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Sleep Extension: Getting as Much Extra Sleep as Possible
Abstract
Nearly all people, whether they consider themselves sleep deprived or not, can initially obtain extra sleep. However, as accumulating extra sleep reduces carryover sleep debt, a point is reached where it is no longer possible to obtain extra sleep. If there were a practical method to make a precise measurement of a person's daily sleep requirement, it may be possible to show that most individuals are carrying a very large sleep debt. Several observations and studies demonstrate that almost everyone is sleep deprived and carries some amount of sleep debt. How long such an indebtedness will persist without change if no extra sleep is obtained is not known.
... 17 Ultimately, this highlights the complexities of obtaining additional sleep within an apparently healthy population and reintroduces the contention that continued periods of nightly sleep extension could have little usefulness for some individuals. 17,18 Indeed, it has been theorized that humans, whether sleep deprived or not, can initially obtain additional sleep. 18 However the accumulation of additional sleep is contemporaneous with reductions in sleep debt, with further sleep beyond this point becoming challenging. ...
... 17,18 Indeed, it has been theorized that humans, whether sleep deprived or not, can initially obtain additional sleep. 18 However the accumulation of additional sleep is contemporaneous with reductions in sleep debt, with further sleep beyond this point becoming challenging. 18 This notion may be particularly applicable to the SH athletes of this investigation given that they appeared to obtain sufficient quantities and quality of sleep prior to SH education. ...
... 18 However the accumulation of additional sleep is contemporaneous with reductions in sleep debt, with further sleep beyond this point becoming challenging. 18 This notion may be particularly applicable to the SH athletes of this investigation given that they appeared to obtain sufficient quantities and quality of sleep prior to SH education. 19 In fact, throughout the entire duration of the investigation, SH athletes averaged 8 hours or greater time in bed and 7 hours or greater sleep duration. ...
Objective:
To examine the usefulness of sleep hygiene education on the sleep of professional rugby league athletes during a 10-week period of the competitive season.
Design:
Case study.
Participants:
Twenty-four professional rugby league athletes.
Measurements:
Initially, participants were monitored for a 2-week period using wrist activity monitors allowing baseline estimation of sleep. Following this, 12 athletes attended two 30-minute sleep hygiene education seminars delivered over successive weeks, whereas the remaining 12 athletes received no education. Sleep was monitored in all athletes across the 2-week education period and for a 2-week period 1 month following the end of education. Split-plot analysis of variance and paired t tests were used to examine differences in sleep across the duration of the investigation.
Results:
An initial sleep hygiene education seminar resulted in an earlier bedtime (effect size [ES] = 0.53 ± 0.48), more time in bed (ES = 0.53 ± 0.49), and increased sleep duration (ES = 0.47 ± 0.44). A second sleep hygiene education seminar resulted in more time in bed (ES = 0.84 ± 0.50) but a reduction in sleep efficiency (ES = 1.15 ± 0.48). One month following sleep hygiene education, sleep behavior was comparable to that observed at baseline.
Conclusion:
This study shows that sleep hygiene education can lead to positive changes in sleep behavior. However, changes in sleep from education may not be sustained following the initial intervention.
... Sleep curtailment encountered by players during training and competitive days may lead to large amounts of additional sleep on off days when the number of commitments that compete for the players' time is reduced [33]. Players anecdotally report extended sleep periods (i.e., sleeping late in the morning, long nap) when there are fewer morning requirements. ...
... Regarding the nap timing, sleep efficiency is better, sleep latency is shorter, and the amount of slow-wave sleep is greater with a nap taken closer to the afternoon circadian dip in alertness than with a nap taken during the morning or evening (around 8:00-10:00 pm) forbidden zone for sleep [40,41]. Third, as chronic partial sleep loss is the most important cause of increased daytime sleep tendency [33], players may be tempted by minimal daytime behaviors during off days (e.g., staying on sofa exposed to indoor lighting) rather than active behaviors. However, neurometabolic theories of sleep function propose that sleep repays the neural and metabolic cost of waking [8]. ...
... However, neurometabolic theories of sleep function propose that sleep repays the neural and metabolic cost of waking [8]. Consequently, players may be encouraged to be gently active throughout the day in order to sleep continuously through the subsequent night [33]. Getting up and spending 10 h only out of bed (i.e., 10 h of wakefulness) may not provide enough waking sleep deprivation to foster a continuous occurrence of the constitutional nightly requirement [33]. ...
In elite soccer, players are frequently exposed to various situations and conditions that can interfere with sleep (e.g., playing night matches interspersed with 3 days; performing activities demanding high levels of concentration close to bedtime; use of products containing caffeine or alcohol in the period preceding bedtime; regular daytime napping throughout the week; variable wake-up times or bedtime), potentially leading to sleep deprivation. We outline simple, practical, and pharmaceutical-free sleep strategies that are coordinated to the constraints of elite soccer in order to promote sleep. Sleep deprivation is best alleviated by sleep extension; however, sleep hygiene strategies (i.e., consistent sleep pattern, appropriate napping, and active daytime behaviors) can be utilized to promote restorative sleep. Light has a profound impact on sleep, and sleep hygiene strategies that support the natural environmental light-dark cycle (i.e., red-light treatment prior to sleep, dawn-simulation therapy prior to waking) and prevent cycle disruption (i.e., filtering short wavelengths prior to sleep) may be beneficial to elite soccer players. Under conditions of inordinate stress, techniques such as brainwave entrainment and meditation are promising sleep-promoting strategies, but future studies are required to ascertain the applicability of these techniques to elite soccer players. Consuming high-electrolyte fluids such as milk, high-glycemic index carbohydrates, some forms of protein immediately prior to sleep, as well as tart cherry juice concentrate and tryptophan may promote rehydration, substrate stores replenishment, muscle-damage repair and/or restorative sleep. The influence of cold water immersion performed close to bedtime on subsequent sleep is still debated. Conversely, the potential detrimental effects of sleeping medication must be recognized. Sleep initiation is influenced by numerous factors, reinforcing the need for future research to identify such factors. Efficient and individualized sleep hygiene strategies may consequently be proposed.
... Historically, the term 'sleep extension' was used to describe protocols designed to maximize time in bed, effectively extending total sleep duration. Broadly, the goal of earlier sleep extension research was to quantify changes in sleep structure and cognition resulting from sleep extension, in part, to help understand the homeostatic regulation of sleep (Barbato & Wehr, 1998;Barbato et al., 1994;Dement, 2005;Roehrs et al., 1989;Wehr, 1991;Wehr et al., 1993). For example, findings from one study in eight healthy men showed that 4 weeks of extending time in bed from 8 to 14 h per day led to lower fatigue, increased vigour and higher rapid eye movement (REM) density during REM sleep episodes that terminated in wakefulness (Barbato et al., 1994). ...
... For example, findings from one study in eight healthy men showed that 4 weeks of extending time in bed from 8 to 14 h per day led to lower fatigue, increased vigour and higher rapid eye movement (REM) density during REM sleep episodes that terminated in wakefulness (Barbato et al., 1994). Additionally, early research from Carskadon and Dement showed that four nights of 10 h time in bed led to improved scores on the multiple sleep latency test, reflecting decreased homeostatic sleep pressure from sleep extension (Dement, 2005). Although promising, such findings might not apply directly to people with free-living HSSD, because previous sleep extension studies were often conducted in laboratory settings in healthy adults who otherwise maintained adequate sleep duration. ...
Short sleep duration is associated with heightened cardiometabolic disease risk and has reached epidemic proportions among children, adolescents and adults. Potential mechanisms underlying this association are complex and multifaceted, including disturbances in circadian timing, food intake and appetitive hormones, brain regions linked to control of hedonic eating, physical activity, an altered microbiome and impaired insulin sensitivity. Sleep extension, or increasing total sleep duration, is an emerging and ecologically relevant intervention with significant potential to advance our understanding of the mechanisms underlying the association between short sleep duration and the risk of cardiometabolic disease. If effective, sleep extension interventions have potential to improve cardiometabolic health across the lifespan. Existing data show that sleep extension is feasible and might have potential cardiometabolic health benefits, although there are limitations that the field must overcome. Notably, most existing studies are short term (2–8 weeks), use different sleep extension strategies, analyse a wide array of cardiometabolic health outcomes in different populations and, frequently, lack adequate statistical power, thus limiting robust scientific conclusions. Overcoming these limitations will require fully powered, randomized studies conducted in people with habitual short sleep duration and existing cardiometabolic risk factors. Additionally, randomized controlled trials comparing different sleep extension strategies are essential to determine the most effective interventions. Ongoing and future research should focus on elucidating the potential cardiometabolic health benefits of sleep extension. Such studies have high potential to generate crucial knowledge with potential to improve health and quality of life for those struggling with short sleep duration. image
... Sleep debt is a concept that indicates the total amount of sleep lost by an individual [5]. Sleep debt worsened presenteeism on linear distribution and indicated that absolute sleep duration does not reflect the amount of sleep an individual required [6]. ...
... Participants with a negative sleep debt index were excluded following previous studies [6]. A negative value for the sleep debt index is not the definition of sleep debt [5]. Participants with more than 16 h of sleep duration on weekdays were excluded. ...
Background
Presenteeism is an indicator of productivity loss and the risk of absence from work due to mental health problems. The purpose of this study was to determine the impact of sleep debt, social jetlag, and insomnia symptoms on presenteeism and psychological distress.
Methods
The participants were 351 Japanese workers (271 males, 79 females, and one of other gender, with a mean age of 49 ± 9.49 years). The eligibility criteria for this study were full-time employment, working eight hours per day, five days per week, and no night shifts. The participants answered questionnaires measuring sleep debt, social jetlag, insomnia symptoms, presenteeism, and psychological distress.
Results
Insomnia symptoms had the greatest impact on presenteeism and psychological distress when compared with sleep debt and social jetlag (adjusted odds ratio (OR) = 5.61, 95% confidence interval (CI) = 2.88–10.91; adjusted OR = 7.29, 95%CI = 3.06–17.35). Sleep debt had a greater impact on presenteeism and psychological distress than did social jetlag (adjusted OR = 1.61, 95%CI = 1.14–2.27; adjusted OR = 1.68, 95%CI = 1.11–2.54), which had no impact on these variables (adjusted OR = 1.04, 95%CI = 0.91–1.20; adjusted OR = 0.96, 95%CI = 0.76–1.22).
Conclusions
The findings of this study indicated that insomnia symptoms had a more significant impact on presenteeism and psychological distress than social jetlag and sleep debt. Although sleep debt might have an independent impact on presenteeism and psychological distress, social jetlag did not.
... It is assumed that great parts of the general population as well as athletes experience regular sleep restriction and, therefore, are accumulating sleep debt (Dement, 2005). A simple and obvious countermeasure is to get as much extra sleep as possible, until extra benefits are no longer produced (Dement, 2005). ...
... It is assumed that great parts of the general population as well as athletes experience regular sleep restriction and, therefore, are accumulating sleep debt (Dement, 2005). A simple and obvious countermeasure is to get as much extra sleep as possible, until extra benefits are no longer produced (Dement, 2005). Substantial benefits for alertness, mood and performance have been shown following extended sleep for several nights in non-athletic individuals (Kamdar et al., 2004). ...
Recovery is essential for high athletic performance, and therefore especially sleep has been
identified as a crucial source for physical and psychological well-being. However, due to earlymorning
trainings, which are general practice in many sports, athletes are likely to experience
sleep restrictions. Therefore, this study investigated the sleep–wake patterns of 55 junior
national rowers (17.7 ± 0.6 years) via sleep logs and actigraphy during a four-week training
camp. Recovery and stress ratings were obtained every morning with the Short Recovery and
Stress Scale on a 7-point Likert-type scale ranging from 0 (does not apply at all) to 6 (fully
applies). The first training session was scheduled for 6:30 h every day. With two to four
training sessions per day, the training load was considerably increased from athletes’ home
training. Objective sleep measures (n = 14) revealed less total sleep time (TST) in the first two
weeks (409.6 ± 19.1 and 416.0 ± 16.3 min), while training volume and intensity were higher. In
the second half of the camp, less training sessions were implemented, more afternoons were
training free and TSTs were longer (436.3 ± 15.8 and 456.9 ± 25.7 min). A single occasion of
1.5-h delayed bedtime and usual early morning training (6:30 h) resulted in reduced ratings of
Overall Recovery (OR) (M = 3.3 ± 1.3) and greater Negative Emotional State (NES) (M = 1.3 ± 1.2,
p < .05), which returned to baseline on the next day. Following an extended night due to the
only training-free day, sleep-offset times were shifted from ~5:30 to ~8:00 h, and each
recovery and stress score improved (p < .01). Moreover, subjective ratings of the first six
days were summarised as a baseline score to generate reference data as well as to explore the
association between sleep and recovery. Intercorrelations of these sleep parameters emphasised
the relationship between restful sleep and falling asleep quickly (r = .34, p < .05) as well
as few awakenings (r = .35, p < .05). Overall, the findings highlight the impact of sleep on
subjective recovery measures in the setting of a training camp. Providing the opportunity of
extended sleep (and a day off) seems the most simple and effective strategy to enhance
recovery and stress-related ratings.
... Interestingly, longer sleep is associated with lower risk of injury and may help protect cognitive capacities that underlie most cognitive processes during subsequent sleep loss. 25 Preserving sleep prior to mission may therefore be an important health and performance enhancement intervention. ...
Cold weather operations are logistically difficult to orchestrate and extremely challenging for soldiers. Decades of research and empirical evidence indicate that humans are extremely vulnerable to cold and that individual responses are highly variable. In this context, it may be necessary to develop personalised strategies to sustain soldiers’ performance and ensure overall mission success in the cold. Systematic cold weather training is essential for soldiers to best prepare to operate during, and recover from, cold weather operations. The purpose of this review is to highlight key aspects of cold weather training, including (1) human responses to cold, (2) nutrition, (3) sleep and (4) protective equipment requirements. Bringing science to practice to improve training principles can facilitate soldiers performing safely and effectively in the cold. Cold weather training prepares soldiers for operations in cold, harsh environments. However, decreases in physical, psychological and thermoregulatory performance have been reported following such training, which influences operational ability and increases the overall risk of injuries. When optimising the planning of field training exercises or operational missions, it is important to understand the soldiers’ physical and cognitive performance capacity, as well as their capacity to cope and recover during and after the exercise or mission. Even though the body is fully recovered in terms of body composition or hormonal concentrations, physical or cognitive performance can still be unrecovered. When overlooked, symptoms of overtraining and risk of injury may increase, decreasing operational readiness.
... Wehr et al. [46] reported that in a study with 15 healthy young adults aged 20-36 years, the total sleep duration was significantly longer during nights, with a 10 h daily photoperiod (mean: 8.23 hours; standard deviation: 0.85 h) compared to nights with a 16 h daily photoperiod (mean: 7.18 h; standard deviation: 0.26 h). According to Dement [47], Barbato et al. [48] monitored the sleep of eight healthy males with an average age of 29.0 years over five weeks. The daily photoperiod was set at 16 h in the first week and was reduced to 10 h over the following four weeks. ...
A significant number of adolescents experience sleepiness, primarily due to sleep deprivation. The detrimental effects of inadequate sleep on both physical and mental health are well documented, particularly during adolescence—a critical developmental stage that has far-reaching implications for later life outcomes. The International Classification of Diseases 11th Revision recently introduced the disorder termed ‘insufficient sleep syndrome,’ characterized by a persistent reduction in sleep quantity. However, diagnosing this condition based solely on sleep duration is challenging due to significant individual variation in what constitutes optimal sleep. Despite this, managing sleep debt remains difficult without a clear understanding of individual optimal sleep needs. This review aims to reassess recommended sleep durations, with a focus on enhancing sleep literacy. Beginning with an exploration of insufficient sleep syndrome, this review delves into research on optimal sleep duration and examines foundational studies on sleep debt’s impact on the developing brain. Finally, it addresses the challenges inherent in sleep education programs from the perspective of sleep literacy. By doing so, this review seeks to contribute to a deeper understanding of the chronic sleep debt issues faced by adolescents, particularly those affected by insufficient sleep syndrome.
... Obtaining sufficient sleep during weekdays decreases the degree to which CUS is required on weekends. Moreover, consistent with the idea that almost everyone is constantly sleep deprived and carries some amount of sleep debt [7,9,10], weekend sleep extension may have a favorable effect [7]. Nonetheless, this possible favorable effect is more likely to emerge among individuals who maintain their ability to obtain sufficient sleep and need only a small amount of weekend CUS within their controllable range, than among those who are impaired in their ability to obtain sufficient sleep or need a greater amount of weekend CUS beyond their controllable range. ...
Health effects of weekend catch-up sleep (CUS) could differ depending on both the ability to obtain sufficient sleep during weekdays and amount of weekend CUS required to compensate for sleep lost during the week. Using data from 3128 middle-aged (40–64 years) participants of the Sleep Heart Health Study, we examined the longitudinal association of these two aspects of sleep with all-cause mortality. CUS was calculated as the difference in self-reported habitual sleep duration between weekends and weekdays, and classified into no, short (1 h), and long (2 h or more) CUS. Polysomnography-measured total sleep time, representing the ability to obtain sufficient sleep, was classified into short (< 360 min) or normal (≥ 360 min) sleep durations. We estimated multivariable-adjusted mortality hazard ratios (HRs) and 95% confidence intervals (CIs) for six groups divided by the extent of CUS and sleep duration. Participants were followed up for a median (interquartile range) of 12.3 (11.3–13.5) years. Short weekend CUS with normal sleep duration was associated with lower mortality compared to no CUS with normal sleep duration (HR, 0.48; 95% CI 0.27–0.83). When stricter cutoffs were applied for sleep durations, while the protective effect of short CUS with normal sleep duration (≥ 390 min) was strengthened (HR, 0.36; 95% CI 0.17–0.78), the harmful effect of short CUS with short sleep duration (< 330 min) emerged (HR, 1.84; 95% CI 1.08–3.14). Results highlight the importance of balancing sleep ability and CUS. Sufficient sleep may reduce weekday sleep debt and only a short CUS would be required on weekends, improving mortality in middle-aged adults.
... Sleep homeostasis preserves physiologic stability; prolonged wakefulness increases the pressure to fall asleep, whereas prolonged sleep time relieves sleep pressure and promotes wakefulness [14]. Studies on the regulatory mechanisms of sleep have identified distinct neural circuits and multiple neurotransmitters that are responsible for maintaining sleep homeostasis and circadian rhythm [15][16][17][18] using model animals such as flies, zebrafish, and mice [8,19]. Based on different model animals, we are increasingly understanding the neural circuits and regulatory molecules that regulate sleep. ...
Sleep is a fundamental, evolutionarily conserved, plastic behavior that is regulated by circadian and homeostatic mechanisms as well as genetic factors and environmental factors, such as light, humidity, and temperature. Among environmental cues, temperature plays an important role in the regulation of sleep. This review presents an overview of thermoreception in animals and the neural circuits that link this process to sleep. Understanding the influence of temperature on sleep can provide insight into basic physiologic processes that are required for survival and guide strategies to manage sleep disorders.
... Sleep extension has been shown to improve visuospatial processing [21,23] and sports performance requiring motor procedural learning [24][25][26]. The improvement in performance due to extended sleep may be the result of eliminating "sleep debt," which is considered chronic sleep loss [27]. Although consecutive napping may be useful for reducing cognitive deficit due to sleep deprivation, no studies have examined motor memory consolidation through consecutive napping. ...
Daytime napping offers benefits for motor memory learning and is used as a habitual countermeasure to improve daytime functioning. A single nap has been shown to ameliorate motor memory learning, although the effect of consecutive napping on motor memory consolidation remains unclear. This study aimed to explore the effect of daytime napping over multiple days on motor memory learning. Twenty university students were divided into a napping group and no-nap (awake) group. The napping group performed motor adaption tasks before and after napping for three consecutive days, whereas the no-nap group performed the task on a similar time schedule as the napping group. A subsequent retest was conducted one week after the end of the intervention. Significant differences were observed only for speed at 30 degrees to complete the retention task, which was significantly faster in the napping group than in the awake group. No significant consolidation effects over the three consecutive nap intervention periods were confirmed. Due to the limitations of the different experimental environments of the napping and the control group, the current results warrant further investigation to assess whether consecutive napping may benefit motor memory learning, which is specific to speed.
... Sleep extension has been shown to improve visuospatial processing [21,23] and sports performance requiring motor procedural learning [24][25][26]. The improvement in performance due to extended sleep may be the result of eliminating "sleep debt," considered as chronic sleep loss [27]. Although consecutive napping may be useful for reducing cognitive deficit due to sleep deprivation, no studies have examined motor memory consolidation through consecutive habitual napping. ...
Daytime napping offers benefits for motor memory learning and is used as habitual countermeasure to improve daytime functioning. A single napping is shown to ameliorate motor memory learning, although the effect of consecutive napping on motor memory consolidation remains unclear. This study aimed to explore the effect of daytime napping over multiple days on motor memory learning. Twenty university students were divided into the napping group and no-nap (awake) group. Napping group performed motor adaption tasks before and after napping for three consecutive days, whereas no-nap group performed the task on the similar time schedule as the napping group. In addition, a subsequent retest was conducted one week after the end of the intervention. The speed to complete the task of the napping group was significantly shorter than that of the awake group in the retention test. No significant difference was confirmed for trajectory length to complete the task. Thus, consecutive napping may facilitate motor learning and motor memory consolidation in the long term.
... E78 rivation [33,34]. Thus, a single nap, regardless of duration, may not result in a significant change in performance. ...
This study explored the effect of long naps on handball-related performance and assessed the role of the cardiac autonomic nervous system in this process. Eleven male collegiate handball players performed a repeated sequential trial consisting of a 20-m consecutive turnaround run, 10-m run with a load, and shooting the ball into a target. Participants were allocated randomly and sequentially to have a short (20 minutes) nap, long (60 minutes) nap, or no nap. The Pittsburgh Sleep Quality Index was used to assess regular sleep quality. Subjective sleepiness before and after napping was measured using the Karolinska Sleepiness Scale. Heart rate variability was recorded to assess cardiac autonomic nervous function during napping. The Pittsburgh Sleep Quality Index score was correlated with shot accuracy only after long naps (ρ=0.636, r=0.048). A negative correlation was observed between the root mean square of successive differences and average load run time (ρ=−0.929, p<0.001). Long napping was associated with a significant benefit on performance in athletes with poor sleep quality, implying a role of the autonomic nervous system in this regard. Our findings indicate the effect of sleep quality on the endurance and resistance of handball players.
... °C between a night-time minimum and a daytime maximum in a rhythmic 24-h pattern [42,43], with CBTmin typically occurring between 03:00 and 07:00 [44,45]. Table 1 Terminology of specific terms and phrases of the human circadian system [2,5,13,[15][16][17][18][25][26][27][28][29][30][31][32][33][34] ...
Athletes are increasingly required to travel domestically and internationally, often resulting in travel fatigue and jet lag. Despite considerable agreement that travel fatigue and jet lag can be a real and impactful issue for athletes regarding performance and risk of illness and injury, evidence on optimal assessment and management is lacking. Therefore 26 researchers and/or clinicians with knowledge in travel fatigue, jet lag and sleep in the sports setting, formed an expert panel to formalise a review and consensus document. This manuscript includes definitions of terminology commonly used in the field of circadian physiology, outlines basic information on the human circadian system and how it is affected by time-givers, discusses the causes and consequences of travel fatigue and jet lag, and provides consensus on recommendations for managing travel fatigue and jet lag in athletes. The lack of evidence restricts the strength of recommendations that are possible but the consensus group identified the fundamental principles and interventions to consider for both the assessment and management of travel fatigue and jet lag. These are summarised in travel toolboxes including strategies for pre-flight, during flight and post-flight. The consensus group also outlined specific steps to advance theory and practice in these areas.
... A high sleep pressure might additionally have led to the observed earlier bedtimes on Friday nights and to later getting up times on Saturday mornings. The observed longer time in bed and total sleep time on Sunday nights in the total group might also reflect such an accumulated sleep debt [7] with subsequent recovery sleep, a phenomenon which is observed in many adolescents and adults [1,23]. Similar to the present findings, in the American time use survey, sleep duration was also longest on Sundays nights [1]. ...
Background and objective
The extent to which adult sleep varies depending on the day of the week has not yet been systematically investigated with electroencephalography (EEG) data. Whether such effects exist and whether they are related to age, gender, and employment status was retrospectively analyzed based on data from an experimental double-blind cross-over study in which effects of electromagnetic fields of a cell phone base station on the sleep of a general rural population had been examined.
Methods
The sleep of 397 adults (age 45.0 ± 14.2 years, range 18–81 years; 50.9% women) from ten different rural German villages was recorded for 12 nights with ambulatory devices. Self-reported sleep quality was recorded in morning and evening protocols. Friedman tests were used for statistical analysis of the comparison between the days, and the Kruskal–Wallis and Mann–Whitney U tests were used for pairwise comparisons of independent parameters between groups.
Results
For the present analysis, data from 335 participants were considered. Overall, the differences between nights were small and the quality of sleep was good. Three of the five objective and all six self-rated sleep parameters differed significantly between the days of the week. While the objective and the self-estimated total sleep time were longest on Sunday nights, the qualitatively poorest values occurred on Monday nights. People who worked fulltime had the longest sleep latencies on Sunday nights. Friday nights were rated the best.
Conclusion
The objective and self-rated sleep quality varied relatively little in a rural adult population over the course of the week, being worst on Monday nights and best on Friday nights.
... It has been more than a decade since the concept of sleep debt was introduced [22], and nowadays lack of sleep is a serious problem worldwide [1]. We con- level is normally high in the morning and low from daytime to night-time due to a phenomenon known as the cortisol awakening response (CAR) [23] [24], in which the amount of cortisol secretion increases rapidly upon waking up in the morning, and it has been reported that those who are exposed to chronic or long-term stress have a higher rate of this increase [25]. ...
... [20][21][22] Banking sleep refers to extending time in bed prior to a period of anticipated sleep loss, or for purposes of addressing accumulated sleep debt. 23,24 Extending the main nocturnal sleep period over a series of days improves performance, alertness, and indicators of sleep health (eg, daytime sleepiness) in diverse groups. 23,[25][26][27] Previous studies have also examined sleep banking in relation to mood and performance 25,28 ; diet and lifestyle 29 ; the potentially harmful effects of long duration sleep 30 ; and determining optimal sleep duration. ...
Background:
Sleep deprivation is common in shift work occupations, including safety-sensitive occupations. While extending sleep prior to scheduled shifts (i.e., "banking sleep") may be an intuitive strategy for fatigue mitigation, the evidence behind this strategy is unclear.
Methods:
We performed a systematic review of literature retrieved in searches of four databases. We examined agreement between two independent screeners, abstracted key findings, reviewed and synthesized findings, and evaluated the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. The Cochrane Collaboration's risk of bias tool was used to evaluate bias of individual studies. We reported findings as prescribed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.
Results:
Of the 3007 records screened, five met inclusion criteria. The inter-rater agreement for inclusion/exclusion was high (κ = 0.87). One study addressed patient safety outcomes. Four studies assessed the impact of banking sleep on performance, five assessed measures of acute fatigue, and three evaluated banking sleep on indicators of health. All five studies presented a very serious risk of bias and the quality of evidence was very low. Given these caveats, the findings, in aggregate, support banking sleep as a strategy to improve indicators of performance and acute fatigue.
Conclusions:
This systematic review identifies gaps in research of shift workers on the efficacy of banking sleep as a fatigue risk management strategy. The available evidence supports banking sleep prior to shiftwork as a strategy for improved patient safety, performance, and reducing acute fatigue.
... Il sonno ha una struttura attiva con andamento ciclico, con stadi alternati di fasi NREM (Non-Rapid Eye Movement) e fasi REM (Rapid Eye Movement), caratterizzate da movimenti rapidi degli occhi. Durante una normale notte di sonno si verificano da quattro a sei cicli alternati di fasi NREM e REM [5] . ...
di specializzazione in ortognatodonzia 2 Università degli studi di Roma Tor Vergata, Scuola di specializzazione in ortognatodonzia; UNSBC Tirana (Albania) RIASSUNTO OBIETTIVI Scopo del seguente lavoro è quel-lo di fornire all'ortodontista una serie di raccomandazioni e indica-zioni evidence based aggiornate per la diagnosi e il trattamento del russamento e delle apnee ostrutti-ve nel sonno (OSA) nell'adulto. MATERIALI E METODI È stata eseguita un'analisi siste-matica della letteratura esistente relativa all'OSA nell'adulto usu-fruendo della banca dati di PubMed e utilizzando le seguenti parole chiave: sleep apnea AND oral appliance OR mandibular re-positioning OR mandibular advancement OR Non-CPAP therapie NOT orthognatic surgery NOT osteotomy NOT children e con i seguenti filtri: article types (Clinical Trial, Guideline, Meta-Analysis), publication dates (10 years), languages (english). L'analisi delle pubblicazioni è stata limitata a stu-di condotti sull'uomo. Alle pubbli-cazioni selezionate sono state ag-giunte le linee di indirizzo della So-cietà Italiana Medicina del Sonno Odontoiatrica e le linee guida del Ministero della Salute Italiano. RISULTATI Il russamento è un rumore inspira-torio che può originare da varie sedi anatomiche, mentre le apnee ostruttive nel sonno (OSA) sono at-tribuibili al collasso delle alte vie aeree che determinano una par-ziale (ipopnea) o completa ostru-zione (apnea) al passaggio dell'a-ria con conseguente decremento dell'ossigenazione sanguigna. Le ABSTRACT OBJECTIVES The purpose of the following work is to provide the orthodontist with a series of updated evidence based recommendations and indications for the diagnosis and treatment of snoring and obstructive sleep apnea (OSA) in adults. RESULTS Snoring is an inspirational noise that can originate from various anatomic sites, while obstructive sleep apnea (OSA) is attributable to the collapse of the upper airways that results in partial (hypo-pnea) or complete obstruction (apnea) of the passage of air, resulting in a decrease in blood oxy
... Long sleep has been linked to greater mortality in the case of cardiovascular, metabolic, and other diseases, but it is unclear what role sleep plays beyond the disease or simply being in bed and sedentary (Cappuccio, D'Elia, Strazzullo, & Miller, 2010;Knutson, 2010). There are some studies available that show that extending sleep or "sleep banking" can maintain performance during subsequent periods of sleep loss (Rupp, Wesensten, Bliese, & Balkin, 2009) and it is likely that individuals are carrying around a "sleep debt" so getting more sleep is generally encouraged (Dement, 2005). It is necessary for leaders to monitor effects of insufficient sleep on performance for not only themselves, but also their followers, and make adjustments when possible. ...
Many leader types have been described and are useful. Because so many leader types have been identified, they may be interpreted as competing with each other rather than as complementary or alternative types that depend on individual leaders, the groups that are being led, or the situations in which leadership occurs. This chapter suggests that it is valuable to identify a leader type that can serve as an umbrella term and concept to capture principles relevant to all types of effective leadership. The identification of an overarching, effective leader type is based on a psychobiosocial perspective that draws from field theory in the social sciences and from the stress literature. Based on these literatures, the term “allostatic leader” is offered to describe an ideal leader who responds, adapts, learns, and changes with experience to become even more effective in subsequent situations. Consequently, a clear operational and holistic definition can best focus leader education and development programs to optimally grow effective leaders.
... Sleep Debt (SD) was defined as the difference between the amount of sleep you should be getting and the amount you actually get [44]. We calculated SD making 2 answers: "On average, how many hours of sleep do you get in a 24-hour period? ...
Background
Recent research has found evidence of an association between motor vehicle accidents (MVAs) or near miss accidents (NMAs), and excessive daytime sleepiness (EDS) or its main medical cause, Obstructive Sleep Apnea (OSA). However, EDS can also be due to non-medical factors, such as sleep debt (SD), which is common among professional truck drivers. On the opposite side, rest breaks and naps are known to protect against accidents.
Study Objectives
To investigate the association of OSA, SD, EDS, rest breaks and naps, with the occurrence of MVAs and NMAs in a large sample of truck drivers.
Methods
949 male truck drivers took part in a cross-sectional medical examination and were asked to complete a questionnaire about sleep and waking habits, risk factors for OSA and EDS.
Results
MVAs and NMAs were reported by 34.8% and 9.2% of participants, respectively. MVAs were significantly predicted by OSA (OR = 2.32 CI95% = 1.68–3.20), SD (OR = 1.45 CI95% = 1.29–1.63), EDS (OR = 1.73 CI95% = 1.15–2.61) and prevented by naps (OR = 0.59 CI95% = 0.44–0.79) or rest breaks (OR = 0.63 CI95% = 0.45–0.89). NMAs were significantly predicted by OSA (OR = 2.39 CI95% = 1.47–3.87) and SD (OR = 1.49 CI95% = 1.27–1.76) and prevented by naps (OR = 0.52 CI95% = 0.32–0.85) or rest breaks (OR = 0.49 CI95% = 0.29–0.82).
Conclusions
When OSA, SD or EDS are present, the risk of MVAs or NMAs in truck drivers is severely increased. Taking a rest break or a nap appear to be protective against accidents.
... This improvement could be beneficial regardless of the level of sleep debt and initial sleep pressure. 15,32 Indeed, Roehrs et al. 14 have shown that reaction time and sleep latencies of MSLT were improved after 6 nights of EXT in both subjects with MSLT > 16 min (called "alert") and others with MSLT < 6 min (called "sleepy"). As expected, the sleepy subjects showed an immediate and uniform increase in alertness, while alert subjects did not show improvements until late in the extension period. ...
To investigate the effects of 6 nights of sleep extension on sustained attention and sleep pressure before and during total sleep deprivation and after a subsequent recovery sleep.
Subjects participated in two experimental conditions (randomized cross-over design): extended sleep (EXT, 9.8±0.1 h (mean±SE) time in bed) and habitual sleep (HAB, 8.2±0.1 h time in bed). In each condition, subjects performed two consecutive phases: (1) 6 nights of either EXT or HAB (2) three days in-laboratory: baseline, total sleep deprivation and after 10 h of recovery sleep.
Residential sleep extension and sleep performance laboratory (continuous polysomnographic recording).
14 healthy men (age range: 26-37 years).
EXT vs. HAB sleep durations prior to total sleep deprivation.
Total sleep time and duration of all sleep stages during the 6 nights were significantly higher in EXT than HAB. EXT improved psychomotor vigilance task performance (PVT, both fewer lapses and faster speed) and reduced sleep pressure as evidenced by longer multiple sleep latencies (MSLT) at baseline compared to HAB. EXT limited PVT lapses and the number of involuntary microsleeps during total sleep deprivation. Differences in PVT lapses and speed and MSLT at baseline were maintained after one night of recovery sleep.
Six nights of extended sleep improve sustained attention and reduce sleep pressure. Sleep extension also protects against PVT lapses and microsleep degradation during total sleep deprivation. These beneficial effects persist after one night of recovery sleep.
Copyright © 2015 Associated Professional Sleep Societies, LLC. All rights reserved.
... Durch Informationen über den Schlaf und kognitive Techniken werden ohne Anwendung "äußerer" Mittel (Schlafmedikamente) langfristig die Voraussetzungen zu einer positiven Einstellung zum Schlaf geschaffen (Müller & Paterok, 1999). Ein ausgeruhter Athlet dürfte durchaus von dem zusätzlichen Schlaf profitieren (Dement, 2005). Im Hinblick auf die teilweise vielen Transferreisen im Sport sind solche Eingriffe im Umfeld des Profisports als besonders erfolgversprechend anzusehen. ...
Der Schlaf ist eine wichtige Ressource für das psychische und physische Wohlbefinden. Die Erkenntnisse aus der Schlafforschung spielten jedoch in der Sportwissenschaft bislang nur eine untergeordnete Rolle. Nach einer kurzen Einführung zur physiologischen Erfassung von Schlaf werden in diesem Beitrag drei Bereiche aufgeführt, die fruchtbare Verknüpfungen zwischen Schlaf- und Sportwissenschaft aufweisen. Im ersten Bereich wird auf die schlafbegleitende Konsolidierung von motorischen Gedächtnisinhalten eingegangen. Dieser eher grundlagenorientierte Forschungszweig beleuchtet den Zusammenhang zwischen der Aneignung bzw. Optimierung von motorischen Fertigkeiten und verschiedenen Schlafstadien und Schlafparametern (z. B. Schlafspindeln). In dem zweiten Bereich geht es um den Schlaf vor sportlichen Wettkämpfen. Für den Sport liegt eine Vielzahl von anekdotischen Belegen über eine schlecht geschlafene Nacht vor einem sportlichen Wettkampf vor. Systematische Erhebungen existieren jedoch kaum. Anhand verschiedener Studien sollen Aspekte geklärt werden, die die Ursachen und Häufigkeiten von schlechtem Schlaf vor Wettkämpfen und die Auswirkung auf die Wettkampfleistung betreffen. Der dritte Bereich widmet sich dem Einfluss von körperlicher Aktivität auf den Schlaf. Es zeigt sich, dass der Sport einen positiven Effekt auf den Schlaf bei Menschen mit Schlafstörung aufweist. Diese Befunde weisen auf einen therapeutischen Ansatz für Sportwissenschaftler in der Schlafmedizin. Abschließend werden sportpraktische Implikationen erörtert und Perspektiven auf weitere Forschungsfragen eröffnet.
... The earliest studies on human sleep deprivation performed by Dement and colleagues centered primarily on the concept of sleep debt. 1 The current debate over daily sleep need in humans involves theoretical concepts such as sleep debt, sleep tendency, homeostatic tendency, excess wakefulness, and core versus optional sleep. Although it is well known that sleep restriction and sleep deprivation results in neurocognitive consequences, studies have shown conflicting results on the amount of sleep restriction required to see this effect or the time required for full recovery. ...
... Van Dongen & Dinges, 2005). Alternatively, studies from sleep research have shown that prolonged sleep improves daytime performance and have even demonstrated positive results for athletic performance (Dement, 2005;Mah, Mah, & Dement, 2009). Therefore, good sleep management might play a key role in professional sports. ...
Sleep is generally regarded as a valuable resource for psychological and physiological well-being. Although the effects of sleep on athletic performance have been acknowledged in sport science, few studies have investigated the prevalence of sleep problems and their effects on elite athletes before a sport event. In this study, 632 German athletes from various sports were asked about their sleep habits during the night(s) before an important competition or game. The findings indicate that 65.8% of the athletes experienced poor sleep in the night(s) before a sports event at least once in their lives and a similarly high percentage (62.3%) had this experience at least once during the previous 12 months. Athletes of individual sports reported more sleep difficulties than athletes of team sports. The main sleep problem was not being able to fall asleep. Internal factors such as nervousness and thoughts about the competition were rated highest for causing sleep problems. Most athletes stated that disturbed sleep had no influence on their athletic performance; however, athletes also reported effects such as a bad mood the following day, increased daytime sleepiness, and worse performance in the competition or game. The differences between individual and team sports indicate that athletes in some sports need more help than those in other sports in managing sleep problems.
... This implies that fasting during Ramadan would render sleep more diffi cult in the daytime (lower insulin levels), but this will be offset by the decreased amount of nocturnal sleep. 56 Tyrosine is the precursor of catecholamines, and it is known that a high-protein meal increases plasma tyrosine and its uptake into the brain. It has been argued that this would promote the synthesis and release of catecholamines, increasing alertness. ...
This article focuses on changes in Ramadan during the course of the waking day in physical performance, mental performance and gastrointestinal function. Possible explanations of the changes are considered by reference to the roles of the body clock and external factors such as the environment and the individual's lifestyle. The effects of these factors upon training schedules and upon changing the times of training are then discussed in terms of physiology and biochemistry. Delaying the time of training until after sunset has advantages and disadvantages, but it is a regimen that is unlikely to be widely accepted in non-Muslim countries. It is clear that the detailed nature of the problems involved and dealing with them in a manner based upon a firm body of knowledge requires far more experimental investigation.
... Most of the decline in our nightly sleep occurred very recently in terms of geologic time: we now sleep roughly 2 h less per night than we did even 50Y100 yr ago (47,57,73). Research terminology presents further evidence of our current sleep restricted state: we use ''sleep extension'' to describe studies involving nightly sleep duration beyond current ''norms'' (18,30,39,40). ''Sleep repletion'' may describe the concept better. ...
Natural selection defined our genotype as athletes who sleep 8-9 h each night. Physical activity and sleep exhibit positive synergy, whereby each optimizes quality of and capability for the other. Our sedentary, sleep-restricted lifestyle conflicts with our genotype to generate pathophysiologic phenotypes, especially obesity. Insufficient sleep is pandemic, and other sleep disorders are increasingly common. Sleep dysfunction promotes obesity due to inactivity from sleepiness and to metabolic changes. Obesity is the primary risk factor for obstructive sleep apnea, which commonly disrupts sleep. This represents one of many pathophysiologic vicious cycles involving inactivity, sleep disorders, and obesity. Solutions include better education of the medical community, which remains surprisingly ignorant about these disease processes and therapeutic advantages of exercise and sleep repletion. Doctors commonly prescribe medications with sleep disruption or weight-gain side effects instead of lifestyle modifications. Lifestyle improvements often provide superior treatment to medications and impose no side effects.
... In addition, environmental factors like light or noise can also be detrimental to people trying to sleep late into the morning or day. Many studies have reported that an accumulated sleep deprivation induces impairments of cognition, vigilance, and memory, and disturbances of mood [30][31][32][33]. We suggest that students with an irregular bedtime schedule should be encouraged to maintain a regular bedtime, and to increase their total sleep time. ...
An irregular bedtime schedule is a prevalent problem in young adults, and could be a factor detrimentally affecting sleep quality. The goal of the present study was to explore the association between an irregular bedtime schedule and sleep quality, daytime sleepiness, and fatigue among undergraduate students in Taiwan.
A total of 160 students underwent a semi-structured interview and completed a survey comprising 4 parts: Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and a rating of irregular bedtime frequency. Participants were grouped into 3 groups in terms of irregular bedtime frequency: low, intermediate, or high according to their 2-week sleep log. To screen for psychological disorders or distress that may have affected responses on the sleep assessment measures, the Chinese health questionnaire-12 (CHQ-12) was also administered.
We found an increase in bedtime schedule irregularity to be significantly associated with a decrease in average sleep time per day (Spearman r = -0.22, p = 0.05). Multivariate regression analysis revealed that irregular bedtime frequency and average sleep time per day were correlated with PSQI scores, but not with ESS or FSS scores. A significant positive correlation between irregular bedtime frequency and PSQI scores was evident in the intermediate (partial r = 0.18, p = 0.02) and high (partial r = 0.15, p = 0.05) frequency groups as compared to low frequency group.
The results of our study suggest a high prevalence of both an irregular bedtime schedule and insufficient sleep among university students in Taiwan. Students with an irregular bedtime schedule may experience poor sleep quality. We suggest further research that explores the mechanisms involved in an irregular bedtime schedule and the effectiveness of interventions for improving this condition.
... Interestingly, sleep deprivation studies indicate that subjects are often not aware of their level of sleep debt, as they do not necessarily experience daytime sleepiness. 33,35 Lack of insight increases the risk of accidents and sleep-related errors. 36 These results are worrisome, given the prevalence of chronic sleep restriction in the U.S. 3 The impact of sleep loss is potentially more devastating for the elderly, the medically compromised, and for individuals with psychiatric disorders. ...
... In contrast to the sleep profile of athletes, many individuals habitually incur and carry a sleep debt which leads to an increased homeostatic drive to sleep and a likely fall in physical performance. The extent of the sleep debt can be determined by a formal sleep latency test [66]. This phenomenon is likely to explain the beneficial effects of so-called power naps (see [51,52]), and the sensitivity of cognitive function and motivation to time-on-task in sleep-deprivation studies [36]. ...
Sleep-waking cycles are fundamental in human circadian rhythms and their disruption can have consequences for behaviour and performance. Such disturbances occur due to domestic or occupational schedules that do not permit normal sleep quotas, rapid travel across multiple meridians and extreme athletic and recreational endeavours where sleep is restricted or totally deprived. There are methodological issues in quantifying the physiological and performance consequences of alterations in the sleep-wake cycle if the effects on circadian rhythms are to be separated from the fatigue process. Individual requirements for sleep show large variations but chronic reduction in sleep can lead to immuno-suppression. There are still unanswered questions about the sleep needs of athletes, the role of 'power naps' and the potential for exercise in improving the quality of sleep.
... The diurnal regimen of abstinence during Ramadan would render it more difficult to sleep during daytime when insulin levels have fallen. This difficulty may be partly offset by the so-called 'sleep debt' likely to be carried into each new day when nocturnal sleep is inadequate for sleep homeostasis [43]. It cannot be assumed that findings of circadian disruption in male subjects apply equally to females. ...
In this review the effects of diurnal fasting on normal physiological processes are considered. Ramadan is placed in a circadian context, food and fluid ingestion being displaced to the pre-sunrise and post-sunset hours. Over the holy month, negative energy balance is often experienced, though this deficit is not a universal finding. Responses to exercise during the day show influences consistent with hypohydration and an increased reliance on fat as a source of fuel for exercise. Muscle performance and psychomotor performance are impaired as the month of fasting progresses but it is not clear how circadian rhythms in responses to activity are altered. For some measures at rest there is a reduction in amplitude and a delay in acrophase. Health-related benefits are reflected in a rise in high-density lipoprotein cholesterol and individuals with predispositions for coronary heart disease are not at increased risk of cardiovascular disorders due to fasting. The physiological adjustments during the month have some similarities to the disturbances in circadian rhythms experienced in different circumstances. The Ramadan model provides an alternative to those for ageing, nocturnal shift-work and time-zone transitions in understanding the links between behaviour and endogenous circadian rhythms.
There is good evidence for cognitive and physiological arousal in insomnia. Accordingly, clinical trial studies of insomnia treatments aimed at reducing arousal, including relaxation and meditation, have reported positive results. Yoga is a good practice that is also known to be effective in reducing arousal, although it has not been well evaluated as a treatment for insomnia. Previous studies showed that insomnia is increasing by the rate of 5-10% in Indian population and its prevalent therapeutic/preventive measures has been found fragile. The aging process is associated with physiological changes that affect sleep. In older adults, it not diagnosed and untreated insomnia may cause impaired daily function and reduced quality of life. Insomnia is also a risk factor for accidents and falls that are the main cause of accidental deaths in older adults and, therefore, is associated with higher morbidity and mortality rates in older populations.
Sleep debt is pervasive in society and generally refers to the effects of chronic sleep loss over time. Using a variety of measurement, epidemiological and laboratory studies have demonstrated physiological and neurophysiological consequences of sleep debt. Chronic sleep loss shows differences in effects compared to acute, total sleep deprivation. Concepts of extended wakefulness are theorized to underly these effects. Individuals may demonstrate different amounts of sleep need or core sleep needed before functioning deteriorates. Laboratory studies have shown that prior sleep history is a factor influencing the effects of subsequent sleep loss and sleep intensity increases with recovery sleep.
Nédélec, M, Dawson, B, and Dupont, G. Influence of night soccer matches on sleep in elite players. J Strength Cond Res XX(X): 000-000, 2018-This study examined the impact of night matches on the sleep/wake behavior of elite soccer players participating in the UEFA Champions League and French Ligue 1. A mixed method approach was used, combining objective sleep assessment with wrist activity monitors, and a survey to ascertain the sleep complaints after night matches (kick off after 18:00 hours). Most players (90%) indicated worse sleep in the nights after evening matches than after training days. Objective time in bed (-01:39 hours; effect size [ES] = 1.7; p < 0.001) and total sleep time (-01:32 hours; ES = 1.4; p < 0.001) were both lower after night matches than after training days. Night matches had a marked influence on sleep quantity later that night, both objectively and subjectively. The survey revealed that players may not have appropriate methods for better managing their sleep after night matches. It is yet to be determined whether players may benefit from individualized sleep interventions in these circumstances.
Sleep loss impairs task performance and post-physical activity recovery, cognitive performance and mood, heightens fatigue and decreases vigour; poor sleep quality impairs decision-making, the speed and accuracy of task performance, and post-exercise recovery.
Sleep time and quality are affected by age, psychological and physiological conditions, culture and environmental factors. Skin temperature, rapid temperature change and sweating during sleep can significantly reduce sleep quality. Hence, the thermal properties of bedding and sleepwear, both in steady-state and transient ambient temperature conditions, are logically important factors.
Research to date on sleeping thermal microclimates and their effect on sleep quality is scarce. This present review covers the fundamental elements of human sleep, highlighting physically active people, such as athletes, and the influence of sleepwear and bedding on sleep thermal microclimates, as well as the research methods that have been and could be used in this field. This review identifies opportunity for future research direction and approaches to understanding thermal environments that may support better human sleep.
We conducted sleep education for 53 pregnant women participating in a class for parents and examined its effects on sleep habits, sleep satisfaction level and depression during pregnancy. We used educational material and instructed participants about responses to the physical effects of pregnancy, and provided information on biological rhythms of the newborn, as well as the importance of regulating biological rhythms. After sleep education, we explained sleep promotion activities resulting in high-quality sleep for pregnant women. Then, we set target activities for two weeks. After two weeks, we analyzed questionnaire entries of 10 women whose informed consent was obtained before the study. The results demonstrated that their sleep debt decreased and sleep satisfaction increased after sleep education. However, there was no significant improvement in depression during pregnancy. These results suggest that sleep education for pregnant women is effective for improving their sleep.
In this chapter, a brief overview of normal sleep is given for a clearer understanding of subsequent chapters dealing with basic science, technical considerations, and clinical aspects. After a short historical perspective of sleep and sleep medicine, the chapter succinctly summarizes the definition of sleep, sleep architecture, the ontogeny and phylogeny of sleep, sleep habits and need, dreams, circadian sleep–wake rhythm, chronobiology, cytokines, immune system and sleep factors, and ending with theories of the functions of sleep.
The use of exercise testing is an important tool for the pediatric pulmonologist. Physical stress often reveals cardiorespiratory abnormalities that are not apparent on conventional static tests. There is little doubt the information acquired from exercise tests have diagnostic and prognostic value, but exercise tests may also be critical to determine success or failure of treatment strategies. The purpose of this chapter is to provide the pediatric specialist with an overview of exercise evaluation that may assist in the diagnosis of and management of disease in pediatric and adolescent patients with physical activity intolerance, especially those with cardiorespiratory diseases. The specific aims of this chapter are to: (1) describe various exercise tests and the biomechanical and physiological principles of those tests necessary to assess patients; (2) discuss methods to assess the physical fitness profile of patients with cardiorespiratory diseases and physical limitations; (3) provide specific strategies for an exercise prescription based on the fitness and clinical profile of the patient and; (4) assist the provider in developing a center for exercise evaluation. Although each aim provides unique information, the overall goal of this chapter is to stimulate the pediatric pulmonologist to develop an understanding of indications for cardiopulmonary exercise testing (CPET) and implement strategies to systematically assess each patient’s fitness profile; to track patient’s disease or training progression or alternatively to monitor responses of medical interventions; and to prescribe a well-rounded exercise prescription to maximize functional ability and wellness of individual patients. This chapter is not intended to be an in depth review for exercise physiologists, but is designed to assist the practicing clinician in the logistics of developing a program and a comfort in interpreting studies.
The intermittent fasting of Ramadan could affect various aspects of body physiology and biochemistry important to athletic success. Much of the available information on this subject has been collected from sedentary subjects or low-level competitors, often without well matched controls. Other issues requiring clearer definition include the duration of fasting, the local environment, the timing of observations, and changes in training, diet and sleep patterns. Sleep may be shortened or made good with daytime naps. Circadian rhythms of temperature, metabolism, hormonal secretions and physical performance may be disrupted and incidental activities curtailed. Disturbances of psychomotor performance include daytime sleepiness, impaired vigilance and slower reactions. Food intake is limited to night-time meals. Sedentary individuals sometimes exploit Ramadan to reduce body fat stores. Well disciplined athletes usually maintain energy balance unless daily energy expenditures are very high. Protein intake must allow for gluconeogenesis, and provide quality protein ingested around training times. Blood sugar levels are likely to fall over a long and active day, even if morning glycogen reserves are maximized. Metabolism of fat should be encouraged, beginning prior to Ramadan; inclusion of fat in the pre-dawn meal also slows gastric emptying. Daytime fluid depletion is inevitable if athletes exercise in the heat, but the immediate deficit can usually be made good at night. Some studies show an initial fluid depletion, with recovery as Ramadan continues, possibly reflecting changes in urine and sweat production. Top athletes can maintain training throughout Ramadan, although coaches sometimes reduce demands through a pre-competitive tapering of effort. Late night or early morning training requires negotiation with players who are not observing Ramadan, and dietary adjustments to maintain optimal plasma amino acid levels when training. Performance of repeated anaerobic exercise is impaired, but aerobic power and muscular strength show little change during Ramadan. Ratings of fatigue are increased, and vigilance and reaction times are impaired, particularly during the afternoon. Medical issues during Ramadan are few. Athletes with diabetes mellitus should seek a medical exemption from fasting, and prescribed drug schedules should be carefully maintained. There is no major increase of injury rates, but competitors may have difficulty in producing urine for doping controls. Logical measures to minimize the effects of Ramadan include the optimization of mood state, maintenance of training, minimization of sleep loss, appropriate adjustments of diet, and the monitoring of competitors for chronic dehydration. Future research should concentrate on the changes observed in top athletes, particularly women, with data collected in the late afternoon after a known period of fasting in a well defined environment. It will be important to ensure that the lifestyle of those studied has been optimized. Implications of chronic dehydration for doping control also merit further investigation. Current data suggest that the impact of Ramadan upon athletic performance is small relative to the precision of test procedures, although it may be sufficient to cause a loss of medals. Negative effects vary widely with the type of sport, the season when fasting is observed, the local culture and the discipline exercised by the athlete.
Human performances are highly dependent on one of the main biological rhythms, namely the sleep–wake rhythm. This rhythm is driven by the living clock and is functional in the adaptation to day–night differences in the environment. The athlete, like all humans, is set up to be awake and in good shape to exercise during the day, and to sleep and recover during the night. Regular vigorous physical activity, such as the light–dark cycle or social cues, can be considered as a zeitgeber. It has been shown to reinforce the synchronisation of human circadian rhythms, which means that physically active people have a stronger circadian rhythmicity than those who are sedentary. Sleep and exercise also have strong relationships that are independent of the biological clock. On the one hand, athletic performances have been shown to be dependent upon both the quality and the quantity of sleep that has been taken before the competition. The detrimental effects of sleep deprivation are shown by increased lapsing, cognitive slowing, memory impairment, decreased vigilance and sustained attention, and shift in optimum response capability. Its effects on physical performance are manifested as a decline in the ability to perform maximal exercise. Aerobic and anaerobic pathways are both affected, as are fatigue and recovery processes. Sleep deprivation can also phase shift and decrease the amplitude of many individual rhythms. All these effects are dependent on the timing and the length of the waking state, but many of them are seen after only few hours of sleep deprivation. On the other hand, exercise by itself has been shown to have an impact on subsequent sleep. Sleep latencies and fragmentation are reduced and the deep slow wave sleep is increased. It is beyond doubt that athletes need more sleep than sedentary people, and so athletes, in order to perform optimally, need to respect the “rules” imposed by the circadian pacemaker for establishing consistent sleep periods.
This review considers the relationship between sleep need and sleepiness. In healthy adults, objective measures of sleepiness (e.g. Multiple Sleep Latency Test; Psychomotor Vigilance Test) and subjective indices (e.g. Stanford Sleepiness Scale) often poorly inter-correlate and have been seen as orthogonal dimensions. This is perhaps not surprising as the methodology of these tests is quite different in, for example, their duration, testing environment, whether they are experimenter versus participant-paced, and the understanding and expectancy of participants. It is argued, here, that ‘sleepiness’, the ‘propensity to fall asleep’ and the ‘need for sleep’ are not synonymous, but qualitatively different. They may represent different positions on a dimension ranging from essential to non-essential sleep/sleepiness, and the position on this dimension is detected to varying extents by the different measures. As these tests can detect – and perhaps induce – levels of sleepiness which would be undetectable by, and of little concern to people under everyday situations, they can reveal a sleepiness having the potential to be misinterpreted as sleep debt.
It is argued that the latter part of usual human sleep is phenotypically adaptable (without 'sleep debt') to habitual shortening or lengthening, according to environmental influences of light, safety, food availability and socio-economic factors, but without increasing daytime sleepiness. Pluripotent brain mechanisms linking sleep, hunger, foraging, locomotion and alertness, facilitate this time management, with REM acting as a 'buffer' between wakefulness and nonREM ('true') sleep. The adaptive sleep range is approximately 6-9h, although, a timely short (<20 min) nap can equate to 1h 'extra' nighttime sleep. Appraisal of recent epidemiological findings linking habitual sleep duration to mortality and morbidity points to nominal causal effects of sleep within this range. Statistical significance, here, may not equate to real clinical significance. Sleep durations outside 6-9h are usually surrogates of common underlying causes, with sleep associations taking years to develop. Manipulation of sleep, alone, is unlikely to overcome these health effects, and there are effective, rapid, non-sleep, behavioural countermeasures. Sleep can be taken for pleasure, with minimal sleepiness; such 'sleepability' is 'unmasked' by sleep-conducive situations. Sleep is not the only anodyne to sleepiness, but so is wakefulness, inasmuch that some sleepiness disappears when wakefulness becomes more challenging and eventful. A more ecological approach to sleep and sleepiness is advocated.
Health-related quality of life (HRQOL) has been viewed as the most important clinical outcome of heart failure (HF) management. However, information about the predictors of HRQOL in Taiwanese people with HF is limited, especially for the effects of sleep disturbances on HF.
The purpose of this study was to identify predictors of HRQOL in Taiwanese people with HF, especially focusing on the extent to which sleep variables are related to HRQOL.
A cross-sectional, descriptive correlational design was used. A nonprobability sample of 125 participants was recruited from the outpatient departments of 2 hospitals located in southern Taiwan. Participants were face-to-face individually interviewed to complete the Kansas City Cardiomyopathy Questionnaire, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Charlson Comorbidity Index. Data for concomitant health problems and HF characteristics were collected from the medical records.
The mean Kansas City Cardiomyopathy Questionnaire overall summary score for HRQOL in this sample was 70.50 (SD, 19.63). Health-related quality of life physical symptom had the highest score, and the psychological satisfaction domain had the lowest. Six predictors of the HRQOL were identified by using a 3-step hierarchical multiple regression analysis with forward method. The predictors were education (R² = 0.09), New York Heart Association functional class (R² = 0.398), Charlson Comorbidity Index number (R² = 2.6), subjective sleep quality (R² = 0.037), sleep disturbances (R² = 0.015), and sleep latency (R² = 0.018), and together they accounted for a total of 58.5% of the variance in HRQOL.
Nurses should use a holistic perspective to help patients understand and manage the impact of HF on their daily lives. Effective interventions for improving HRQOL should be designed based on patients' needs and lifestyles. The study findings could serve as a baseline for further longitudinal studies to explore the long-term effects of correlates and causal relationships among the variables in this Taiwanese population with HF.
Seemingly, many healthy adults have accrued a sleep debt, as determined by findings based on the multiple sleep latency test (MSLT). However, our recent, extensive survey found self-reported sleep deficit was not linked to daytime sleepiness determined by the Epworth sleepiness scale (ESS). Here, we report on the link between self-reported sleep deficit and gold standard measures of sleepiness: MSLT, Psychomotor vigilance test (PVT) and Karolinska Sleepiness Scale (KSS). Habitual sleep time in forty-three participants, from using a week long sleep diary and actiwatch data, compared with self-ratings of how much sleep they needed, provided estimates of apparent sleep deficit or otherwise. They were split into categories: 'sleep deficit' (Av. -47 min), 'sleep plus' (Av. 47 min) or 'neutral' (Av. 0+/-15 min), depicting perceived shortfall (or excess) sleep. Although the deficit group desired to sleep longer than the other groups, they actually obtained similar habitual nightly sleep as the neutral group, but less than the sleep plus group. 'Survival curves' based on those falling asleep during the MSLT showed no difference between the groups. Neither was there any difference between the groups for the PVT, KSS, or ESS. Here, factors other than sleepiness seem to influence self-perceived sleep deficits.
Approximately 10% to 70% of people living with chronic heart failure (HF) experience significant sleep disturbances, which have been shown to impair their health-related quality of life and overall functional performance. Research findings, however, report inconsistent conclusions about sleep disturbances and their adverse effects on HF. The purpose of this article is to review several research studies addressing sleep disturbances in patients with HF and to highlight contradictory and inconsistent findings. Further nursing research about the phenomena related to sleep disturbances in people with HF is warranted so that evidence-based assessments and interventions can be tested in the future.
The sleep literature increasingly points to an apparent chronic sleep debt in the general population. We investigated this by examining perceived shortfalls in daily sleep, using more indirect questioning methods.
To determine perceived sleep deficits, 10,810 adults completed a simple questionnaire, which avoided leading questions and provided information on sleep length, daytime sleepiness, desired sleep length, a choice of attractive daytime activities in a "free hour", and "stressful lifestyle". From this we assessed whether deficits were reflected by increased daytime sleepiness or opting for more sleep when given attractive waking alternatives. Respondents were divided according to age and sex.
Half of men and women seemed to desire more sleep, but this apparent sleep deficit was not correlated with daytime sleepiness, for any age or sex group. Irrespective of deficit, few people opted for sleep when given waking alternatives. "Stressful lifestyle" was independently related to this sleep deficit.
Desiring more sleep may also be synonymous with a need for more "time out", as sleep deficit was unrelated to daytime sleepiness but rather related to "stressful lifestyle." Extra sleep may not be the only anodyne for sleep deficit.
We observed how sailors manage their sleep and alertness before and during competition in a long-haul yacht race. Global performance of the teams was also recorded. We assessed eight sailors aged 21-30 years, split into four teams, who competed in the Tour de France à la Voile 2002 yacht race. Two phases of the race were examined: two legs in both the Atlantic Ocean and Mediterranean Sea. Sleep length, sleep debt, and sleepiness before competition and on board during the race were assessed using ambulatory polysomnography. Intermediate and final rankings were considered as a reflection of performance. A significant correlation was observed between the sleep debt before competition and the total sleep time on board during the Atlantic legs. The greater the sleep debt, the more sleepy the participants were. During the Mediterranean legs, almost all the sailors were deprived of sleep and slept during the daytime competitions. We observed that the final ranking in the race related to the sleep management strategy of the participants. In extreme competitive conditions, the effect of a good night's sleep before competition on performance is important. The strategy of the winners was to get sufficient sleep before each leg so as to be the most alert and efficient during the race.
Napping can enhance alertness during sustained wakefulness, but the importance of the temporal placement of the nap between days and within the circadian cycle remains controversial. To resolve these issues, a between-groups study was conducted with 41 healthy, young adults permitted a 2-h nap at one of five times during a 56-h period otherwise devoid of sleep. Naps were placed 12 h apart, near the circadian peak (P) or trough (T), and were preceded by 6, 18, 30, 42, or 54 h of wakefulness. Visual reaction time (RT) performance, Stanford Sleepiness Scale (SSS) ratings, and sublingual temperature were assessed every few hours throughout the 56 h, which took place in an environment free of time cues. All groups displayed a circadian-modulated decline in RT measures and increases in SSS functions as sleep loss progressed. A nap placed at any time in the protocol improved RT performance, particularly in the lapse domain, but not SSS ratings. Comparisons within groups of circadian temperature cycles for the first versus second day of the protocol indicated that early naps (P6, T18, P30) tended to prevent the mean drop in temperature across days. The earlier naps (P6, T18) yielded more robust and longer lasting RT performance benefits, which extended beyond 24 h after the naps, despite the fact that they were comprised of lighter sleep than later naps. Circadian placement of naps (P vs. T) did not affect the results on any parameter. In terms of temporal placement, therefore, napping prior to a night of sleep loss is more important for meeting subsequent performance demands than is the circadian placement of the nap. SSS ratings suggest that the napper is not aware of these performance benefits. Because the longest lasting RT gains followed early naps, which were composed of less deep sleep than later naps, napping during prolonged sleep loss may serve to prevent sleepiness more readily than it permits recovery from it.
Thirty-four healthy, normal young men and women (21-35 years), with no sleep complaints and a normal screening polysomnogram, some with short (< or = 6-minute) and some with long (> or = 16-minute) average daily sleep latencies on a screening multiple sleep latency test, were studied on two baseline nights (8 hours) and in the "sleepy" group, for 14 consecutive nights of extended (10-hour) or habitual (7.8 +/- 0.7-hour) bedtimes. The screening differences between the groups in average daily sleep latency were consistently seen on the two further baseline nights and days. The extension of bedtime in sleepy subjects was followed by an increase in average daily sleep latency relative to randomly chosen sleepy subjects maintained on their habitual sleep schedule for the 14 nights. The increase in average daily sleep latency was associated with a gradual reduction in sleep efficiency over the 14 nights. Some (36%) of the sleepy subjects did not have increased average sleep latencies during the 10-hour bedtime extension. Those showing no increase in average daily sleep latency had an immediate drop in sleep efficiency when the bedtime was increased to 10 hours, suggesting they were unable to sleep longer during the extension. Their short average daily sleep latency was a result of causes other than chronic insufficient sleep.
The maintenance of wakefulness test (MWT) is a daytime polysomnographic procedure which quantifies wake tendency by measuring the ability to remain awake during soporific circumstances. We present normative data based on 64 healthy subjects (27 males and 37 females) who adhered to uniform MWT procedural conditions including polysomnographic montage, illuminance level, seating position, room temperature, meal timing, and subject instructions. When allowed a maximum trial duration of 40 min, subjects' mean sleep latency to the first epoch of sustained sleep was 35.2 +/- 7.9 min. The lower normal limit, defined as two standard deviations below the mean, was 19.4 min. Calculation of data on the basis of a maximum trial duration of 20 min and sleep latency to the first appearance of brief sleep (a microsleep episode or one epoch of any stage of sleep) yielded a mean sleep latency of 18.1 +/- 3.6 min and a lower normal limit of 10.9 min. Sleep latency scores were significantly higher than those previously reported in patients with disorders of excessive somnolence. Therefore, the MWT appears to be a useful procedure in differentiating groups with normal daytime wake tendency from those with impaired wake tendency and in identifying individuals with pathologic inability to remain awake under soporific circumstances.
A report on the stress management is presented. Stress management encourages regular exercise, a healthy diet and learning to maintain a positive attitude. These are good habits, but it was found that when people were in burnout, these changes are the hardest to make. The successful adults who enjoyed abundant energy had much in common with young children.
24 healthy men (aged 21–35 yrs) with no complaints of daytime sleepiness, no habitual napping, and polysomnographically verified normal nocturnal sleep extended their time in bed (TIB) to 10 hrs for 6 consecutive nights to assess the effects of sleep extension on daytime sleepiness and performance. 12 Ss had basal average daily sleep latencies of ≤6 min on the Multiple Sleep Latency Test (M. A. Carskadon et al; 1986) and 12 had latencies of ≥16 min before TIB was extended. The sleep extension improved daytime sleepiness differentially in the 2 groups. Sleepy Ss showed an immediate and uniform increase in alertness, while alert Ss did not show improvements until late in the extension. However, sleepy Ss never achieved the baseline level of sleepiness/alertness seen in the alert Ss. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
To determine whether a cumulative sleep debt (in a range commonly experienced) would result in cumulative changes in measures of waking neurobehavioral alertness, 16 healthy young adults had their sleep restricted to an average 4.98 hrs per night for 7 consecutive nights. Ss slept in the laboratory, and sleep and waking were monitored. Three times each day, Ss were assessed for subjective sleepiness and mood and were evaluated on a brief performance battery that included psychomotor vigilance (PVT), probed memory (PRM), and serial-addition testing. Once each day they completed a series of visual analog scales (VASs) and reported sleepiness and somatic and cognitive/emotional problems. Sleep restriction resulted in statistically robust cumulative effects on waking functions. Subjective sleepiness ratings, subscale scores for fatigue, confusion, tension, and total mood disturbance from the mood and VAS ratings of mental exhaustion and stress were elevated across days of restricted sleep. PVT performance parameters were also significantly increased by restriction. Significant time-of-day effects were evident in subjective sleepiness and PVT data. Findings suggest that cumulative nocturnal sleep debt had a dynamic and escalating analog in cumulative daytime sleepiness and that asymptotic or steady-state sleepiness was not achieved in response to sleep restriction. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
• The circadian timing system has been implicated in age-related changes in sleep structure, timing and consolidation in humans. • We investigated the circadian regulation of sleep in 13 older men and women and 11 young men by forced desynchrony of polysomnographically recorded sleep episodes (total, 482; 9 h 20 min each) and the circadian rhythms of plasma melatonin and core body temperature. • Stage 4 sleep was reduced in older people. Overall levels of rapid eye movement (REM) sleep were not significantly affected by age. The latencies to REM sleep were shorter in older people when sleep coincided with the melatonin rhythm. REM sleep was increased in the first quarter of the sleep episode and the increase of REM sleep in the course of sleep was diminished in older people. • Sleep propensity co-varied with the circadian rhythms of body temperature and plasma melatonin in both age groups. Sleep latencies were longest just before the onset of melatonin secretion and short sleep latencies were observed close to the temperature nadir. In older people sleep latencies were longer close to the crest of the melatonin rhythm. • In older people sleep duration was reduced at all circadian phases and sleep consolidation deteriorated more rapidly during the course of sleep, especially when the second half of the sleep episode occurred after the crest of the melatonin rhythm. • The data demonstrate age-related decrements in sleep consolidation and increased susceptibility to circadian phase misalignment in older people. These changes, and the associated internal phase advance of the propensity to awaken from sleep, appear to be related to the interaction between a reduction in the homeostatic drive for sleep and a reduced strength of the circadian signal promoting sleep in the early morning.
Sleep and daytime sleepiness were evaluated in 10 young adult subjects to determine whether restricting nocturnal step by a constant amount produces cumulative impairment. Subjects were studied for 12 consecutive days, including 3 baseline days with a 10-hr time in bed, 7 days with sleep restricted to 5 hrs, and 2 recovery days. In 5 subjects, recovery included a 10-hr time in bed; in the remaining subject, recovery induced a 5-hr time in bed with a 1-hr daytime nap. Sleepiness was measured using two self-rating scales and the multiple sleep latency test. During sleep restriction, nocturnal stage 2 and REM sleep were reduced and slow wave sleep was unaffected. Stanford Sleepiness Scales showed an immediate increase in daytime sleepiness that reached a plateau after 4 days. An analog sleepiness rating scale showed increased sleepiness after 2 restricted nights and leveled off after the fourth restricted night. The multiple sleep latency tests showed no effect of sleep restriction until the second day, followed by a progressive increase in sleepiness that persisted through the seventh sleep restriction day. During the recovery period, daytime sleepiness returned to basal values on all three measures following one full night of sleep; with a daytime nap, no further cumulative effects of sleep restriction were seen.
The electroencephalogram (EEG) and electromyogram of rats with lesions in the suprachiasmatic nuclei (SCNx) were recorded during two series of 24-h baseline, 6-h sleep deprivation (SD), and 24-h recovery. At recovery onset, rats were injected i.p. with vehicle (VEH) control solution or 0.4 mg/kg triazolam (TRZ) in a balanced crossover design. Consecutive 10-s epochs were scored for vigilance states and EEG power spectra were computed. Arousal states were uniformly distributed during 24-h baseline (wake 47% of recording time, non-rapid-eye movement sleep (nonREMS) 47%, REMS 7%), and EEG spectra (0-25 Hz) were devoid of significant trends. State-specific EEG power spectra profiles in SCNx rats were similar to those of intact animals reported previously. However, EEG delta power (0.5-3.5 Hz) of nonREMS was markedly lower in SCNx rats. Recovery from 6-h SD was characterised by a short-lasting reduction of REMS, and a long-lasting increase of nonREMS time at the cost of wakefulness. EEG delta power rebounded during the first 8 h in recovery, and fell below baseline level after 12 h in recovery. During 0-2 h TRZ recovery, rats spent more time in nonREMS with higher EEG slow wave activity as compared to the corresponding VEH recovery period. EEG slow wave activity fell below baseline levels 10 h after TRZ injection and termination of SD. We conclude that major features of homeostatic sleep EEG regulation are present in SCNx rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Rats with suprachiasmatic nuclei (SCN) lesions did not show increased sleep after triazolam (TRZ) injections at any dose from 0.2 to 1.6 mg/kg, whereas 0.4 mg/kg TRZ given intact rats in the middle of their activity phase significantly increased sleep. Across SCN-lesioned and intact rats, the amount of sleep before and after TRZ 0.4 mg/kg was negatively correlated. SCN-lesioned rats did not have a circadian activity-dominant period and so did not accumulate a biological sleep debt. Their lack of response to TRZ may have resulted from the absence of a sleep debt compared to intact rats injected in the middle of their activity phase. These data support our hypothesis that the homeostatic process controlling sleep gates benzodiazepine hypnotic efficacy.
A neurophysiological technique that quantifies drowsiness as the speed of falling asleep at intervals across a day is used to identify patterns of sleepiness/alertness. The Multiple Sleep Latency Test (MSLT) reveals a daily biphasic organization of sleepiness that is affected in predictable ways by the length and continuity of nocturnal sleep on one or several nights, and by maturation, aging, sleep pathology, and drug ingestion. The systematic nature of these relationships provides impetus to efforts examining the neurobiological mechanisms subserving the delicate balance of sleep and wakefulness.
Simultaneous recordings of EEG, EOG, EMG, 11R, GSR, respiration, skin tem- perature, and plethysmogram were obtained from a 17-year-old boy following 236, 246, and 264 hr. of wakefulness, during 3 recovery nights, 1 week, 6 weeks, and 7 months after end of deprivation. The EEG indicated dominant slow activity with minimum alpha during deprivation. Opening and closing of eyes had little effect on the EEC and stimuli did not produce alpha enhancement. Prolonged sleep loss caused a chronic shift to increased activity of the autonomic nervous system but with diminished responsiveness to external stimuli. During the early period of the first recovery sleep, increased responsiveness to stimuli was seen in all autonomic variables except GSR. Specific GSR's did not appear until the sec- ond recovery night. There was an increase in REM sleep during the first 3 recov- ery nights.
The sleep patterns of 8 normal subjects living in a winter-type photoperiod (10 h light and 14 h darkness; LD 10:14) for 4 weeks were characterized by the presence of periods of spontaneous wakefulness alternating with periods of spontaneous sleep. Transitions from sleep to wakefulness occurred much more frequently out of REM sleep than out of NREM sleep (P < 0.002). REM periods that terminated in wakefulness showed shorter REM durations (P < 0.0005) and higher REM densities (P < 0.0005) than REM periods that did not terminate in wakefulness. The authors discuss these results in terms of a possible relationship between REM density and arousal level. The higher REM density preceding wakefulness and the increased number of REM periods terminating in spontaneous awakenings could reflect an enhanced level of a brain arousing process, resulting from reduced sleep pressure in the extended nights.
During 26 consecutive nights, electroencephalographic recordings and/or actigraphs were used to monitor the nighttime sleep of 10 asymptomatic healthy sleepers (mean age = 23.6 years). The schedule comprised: 7 nights of baseline sleep, 14 nights of extended sleep (up to 10 hr/night), and 5 nights of recovery sleep. During extended sleep, subjects slept significantly longer (approximately 1 hr), but sleep latency and interim wakefulness deteriorated. Extended sleep produced no improvements to self-rated mood or subjective sleepiness. Vigilance tests showed a small but significant reduction in reaction time following extended compared with both baseline and recovery nights. Ability to detect target tones did not change significantly. Multiple Sleep Latency Test scores during extended sleep showed small (about 1 min) reductions. These findings give little support to the view of chronic sleep deprivation in the average 7.5-hr sleeper.
The aim of the study is to examine the effects of a 20 min nap in the mid-afternoon on mood, performance and EEG activities.
Seven young adults who had normal sleep-wake habits without habitual daytime napping participated in the study. They underwent Nap and No-nap conditions at intervals of 1 week. After a nocturnal sleep recording (00:00-08:00 h), their EEG recordings during relaxed wakefulness, and their mood, performance and self-ratings of performance level were measured every 20 min from 10:00 to 18:00 h. For the nap condition, they went to bed at 14:00 h and were awakened when 20 min had elapsed from the onset of sleep stage 1. For the No-nap condition, they took a rest without sleep by sitting on a semi-reclining chair.
All of the subjects were awakened from sleep stage 2 during the nap. The 20 min nap improved the subjective sleepiness, performance level and self-confidence of their task performance. The nap also suppressed EEG alpha activity during eyes-open wakefulness.
The results suggest that a short 20 min nap in the mid-afternoon had positive effects upon the maintenance of the daytime vigilance level.
Studied the effect of extended sleep on the performance of calculation, vigilance, and complex motor tasks. 12 normal male undergraduates, who regularly slept 7-8 hr/night, were studied after 2 control nights of habitual sleep (7.1 hr. average) and 2 extended sleep nights (9.1 hr. average). Combined number of omissions and false reports on the vigilance task and average score/game on the pinball task indicated significant decrements in performance after extended sleep. No significant differences in errors or speed were found for the calculation task. Possible factors causing this decrement in performance are considered. It is suggested that any general theory of sleep should attempt to explain both the effects of sleep deprivation and of extended sleep. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Daytime performance changes were examined during chronic sleep restriction or augmentation and following subsequent recovery sleep. Sixty-six normal volunteers spent either 3 (n = 18), 5 (n= 16), 7 (n = 16), or 9 h (n = 16) daily time in bed (TIB) for 7 days (restriction/augmentation) followed by 3 days with 8 h daily TIB (recovery). In the 3-h group, speed (mean and fastest 10% of responses) on the psychomotor vigilance task (PVT) declined, and PVT lapses (reaction times greater than 500 ms) increased steadily across the 7 days of sleep restriction. In the 7- and 5-h groups speed initially declined, then appeared to stabilize at a reduced level; lapses were increased only in the 5-h group. In the 9-h group, speed and lapses remained at baseline levels. During recovery, PVT speed in the 7- and 5-h groups (and lapses in the 5-h group) remained at the stable, but reduced levels seen during the last days of the experimental phase, with no evidence of recovery. Speed and lapses in the 3-h group recovered rapidly following the first night of recovery sleep; however, recovery was incomplete with speed and lapses stabilizing at a level comparable with the 7- and 5-h groups. Performance in the 9-h group remained at baseline levels during the recovery phase. These results suggest that the brain adapts to chronic sleep restriction. In mild to moderate sleep restriction this adaptation is sufficient to stabilize performance, although at a reduced level. These adaptive changes are hypothesized to restrict brain operational capacity and to persist for several days after normal sleep duration is restored, delaying recovery.
To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation.
The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days.
Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring.
A total of n = 48 healthy adults (ages 21-38) participated in the experiments.
Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited.
Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h).
Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
Sleep deprivation causes physiologic and subjective sleepiness. Studies of fatigue effects on anesthesiologist performance have given equivocal results. The authors used a realistic simulation environment to study the effects of sleep deprivation on psychomotor and clinical performance, subjective and objective sleepiness, and mood.
Twelve anesthesia residents performed a 4-h anesthetic on a simulated patient the morning after two conditions of prior sleep: sleep-extended (EXT), in which subjects were allowed to arrive at work at 10:00 AM for 4 consecutive days, thus allowing an increase in nocturnal sleep time, and total sleep deprivation (DEP), in which subjects were awake at least 25 h. Psychomotor testing was performed at specified periods throughout the night in the DEP condition and at matched times during the simulation session in both conditions. Three types of vigilance probes were presented to subjects at random intervals as well as two clinical events. Task analysis and scoring of alertness were performed retrospectively from videotape.
In the EXT condition, subjects increased their sleep by more than 2 h from baseline (P = 0.0001). Psychomotor tests revealed progressive impairment of alertness, mood, and performance in the DEP condition over the course of the night and when compared with EXT during the experimental day. DEP subjects showed longer response latency to vigilance probes, although this was statistically significant for only one probe type. Task analysis showed no difference between conditions except that subjects "slept" more in the DEP condition. There was no significant difference in the cases' clinical management between sleep conditions. Subjects in the DEP condition had lower alertness scores (P = 0.02), and subjects in the EXT condition showed little video evidence of sleepiness.
Psychomotor performance and mood were impaired while subjective sleepiness and sleepy behaviors increased during simulated patient care in the DEP condition. Clinical performance between conditions was similar.
To measure the effects of prolonged sleep extension on daytime alertness, vigilance, and mood in healthy young adults. Little research has documented the effects of increased sleep on daytime function despite a high prevalence of daytime fatigue and sleepiness in the adult population. Past extension studies report conflicting results with regard to Multiple Sleep Latency Test (MSLT) scores, vigilance, and mood ratings. No study has challenged subjects to maximum sleep extension, defined by an MSLT score of 20.
Fifteen healthy college students reporting minimal daytime sleepiness were allowed to sleep as much as possible during a sleep extension period. MSLT scores, psychomotor vigilance task (PVT) reaction times, and profile of mood states (POMS) ratings were measured at baseline, mid-extension, and end-extension.
There was a significant increase in both journal and actigraphy sleep totals during all extension segments (P<0.01). MSLT scores increased significantly from baseline to both mid- and end-extension (P<0.01). Five of eight tabulated PVT measures also improved significantly at mid- and end-extension with respect to baseline (P<0.05). POMS vigor and fatigue scores showed a similar improvement (P<0.01). Seven subjects achieved an MSLT score of 20. Six subjects showed substantial improvements while two subjects obtained relatively little extra sleep and showed little or no MSLT improvement. The maximum extension group displayed exceptional improvements in vigilance and POMS ratings.
Extended sleep leads to substantial improvements in daytime alertness, reaction time, and mood.
Cumulative neurobehavioral performance deficits on a 24-hr day with 8-hr of scheduled sleep
- Wright
Wright Jr K, Hughes R, Hull J, et al. Cumulative neurobehavioral performance deficits on a 24-hr day with 8-hr of scheduled sleep. Sleep 2000;23(Suppl):A21.
The Promise of Sleep
- W Dement
- Vaughn
Dement W, Vaughn C. The Promise of Sleep. New York7 Delacorte Press; 1999.