fatigue (-0.2 AU, p = 0.01, d = 0.37), and muscle soreness (-0.1 AU, p = 0.04, d = 0.75) in favor of the NAP condition. A significantly lower perceived exertion rating (-1.2 AU, p < 0.01, d = 1.72) was recorded for the fixed-intensity session in favor of NAP. This study highlights that utilizing daytime naps between training sessions on the same day improved afternoon peak power and lowered perceptions of fatigue, soreness, and exertion during afternoon training in professional rugby union athletes.

To Sleep Dreaming Medals: Sleep Characteristics, Napping Behavior, and Sleep-Hygiene Strategies in Elite Track-and-Field Athletes Facing the Olympic Games of Tokyo 2021

PURPOSE

Few data are available on sleep characteristics of elite track-and-field athletes. Our study aimed to assess (1) differences in sleep between sexes and among different track-and-field disciplines, (2) the effect of individualized sleep-hygiene strategies on athletes' sleep parameters, and (3) daytime nap characteristics in track-and-field athletes.

METHODS

Sleep characteristics of 16 elite Olympic-level track-and-field athletes (male: n = 8; female: n = 8) were assessed during the preseason period, at baseline (T0), and during the in-season period, after the adoption of individualized sleep-hygiene strategies (T1). Sleep parameters were objectively monitored by actigraphy for a minimum of 10 days, for each athlete, at both T0 and T1. A total of 702 nights were analyzed (T0 = 425; T1 = 277).

RESULTS

Female athletes displayed better sleep efficiency (88.69 [87.69-89.68] vs 91.72 [90.99-92.45]; P = .003, effect size [ES]: 0.44), lower sleep latency (18.99 [15.97-22.00] vs 6.99 [5.65-8.32]; P < .001, ES: 0.65), higher total sleep time (07:03 [06:56-07:11] vs 07:18 [07:10-07:26]; P = .030, ES: 0.26), earlier bedtime (00:24 [00:16-00:32] vs 00:13 [00:04-00:22]; P = .027, ES: 0.18), and lower nap frequency (P < .001) than male athletes. Long-distance runners had earlier bedtime (00:10 [00:03-00:38] vs 00:36 [00:26-00:46]; P < .001, ES: 0.41) and wake-up time (07:41 [07:36-07:46] vs 08:18 [08:07-08:30]; P < .001, ES: 0.61), higher nap frequency, but lower sleep efficiency (88.79 [87.80-89.77] vs 91.67 [90.95-92.38]; P = .013, ES: 0.44), and longer sleep latency (18.89 [15.94-21.84] vs 6.69 [5.33-8.06]; P < .001, ES: 0.67) than athletes of short-term disciplines. Furthermore, sleep-hygiene strategies had a positive impact on athletes' total sleep time (429.2 [423.5-434.8] vs 451.4 [444.2-458.6]; P < .001, ES: 0.37) and sleep latency (14.33 [12.34-16.32] vs 10.67 [8.66-12.68]; P = .017, ES: 0.19).

CONCLUSIONS

Sleep quality and quantity were suboptimal at baseline in Olympic-level track-and-field athletes. Large differences were observed in sleep characteristics between sexes and among different track-and-field disciplines. Given the positive effect of individualized sleep-hygiene strategies on athlete's sleep, coaches should implement sleep education sessions in the daily routine of top-level athletes.

The Impact of Multisession Sleep-Hygiene Strategies on Sleep Parameters in Elite Swimmers

PURPOSE

Short sleep duration and poor sleep quality are common in swimmers. Sleep-hygiene strategies demonstrated beneficial effects on several sleep parameters. The present study assessed the impact of a multisession sleep-hygiene training course on sleep in elite swimmers.

METHODS

Twenty-eight elite swimmers (17 [2] y) participated. The sleep-hygiene strategy consisted of 3 interventions. Sleep was measured by actigraphy for 7 days before the beginning of the intervention (baseline), after the first collective intervention (postintervention), after the second collective intervention (postintervention 2), and, finally, after the individual intervention (postintervention 3). The Epworth Sleepiness Scale (ESS) was completed concurrently. Swimmers were classified into 2 groups: nonsomnolent (baseline ESS score ≤ 10, n = 13) and somnolent (baseline ESS score ≥ 11, n = 15).

RESULTS

All swimmers had a total sleep time of <8 hours per night. Sixty percent of swimmers were moderately morning type. Later bedtime, less time in bed, and total sleep time were observed in the somnolent group compared with the nonsomnolent group at baseline. An interaction between training course and group factors was observed for bedtime, with a significant advance in bedtime between baseline, postintervention 2, and postintervention 3 for the somnolent group.

CONCLUSIONS

The present study confirms the importance of implementing sleep-hygiene strategies, particularly in athletes with an ESS score ≥11. A conjunction of individual and collective measures (eg, earlier bedtime, napping, and delaying morning training session) could favor the total sleep time achieved.

Effects of a Sleep Hygiene Strategy on Parameters of Sleep Quality and Quantity in Youth Elite Rugby Union Players

PURPOSE

To assess the effects of a sleep hygiene strategy on parameters of sleep quality and quantity in youth elite rugby union players.

METHOD

Eleven male players (age: 19.0 [1.4] y) undertook a sleep hygiene strategy composed of 2 theoretical sessions and 3 practical sessions over a 4-week period. Sleeping time, time in bed, total sleep time, sleep latency (SL), sleep efficiency (SE), wake after sleep onset, and wake bouts were recorded with an actigraphic device during the 4-week sleep hygiene strategy (baseline) and during 4 weeks after the last intervention (postintervention).

RESULTS

At baseline, the overall group reported poor sleep quantity (total sleep time = 6:27 [0:30] min), but sleep quality was considered acceptable (SL = 0:18 [0:08] min and SE = 77.8% [5.8%]). Postintervention, the overall group showed a small improvement in SL (d = -0.23 [-0.42 to -0.04], P = .003) and SE (d = 0.30 [0.03 to 0.57], P = .0004). For individual responses, sleeping time, time in bed, and total sleep time were positively influenced in only 4, 3, and 5 players, respectively. For parameters of sleep quality, SL and SE were positively influenced in a majority of players (n = 7 and 8, respectively). The magnitude of difference between baseline and postintervention was strongly associated with baseline values in SE (r = -.86; P = .0005) and wake after sleep onset (r = -.87; P = .0007).

CONCLUSION

A sleep hygiene strategy is efficient to improve sleep quality but not sleep quantity in young rugby union players. The strategy was more efficient in players with lower initial sleep quality and should be implemented prior to a high cumulative fatigue period.

The Use of Recovery Strategies in Gaelic Games: A Mixed-Methods Analysis

PURPOSE

This study investigated Gaelic games players' (1) use of postexercise recovery strategies; (2) recovery strategies according to sport, biological sex, and playing standard; and (3) recovery strategy periodization.

METHODS

Participants were a total of 1178 Gaelic players (n = 574 female), age 24.6 (6.6) years. These players completed a questionnaire investigating postexercise recovery strategies. Participants were further dichotomized by playing standard into developmental (club/collegiate; n = 869) and national (intercounty; n = 309) levels and by sporting codes: Gaelic football (n = 813), Camogie/hurling (n = 342), and handball (n = 23).

RESULTS

Active recovery (90.4%), cold temperature exposure (79.5%), regular sleep routine (79.1%), strategic nutritional intake (72.3%), and massage (68.8%) were the most commonly used recovery strategies. Recovery strategy use was periodized by 30% of players. A significantly larger proportion of national-level players apply cold temperatures (86.7% vs 73.1%; P = .001) and nutritional strategies (80.1% vs 69.2%; P = .012) when compared with developmental players. A significantly larger proportion of female players have a regular sleep routine (82.6% vs 75.1%; P = .037), apply external heat (63.4% vs 48.5%; P = .002), and perform stretching (76.5% vs 66.4%; P = .002) postexercise when compared with male players. A significantly larger proportion of male players employ nutritional strategies (77.6% vs 67.5%; P = .007) and consume a combination of protein and carbohydrate (62.1% vs 28.0%; P < .001) postexercise when compared with female players.

CONCLUSION

Gaelic games players regularly implement a range of postexercise recovery strategies in an attempt to expediate the return of performance capacity and psychophysiological status to preexercise levels. The current findings may support practitioners who seek to prescribe effective and periodized recovery interventions targeting optimized preference/compliance.

Napping behaviour, daytime sleepiness, and arousal in high performance athletes and non-athlete controls

Napping offers a strategy to manage sleep, aid recovery and enhance performance in elite sport. However, relatively little research attention has focussed on the natural history of athlete napping or tested the widely held assumption that athlete napping is mainly a consequence of degraded night-time sleep. Within a sample of 158 team (n = 76) and individual (n = 80) sport athletes, and 82 non-athlete controls, we analysed napping behaviour in relation to sleep quality, daytime sleepiness, and pre-sleep somatic and cognitive arousal. There was no significant association between athlete/non-athlete status and the prevalence, frequency, or duration of naps. Comparisons of athlete nappers and non-nappers found no significant differences in sleep quantity or quality. While nap propensity was significantly related to higher daytime sleepiness, this influence was moderated or augmented by levels of pre-sleep cognitive arousal. For some nappers, those with higher levels of arousal may need to be sleepier than those with lower levels of arousal in order to successfully initiate daytime sleep. Approximately 50% of athletes did not nap. If the benefits of athlete napping are to be fully exploited, the needs of this substantial group for whom napping may be problematic should be recognised and addressed.

Dawn of a New Dawn: Advances in Sleep Health to Optimize Performance

Optimal sleep health is a critical component to high-level performance. In populations such as the military, public service (eg, firefighters), and health care, achieving optimal sleep health is difficult and subsequently deficiencies in sleep health may lead to performance decrements. However, advances in sleep monitoring technologies and mitigation strategies for poor sleep health show promise for further ecological scientific investigation within these populations. The current review briefly outlines the relationship between sleep health and performance as well as current advances in behavioral and technological approaches to improving sleep health for performance.

The Impact of Sleep Interventions on Athletic Performance: A Systematic Review

BACKGROUND

Sleep is essential for maximal performance in the athletic population. Despite that, the sport context has many factors that can negatively influence athletes' sleep and subsequent recovery.

OBJECTIVES

The purpose of this systematic review was to synthesize the most recent literature regarding sleep interventions aimed at improving sleep and subsequent performance in athletes.

METHODS

The present systematic review was conducted based on the PRISMA guidelines and the PICOS approach. The search was conducted in May 2022 using the electronic database PubMed, SPORTDiscus via EBSCOhost, and Web of Science. Once extracted, studies were included if they met the following criteria: (1) participants were athletes of individual or team sports; (2) implemented an intervention aimed at improving sleep; (3) measured at least one objective performance/recovery outcome; and (4) reported the relationship between sleep and performance.

RESULTS

The search returned 1584 records. Following the screening, a total of 25 studies met our inclusion criteria. All the included articles were intervention studies published between 2011 and 2021. The included studies implemented various sleep interventions, such as sleep hygiene, naps, sleep extension, light manipulation, cold water immersion, mindfulness, or a combination of two or more strategies. Sleep extension and naps were the most representative and most effective strategies to improve sleep and performance. Mindfulness and light manipulation demonstrated promising results, but more studies are needed to confirm these findings. Sleep hygiene, removing electronic devices at night, and cold water immersion had no effects on sleep and subsequent performance/recovery, but these results are based on a few studies only.

CONCLUSION

While acknowledging the limited amount of high-quality evidence reviewed, it appears that increasing sleep duration at night or through napping was the most effective interventions to improve physical and/or cognitive performance. Protocol Registration This protocol was registered in the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) on May 11, 2022, with the registration number INPLASY202250069.

The combined effects of napping and self-selected motivation music during warming up on cognitive and physical performance of karate athletes

Introduction: It has been established that napping or listening to motivational music during warm-up is an effective strategy to enhance cognitive and physical performances. However, which could provide better enhancement warrants further investigation. This study aimed to examine the effect of a 30-min nap opportunity (N30), a warm-up with self-selected motivational music (WUMM), and the combination of N30 with WUMM (WUMM + N30) on cognitive and physical performances in karate athletes. Method: In a randomized order, 14 national-level male karate athletes performed four experimental sessions: control, N30, WUMM, and WUMM + N30. Simple (SRT) and choice (CRT) reaction times, selective attention, subjective sleepiness (ESS), mood state (POMS), countermovement jump (CMJ), and karate agility test (KAT) were evaluated before and after an all-out exhaustive task [i.e., the Karate Specific Test (KST)]. Ratings of perceived exertion (RPE) were measured immediately after the KST. Results: Compared to the control, all interventions improved cognitive outcomes, mood, and sleepiness. No effects on physical performances (CMJ and KAT) were found after N30. Compared to N30, WUMM + N30 improved SRT pre- and post-exercise (pre: p < 0.05, d = 0.72; post: p < 0.001, d = 0.14), CRT (pre: p < 0.001, d = 0.07; post: p < 0.001, d = 0.10), attention (pre: p < 0.05, d = 0.06; post: p < 0.01, d = 0.06), mood (pre: p < 0.001, d = 2.53; post: p < 0.001, d = 0.23), and decreased ESS scores (pre: p < 0.01, d = 1.41; post: p < 0.05, d = 1.18). However, there was no significant difference between WUMM and N30. KST performance was not affected by the experimental conditions. However, the KST-induced performance deficit in CMJ and KAT was smaller following WUMM + N30 compared to WUMM and N30. RPE scores were lower following WUMM + N30 and WUMM. Conclusion: These findings suggest that a combination of listening to self-selected motivational music during warm-up with a 30-min nap could be an effective strategy to enhance cognitive and physical performance decline caused by fatigue induced by exercise.

The Effects of Napping on Wakefulness and Endurance Performance in Athletes: A Randomized Crossover Study

Background: Athletes often experience poor sleep quality due to stress, altitude exposure, travel across different time zones, and pre-competition nervousness. Coaches use daytime naps to counteract the negative effects of fragmented nighttime sleep. Napping before competitions has also been used to enhance performance in athletes without sleep problems, with mixed results in previous studies, particularly for endurance performance. Thus, we investigated the effects of napping after partial sleep deprivation (PSD) on endurance performance and wakefulness in athletes. Methods: We recruited 12 healthy and trained participants (seven female and five male) for a randomized crossover study design. The participants underwent two test sessions: a five-hour night of sleep without a nap (noNap) and a five-hour night of sleep with a 30-min nap opportunity (Nap30). Participants recorded their sleep-wake rhythm one week before and during the study using the Consensus Sleep Diary-Core and the Morningness-Eveningness Questionnaire to examine their circadian rhythm type. We quantified PSD and the nap with pupillography (pupil unrest index, PUI), a subjective level of sleepiness questionnaire (Karolinska Sleepiness Scale, KSS), and polysomnography. After each night, participants performed a maximal cycling ergometry test to determine time to exhaustion (TTE) and maximal oxygen uptake (VO _2max). Results: Participants had an average sleep duration of 7.2 ± 0.7 h and were identified as moderately morning types (n = 5), neither type (n = 5), and moderately evening types (n = 2). There was a significant difference in both sleepiness parameters between the two conditions, with the PUI (p = 0.015) and KSS (p ≤ 0.01) significantly decreased at 5 h and nap compared with only 5 h of sleep. The PUI (p ≤ 0.01) and KSS (p ≤ 0.01) decreased significantly from before to after the nap. However, there was no significant difference in physical exercise test results between the conditions for TTE (p = 0.367) or VO _2max (p = 0.308). Conclusions: Our results suggest that napping after light PSD does not significantly influence endurance performance. We conclude that aerobic performance is a multidimensional construct, and napping after PSD may not enhance it. However, napping is an effective method to increase wakefulness and vigilance, which can be beneficial for sports competitions.

How do patients sleep after orthopaedic surgery? Changes in objective sleep parameters and pain in hospitalized patients undergoing hip and knee arthroplasty

PURPOSE

The aim of this observational cohort study was to assess actigraphy-based sleep characteristics and pain scores in patients undergoing knee or hip joint replacement and hospitalized for ten days after surgery.

METHODS

N=20 subjects (mean age: 64.0±10.39 years old) wore the Actiwatch 2 actigraph (Philips Respironics, USA) to record sleep parameters for 11 consecutive days. Subjective scores of pain, by a visual analog scale (VAS), were constantly monitored and the following evaluation time points were considered for the analysis: pre-surgery (PRE), the first (POST1), the fourth (POST4), and the tenth day (POST10) after surgery.

RESULTS

Sleep quantity and timing parameters did not differ from PRE to POST10, during the hospitalization whereas sleep efficiency and immobility time significantly decreased at POST1 compared to PRE by 10.8% (p=0.003; ES: 0.9, moderate) and 9.4% (p=0.005; ES: 0.86, moderate) respectively, and sleep latency increased by 18.7 min (+320%) at POST1 compared to PRE (p=0.046; ES: 0.70, moderate). Overall, all sleep quality parameters showed a trend of constant improvement from POST1 to POST10. VAS scores were higher in the first day post-surgery (4.58 ± 2.46; p=0.0011 and ES: 1.40, large) compared to POST10 (1.68 ± 1.58). During the time, mean VAS showed significant negative correlations with mean sleep efficiency (r = -0.71; p=0.021).

CONCLUSION

Sleep quantity and timing parameters were stable during the entire hospitalization whereas sleep quality parameters significantly worsened the first night after surgery compared to the pre-surgery night. High scores of pain were associated with lower overall sleep quality.

Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To estimate the association between daytime napping and cognitive and physical sport performance and fatigue after normal sleep and partial sleep deprivation (less sleep duration than necessary).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

The PubMed, Scopus, Web of Science, Cochrane Central, SportDiscus and PsycINFO databases.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials on the effect of daytime napping on sport performance and fatigue available from inception to 2 December 2022. Standardised mean differences (SMD) and their 95% compatibility intervals (CI) were estimated with the DerSimonian-Laird method through random effect models.

RESULTS

In the 22 included trials, 291 male participants (164 trained athletes and 127 physically active adults) aged between 18 and 35 years were studied. When performed after a normal night of sleep, napping from 12:30 hours to 16:50 hours (with 14:00 hours being the most frequent time) improved cognitive (SMD=0.69, 95% CI: 0.37 to 1.00; I²=71.5%) and physical performance (SMD=0.99, 95% CI: 0.67 to 1.31; I²=89.1%) and reduced the perception of fatigue (SMD=-0.76, 95% CI: -1.24 to -0.28; I²=89.5%). The positive effects of napping were also confirmed after partial sleep deprivation. Overall, the benefits were higher with a nap duration between 30 and <60 min and when the time from nap awakening to test was greater than 1 hour.

CONCLUSIONS

After a night of normal sleep or partial sleep deprivation, a daytime nap between 30 and <60 min has a moderate-to-high effect on the improvement of cognitive performance and physical performance and on the reduction of perceived fatigue.

PROSPERO REGISTRATION NUMBER

CRD42020212272.

Longitudinal associations between daytime napping and cognitive function in Chinese older adults

BACKGROUND

Little was known about the longitudinal associations between daytime napping and cognitive function in China. Thus, the study aimed to explore the cross-sectional and the longitudinal relationship between daytime napping and cognitive performance in the elderly Chinese population.

METHODS

The data was from the China Health and Retirement Longitudinal Study (CHARLS). Daytime napping was self-reported. Cognitive function was assessed via a structured questionnaire in two dimensions: episodic memory and mental status. Linear regression and mixed-effect model were applied to explore the association between daytime napping and cognitive function.

RESULTS

A total of 2,875 and 2,440 participants aged over 65 years were included in the cross-sectional and the longitudinal studies, respectively. In the cross-sectional study, non-nappers and extended nappers had significantly lower global cognition scores (P<0.01), as well as significantly lower scores for episodic memory (P<0.05) and mental status (P<0.01), compared with moderate nappers. In the longitudinal analysis, no napping and extended napping were significantly associated with global cognitive decline (P<0.05) and only extended napping showed the significant association for the decline in episodic memory as well as mental status (P<0.01).

LIMITATIONS

Daytime napping duration was self-reported by participants.

CONCLUSION

The study found a longitudinal association between extended napping duration and worse cognitive function.

Daytime Napping Benefits Passing Performance and Scanning Activity in Elite Soccer Players

The present study explored the effect of a daytime napping opportunity on scanning activity, which is an essential component of successful soccer performance. Fourteen male elite collegiate soccer players performed the Trail Making Test (TMT), which was used to assess complex visual attention. In addition, a soccer passing test, modified with reference to the Loughborough Soccer Passing Test, was used to evaluate passing performance as well as scanning activity. A cross-over design was applied to examine nap and no-nap interventions. Participants (N = 14, mean age: 21.6 SD = 0.5 years, height: 1.73 ± 0.06 m, body mass: 67.1 ± 4.5 kg) were randomly allocated to a midday nap (40 minutes) or no-nap group. Subjective sleepiness was measured using the Karolinska Sleepiness Scale, and perceptive fatigue was evaluated by the visual analog scale. There were no significant differences in subjective measurements or TMT between the nap and no-nap groups. However, the performance time for the passing test and scanning activity was significantly shorter (p < 0.001) and scanning activity was significantly more frequent in the nap condition than in the no-nap condition (p < 0.00005). These results suggest that daytime napping is beneficial for soccer-related cognitive function, represented by visuospatial processing and decision-making, and particularly as a potential countermeasure to mental fatigue. Considering that inadequate sleep and residual fatigue are commonly observed in elite soccer, this finding may have practical implications for the preparation of players.

Sleep and Performance in Professional Athletes

Purpose of Review

Sleep is an essential human behavior that plays a key role in proper biopsychosocial development as well as short- and long-term biological, physical, psychological, and cognitive health. Sleep plays a key role in athletic performance, influencing an athlete's ability to train, recover, and perform, as well as their overall wellness. Over the recent decade, the awareness of sleep's import has penetrated just about every professional sport domain. The purpose of the review was to identify and synthesize the literature published within the past 5 years (2018-2022) that relates to sleep and performance in professional athletes. Literature related to nonprofessional, high-level athletes (e.g., collegiate; Olympic) was omitted as well as those associated with non-traditional professional sports (e.g., eSports).

Recent Findings

Results from 38 articles were incorporated into this review, which covered (1) the sleep's role in the training, physical injury prevention and recovery, competitive performance, and mental health of professional athletes, (2) common sleep problems and disorders in professional athletes, and (3) the impact of unique challenges from training, travel, competition, and other factors on sleep health. Additionally, we provide an orientation to utilized strategies and interventions to assist with sleep health in professional athletes, as well as conclude with a commentary on critical steps forward.

Summary

Sleep plays a critically important role in the training, recovery, performance, and overall wellness of professional athletes. Professional athletes are vulnerable to a variety of sleep-related problems and disorders, due to unique factors related to training, travel, and competition, among other factors. Improved, standardized research methodology and partnerships between professional athletes, coaches, teams, and organizations and researchers are necessary to advance the knowledge of sleep and performance in professional athletes, including identifying sport-specific differences and variation across individual characteristics, as well as developing individualizable, dynamic, and appropriate interventions for improving sleep health among professional athletes.

Daytime naps and depression risk: A meta-analysis of observational studies

Background

The relationship between daytime napping and depression remains debatable. Thus, a meta-analysis in this study was conducted to evaluate the relationship between daytime napping and depression.

Methods

The PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched up to February 2022, and the reference lists of the included studies were also retrieved. A random-effects model was used to estimate the combined effect size.

Results

Nine studies with 649,111 participants were included in the final analysis. The pooled odds ratio (OR) was 1.15 (95% confidence interval: 1.01-1.31) with a significant heterogeneity (I ² = 91.3%, P for heterogeneity <0.001), and the results demonstrated an increased risk of depressive symptoms among daytime nappers. Visual inspection of the funnel plot and Egger's and Begg's tests identified no obvious evidence of publication bias.

Conclusion

This meta-analysis indicates that daytime naps are a predictor of depression. The effects of daytime napping on depression may vary depending on the characteristics of people, the pattern of naps, and the individual's sleep experience. The findings may have significant implications for future research on depression.

Daytime fluctuations of endurance performance in young soccer players: a randomized cross-over trial

OBJECTIVES

Fluctuations of physical performance and biological responses during a repetitive daily 24-h cycle are known as circadian rhythms. These circadian rhythms can influence the optimal time of day for endurance performance and related parameters which can be crucial in a variety of sports disciplines. The current study aimed to evaluate the daytime variations in endurance running performance in a 3.000-m field run and endurance running performance, blood lactate levels, and heart rate in an incremental treadmill test in adolescent soccer players.

RESULTS

In this study, 15 adolescent male soccer players (age: 18.0 ± 0.6 years) performed a 3.000-m run and an incremental treadmill test at 7:00-8:00 a.m. and 7:00-8:00 p.m. in a randomized cross-over manner. No significant variations after a Bonferroni correction were evident in endurance running performance, perceived exertion, blood lactate levels, and heart rates between the morning and the evening. Here, the largest effect size was observed for maximal blood lactate concentration (9.15 ± 2.18 mmol/l vs. 10.64 ± 2.30 mmol/l, p = .110, ES = 0.67). Therefore, endurance running performance and physiological responses during a field-based 3.000-m run and a laboratory-based test in young male soccer players indicated no evidence for daytime variations.

Benefits and risks of napping in older adults: A systematic review

A growing body of evidence indicates that napping is common among older adults. However, a systematic review on the effect of napping on the elderly is lacking. The aim of this systematic review was to (i) determine how studies evaluated napping behavior in older adults (frequency, duration and timing); (ii) explore how napping impacts perceptual measures, cognitive and psychomotor performance, night-time sleep and physiological parameters in the elderly (PROSPERO CRD42022299805). A total of 738 records were screened by two researchers using the PICOS criteria. Fifteen studies met our inclusion criteria with a mean age ranging from 60.8 to 78.3 years and a cumulative sample size of n = 326. Daytime napping had an overall positive impact on subjective measures (i.e., sleepiness and fatigue), psychomotor performances (i.e., speed and accuracy) and learning abilities (i.e., declarative and motor learning). Additionally, studies showed (i) consistency between nap and control conditions regarding sleep duration, efficiency and latency, and proportion of sleep stages, and (ii) increase of 24 h sleep duration with nap compared to control condition. Based on the findings of the present review, there is minimal evidence to indicate that napping is detrimental for older adults' nighttime sleep. Future studies should consider involving repeated naps during a micro-cycle in order to investigate the chronic effect of napping on older adults.

Running on Empty: Self-Reported Sleep/Wake Behaviour during Ultra-Marathon Events Exceeding 100 Miles

The aim of this study was to examine sleep/wake behaviour and sleep strategies before, during and after ultra-marathon running events exceeding 100 miles (161 km). A total of 119 athletes completed a web-based questionnaire regarding their habitual sleep/wake behaviour before, during, and after ultra-marathon participation. Event-specific data were grouped by race distance categories; 100–149 miles (161–240 km), 150–199 miles (241–321 km), and ≥200 miles (322 km). Athletes commonly reported not sleeping throughout the duration of their races (74%). However, for events that were ≥200 miles, athletes reported more sleep opportunities, longer sleep duration, and more total sleep when compared to events that were 100–149 miles in distance (p ≤ 0.001). This suggests that for races of shorter distances, the benefit of continuous racing outweighs the negative impact of continuous wakefulness/sleep deprivation. However, for longer races (≥200 miles), there is an apparent tradeoff between sleep deprivation and race strategy, whereby athletes cannot sustain a desired level of performance without obtaining sleep. This is consistent with established sleep/wake behaviour models suggesting that sleep need increases as wakefulness increases, or in this case, as race duration increases. For athletes participating in ultra-marathons, sleep management education and/or consultation with a sleep scientist prior to racing may be beneficial. Future research should examine the optimal strategies concerning the frequency and duration of sleep during ultra-marathons and the subsequent impact on performance.

Ramadan Observance Exacerbated the Negative Effects of COVID-19 Lockdown on Sleep and Training Behaviors: A International Survey on 1,681 Muslim Athletes

Objective

Disrupted sleep and training behaviors in athletes have been reported during the COVID-19 pandemic. We aimed at investigating the combined effects of Ramadan observance and COVID-19 related lockdown in Muslim athletes.

Methods

From an international sample of athletes (n = 3,911), 1,681 Muslim athletes (from 44 countries; 25.1 ± 8.7 years, 38% females, 41% elite, 51% team sport athletes) answered a retrospective, cross-sectional questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: (i) Pittsburgh sleep quality index (PSQI); (ii) insomnia severity index (ISI); (iii) bespoke questions about training, napping, and eating behaviors, and (iv) questions related to training and sleep behaviors during-lockdown and Ramadan compared to lockdown outside of Ramadan. The survey was disseminated predominately through social media, opening 8 July and closing 30 September 2020.

Results

The lockdown reduced sleep quality and increased insomnia severity (both p < 0.001). Compared to non-Muslim (n = 2,230), Muslim athletes reported higher PSQI and ISI scores during-lockdown (both p < 0.001), but not pre-lockdown (p > 0.05). Muslim athletes reported longer (p < 0.001; d = 0.29) and later (p < 0.001; d = 0.14) daytime naps, and an increase in late-night meals (p < 0.001; d = 0.49) during- compared to pre-lockdown, associated with lower sleep quality (all p < 0.001). Both sleep quality (χ² = 222.6; p < 0.001) and training volume (χ² = 342.4; p < 0.001) were lower during-lockdown and Ramadan compared to lockdown outside of Ramadan in the Muslims athletes.

Conclusion

Muslim athletes reported lower sleep quality and higher insomnia severity during- compared to pre-lockdown, and this was exacerbated by Ramadan observance. Therefore, further attention to Muslim athletes is warranted when a circadian disrupter (e.g., lockdown) occurs during Ramadan.

Physical Exercise for Health and Performance Post-Pandemic COVID-19 Era, a Renewed Emphasis on Public Health

After the period of forced quarantine due to the COVID-19 epidemic, the physiological principle of detraining became more evident than ever [...].

Hypoxia Differentially Affects Healthy Men and Women During a Daytime Nap With a Dose-Response Relationship: a Randomized, Cross-Over Pilot Study

Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years (Clinicaltrials identifier: NCT04146857, https://clinicaltrials.gov/ct2/show/NCT04146857?cond=napping&draw=3&rank=12). Interventions: Volunteers underwent a polysomnography, hematological and cognitive evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: normobaric normoxia (NN), normobaric hypoxia at FiO2 14.7% (NH15) and 12.5% (NH13), with a washout period of 1 week between conditions. Results: Primary outcome was the interbeat period measured by the RR interval with electrocardiogram. Compared to normobaric normoxia, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p < 0.001). Sympathetic predominance was evident by heart rate variability analysis and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as erythropoietin (∼6 UI/L) and cortisol (∼100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Additionally, although sleep efficiency was preserved, polysomnography showed lesser deep sleep and REM sleep, and periodic breathing, predominantly in men. Conclusion: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.

The Impact of Sleep Inertia on Physical, Cognitive, and Subjective Performance Following a 1- or 2-Hour Afternoon Nap in Semiprofessional Athletes

PURPOSE

This study examined the impact of sleep inertia on physical, cognitive, and subjective performance immediately after a 1- or 2-hour afternoon nap opportunity.

METHODS

Twelve well-trained male athletes completed 3 conditions in a randomized, counterbalanced order-9 hours in bed overnight without a nap opportunity the next day (9 + 0), 8 hours in bed overnight with a 1-hour nap opportunity the next day (8 + 1), and 7 hours in bed overnight with a 2-hour nap opportunity the next day (7 + 2). Nap opportunities ended at 4:00 PM. Sleep was assessed using polysomnography. Following each condition, participants completed four 30-minute test batteries beginning at 4:15, 4:45, 5:15, and 5:45 PM. Test batteries included a warm-up, self-ratings of readiness to perform, motivation to perform and expected performance, two 10-m sprints, 2 agility tests, a 90-second response-time task, and 5 minutes of seated rest.

RESULTS

Total sleep time was not different between conditions (P = .920). There was an effect of condition on readiness (P < .001), motivation (P = .001), and expected performance (P = .004)-all 3 were lower in the 8 + 1 and 7 + 2 conditions compared with the 9 + 0 condition. There was no effect of condition on response time (P = .958), sprint time (P = .204), or agility (P = .240), but a large effect size was observed for agility.

CONCLUSIONS

After waking from a nap opportunity, agility may be reduced, and athletes may feel sleepy and not ready or motivated to perform. Athletes should schedule sufficient time (∼1 h) after waking from a nap opportunity to avoid the effects of sleep inertia on performance.

On the Road to Camarón: The Sleep of an Ultra-Endurance Athlete Cycling 10,000 km in 24 Days

The impact of sleep on performance is fundamental for ultra-endurance athletes, but studies on this issue are rare. The current investigation examined the sleep and performance of a cyclist engaged in a simulated 10,000 km tour. The sleep behavior of the athlete (age, 57; height, 1.85 m; mass, 81 kg) before, during (i.e., 23 nights), and after the tour was monitored using a reduced-montage dry-electroencephalographic (EEG) device. The daily performance (i.e., number of kms) was recorded throughout the race. The cyclist set a new world record, completing 10,358 km in 24 days with a mean daily distance of ≈432 km in approximately 16 h, i.e., an average speed of ≈27 km/h. Sleep duration throughout the tour (5:13 ± 0:30) was reduced compared to the baseline sleep duration (7:00 ± 1:00), with a very large difference (ES = 2.3). The proportion of N3 during the tour (46 ± 7%) was compared to the measured N3 proportion during the baseline (27 ± 5%) and was found to be systematically outside the intra-individual variability (mean ± 1 SD), with a very large difference (ES = 3.1). This ultra-endurance event had a major influence on sleep-duration reduction and a notable modification in sleep architecture. The increase in slow-wave sleep during the race may be linked to the role of slow-wave sleep in physiological recovery.

Barriers to high school and university students' physical activity: A systematic review

Physical inactivity commonly occurs throughout one's life, particularly during adolescence and young adulthood. Multiple factors can negatively influence participation in physical activity, but there has been no review examining the barriers to physical activity among high school and university students. Therefore, the aim of this systematic review was to summarize evidence of barriers to the practice of physical activity among high school and university students. The literature search was conducted without time limits using five databases, including CINAHL, Cochrane Library, Embase, PubMed, and Scopus. In total, 59 studies (37 with high school students [n = 22,908] and 22 with university students [n = 15,411]) were included. The main barriers identified in high school and university students were lack of time, lack of motivation, and lack of accessible places. These findings may be useful in designing and implementing evidence-informed interventions and programs for physical activity promotion in students.

The Impact of a 14-Day Altitude Training Camp on Olympic-Level Open-Water Swimmers' Sleep

Despite the common belief that sleep quality at altitude is poor, the scientific evidence to support this notion is still modest. Therefore, the purpose of the present study was to evaluate possible changes of actigraphy-based and subjective sleep parameters in a group of elite open-water swimmers during a 14-day altitude training camp (ATC) at 1500 m. The study subjects were five Olympic-level open-water swimmers (mean age: 25.0 ± 3.2 years; 3 females and 2 males). All subjects wore a wrist activity monitor and filled a sleep diary for 18 consecutive nights, 4 nights before and 14 nights during ATC. The data were then analyzed at four different time points: before ATC (PRE), the first two days of ATC (T1), and after one (T2) and two weeks of ATC (T3). Training load, assessed as the covered distance (km), session rating of perceived exertion (sRPE), and heart rate (HR), was monitored during the week before and the first and second week of ATC. No significant differences in objective and subjective scores of sleep quality were detected, whereas the sleep onset time (p = 0.018; η2p = 0.83, large) and sleep offset time (p < 0.001; η2p = 0.95, large) significantly differed among PRE, T1, T2, and T3: elite athletes started to sleep and woke up ≃ 1 h earlier the first two days of ATC compared to PRE (sleep onset time: p = 0.049; sleep offset time: p = 0.016). Further, an increase in the training volume during the two weeks of the ATC was observed, with the most time spent in a low-intensity regime and an increase in time spent in a high-intensity regime compared to PRE. Sleep quality was not negatively influenced by a 14-day altitude training camp at 1500 m in a group of Olympic-level elite swimmers despite an increase in perceived exertion during training sessions. Nonetheless, early sleep onset and sleep offset times were observed for the first two nights of ATC: elite athletes started to sleep and woke up ≃ 1 h earlier compared to the baseline nights.

The Relationships of Sleep Duration and Inconsistency With the Athletic Performance of Collegiate Soft Tennis Players

We evaluated the relationships of daily sleep duration and inconsistency with soft tennis competitive performance among 15 healthy collegiate soft tennis players (13 male, 2 female, mean age = 19.7 ± 0.8 years, height = 170.8 ± 7.3 cm, weight = 60.3 ± 5.6 kg, soft tennis experience = 8.7 ± 2.0 years). Sleep duration and inconsistency were determined by a 50-day sleep diary, which recorded sleep and wake times of sleep. Soft tennis athletic performance was evaluated by a service and baseline stroke accuracy test and the spider run test. Mean sleep duration was 7.4 ± 1.7 h. No correlation was found between long-term mean sleep duration and athletic performance. But inconsistency in sleep duration (SD of sleep duration) was inversely correlated with service score after controlling for soft tennis experience and sex (r = −0.56, p = 0.046). There was no significant relationship between sleep inconsistency and other athletic performance. This result indicates that reducing the instability of sleep duration (i.e., sleep regular hours) in the long-term may have a positive effect on soft tennis players’ service performance. Although participants’ current mean sleep duration (7.4 h) was not as sufficient as the recommendation in sleep extension experiments (9–10 h), it revealed the importance for athletes to maintain regular sleep in daily life.

Sleep Architecture in Response to a Late Evening Competition in Team-Sport Athletes

Purpose: The aim of this study was to assess the effect of a late evening competition on sleep characteristics and perceived recovery in team-sport players using a validated self-applicable and portable polysomnographic device. Methods: Sixteen team-sport players (age: 25.4 [1.4] y; body mass index: 23.6 [0.5] kg/m2) completed the study. Objective and subjective sleep data were collected for 4 consecutive nights: 2 nights before (PRE2 and PRE1) and the 2 nights after an evening match (POST1), performed between 6:00 PM and 9:00 PM. Total quality of recovery values were also collected in the morning. Results: A significantly delayed bedtime (P < .0001; , large) was observed in the first night after the competition (2 h 29 min [1 h 15 min]) compared both to PRE2 (+88 min; P < .0001), PRE1 (+98 min; P < .0001), and POST1 (+100 min; P < .0001), and similar results were observed for wake-up time (P = .033; , large): Players woke up significantly later in evening match (9 h 20 min [1 h 55 min]) compared with PRE2 (+85 min; P = .050) and POST1 (+85 min; P = .049). Conversely, total sleep time; sleep efficiency; sleep onset latency; wake after sleep onset; cortical arousals; N1, N2, N3, and REM (rapid eye movement) percentages; total quality of recovery values; and scores of subjective sleep quality did not vary among the 4 study nights. Conclusions: Team-sport players had delayed bedtime and wake-up time following an evening competition; however, sleep quality, duration, and subjective scores of recovery were not affected by the evening match. The delayed wake-up time seems to protect athletes’ sleep efficiency/duration against the evening-match-induced delayed bedtime.

Are elite track and field athletes on track? The impact of COVID-19 outbreak on sleep behavior and training characteristics

The Covid-19 outbreak forced many governments to enter a nationwide lockdown. The aim of this study was to evaluate, by means of a survey, changes in sleep parameters and physical activity characteristics of elite track and field athletes in three periods: before the lockdown (T0), during the lockdown (09th March – 03rd May 2020, T1) and the first month after the lockdown (T2). This study was conducted from May 2020 to June 2020 and data were collected using an offline survey with 89 elite track and field athletes (mean age: 24.7 ± 5.4; n = 43 males; n = 46 females). The survey consisted of demographic data and questions on physical activity and sleep behavior at T0, T1 and T2. Athletes reported lower sleep quality scores at T1 compared to T0 and T2 (p < 0.0001) and registered delayed bedtime, wake-up time and longer sleep latency during the lockdown compared to pre-lockdown and post-lockdown whereas no changes in total sleep time were reported. No inter-group differences were detected in sleep characteristics between short- and long-term disciplines and between genders. The weekly training volume decreased from 16.1 ± 5.7 hours at T0 to 10.7 ± 5.7 hours at T1 (p < 0.0001) whereas no significant differences were detected in training volume during the lockdown in relation to the square footage of the house (p = 0.309). Alcohol (p = 0.136) and caffeine intake (p = 0.990) and use of electronic devices (p = 0.317) were similar pre-, during, and post-lockdown. The unprecedented circumstances of the Covid-19 pandemic had negative impacts on the Italian track and field athletes’ sleep and training volumes.

Sleep Quality in Elite Athletes: Normative Values, Reliability and Understanding Contributors to Poor Sleep

BACKGROUND

The aims of this retrospective study were to (i) provide a description of sleep quality in elite athletes as measured by the Pittsburgh Sleep Quality Index (PSQI), (ii) provide normative PSQI data, (iii) identify differences across sex and sport, (iv) identify components that contribute to high PSQI scores and (v) assess PSQI test-retest reliability.

METHODS

The PSQI was completed by 479 athletes (371 female and 108 male) across 20 Olympic team and individual sports. For ordinal and categorical variables, the Wilcoxon rank sum test and Chi Squared tests were used, respectively. A random forest regression was built to determine the importance of each PSQI component. Test-retest reliability was assessed using two-way mixed effects intraclass correlation coefficients.

RESULTS

Fifty-two percent of athletes had a global PSQI score ≥ 5. Team sport athletes reported significantly longer sleep onset latency times but longer sleep durations compared with individual sport athletes. Sleep onset latency and sleep quality made the greatest contribution to the global PSQI scores. The PSQI demonstrated variability over periods of 2 months or more, with a minimal detectable change of 3 arbitrary units (AU).

CONCLUSION

Long sleep onset latency and poor perceived sleep quality made the greatest contribution to the high PSQI scores observed in approximately half of elite athletes investigated. The PSQI should be administered at regular intervals due to variability within individuals over periods of 2 months or more. Individual questionnaire items or component scores of the PSQI may be useful for practitioners in guiding decision-making regarding sleep interventions in athletes.