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The effect of partial sleep deprivation on weight-lifting performance
Ergonomics
Abstract
This study examined the effects of partial sleep deprivation on submaximal and maximal weight-lifting tasks and on subjective states pre- and post-activity. Eight male subjects (aged 18-24 years) were restricted to a nightly ration of 3 h sleep for 3 successive nights after baseline measures on the first day. A 4 day period where normal sleep was permitted fulfilled a control condition, the normal and sleep-deprived conditions being counterbalanced and separated by 10 days. The weight-lifting tasks consisted of biceps curl, bench press, leg press, and dead lift. For each exercise a submaximal load, corresponding to a fixed value on a category ratio scale of exertion, was determined for 20 repetitions; the maximal lift for that exercise was then obtained. A profile of mood states and subjective sleepiness were determined at each test occasion, tests being conducted in the evening of each day. There was no significant effect of sleep loss on performance of maximal biceps curl (p < 0.05) but a significant effect was noted on maximal bench press, leg press, and dead lift (p < 0.001). Trend analysis indicated decreased performance in submaximal lifts for all the 4 tasks: the deterioration was significant after the second night of sleep loss (p < 0.01). Performing the lifts had little influence on sleepiness ratings which increased linearly with successive days of sleep loss. Mood states of confusion, vigour, and fatigue were affected significantly by the sleep deprivation regimen (p < 0.001), but there was no significant effect of sleep loss or anger, tension, and depression (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
... Strength performance, defined as the ability to exert force on an external object or resistance (Suchomel et al., 2016), is determined by many factors, including musculotendinous stiffness, motor unit recruitment and synchronisation, rate coding (the rate at which action potentials are discharged), intra and intermuscular coordination and neural drive [18], whilst power can be defined as force × velocity. It has previously been noted that any physical performance requiring motor control can be impaired by insufficient sleep [19], with previous studies reporting sleep restriction to decrease vertical jump height [7,20], and negatively affect maximal strength performance [21]. ...
... Scores were summed to provide an ASBQ global score,higher scores were considered indicative of worse sleep habits and sleep hygiene. Participants also completed the reduced morningness:eveningness questionnaire (rMEQ, [27]), with scores summed to determine chronotype classification as reported in Adan and Almirall [27]: definitely morning type (22)(23)(24)(25), moderate morning type (18)(19)(20)(21), neither type (12)(13)(14)(15)(16)(17), moderate evening type (8)(9)(10)(11), definitely evening type (4-7). ...
... Results from the present study demonstrated improved sleep factors to have no significant effect on strength performance. Previous literature regarding the effects of sleep on strength performance are mixed; [21] showed decreased performance of deadlift, leg press and bench press following sleep restriction, whilst other studies have demonstrated strength performance to be maintained during periods of sleep deprivation [52]. Differences in previous findings could be attributed to methodological differences, with Reilly and [21] utilising strength movements requiring a greater degree of technical ability (deadlift, bench press, leg press) and therefore neurological processing, than maximal tests requiring less technical aspects and less coordinated movements, such as handgrip [52] or IMTP, as used in the present study. ...
Improved sleep can enhance sprint, endurance, and sports-specific skills; however, it is yet to be investigated whether improved sleep indices could enhance strength and power performance. Sleep hygiene (SH) is growing in popularity as a tool to enhance sleep indices amongst athletic cohorts, yet the optimal delivery strategy of sleep hygiene education is yet to be determined. Using a randomised, controlled design with repeated measures, this study recruited 34 female footballers playing in WSL or WSL academy league. Participants were split into 3 groups: one receiving both group-based and individualised sleep hygiene education, one receiving only group-based SH education and a control group receiving no education. Monitoring of sleep (actigraphy, diaries) and physical performance (countermovement jump, isometric mid-thigh pull) was carried out at week 1, week 4 and week 7. Split-plot ANOVAs were used to assess for differences between groups × weeks, and groups × time. Individualised sleep hygiene education resulted in significantly improved sleep duration (p = 0.005), latency (p = 0.006) and efficiency (p = 0.004) at week 7 compared to controls, whilst also resulting in significantly improved countermovement jump scores (p = 0.001) compared to control. Results of this study suggest that jump performance may be affected by sleep factors, and that individualised SH may be superior to group-based SH, providing information to coaches regarding training optimisation and the efficacy of SH education methods.
... However, SB could affect health and performance in highly trained athletes. It is interesting that there has been very little research on athletes' SB, and according to the limited available studies specifically on the prevalence of SB in athletes, elite athletes spend a considerable amount of time in SB (7-11 h/day) (Exel et al. 2019;Júdice et al. 2014;Sperlich et al. 2017;Weiler et al. 2015). Moreover, it is known that regular PA may improve both sleep quantity and quality (Lang et al. 2016). ...
... Elite athletes do not meet the traditional 8 h/night recommendation and have reported sleeping 6.5-6.8 h/night (Lastella et al. 2015;Leeder et al. 2012). A number of studies have reported that sleep deprivation has a negative impact on athletic performance, including weightlifting, cardiorespiratory functioning, and psychomotor tasks that require consistent accuracy and performance (Edwards and Waterhouse 2009;Mougin et al. 1991;Reilly and Piercy 1994). A recent study also summarises the effects of reduced sleep on athletic performance and shows that sleep deprivation decreases running performance, muscle glycogen concentration, submaximal strength, isokinetic peak torque, minute ventilation, distance covered, sprint times, tennis-serve accuracy, soccer kicking skills, and time to exhaustion (Vitale et al. 2019). ...
... Although SB is particularly common in our daily life, less attention has been paid to its prevalence with respect to elite athletes; hence, there is a dearth studies about it. Conversely, elite rowers were found to display a considerable sedentary off-training behaviour, thereby spending more than 11.5 h/day (Sperlich et al. 2017). Another study conducted on marathon and half-marathon participants showed that their total sitting time was more than 10 h/day (Whitfield, Pettee Gabriel Kk Fau -Kohl and Kohl 2014). ...
This Sedentary behaviour (SB) affects health and performance in highly trained athletes. A number of research efforts have demonstrated that physical inactivity and SB are two independent entities. However, SB in highly trained athletes in Saudi Arabia has not been studied. Therefore, the aim of this study was to assess SB in Saudi basketball players. Sixteen basketball players (mean ± Standard Deviation (SD), age, 22.6 ± 3.3 years; body mass, 77.8 ± 10.5 kg; height, 182.9 ± 10.8 cm) participated in this study. A self-report SB questionnaire was used to assess time spent on watching television, using a computer/Internet, playing electronic games; total sedentary time; and sleep duration. The cutoff point of ≥2 h/day was used to categorise the outcome. Inadequate sleep duration was defined as <7 (h/night). The results show that 93.7% of basketball payers spent more than 2 h/day in sedentary activities. On average, the total amount of time spent on sedentary activities was 455 ± 218 min/day. Computer/Internet use was the predominant SB (191.8 ± 115.8 min/day) among basketball players, followed by electronic games playing (186.2 ± 113.9 min/day). The mean (±SD) sleep duration for weekdays and weekends were 7.2 ± 1.5 and 7.8 ± 1.6 (h/night), respectively. The weekday and weekend sleep duration analysis also shows that 25% and 12.5% of basketball players had insufficient sleep (<7 h/night) during weekdays and weekends, respectively. These findings indicate that athletes spent significant amounts of time in SB. This may suggest that SB still exists in highly trained athletic people. A quarter of the basketball players had an inadequate weekday sleep duration, and this short weekday sleep was compensated for during the weekend.
... O sono usualmente cumpre uma função de restituição fisiológica no organismo e tem sido considerado um importante fator para o desempenho de atletas (AKERSTEDT; NILSSON, 2003;REARDON et al., 2019), visto que muitos atletas, amadores ou de elite, são maus dormidores e dormem menos do que o suficiente (CARTER et al., 2020;DREW et al., 2018;PEIFFER, 2015;ROBERTS;TEO;WARMINGTON, 2019). Ademais, a PS e a PPS, que diferem entre si no tempo total de PS, usualmente provocam alterações de humor que podem cooperar para prejuízos de desempenho (ANGUS; HESLEGRAVE; MYLES, 1985;BOONSTRA et al., 2007;EDWARDS;WATERHOUSE, 2009;MENEY et al., 1998;REILLY;PIERCY, 1994;SKEIN et al., 2011). ...
... A literatura científica especializada mostra que a PPS promove prejuízos ao desempenho físico e percepto-cognitivo, às respostas fisiológicas ao exercício físico e ao desempenho específico de algumas modalidades esportivas (ABEDELMALEK et al., 2013;AXELSSON et al., 2008;EDWARDS;WATERHOUSE, 2009;LÉGER et al., 2008;MOUGIN et al., 1991MOUGIN et al., , 2001OTMANI et al., 2005;REILLY;PIERCY, 1994;REYNER;HORNE, 2013;SOUISSI et al., 2013;VGONTZAS et al., 2004). Apesar disso, os resultados, que ainda são conflitantes (FULLAGAR et al., 2015(FULLAGAR et al., , 2019VAN CUTSEM et al., 2017b), são incipientes em apontar os mecanismos pelos quais a PPS compromete o desempenho. ...
... Dito isto, apesar do caráter pouco ecológico de alguns procedimentos metodológicos adotados, estudos têm demonstrado prejuízos da PS (AZBOY; KAYGISIZ, 2009;FRÖBERG et al., 1975;PALLESEN et al., 2017;SKEIN et al., 2011SKEIN et al., , 2013SOUISSI et al., 2003;SYMONS;MYLES, 1988;TAKEUCHI et al., 1985) e da PPS (ABEDELMALEK et al., 2013;AXELSSON et al., 2008;EDWARDS;WATERHOUSE, 2009;JARRAYA et al., 2014;LÉGER et al., 2008;MOUGIN et al., 1991MOUGIN et al., , 2001OTMANI et al., 2005;REILLY;PIERCY, 1994;REYNER;HORNE, 2013;SOUISSI et al., 2013;VGONTZAS et al., 2004) no desempenho físico e comportamental de atletas. ...
A fadiga mental (FM) e a privação/privação parcial do sono (PS/PPS), por si só, prejudicam o desempenho percepto-cognitivo e físico de atletas das mais variadas modalidades esportivas. Estudos que avaliem os efeitos da FM e PPS conjugados, que individualizem a carga cognitiva e a duração da PPS e que analisem o desempenho percepto-cognitivo e físico de atletas de voleibol de praia a partir de testes ecológicos são necessários. Esse estudo teve como objetivo analisar os efeitos da PPS e da FM, conjugadas e isoladas, no desempenho percepto-cognitivo e físico em atletas treinados de voleibol de praia. Participaram do estudo 14 atletas treinados de voleibol de praia (12 homens; 17,6±1,5 anos). O estudo foi do tipo experimental de medidas repetidas, cruzado e randomizado e adotou quatro condições experimentais: a) Controle (CT), b) FM, c) PPS e d) PPS+FM. A FM foi induzida pelo Stroop task incongruente e a atividade de sono dos voluntários foi monitorada por oito noites consecutivas. A carga cognitiva e a duração da PPS foram individualizadas. O cumprimento da PPS foi monitorado por formulário online, preenchido em intervalos de 15 minutos pelo tempo que perdurou a PPS. O desempenho físico foi medido por uma série de 50 saltos com contramovimento com intervalos de 5 segundos entre cada salto realizados em esforço máximo e o desempenho percepto-cognitivo foi avaliado via testes visuomotores com luzes de light emitting diode (LED) que simularam ações de defesa e bloqueio no voleibol de praia. Os desfechos primários do estudo foram analisados pela análise de variância ANOVA de um fator (condição [4]) e o post-hoc de bonferroni foi aplicado para localizar as eventuais diferenças estatisticamente significantes. Os dados contínuos estão apresentados como média e desvio padrão e os categóricos como valores absolutos e relativos. A condição PPS causou respostas mais lentas no tempo de reação (TR) “mais rápido” (p=0,02; d de Cohen=1,12; PPS: 1562.14±109.06 ms vs CT: 1440.71±101.41 ms) e “média” (p=0,02; d de Cohen=1,13; PPS: 1874.29±144.63 ms vs CT: 1727.14±113.30 ms) do teste visuomotor de defesa comparado ao CT e a condição PPS+FM apresentou prejuízo no TR “média” (p<0,01; d de Cohen=1,38; PPS+FM: 1906.43±133.45 ms vs CT: 1727.14±113.30 ms) do mesmo teste comparado ao CT. Para o teste visuomotor de bloqueio foi observado que a condição PPS+FM prejudicou o TR “média” (p=0,04; d de Cohen=1,06; PPS+FM: 722.14±100.09 ms vs CT: 631.42±82.17 ms) e “índice de desempenho” (p=0,02; d de Cohen=1,18; PPS+FM: 0,14±0,02 u.a vs CT: 0,16±0,02 u.a) comparado ao CT. O desempenho físico não foi prejudicado por nenhuma condição experimental. Conclui-se, portanto, que a PPS, isolada e conjugada à FM, prejudicam o desempenho percepto-cognitivo de atletas treinados de voleibol de praia, entretanto, os prejuízos da PPS conjugados à FM não se sobrepõem àqueles observados na PPS quando isolada. Adicionalmente, o desempenho físico não foi prejudicado nem pela FM nem pela PPS em atletas treinados de voleibol de praia.
... Compared to baseline values, the experimental group saw a reduction in the upper body mean power by 7.3% while the control group saw no change. Reilly et al. (Reilly and Piercy 1994) showed that short-term sleep restriction (3 h·night −1 for 3 nights) decreased 1-repetition maximum (1RM) for the bench press, leg press, and deadlift. Similarly, Brotherton et al. (Brotherton et al. 2019) showed two consecutive nights of 3 h·night −1 sleep decreased the total force produced at 80% of a bench press 1-RM. ...
... Given the apparent sex-dependent differences in A-and B-terms of the normalized Torque-sEMG relationship, future work should consider sex as an important biological mediator of motor unit behavior with regard to sleep restriction. The magnitude of MVIC difference between SA and SR observed here agrees with previous data reported by others examining short-term exposure to insufficient sleep (Craven et al. 2022;Reilly and Piercy 1994;Brotherton et al. 2019). Brotherton et al. (Brotherton et al. 2019), showed peak force in the bench press was significantly 6.9% lesser following two nights of 3 h night −1 of sleep. ...
Acute sleep restriction (SR) reduces strength through an unknown mechanism. Purpose: To determine how SR affects quadriceps contractile function and recruitment. Methods: Eighteen healthy subjects (9 M, 9F, age 23.8 ± 2.8y) underwent isometric (maximal and submaximal), isokinetic (300–60°·s⁻¹), and interpolated twitch (ITT) assessment of knee extensors following 3d of adequate sleep (SA; 7–9 h·night⁻¹), 3d of SR (5 h·night⁻¹), and 7d of washout (WO; 7-9 h·night⁻¹). Results: Compared to SA (227.9 ± 76.6Nm) and WO (228.19 ± 62.9Nm), MVIC was lesser following SR (209.9 ± 73.9Nm; p = 0.006) and this effect was greater for males (− 9.8 v. − 4.8%). There was no significant effect of sleep or sleep x speed interaction on peak isokinetic torque. Peak twitch torque was greater in the potentiated state, but no significant effect of sleep was noted. Males displayed greater potentiation of peak twitch torque (12 v. 7.5%) and rate of torque development (16.7 v. 8.2%) than females but this was not affected by sleep condition. ITT-assessed voluntary activation did not vary among sleep conditions (SA: 81.8 ± 13.1% v. SR: 84.4 ± 12.6% v. WO 84.9 ± 12.6%; p = 0.093). SR induced a leftward shift in Torque-EMG relationship at high torque output in both sexes. Compared to SA, females displayed greater y-intercept and lesser slope with SR and WO and males displayed lesser y-intercept and greater slope with SR and WO. Conclusions: Three nights of SR decreases voluntary isometric knee extensor strength, but not twitch contractile properties. Sex-specific differences in neuromuscular efficiency may explain the greater MVIC reduction in males following SR.
... The consequences of sleep loss (e.g., altered training adaptations, increased workplace accidents [38,39]) are likely to have multiple aetiologies. Negative consequences may result from a decrease in muscular strength [40] and/or endurance [41], change in mood (e.g., decreased motivation) [42], an increase in perceived effort [43,44], changes to cognitive processing ability (e.g., decision making, executive function) and/or a reduction in fine motor skills [45], or a combination of these factors. ...
... Some studies included in this meta-analysis assessed the influence of sleep loss on more than one performance task, either belonging to the same category [40,41,53,58,59,63,64,[75][76][77][78][79][80][81][82][83][84], or different categories [41, 43, 44, 56-59, 61, 62, 64, 65, 75, 77-81, 85-102]. For example, Souissi et al. [78] measured anaerobic power in two separate tasks (i.e., squat jump and Wingate test). ...
Background
Sleep loss may influence subsequent physical performance. Quantifying the impact of sleep loss on physical performance is critical for individuals involved in athletic pursuits.
Design
Systematic review and meta-analysis.
Search and Inclusion
Studies were identified via the Web of Science, Scopus, and PsycINFO online databases. Investigations measuring exercise performance under ‘control’ (i.e., normal sleep, > 6 h in any 24 h period) and ‘intervention’ (i.e., sleep loss, ≤ 6 h sleep in any 24 h period) conditions were included. Performance tasks were classified into different exercise categories (anaerobic power, speed/power endurance, high-intensity interval exercise (HIIE), strength, endurance, strength-endurance, and skill). Multi-level random-effects meta-analyses and meta-regression analyses were conducted, including subgroup analyses to explore the influence of sleep-loss protocol (e.g., deprivation, restriction, early [delayed sleep onset] and late restriction [earlier than normal waking]), time of day the exercise task was performed (AM vs. PM) and body limb strength (upper vs. lower body).
Results
Overall, 227 outcome measures (anaerobic power: n = 58; speed/power endurance: n = 32; HIIE: n = 27; strength: n = 66; endurance: n = 22; strength-endurance: n = 9; skill: n = 13) derived from 69 publications were included. Results indicated a negative impact of sleep loss on the percentage change (%Δ) in exercise performance (n = 959 [89%] male; mean %Δ = − 7.56%, 95% CI − 11.9 to − 3.13, p = 0.001, I² = 98.1%). Effects were significant for all exercise categories. Subgroup analyses indicated that the pattern of sleep loss (i.e., deprivation, early and late restriction) preceding exercise is an important factor, with consistent negative effects only observed with deprivation and late-restriction protocols. A significant positive relationship was observed between time awake prior to the exercise task and %Δ in performance for both deprivation and late-restriction protocols (~ 0.4% decrease for every hour awake prior to exercise). The negative effects of sleep loss on different exercise tasks performed in the PM were consistent, while tasks performed in the AM were largely unaffected.
Conclusions
Sleep loss appears to have a negative impact on exercise performance. If sleep loss is anticipated and unavoidable, individuals should avoid situations that lead to experiencing deprivation or late restriction, and prioritise morning exercise in an effort to maintain performance.
... Therefore, sleep disturbance causes weight gain [1,2], hastening the onset of diseases and endangering mental health [3], which further results in secondary problems such as lack of concentration and poor academic performance. In athletes, sleep is considered to play an essential role in physical and psychological recovery [4], and inadequate sleep has been associated with muscle weakness [5], increased heart rate, ventilation, lactate production [6], and subjective exercise intensity [5] at specific exercise intensities. Furthermore, numerous previous studies have demonstrated the importance of sleep in health and performance [7,8]. ...
... Therefore, sleep disturbance causes weight gain [1,2], hastening the onset of diseases and endangering mental health [3], which further results in secondary problems such as lack of concentration and poor academic performance. In athletes, sleep is considered to play an essential role in physical and psychological recovery [4], and inadequate sleep has been associated with muscle weakness [5], increased heart rate, ventilation, lactate production [6], and subjective exercise intensity [5] at specific exercise intensities. Furthermore, numerous previous studies have demonstrated the importance of sleep in health and performance [7,8]. ...
Objectives:
This study aimed to characterize the sleep quality and nutrient intake of Japanese female college athletes to provide specific conditioning support.
Methods:
A cross-sectional survey conducted between December 2019 and January 2020 during the regular training season in Niigata City, located at 139°02' E longitude and 37°55' N latitude. Overall, 120 female university student-athletes from eight clubs were selected. All sports were at the national level of competition. The Pittsburgh Sleep Quality Index (PSQI) assessed sleep quality. Nutrient intake was assessed using Excel nutrition software through the Food Intake Frequency Questionnaire.
Results:
The mean PSQI score was 4.5 ± 2.5, with 29% of participants having a PSQI score ≥ 5.5. The sleep duration was 6.8 ± 1.1 h, with 45% of participants sleeping <7 h. The energy intake was 1800 ± 419 kcal, with no correlation between PSQI score and nutrient intake.
Conclusions:
PSQI scores were higher compared with other studies, but many participants had shorter sleep duration and lower nutrient intake, these data suggest that there is the possibility of improving the habits of Japanese athletes by increasing the subjects' amount of sleep time and food intake.
... The last component that we will review and suggest as a potential modifier of maximal isometric strength over time of day is the potential for the muscle circadian clock to effect intrinsic muscle properties that modulate strength. Increasingly, data in both humans and mice suggest that systemic or muscle-specific disruption of the circadian clock results in a reduction of maximal isometric muscle strength (5,24,51,77,83,105). Studies in humans have shown that disruption of the circadian clock mechanism by sleep disruption or sleep deprivation using protocols of 36 h or more of interrupted sleep have been shown to significantly reduce maximal isometric strength by 17% (51,77,105). ...
... Increasingly, data in both humans and mice suggest that systemic or muscle-specific disruption of the circadian clock results in a reduction of maximal isometric muscle strength (5,24,51,77,83,105). Studies in humans have shown that disruption of the circadian clock mechanism by sleep disruption or sleep deprivation using protocols of 36 h or more of interrupted sleep have been shown to significantly reduce maximal isometric strength by 17% (51,77,105). We note that among these studies, Vaara et al. (105) report no significant differences among EMG measures during maximal isometric contractions after sleep deprivation, yet additional studies are needed to fully characterize the effect of sleep deprivation on central motivation and its downstream consequences on isometric strength. ...
For more than 20 years, physiologists have observed a morning-to-evening increase in human muscle strength. Recent data suggest that time-of-day differences are the result of intrinsic, nonneural, muscle factors. We evaluate circadian clock data sets from human and mouse circadian studies and highlight possible mechanisms through which the muscle circadian clock may contribute to time-of-day muscle strength outcomes.
... Sleep has been identified as one of the most important factors in post-performance recovery [29e31]. A lack of sleep has been shown to impair inflammatory and endocrine system responses in exercise-induced muscle damage [31], reduce submaximal performance in strength, whilst inadvertently increasing perceived effort [32] and impair an athlete's immune system [33]. Considering the negative effects on sleep, the risk-benefit ratio of acute caffeine intake by athletes remains ambiguous. ...
Objective
This systematic review aimed to assess the effects of caffeine supplements on sleep parameters among professional athletes.
Methods
A systematic search of randomized controlled trials (PROSPERO: CRD42024505377) was performed from 1980 to December 2023 through Web of Science (ISI), Cinahl, Embase, CENTRAL, PubMed/MEDLINE, Scopus, and Scienceopen. The effect of caffeine supplement on all sleep parameters (e.g. duration, quality, insomnia), assessed through objective and subjective methods, was investigated among the athletic community.
Results
Of 1469 records, nine trials were eligible for the current review. The studies showed varying results concerning sleep quality, quantity, efficiency, number of awakenings, sleep onset latency, and other sleep-related variables. These differences in findings may be attributable to factors such as the timing of caffeine consumption in relation to sleep time and the time of exercise, habitual caffeine use, and the dose of caffeine prescribed. Given the nature of caffeine, insomnia following ingestion is likely to occur.
Conclusions
This review explores the mechanisms by which caffeine influences sleep in athletes. While caffeine supplementation may enhance athletic performance, it could have a detrimental effect on sleep and therefore recovery. It is important that supplementation considers individual responses to caffeine so that it does not adversely affect sleep in this population.
PROSPERO registration number
CRD42024505377
... For instance, regarding muscle strength, some studies suggest that sleep deprivation has detrimental effects [6], manifested by a significant decrease in maximum weights lifted in exercises like bench press, leg press, and deadlifts [7]. However, other research argues that sleep deprivation does not significantly affect muscle explosive strength (both upper and lower body) [8] or sprinting abilities (including linear and agility sprints) [9]. When exploring the effects of sleep deprivation on athletic performance, it is essential to consider multiple factors and conduct specific analyses based on different sports disciplines and individual differences. ...
This study explored the effects of partial sleep deprivation (PSD) on Sanda athletes' athletic performance, an area with limited research. Using a randomized crossover controlled trial with 18 male athletes, the PSD group had 4 h of sleep while the NSN group had 8 h. Results showed that after PSD intervention, the RAT time significantly increased compared to the NSN group (P = 0.0311). However, there was no significant change in CMJ (P = 0.2396) or YBT (left leg: P = 0.2767, right leg: P = 0.3225) between the PSD and NSN groups. In the Wingate test, the PSD group exhibited significant reductions in Pmax and Pave at 10s, 30s, and 60s (P＜0.0001), as well as a significant decrease in Prel at 60s (P＜0.0001), with no significant differences in Prel at 10s and 30s. These findings underscore the detrimental impact of limited sleep on anaerobic performance and agility in Sanda athletes, emphasizing the need for proper sleep management for optimal athletic outcomes.
... The consequences of sleep loss have multiple causes. Negative consequences may result from decreased muscle strength (14) and endurance (15), changes in mood (e.g., decreased motivation) (16), increased perceived effort (17), changes in cognitive processing ability (e.g., decision-making, executive function) and decreased fine motor skills (18), or a combination of these factors. Sleep has two distinct dimensions: quantity and quality. ...
Sleep deprivation negatively affects a person's emotions, cognition, and performance and ultimately reduces safety. The main purpose of this systematic review is to study and report the evidence on the effect of sleep deprivation on the performance of pilots. This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. International databases including PubMed, Web of Science (WOS) and Scopus were considered for the search of English articles up to April of 2023. Keywords were sleep deprivation, pilot, flight, performance, airline, air force, flight safety, fatigue, pilot performance, flight performance, eye movement, workload, motion, visual, attention, errors, cognition, sleep quality, and circadian rhythm. In this systematic review, 12 studies consisting of 259 subjects remained. Most of the studies have reported the negative effects of sleep deprivation in a different way, and the decrease in performance was expressed as one of the important issues following sleep deprivation. As various studies show, any type of sleep deprivation in pilots can have negative effects on their performance, and this decrease in performance can have irreparable consequences.
... 9 Insufficient sleep also affects physical performance, impairing the ability to perform in sports, such as basketball, tennis, running, and weight lifting. [41][42][43] ...
Sleep is what we spend (or should spend) one third of our lives doing. Unfortunately, many individuals fall short of their biological need for sleep many nights of the week. The reasons for this are varied and include professional or personal obligations and social determinants, including loud noises or safety concerns in one's neighborhood. This article reviews the architecture of sleep; evidence for sleep health, including impacts of sleep health on mental and emotional health as well as cognitive function and performance; and strategies for improving sleep health.
... Human studies indicate that disruption of the clock, frequently as a result of sleep disruption or deprivation, reduces maximal isometric strength [38][39][40]. Findings from genetic mutant models of clock components reinforce the notion that circadian control is required for skeletal muscle function [18,26]. Bmal1 deficiency in adult skeletal muscle resulted in reduction in maximum specific tension, accompanied by calcification and decreased collagen content. ...
Circadian clock and clock-controlled output pathways exert temporal control in diverse aspects of skeletal muscle physiology, including the maintenance of muscle mass, structure, function, and metabolism. They have emerged as significant players in understanding muscle disease etiology and potential therapeutic avenues, particularly in Duchenne muscular dystrophy (DMD). This review examines the intricate interplay between circadian rhythms and muscle physiology, highlighting how disruptions of circadian regulation may contribute to muscle pathophysiology and the specific mechanisms linking circadian clock dysregulation with DMD. Moreover, we discuss recent advancements in chronobiological research that have shed light on the circadian control of muscle function and its relevance to DMD. Understanding clock output pathways involved in muscle mass and function offers novel insights into the pathogenesis of DMD and unveils promising avenues for therapeutic interventions. We further explore potential chronotherapeutic strategies targeting the circadian clock to ameliorate muscle degeneration which may inform drug development efforts for muscular dystrophy.
... In this context, it is well established that an alteration in sleep quality and/or quantity can affect physical performance the next day. Indeed, reduced sleep time has been shown to alter aerobic capacity [75], sub-maximum force [76], perceived effort [77], and reaction time [74]. While our study allowed for within-subject and pre-post comparison, the lack of a control group and the randomization of the condition order constrain the generalizability of our findings. ...
Nocturnal smartphone use emits blue light, which can adversely affect sleep, leading to a variety of negative effects, particularly in children. Therefore, the present study aimed to determine the effect of acute (AC) (one night) and repeated (RC) (five nights) nocturnal smartphone exposure on sleep, cortisol, and next-day performance in Tunisian children. Thirteen participants (seven girls and six boys, age 9 ± 0.6, height 1.32 ± 0.06, weight 34.47 ± 4.41) attended six experimental nights. The experiment started with a baseline night (BL) with no smartphone exposure, followed by repeated sessions of nocturnal smartphone exposure lasting 90 minutes (08:00 pm–09:30 pm). Actigraphy; salivary cortisol; the Stroop test (selective attention); choice reaction time (CRT); N-back (working memory); counter-movement jump (CMJ), composed of flight time (time spent in the CMJ flight phase) and jump height; and a 30 m sprint were assessed the morning after each condition. Both AC and RC shortened total sleep time (TST) (p < 0.01), with a greater decrease with RC (−46.7 min, ∆% = −9.46) than AC (−28.8 min, ∆% = −5.8) compared to BL. AC and RC significantly increased waking after sleep onset (3.5 min, ∆% = 15.05, to 9.9 min, ∆% = 43.11%) and number of errors made on the Stroop test (1.8 error, ∆% = 74.23, to 3.07 error, ∆% = 97.56%). Children made 0.15 and 0.8 more errors (∆% = 6.2 to 57.61%) and spent 46.9 s and 71.6 s more time on CRT tasks (∆% = 7.22 to 11.11%) with AC and RC, respectively, compared to BL. The high-interference index of the Stroop task, CMJ performance, and 30 m sprint speed were only altered (p < 0.01) following RC (0.36, Δ% = 41.52%; −34 s, Δ% = −9.29%, for flight time and −1.23 m, −8.72%, for jump height; 0.49 s, Δ% = 6.48, respectively) when compared to BL. In conclusion, one- or five-night exposure to smartphones disturbed the children’s sleep quality and their performance, with more pronounced effects following RC.
... Therefore, during these four weeks of fasting, athletes face acute shortages of food and fluids, sleep deprivation (11)(12)(13) and more changes in psychological and social behaviours that alter the rhythmic pattern of many biological variables (14)(15)(16). Thus, it can negatively affect physical performance (17)(18)(19). ...
Background. Ramadan observance has been practiced by many faith groups and cultures worldwide. Moreover , recently, it has been adopted as a natural alternative to promote public health. During Ramadan, our circadian rhythm can be altered. This study investigates how athletes' chronotype and sleep patterns impact aerobic fitness during Ramadan intermittent fasting. Study design. A prospective cohort design with repeated measurements was adopted. We measured the chronotype, maximal Oxygen Uptake as a measure of aerobic performance, and sleep patterns before and during Ramadan intermittent fasting. Then we explored the correlation among these variables. Methods. 50 amateur athletes (Mean age = 17.22 years SD = 1.15) from Morocco participated in this study. The maximal Oxygen Uptake was measured with the 20-m shuttle-run test. The chronotype was assessed by the Morningness-Eveningness Questionnaire. The sleep timing was assessed by Sleep Timing Questionnaire. We also assessed sleep quality with the Pittsburgh Sleep Quality Index. We examined the difference between variable means before and during Ramadan, also considering chronotype and sleep patterns of participants. Results. The results showed a significant decrease in sleep quality and maximal Oxygen Uptake during the Ramadan Intermittent Fasting. Also, we found a significant correlation between the chronotype, time in bed and time spent asleep. However, chronotype and sleep quality did not affect maximal Oxygen Uptake during the Ramadan intermittent fasting. Conclusions. Sleep and chronotype do not influence physical performance during Ramadan Intermittent Fasting. More research is needed to identify the leading cause of the drop in aerobic performance.
... Impaired or restricted sleep can lead to reduced mean power production in male footballers Abedelmalek et al. (2013) and male physical education students (Souissi et al., 2008). Furthermore, evidence suggests that lack of sleep also affects lower body strength (Reilly & Piercy, 1994) and cardiovascular performance (Azboy & Kaygisiz, 2009). Creating a questionnaire and education resource that outlines the athlete's sleep patterns is a good starting point (Rogers et al., 1993). ...
As the demands of training and competition increase so does the potential risk of injury and illness to the athlete whilst seeking to maximize their adaptive processes to promote optimal performance. Therefore, as a strategy to mitigate this risk, strength and conditioning coaches need reliable and valid monitoring tools to track an athlete's status throughout training to ensure the progression of adaptation, and that the athlete remains healthy throughout the adaptation process. The purpose of this article is to provide the reader with an evidence-driven outline of basic, simple, and cost-effective monitoring tools that are reliable and valid to observe the fitness/fatigue paradigm and track overall athlete physical adaptation and health throughout the training process, suitable for most settings. A weekly example calculating sessional ratings of perceived exertion (sRPE), training load, monotony, and strain is provided along with a basic monitoring system as a guide for the reader.
... Therefore, during these four weeks of fasting, athletes face acute shortages of food and fluids, sleep deprivation (11)(12)(13) and more changes in psychological and social behaviours that alter the rhythmic pattern of many biological variables (14)(15)(16). Thus, it can negatively affect physical performance (17)(18)(19). ...
Background:
Ramadan observance has been practiced by many faith groups and cultures worldwide. Mo-reover, recently, it has been adopted as a natural alternative to promote public health. During Ramadan, our circadian rhythm can be altered. This study investigates how athletes' chronotype and sleep patterns impact aerobic fitness during Ramadan intermittent fasting.
Study design:
A prospective cohort design with repeated measurements was adopted. We measured the chronotype, maximal Oxygen Uptake as a measure of aerobic performance, and sleep patterns before and during Ramadan intermittent fasting. Then we explored the correlation among these variables.
Methods:
50 amateur athletes (Mean age = 17.22 years SD = 1.15) from Morocco participated in this study. The maximal Oxygen Uptake was measured with the 20-m shuttle-run test. The chronotype was assessed by the Morningness-Eveningness Questionnaire. The sleep timing was assessed by Sleep Timing Question-naire. We also assessed sleep quality with the Pittsburgh Sleep Quality Index. We examined the difference between variable means before and during Ramadan, also considering chronotype and sleep patterns of participants.
Results:
The results showed a significant decrease in sleep quality and maximal Oxygen Uptake during the Ramadan Intermittent Fasting. Also, we found a significant correlation between the chronotype, time in bed and time spent asleep. However, chronotype and sleep quality did not affect maximal Oxygen Uptake during the Ramadan intermittent fasting.
Conclusions:
Sleep and chronotype do not influence physical performance during Ramadan Intermittent Fasting. More research is needed to identify the leading cause of the drop in aerobic performance.
... However, Reilly and Deykin (1983) partially restricted sleep for three consecutive nights (2.5 h per night) and reported effects on psychomotor function on the first night, with hand grip strength being affected on the third night. This suggests that when partial sleep loss is employed over multiple nights, impairments on weightlifting performance are more pronounced on the second and third day of sleep loss; suggesting tasks that require greater activation and of larger muscle groups, are more susceptible to sleep loss (Bambaeichi et al. 2005;Reilly and Piercy 1994;Thun et al. 2015). Gross muscular tasks that require less "time on task" are least affected by partial sleep restriction, due to the temporary effort required; in contrast extended tasks or those of a repetitive nature such as Wingate's or sprints are affected to a greater degree (Brotherton et al. 2019;Waterhouse et al. 2007). ...
We have investigated the effects that partial-sleep-restriction (PSR0, 4-h sleep retiring at 02:30 and waking at 06:30 h for two consecutive nights) have on 07:30 and 17:00 h cognitive and submaximal weightlifting; and whether this performance improves at 17:00 h following a 13:00 h powernap (0, 30 or 60-min). Fifteen resistance-trained males participated in this study. Prior to the experimental protocol, one repetition max (1RM) bench press and back squat, normative habitual sleep and food intake were recorded. Participants were familiarised with the testing protocol, then completed three experimental conditions: (i) PSR with no nap (PSR0); (ii) PSR with a 30-min nap (PSR30) and (iii) PSR with a 60-min nap (PSR60). Conditions were separated by 7 days with trial order counterbalanced. Intra-aural temperature, Profile of Mood Scores, word-colour interference, alertness and tiredness values were measured at 07:30, 11:00, 14:00, 17:00 h on the day of exercise protocol. Following final temperature measurements at 07:30 h and 17:00 h, participants completed a 5-min active warm-up before performing three repetitions of left and right-hand grip strength, followed by three repetitions at each incremental load (40, 60 and 80% of 1RM) for bench press and back squat, with a 5-min recovery between each repetition. A linear encoder was attached perpendicular to the bar used for the exercises. Average power (AP), average velocity (AV), peak velocity (PV), displacement (D) and time-to-peak velocity (tPV) were measured (MuscleLab software) during the concentric phase of the movements. Data were analysed using general linear models with repeated measures. The main findings were that implementing a nap at 13:00 h had no effect on measures of strength (grip, bench press or back squat). There was a main effect for time of day with greatest performance at 17:00 h for measures of strength. In addition to a significant effect for "load" on the bar for bench press and back squat where AP, AV, PV, D values were greatest at 40% (P < 0.05) and decreased with increased load, whereas tPV and RPE values increased with load; despite this no interaction of "load and condition" were present. A post lunch nap of 30- and 60-minute durations improved mood state, with feelings of alertness, vigour and happiness highest at 17:00 h, in contrast to confusion, tiredness and fatigue (P < 0.05), which were greater in the morning (07:30 h). The word-colour interference test, used as an indicator of cognitive function, reported significant main effect for condition, with the highest total test score in PSR60 condition (P = 0.015). In summary, unlike strength measures the implementation of a 30 or 60-minute nap improved cognitive function when in a partially sleep restricted state, compared to no nap.
... Nonetheless, studies have consistently established that sleep disturbances are more frequent among women than men. Specifically, females are 1.3 to 1.8 times more likely to report sleeping problems (e.g., interrupted and inadequate sleep, lower sleep quality, and struggling to fall and stay asleep) [28][29][30]. In turn, these problems may negatively impact performance (e.g., in relation to strength) [31], enhance perceived effort, provoke changes in mood (e.g., decreased motivation) [32], induce changes in cognitive processing ability (e.g., executive function), and/or precipitate a decline in motor skills [33]. ...
This study aimed to examine female recreational (FRC) athletes' knowledge of the menstrual cycle and their perception of how each phase affects their performance, mood, and sleep. One hundred and sixty-four (n = 164) FRC athletes completed an online survey. The questionnaire employed was based on previously validated questionnaires and consisted of three different sections: (a) knowledge about the menstrual cycle, (b) menstrual cycle symptoms, and (c) menstrual cycle and performance. The results indicated that 70.1% of the surveyed FRC athletes were not knowledgeable regarding the phases of the menstrual cycle, with 55.5% being ignorant of the specific hormones released during the cycle. Furthermore, 37.8% perceived that their performance was sometimes affected during the early follicular phase, with the main symptoms being physical fatigue (17.9%) and a more irritable mood (25.9%). In addition, 19.5% of the FRC athletes reported sleeping disturbances, and 20.4% described changes in sleep quality during menstruation. Lastly, 11.9% of the FRC athletes reported suffering from a combination of mood swings, sleeping problems, bloating or stomach issues, breast tenderness, headaches, and fatigue prior to menstruation. The results of this study provide valuable insights into how FRC athletes experience the menstrual cycle, which can help RC athletes and trainers better understand their needs and support them in achieving optimal performance.
... Regarding relative sleep deprivation, missing the first few hours of the night doesn't seem to affect performance [201,203,204]. However, partial sleep deprivation over multiple days has been shown to have the opposite effect, probably because it increases perceived effort, sleepiness, and weariness [205]. ...
Objectives
This study was a narrative review of the importance of circadian rhythm (CR), describes the underlying mechanisms of CR in sports performance, emphasizes the reciprocal link between CR, endocrine homeostasis and sex differences, and the unique role of the circadian clock in immune system function and coordination.
Method
As a narrative review study, a comprehensive search was conducted in PubMed, Scopus, and Web of Science (core collection) databases using the keywords “circadian rhythm”, “sports performance”, “hormonal regulation”, “immune system”, and “injury prevention”. Inclusion criteria were studies published in English and peer-reviewed journals until July 2023. Studies that examined the role of CR in sports performance, hormonal status, immune system function, and injury prevention in athletes were selected for review.
Results
CR is followed by almost all physiological and biochemical activities in the human body. In humans, the superchiasmatic nucleus controls many daily biorhythms under solar time, including the sleep-wake cycle. A body of literature indicates that the peak performance of essential indicators of sports performance is primarily in the afternoon hours, and the evening of actions occurs roughly at the peak of core body temperature. Recent studies have demonstrated that the time of day that exercise is performed affects the achievement of good physical performance. This review also shows various biomarkers of cellular damage in weariness and the underlying mechanisms of diurnal fluctuations. According to the clock, CR can be synchronized with photonic and non-photonic stimuli (i.e., temperature, physical activity, and food intake), and feeding patterns and diet changes can affect CR and redox markers. It also emphasizes the reciprocal links between CR and endocrine homeostasis, the specific role of the circadian clock in coordinating immune system function, and the relationship between circadian clocks and sex differences.
Conclusion
The interaction between insufficient sleep and time of day on performance has been established in this study because it is crucial to balance training, recovery, and sleep duration to attain optimal sports performance.
... Sleep is a critical component of optimal physiological function and physical recovery. Sleep deprivation and chronic poor sleep have been shown to negatively impact cognitive functioning [39], learning and memory [40], metabolism and endocrine function [41], and physical performance [42,43]. Reserve Officers' Training Corps cadets are often required to wake up in the early morning for daily physical training, followed by their typical school courses and extracurricular activities. ...
The purpose of this study was to assess the dietary habits, prevalence of low energy availability (EA), and sleep quality in a cohort of male army Reserve Officer Training Corps (ROTC) cadets, and to investigate the relationship between EA and sleep quality as well as EA and various body composition variables that are important for tactical readiness. Thirteen male army ROTC cadets (22.2 ± 4.1 yrs; BMI: 26.1 ± 2.3) had their EA and body composition assessed using diet and exercise records alongside bioelectrical impedance analysis. Cadets also completed a validated sleep questionnaire. Sixty-two percent of participants presented with clinically low EA (<30 kcal/kg fat-free mass [FFM]) and none met the optimum EA threshold (≥45 kcals/kg FFM). Dietary analysis indicated that 15%, 23%, 46%, 23%, and 7% of cadets met the Military Dietary Reference Intakes (MDRI) for calories, carbohydrates, protein, fat, and fiber, respectively. Additionally, 85% of cadets exhibited poor sleep quality. Significant associations between EA and fat mass/percent body fat were shown (p < 0.05). There was, however, no statistically significant correlation between EA and sleep quality. The present study found a high prevalence of low EA and sleep disturbance among male army ROTC cadets and that many were unable to meet the MDRIs for energy and macronutrient intake. Further, low EA was associated with higher percent body fat and fat mass but not sleep quality.
... High fatigue levels might be related to disturbances in sleep (Fullagar et al. 2016), and studies in partial sleep deprivation conducted with athletes reported increased fatigue, increased errors, reduced maximal power, and impaired decision-making (Reilly and Edwards 2007). Even though athletes might be able to overcome the adverse effects of sleep loss in single all-out efforts (Reilly and Edwards 2007), this might not be the case in prolonged training sessions and competitions (Reilly and Piercy 1994;Reilly and Edwards 2007). Studies conducted with clinical populations have also found that disrupted sleep is linked with greater fatigue and poorer health (Lorton et al. 2006). ...
The current study aimed to describe sleep habits and analyze the associations between sleep indices, changes in perceived fatigue (Δ Fatigue) and external training load measures in women soccer players during a 7-day training camp. Sixteen elite women soccer players (age: 25.4 ± 3.6 years; mean ± SD) from the Portuguese Women’s National Team participated in the study. Sleep indices (sleep duration and efficiency) were measured using a wrist-worn accelerometer. External training loads measures were measured using GPS devices. Players also reported perceived fatigue using a Likert scale (1 - very, very low to 7 – very, very high) before and immediately after sleep. Players' within- subject coefficient of variation for sleep duration was 5.6%, and 4.6% for sleep efficiency. Individually, 8 players (50%) slept less than 7 h per night throughout the training camp, and the same number of athletes had a sleep efficiency lower than 85%. Similar values (p<0.05) were measured for sleep duration and efficiency between training and match days. A moderate negative within-subjects correlation was found between Δ Fatigue and sleep duration (adjusted for pre-sleep fatigue) [r = -0.32; 95% Confidence Interval (-0.51 – -0.08); p = 0.04]. These findings reinforce the importance of sleep in the recovery process of elite women soccer players, showing that more sleep may help to attenuate fatigue.
... 23 Further, sleep duration and quality during season were found to have an impact on athletes' physical performance during weight-lifting, cardiorespiratory functioning, and psychomotor tasks that require accuracy and consistent performance. [24][25][26][27] While having naps, sleep extension, and sleep-hygiene practices during season appear advantageous to performance. 28,29 Sleep deprivation has cognitive consequences and can negatively affect physical performance during sport tasks including decision making, reaction time and attention, fine motor coordination, and imprinting memories which are crucial for athletic performance. ...
... Auch die Befunde, dass sich eine geringere Schlafdauer und eine längere Einschlaflatenz darauf auswirken, dass das Training am folgenden Tag als intensiver wahrgenommen wird, decken sich mit vorangegangenen Studien. Diese zeigten sowohl, dass die körperliche Leistung nach schlechter Schlafqualität eingeschränkt ist, als auch eine damit einhergehende höhere subjektive Trainingsbelastung und geringere Vitalität während des Trainings (Fullagar et al., 2015;Reilly & Piercy, 1994;Sinnerton & Reilly, 1992). ...
Zusammenfassung. In dieser Studie wurde das Schlaf-Wach-Verhalten jugendlicher Elite-Mannschaftsathleten in Österreich im Zusammenhang mit deren Training untersucht. Dafür wurden 104 Athleten ( M=14.52 Jahre, SD=0.40), die jeweils Mitglied eines U15/U16 Teams im Fußball ( n=69) oder Eishockey ( n =35) waren, über mehrere Wochen (14 – 42 Tage) per Aktigraphie und Schlafprotokoll untersucht. Zusätzlich wurden der Chronotyp (D-MEQ) und die allgemeine Schlafqualität (PSQI) erhoben. Es wurde angenommen, dass die Schlafqualität vor Trainings- und Spieltagen geringer ist als vor Ruhetagen und dass sich eine geringe Schlafqualität negativ auf die Trainingsintensität auswirkt. Es konnte gezeigt werden, dass die Athleten an Ruhetagen eine längere Schlafdauer aufweisen. Es hat sich außerdem bestätigt, dass eine kürzere Schlafdauer und längere Einschlaflatenz einen negativen Einfluss auf die wahrgenommene Trainingsintensität am folgenden Tag haben. Ein stärkerer Einbezug der Schlafqualität bei Leistungsanalysen und in der Gestaltung von Trainingsplänen wird empfohlen.
... Brotherton et al. (2019), in their extensive study, reported favourable effects of nap on components of bench press and leg press, through improvement in sleepiness, alertness and tiredness. However, variables of bench press were more affected than those of leg press, as a result of effective sleep loss being complex in lifts with higher skill-orientation and with a more significant cognitive component, i.e., bench press in this study (Brotherton et al., 2019;Drust et al., 2005;Reilly & Piercy, 1994). Napping had equivocal effects on grip strength as reported by two studies (Brotherton et al., 2019;Waterhouse et al., 2007), with the inconsistent finding estimated due to differences in nap duration. ...
Background
Sleep is the body’s natural recovery process, restoring routine metabolic and regulatory functions. Various sleep interventions have been developed to facilitate recovery, and athletic performance, and daytime napping are among them. However, due to inconsistencies in studies, it remains unclear whether daytime napping affects sports performance. This article aims to review the effects of daytime napping on various variables of sports performance in physically active individuals with and without partial-sleep deprivation.
Methods
A systematic search in three clinical databases, namely Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, and Web of Science, was conducted. To be included in the current review, the study should be a randomized controlled trial that evaluated the influence of daytime napping on one or more components of sports performance in healthy adults, 18 years old or older.
Results
In the accessible data available until December 2021, 1,094 records were found, of which 12 relevant randomized controlled trials were selected for qualitative synthesis. The majority of studies reported favourable effects of daytime napping on sports performance. However, only one study reported no significant impact, possibly due to a different methodological approach and a shorter nap duration.
Conclusion
Napping strategies optimize sports performance in physically active, athletic populations, benefitting partially sleep-deprived and well-slept individuals, with longer nap durations (~90 min) having more significant advantages. Daytime naps can be considered as cost-efficient, self-administered methods promoting recovery of body functions.
... Insufficient sleep results in compromised athletic performance [11]. Interventional studies controlling for sleep duration have shown that subjective effort (rating of perceived exertion: RPE) during an exercise task progressively increased over subsequent days of sleep restriction (~3 h/night) [35]. Though this was shorter sleep than most of the participants in the current study, these results support the notion that 1 week, or an entire semester, of disrupted sleep via early morning PT may exacerbate the response to exercise. ...
Sleep and circadian rhythms are critically important for optimal physical performance and maintaining health during training. Chronotype and altered sleep may modulate the response to exercise training, especially when performed at specific times/days, which may contribute to musculoskeletal injury. The purpose of this study was to determine if cadet characteristics (chronotype, sleep duration, and social jetlag) were associated with injury incidence and inflammation during physical training. Reserve Officers’ Training Corps (ROTC) cadets (n = 42) completed the Morningness/Eveningness Questionnaire to determine chronotype, and 1-week sleep logs to determine sleep duration and social jetlag. Salivary IL-6 was measured before and after the first and fourth exercise sessions during training. Prospective injury incidence was monitored over 14 weeks of training, and Army Physical Fitness Test scores were recorded at the conclusion. Chronotype, sleep duration, and social jetlag were assessed as independent factors impacting IL-6, injury incidence, and APFT scores using ANOVAs, chi-squared tests, and the t-test where appropriate, with significance accepted at p < 0.05. Evening chronotypes performed worse on the APFT (evening = 103.8 ± 59.8 vs. intermediate = 221.9 ± 40.3 vs. morning = 216.6 ± 43.6; p < 0.05), with no difference in injury incidence. Sleep duration did not significantly impact APFT score or injury incidence. Social jetlag was significantly higher in injured vs. uninjured cadets (2:40 ± 1:03 vs. 1:32 ± 55, p < 0.05). Exercise increased salivary IL-6, with no significant effects of chronotype, sleep duration, or social jetlag. Evening chronotypes and cadets with social jetlag display hampered performance during morning APFT. Social jetlag may be a behavioral biomarker for musculoskeletal injury risk, which requires further investigation.
... These findings align with previous literature where maximal speed, power, and strength have been found to not be negatively impacted by acute sleep deprivation (Blumert et al., 2007;Fullagar et al., 2015;Reilly & Edwards, 2007;Watson, 2017). Interestingly, sustained partial sleep deprivation of three hours' sleep per night over three nights has negatively impacted strength performance in weightlifting athletes (Reilly & Piercy, 1994), suggesting that performance decrements may only arise with sustained sleep deprivation. Sleep deprivation was not observed in the seven nights recorded (Figure 2), as all nights met the recommended sleep durations (Hirshkowitz et al., 2015). ...
... Considering that depression and sleep dysfunction can result in poor performance and increased injury incidence 4,18) , the rapid increase in depression and sleep dysfunction is a problem that must be addressed urgently. Psychosocial interventions, such as cognitive behavioral therapy (CBT) promote positive emotional states and increased rehabilitative adherence, both of which facilitate recovery from injury 19) . ...
This study aimed to observe the conditions of Japanese college athletes during the COVID-19 pandemic for the prevention of psychiatric and sleep disorders. A survey was conducted with 100 players before and after they refrained from sports activities due to the emergency measures (April 7–May 14, 2020) against COVID-19. The survey items used were the Hospital Anxiety and Depression Scale (HADS) for psychiatric symptoms (anxiety and depression) and the Pittsburgh Sleep Quality Index (PSQI) for sleep. A survey on the living conditions was based on a web-based questionnaire. Sleep dysfunction (PSQI ≥ 6), anxiety (HADS-A ≥ 8), and depression (HADS-D ≥ 8) were found in 20 (20%), 19 (19%), and 18 (18%) players before the emergency measures, and 32 (32%), 20 (20%), and 31 (31%) players after emergency measures, respectively. Of the 100 participants, 36 (36%) developed sleep dysfunction or depression as they lived alone, were anxious about school life (e.g., friendships), and were financially unstable regarding living expenses (e.g., not able to work part-time). Due to these findings, it is necessary to actively intervene in the mental health of university students.
... Additionally, research has predominantly investigated males undergoing either total sleep 67 deprivation [for example, (Blumert et al., 2007;Meney, Waterhouse, Atkinson, Reilly, & 68 Davenne, 1998)] or severe sleep restriction (e.g. 3 hours' sleep) during limited periods of 69 time [for example, (Reilly & Piercy, 1994;Souissi et al., 2013)]. Sleep restriction impairs 70 muscle strength in multi-joint, compound exercises (Knowles et al., 2018), which are 71 commonly used by practitioners for their transferability to athletic performance (8). ...
... maximal strength) is fluid, and can be impacted by additional stressors such as poor nutrition, sleep deprivation, and residual fatigue. [46][47][48][49][50] VBT, however, allows practitioners to account for such variation in strength through its basic principles. 45 Participants divulged other benefits of VBT. ...
Velocity-based training (VBT) is a contemporary prescriptive, programming, and testing tool commonly utilised in strength and conditioning (S&C). Over recent years, there has been an influx of peer-reviewed literature investigating several different applications (e.g. load-velocity profiling, velocity loss, load manipulation, and reliability of technology) of VBT. The procedures implemented in research, however, do not always reflect the practices within applied environments. The aim of this study, therefore, was to investigate the perceptions and applications of VBT within elite S&C to enhance contextual understanding and develop appropriate avenues of practitioner-focused research. Fourteen high-performance S&C coaches participated in semi-structured interviews to discuss their experiences of implementing VBT into their practices. Reflexive thematic analysis was adopted, following an inductive and realist approach. Three central organising themes emerged: Technology, applications, and reflections. Within these central themes, higher order themes consisting of drivers for buying technology; programming, testing, monitoring, and feedback; and benefits, drawbacks, and future uses also emerged. Practitioners reported varied drivers and applications of VBT, often being dictated by simplicity, environmental context, and personal preferences. Coaches perceived VBT to be a beneficial tool yet were cognizant of the drawbacks and challenges in certain settings. VBT is a flexible tool that can support and aid several aspects of S&C planning and delivery, with coaches valuing the impact it can have on training environments, objective prescriptions, tracking player readiness, and programme success.
... 23 Further, sleep duration and quality during season were found to have an impact on athletes' physical performance during weight-lifting, cardiorespiratory functioning, and psychomotor tasks that require accuracy and consistent performance. [24][25][26][27] While having naps, sleep extension, and sleep-hygiene practices during season appear advantageous to performance. 28,29 Sleep deprivation has cognitive consequences and can negatively affect physical performance during sport tasks including decision making, reaction time and attention, fine motor coordination, and imprinting memories which are crucial for athletic performance. ...
Background:
There is inconsistency in the relationship between sleeping measures and the occurrence of soccer injuries. Further, most studies investigated sleeping quantity and quality during soccer season but not during off-season. The purpose of this study was to determine the influence of sleeping off-season and during soccer season on the occurrence of injuries in professional soccer players. It was hypothesized that lower sleeping hours and players' thought of inadequate sleeping quantity and quality during off-season and soccer season would associate with the occurrence of soccer injuries.
Methods:
One-hundred and fifty-two professional soccer players (premier league and division I teams, age: 21.82±4.44, BMI: 22.21±2.74, sex: men(n=91), women (n=61)) answered questions related to their sleeping duration and whether that amount of sleep was enough prior to (off-season) and during soccer season. The sleep questions related to sleep quantity were derived from the Arabic Pittsburgh Sleep Quality Index. Players indicated also. Players indicated their injury profile, medical treatment, and time loss due to soccer injury. Sleeping measures were evaluated using univariate and multivariate logistic regression models to determine predictors of soccer injuries.
Results:
Sixty-eight players (44.73%) were injured. Lower total sleeping time during off-season (OR:0.66, 95%CI:0.51-0.85, p=0.002), answering no on "did you regularly get enough sleep during off-season" (OR: 5.64, 95%CI: 2.58-12.27, p<0.001), and answering no on "do you think that your sleeping hours during off-season were enough" (OR:4.76, 95%CI: 1.98-11.46, p=0.001) associated significantly with soccer injuries (R2:38).
Conclusions:
Lower total sleeping time and not getting regularly enough sleeping time during off-season associated with more soccer injuries. This highlights the influence of sleeping quantity and quality off-season on the occurrence of soccer injuries among professional players.
... It appears that efforts of sub-maximal strength requiring sustained exertion has greater vulnerability than a single effort of maximal strength or power. Early work examining this revealed that three nights of sleep reduction decreased sub-maximal and maximal deadlift, bench press, and leg press (Reilly & Piercy, 1994). More recently, effects of 24 hours of sleep deprivation on weightlifting performance were examined in national standard collegiate weightlifters. ...
... During resistance exercise, the extent of fatigue may be dependent on the level of effort [6], type of exercise selection [7], degree of active muscle mass [8], or volume of training [9]. Taking into consideration other variables such as sleep [10] and stress [11], the rate of recovery may dictate the readiness for the subsequent workout. Although less recovery time between each resistance training session (i.e., < 24 h between sessions vs. < 48-72 h between sessions) may not necessarily cause negative outcomes in muscle growth and strength within a short period of time (i.e., 12 weeks) [12], it has been suggested that improper post-exercise recovery or sequence of training may result in an increase in accumulated fatigue [13,14]. ...
It has been suggested that improper post-exercise recovery or improper sequence of training may result in an ‘accumulation’ of fatigue. Despite this suggestion, there is a lack of clarity regarding which physiological mechanisms may be proposed to contribute to fatigue accumulation. The present paper explores the time course of the changes in various fatigue-related measures in order to understand how they may accumulate or lessen over time following an exercise bout or in the context of an exercise program. Regarding peripheral fatigue, the depletion of energy substrates and accumulation of metabolic byproducts has been demonstrated to occur following an acute bout of resistance training; however, peripheral accumulation and depletion appear unlikely candidates to accumulate over time. A number of mechanisms may contribute to the development of central fatigue, postulating the need for prolonged periods of recovery; however, a time course is difficult to determine and is dependent on which measurement is examined. In addition, it has not been demonstrated that central fatigue measures accumulate over time. A potential candidate that may be interpreted as accumulated fatigue is muscle damage, which shares similar characteristics (i.e., prolonged strength loss). Due to the delayed appearance of muscle damage, it may be interpreted as accumulated fatigue. Overall, evidence for the presence of fatigue accumulation with resistance training is equivocal, making it difficult to draw the conclusion that fatigue accumulates. Considerable work remains as to whether fatigue can accumulate over time. Future studies are warranted to elucidate potential mechanisms underlying the concept of fatigue accumulation.
... baseline metrics. 25 However, it should be noted that athletes in this study were sleep restricted for three consecutive nights, and significant changes were only noted following the second night. Studies evaluating anaerobic performance following one single night of sleep deprivation have shown that acute sleep loss yielded no difference in power output or weightlifting performance. ...
Young athletes commonly suffer from both acute and chronic sleep deprivation. This has been linked to increased injury rates and decreased athletic and neurocognitive performance. Conversely, sleep optimization in young athletes can lead to improved athletic performance and greater competitive success, with improvement in metrics such as speed, endurance, reaction time, accuracy, alertness, and overall well-being. When aiming to optimize sleep, key elements such as sleep duration, quality, and regularity must be addressed. Clinicians can assess baseline sleep hygiene in young athletes, and educate them on proper methods to optimize sleep. Such methods include limiting screen time before bed, getting exposure to sunlight in the early morning, maintaining an optimal bedroom temperature, avoiding caffeine, and maintaining a consistent sleep schedule throughout the week.
... Frequent maximum testing could therefore create unwanted fatigue, potentially impacting on performances throughout the year [5]. While this is unlikely to be problematic in settings where 1RMs are relatively stable (e.g., strength sports), maximum strength might fluctuate in athletes competing in these sports due to training priorities [5], sleep [6], nutrition [7], and/or fatigue [8]. As a result, alternative strategies such as 1RM prediction from load-velocity profile (LVP) data might be an effective strategy to manipulate load (i.e., autoregulation), which is thought to be vital to optimize athletic development [9]. ...
The study aim was to compare different predictive models in one repetition maximum (1RM) estimation from load-velocity profile (LVP) data. Fourteen strength-trained men underwent initial 1RMs in the free-weight back squat, followed by two LVPs, over three sessions. Profiles were constructed via a combined method (jump squat (0 load, 30–60% 1RM) + back squat (70–100% 1RM)) or back squat only (0 load, 30–100% 1RM) in 10% increments. Quadratic and linear regression modeling was applied to the data to estimate 80% 1RM (kg) using 80% 1RM mean velocity identified in LVP one as the reference point, with load (kg), then extrapolated to predict 1RM. The 1RM prediction was based on LVP two data and analyzed via analysis of variance, effect size (g/), Pearson correlation coefficients (r), paired t-tests, standard error of the estimate (SEE), and limits of agreement (LOA). p < 0.05. All models reported systematic bias < 10 kg, r > 0.97, and SEE < 5 kg, however, all linear models were significantly different from measured 1RM (p = 0.015 <0.001). Significant differences were observed between quadratic and linear models for combined (p < 0.001; = 0.90) and back squat (p = 0.004, = 0.35) methods. Significant differences were observed between exercises when applying linear modeling (p < 0.001, = 0.67–0.80), but not quadratic (p = 0.632–0.929, = 0.001–0.18). Quadratic modeling employing the combined method rendered the greatest predictive validity. Practitioners should therefore utilize this method when looking to predict daily 1RMs as a means of load autoregulation.
... Elite athletes do not meet the traditional 8 h/night recommendation and have reported sleeping 6.5-6.8 h/night (Lastella et al. 2015;Leeder et al. 2012). A number of studies have reported that sleep deprivation has a negative impact on athletic performance, including weight-lifting, cardiorespiratory functioning, and psychomotor tasks that require consistent accuracy and performance (Edwards and Waterhouse 2009;Mougin et al. 1991;Reilly and Piercy 1994). A recent study also summarises the effects of reduced sleep on athletic performance and shows that sleep deprivation decreases running performance, muscle glycogen concentration, submaximal strength, isokinetic peak torque, minute ventilation, distance covered, sprint times, tennis-serve accuracy, soccer kicking skills, and time to exhaustion (Vitale et al. 2019). ...
... In a study by Pallesen et al. (12) in 2017, it was found that soccer players skills were negatively affected by SD. In addition, Reilly et al. (13) measured the effects of SD on lift performance and concluded that SD could negatively affect performance. While sleep and appetite are in relationship, there is still a controversial between sleep and appetite relationship (14). ...
Objective:
Sleep and awakening are a biological cycle that is affected by physiological function, light and darkness, work programs, and other activities. The vital role of sleep in body function and appetite is essential, and this is especially important for athletes. Meanwhile, the conditions of soccer players are such that they are deprived of sleep, and this is a risk to a professional athlete. The aim of the current study was to examine the effects of overnight sleep deprivation on appetite and physical performance in elite female soccer players.
Materials and Methods:
Twelve elite female soccer players in the premier league of Iran with 10-year history were selected to the study (age: 28.50±3.45 yr, height: 160.50±4.07 cm, weight: 55.12±3.52 kg, body mass index: 21.38±1.06 kg/m2). Subjects were evaluated in two rounds with normal sleep and deprivation of night sleep (DNS) and between these two rounds was also a recovery week. The evaluations included physical performance and appetite.
Results:
DNS had a significant effect on appetite (feeling hungry, full, satiate, and eating desire), reaction time, balance (static and dynamic), anaerobic power (peak power, minimum power, average power, and fatigue index), and aerobic performance (p≤0.05).
Conclusion:
DNS may induce disruptions on the appetite and physical performance of elite soccer players. For these, athletes should take into consideration adequate night sleep before performing physical tasks.
This chapter aims to illustrate the impact of sleep deprivation on athletic performance. Sleep research distinguishes between total, partial, and selective sleep deprivation. In rats, sleep deprivation of two to three weeks leads to death under experimental conditions. In humans, due to ethical reasons, only shorter periods of sleep deprivation have been studied. Here too, losses are primarily seen in cognitive performance, with microsleep episodes in particular reducing performance after sleep deprivation. In addition, there are negative changes in memory formation, pain perception, the immune system, and metabolism. The effects on motor skills such as strength and endurance are rather minor due to sleep deprivation. Various recommendations for action arise for sports practice, although various questions still need to be investigated.
Short sleep duration is prevalent in modern society and may be contributing to type 2 diabetes prevalence. This review will explore the effects of sleep restriction on glycemic control, the mechanisms causing insulin resistance and whether exercise can offset changes in glycemic control. Chronic sleep restriction may also contribute to a decrease in physical activity leading to further health complications.
Background
Sleep is often compromised in athletes. The monitoring of athlete’s sleep is an important preventative and educational tool. With many athletes using daily questionnaires to estimate sleep quality, there is a need to understand what this term is indicating when self-reported, and thus whether a self-report of this factor is useful.
Aims
This study aimed to compare self-reported and actigraph reported sleep quality, with a view to further understanding the constructs of this parameter.
Methods
Twenty-two national level female footballers provided a daily self-report of sleep quality (Likert scale) across 7 days, whilst also wearing an actigraph across the same testing period. Linear regression analysis was carried out to see which actigraph derived factors contributed to self-report score.
Results
The incorporation of SE, number of wakings and SFI could only account for 27.5% of variance in self-reported sleep quality scores. Number of wakings was the only significant predictor for self-reported sleep quality score (p = 0.000).
Conclusions
When asking for self-report of sleep quality, coaches should infer that number of wakings may be predicting for the Likert score given. Further discussion around this is advised, given the multifactorial nature of sleep quality and the potential for many contributing factors to affect scoring.
Introduction:
Female athletes sleep less and report more sleep problems than males. Inadequate sleep reduces maximal strength in males; however, little is known about the impact of sleep restriction on the quantity and quality of resistance exercise performed by females. This study investigated the effect of nine nights of moderate sleep restriction on repeated resistance exercise performance, hormonal responses and perceived fatigue in females.
Methods:
Ten healthy, resistance-trained, eumenorrheic females aged 18-35 years underwent nine nights of sleep restriction (SR; 5-h time in bed) and normal sleep (NS; ≥7 h time in bed), in a randomised, cross-over fashion with a minimum 6-week washout. Participants completed four resistance exercise sessions per trial, with blood samples collected pre- and post-exercise. Exercise performance was assessed using volume-load, reactive strength index and mean concentric velocity with rating of perceived exertion recorded post-exercise. Participants completed awakening saliva sampling and the multi-component training distress scale daily.
Results:
Volume-load decreased trivially (<1%, p < 0.05) with SR. Mean concentric velocity per set was slower during SR for lower body (up to 15%, p < 0.05), but not upper body, compound lifts. Intra-set velocity loss was up to 7% greater during SR for back squats (p < 0.05). SR increased salivary cortisol area under the curve (by 42%), total training distress (by 84%) and session perceived exertion (by 11%).
Conclusions:
Sustained SR reduces markers of resistance exercise quality (bar velocity) more than quantity (volume-load), and increases perceived effort at the same relative intensity in resistance-trained females. Markers of exercise quality and internal load may be more sensitive than volume-load, to advise coaches to the decline in lifting performance for females experiencing sleep restriction.
Athletic performance is mutually dependent upon individual constraints and practical interventions. Regarding the former, it is recognised that brain activity and sleep indices can modulate movement planning and execution. Concerning the strategies used in practice, contemporary short-term prescriptions have been adopted by conditioning professionals and physiotherapists with the primary intention to acutely enhance musculoskeletal power output or accelerate post-exercise recovery processes. These includes postactivation performance enhancement (PAPE)-based plyometric warm-up and induced cooling (COOL) through ice packs, respectively. However, it remain unknown whether measures of brain dynamics and natural sleep patterns influence skill-related performance in soccer. To date, the literature does not show a consensus for PAPE effectiveness in young populations. Generally, COOL also negatively affects subsequent lower limb movements requiring high force-velocity levels. Based on these assumptions, the general aim of the current thesis was to investigate the influence of internal individual constraints (EEG and sleep-derived indices) and effects of short-term practical interventions (PAPE and COOL) on the movement kinematics and performance aspects of soccer kicking in youth academy players. A series of six studies is presented. These include a literature review, one technical note and four original experimental research articles (two observational and two interventions) in an attempt to answer the questions defined in the research programme. From the data gathered here, it was possible to provide evidence that a) kick testing in studies systematically lacked resemblance to competition environments; b) occipital brain waves during the preparatory phase determines ball placement while late frontal signalling control both ankle joint in impact phase and post-impact ball velocity; c) poor sleep quality and late chronotype preference are linked to subsequent impaired targeting ability; d) acute enhancements achieved via PAPE/plyometric conditioning are purely neuromuscular, being slightly converted into kicking mechanics or performance improvements; e) in a hot environment, repeated high-intensity running efforts impair both ball placement and velocity whilst a local 5-minutes COOL application assists recovery of overall kick parameters and f) a markerless deep learning-based kinematic system appear as reliable alternative in capturing on-field kicking motion patterns. To conclude, both internal individual constraints (EEG and sleep quality) and a short-term practical intervention (cooling quadriceps/hamstrings with ice packs) have an acute impact in kicking performance in youth soccer context. A model integrating evidence from all papers is presented alongside limitations and recommendations for future studies in this field.
Keywords: Technical skill; 3-dimensional kinematics; Accuracy; EEG; Human movement; Motor Control; Biomechanics.
Many types of research over several decades prove that sleep is a significant factor for human performance. The sleep behaviour of sportspersons in
particular is very different from the normal folks or members of other occupational groups such as police and the military, office-going folks.
Henceforth, this study is projected to investigate the changes in sports persons' sleep behaviour due to the COVID-19 lockdown in India. For which,
the survey was conducted among 514 sportspersons representing various Universities (296 male/218 female) across various states of India using a
simple random sampling technique. The composed data were analyzed using a paired samples t-test. The results of this study indicated that the sleep
behaviour of sportspersons was affected during the COVID-19 lockdown in India.
Objective:This study aims to evaluate the effects of melatonin supplementation on the physical and physiological performance following total night sleep deprivation in trained young males.Materials and Methods:Ten trained young males (23.4±1.71 years, 23.96±1.63 kg/m2) participated in four sessions (sessions 1 and 2, nightly habitual sleep; sessions 3 and 4, total night sleep deprivation). Then, using the double-blind design, subjects were divided into two groups of who took melatonin supplement (10 mg) and placebo, respectively. The subjects were tested by the implementation of the sleep protocol. Then, they consumed the supplement and waited for 30-45 min for secondary measurements. In each measurement, physical and physiological performances were evaluated.Results:Total night sleep deprivation application resulted in a significant decrease in the salivary level of melatonin and impairment in static and dynamic balance, auditory reaction time, jump, upper body, lower body and handgrip strength performance (p
Distinguishes 6 factors in the working situation influencing the effect of environmental stress upon performance: (1) the duration of work on the task, (2) the familiarity of the operator with the stress and with the work he has to do under stress, (3) the level of incentive of the operator, (4) the kind of work he has to do, (5) the aspect of performance which is most important, and (6) the presence of other stresses in the working situation. The examples taken to illustrate the importance of these factors come from only 4 stresses: heat, loss of sleep, noise, and alcohol. (61 ref.)
6 Ss worked a full day, mainly on vigilance and calculation tests, for 2 successive days in each of 6 successive wk. On the preceding nights they were allowed 0, 1, 2, 3, 5, or 7.5 hr. sleep varying according to the week of testing. Less than 5 hr. sleep on a single night impaired vigilance; less than 3 hr. impaired calculation. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Investigated the responses of a 31-yr-old male athlete to continuous paced work at moderate intensity for 100 hrs under conditions of controlled liquid and energy intake. Heart rate (HR) increased at first, then gradually declined to reach a steady state after 44 hrs. Lung function (vital capacity and forced expiratory volume) and reaction time showed a significant deteriorating trend over the experimental period. HR, lung function, and reaction time were significantly intercorrelated. Subjective time perception was correlated with reaction time and HR. Blood glucose levels were not related to any of the other variables. None of the variables exhibited a circadian rhythm. Periodicities over 8, 48, and 96 hr cycles were observed in lung function. Scores in 2 mental performance tests were not greatly affected over the duration of the experiment. (31 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The effect of 60 h of sleep deprivation (SD) upon physical performance and physiological responses to exercise was examined in 11 male subjects. The experiment consisted of two conditions separated by at least 10 d. In the experimental condition (E) subjects remained awake for 60 h and in the control condition (C) the same subjects had 7 h of sleep per night. In both conditions subjects reported to the laboratory on the evening prior to d 1 and slept for 7 h. Physical performance testing was carried out on d 1 and again on d 3 after either two nights of sleep or two nights of SD. Results obtained on d 3 are expressed relative to d 1, the control day. Maximal isometric and isokinetic muscular strength and endurance of selected upper and lower body muscle groups, performance of the Wingate Anaerobic Power Test, simple reaction time, the blood lactate response to cycle exercise at 70% VO2max, and most of the cardiovascular and respiratory responses to treadmill running at 70% and 80% VO2max, were not significantly altered as a result of SD. These results suggest that sleep loss of up to 60 h will not impair the capability for physical work, a finding of considerable importance in sustained military operations which frequently involve the combination of both physical and mental tasks.
Human capabilities in manual materials-handling activities may be influenced by a number of task variables. The psychophysical method of Snook (1978) was used to determine the effects of load and lifting frequency upon workloads selected by eight male soldiers. The subjects repeatedly lifted and lowered a box (38 × 55 × 24 cm) to and from a platform set at 40% stature for 10 minutes and either adjusted the load, or the lifting frequency, or a combination of both variables in order to select a workload which they considered to be a maximum acceptable workload (MAWL) for a work-period of one hour. When the lifting frequency was adjusted, the mean MAWL was 94·5 kg m min (S.D. 28·4). This was significantly greater (P ≤ 0·05) by 27% than when the load alone was adjusted (74·3 kg m min , S. D. 23·3). Control of both variables together produced a MAWL of 76·5 kg m min (S. D. 24·1) which was similar to that selected when the load alone was adjusted.When the soldiers lifted and lowered their selected workloads for a one-hour work-period, the average heart rate was 101 beats min and the mean oxygen cost was 23·3% of their maximal oxygen uptake (determined by cycle ergometry). The work intensity was subjectively assessed as ‘Fairly Light’ using the Rating of Perceived Exertion scale (Borg 1971). In spite of significant differences between the MAWLs selected by the adjustment of the two variables, the physiological measurements and subjective assessments made whilst lifting these workloads were not significantly different. This suggests that other factors may influence an individual's perception of MAWL.The results in this study may have been affected by limitations imposed by the experimental design. However, they do suggest that the frequency of lifting could be a more appropriate variable to manipulate in the self-selection of workloads.
The effects of physical exercise and sleep deprivation on mood and cognitive performance were studied in 12 healthy young male volunteers deprived of sleep on two occasions. During the first 60-hr period without sleep, half of the subjects walked on a treadmill at 25–30% of their maximum aerobic capacity (Exercise condition) for 1 out of every 3 hrs while the remaining 6 subjects remained physically inactive (No Exercise condition) during that same hour. Eight weeks later the same 12 subjects underwent an identical sleep-deprivation protocol except that those who were previously inactive exercised, while those who previously exercised remained inactive. Throughout the sleep deprivation periods, subjects in both conditions completed subjective assessments of fatigue, sleepiness and mood every 3 hrs, performed an auditory vigilance task every 6 hrs, and completed a cognitive test battery every 12 hrs. The results revealed clear decrements in mood and performance as a function of sleep loss. However, with the exception of somewhat more long reaction times in the Exercise condition, exercise neither increased nor decreased the impairment induced by sleep deprivation.
Muscular performance was tested during 64 hours of sleep deprivation with and without intermittent excercise (treadmill walking at 28% of maximum oxygen intake). The subjects (12 males aged 22·7 ± 2·2 years) carried out a cross-over trial with an 8 week interval separating the two periods of sleep deprivation. The sleep deprivation did not change the time for a 40 m dash, isometric handgrip force or balance (stabilometer test). Vertical jump height decreased, the change being significant for simple sleep deprivation, but not for the combination of deprivation and intermittent exercise. Sleep deprivation decreased isokinetic extension force at 60° s−1, while intermittent walking decreased isokinetic extension force at both 60 and 180° −1; however, there was no significant difference between exercise plus sleep deprivation and sleep deprivation alone at either angular velocity. We conclude that the moderate intensity of physical activity likely in industrial work has little influence upon human performance under conditions of sleep deprivation.
Sleep is commonly viewed to be a state of enhanced tissue growth and repair ('restitution'), following the wear and tear of wakefulness. One of the major findings appearing to support this hypothesis is that for certain hormones, which amongst their various activities have anabolic action, a heightened release is displayed during human sleep, and prominent within this group is human growth hormone (hGH). The substantial sleep-hGH output is mostly associated with the deep form of non-dreaming sleep (usually referred to as slow wave sleep, SWS, because of its EEG characteristics), found in the first few hours of sleep. However, the significance of the sleep-hGH release for this restitution starts to become obscure when one notes that other hormones integral to anabolism, such as insulin, display no sleep-related release. As will be seen, there are several other findings which have been taken as signs of this restitution, which on further analysis turn out to be misleading in this respect. In fact it is beginning to appear that for the majority of tissues, excluding the brain, sleep may well be a state of tissue degradation, owing to the night-time fast.
There is a great demand for perceptual effort ratings in order to better understand man at work. Such ratings are important complements to behavioral and physiological measurements of physical performance and work capacity. This is true for both theoretical analysis and application in medicine, human factors, and sports. Perceptual estimates, obtained by psychophysical ratio-scaling methods, are valid when describing general perceptual variation, but category methods are more useful in several applied situations when differences between individuals are described. A presentation is made of ratio-scaling methods, category methods, especially the Borg Scale for ratings of perceived exertion, and a new method that combines the category method with ratio properties. Some of the advantages and disadvantages of the different methods are discussed in both theoretical-psychophysical and psychophysiological frames of reference.
Acute loss of sleep produces few apparent physiological effects at rest. Nevertheless, many anecdotes suggest that adequate sleep is essential for optimum endurance athletic performance. To investigate this question, heavy exercise performance after 36 h without sleep was compared with that after normal sleep in eight subjects. During prolonged treadmill walking at about 80% of the max, sleep loss reduced work time to exhaustion by an average of 11% (p=0.05). This decrease occurred despite doubling monetary incentives for subjects during work after sleeplessness. Subjects appeared to fall into “resistant” and “susceptible” categories: four showed less than a 5% change in performance after sleep loss, while four others showed decrements in exercise tolerance ranging from 15 to 40%. During the walk, sleep loss resulted in significantly greater perceived exertion (p<0.05), even though exercise heart rate and metabolic rate ( and) were unchanged. Minute ventilation was significantly elevated during exercise after sleep loss (p<0.05). Sleep loss failed to alter the continuous slow rises in
E and heart rate that occurred as work was prolonged. These findings suggest that the psychological effects of acute sleep loss may contribute to decreased tolerance of prolonged heavy exercise.
Sleep loss alters the perceptual response to exercise: subjects describe constant external work loads as more severe after sleep deprivation. However, since subjects cannot be "blind" to their sleep status and have knowledge of previous exertional ratings, it remains unknown if this increase in perceived exertion merely represents expectations of increased difficulty of exercise after sleep loss. As one approach to this problem, we asked 24 subjects to produce equivalent "very hard" efforts, once after normal sleep, and once after 30 h without sleep. This was done by allowing the subject, while walking at constant speed, to adjust treadmill grade, without knowledge of the actual elevation. We found that exercise at equal perceived exertion was associated with the choice of a nearly equal absolute work load after sleep deprivation as after normal sleep (17.1 vs. 17.5% grade; p = n.s.). In addition, after 10 min of exercise at the self-selected intensity, subjects displayed identical ventilation, oxygen uptake, and CO2 production. However, heart rate was significantly lower during exercise after sleep loss (170 +/- 3 vs. 178 +/- 3 b X min-1; p less than 0.001). These results suggest that previously measured increases in perceived exertion during constant-load exercise after sleep loss may be spurious.
Psychophysical basis of perceived exertion Human sleep and tissue restitution; some qualifications and doubts
- G 1 Borg
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- J A Horne
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EITS Manual for the Profile of Mood States. San Diego: Educational and Industrial Testing Service
- D M Mcnair
- M Lorr
- MCNAIR D. M.
Effects of partial sleep loss on subjective states, psychomotor and physical performance tasks
- T Reilly
- REILLY T.
Effects of partial sleep deprivation on performance measures in females
- T Reilly
- REILLY T.
Effect of sleep loss and time of day in swimmers
- S Sinnerton
- SINNERTON S.
Development and use of the Stanford Sleepiness Scale
- E Hoddes
- W Dement
- HODDES E.