Sleep and effort in adolescent athletes

Sleep Disturbance and Its Association With Sluggish Cognitive Tempo and Attention in Pediatric Brain Tumor Survivors

Background

Pediatric brain tumor (PBT) survivors are at risk for developing sleep disturbances. While in other pediatric populations sleep disturbance has been associated with worse cognitive functioning, it is unclear to what extent this relationship generalizes to PBT survivors. The aim of the current study was to assess the relationship between sleep disturbance and aspects of cognition, including sluggish cognitive tempo (SCT) as well as attention and working memory.

Materials and Methods

Eighty-three PBT survivors 6–18 years of age who were at least 3 months post-treatment were included in the present cross-sectional study. Level of sleep disturbance was measured as a composite score reflecting various sleep problems as rated by caregivers. Cognitive measures included caregiver-ratings of sluggish cognitive tempo and attention problems, as well as performance-based cognitive measures assessing attention and executive functioning. Hierarchical regression analysis was used to assess associations between sleep and cognition.

Results

Of all caregivers, 32.5% reported one or more sleep disturbances as “very/often true” and over 68% of caregivers rated at least one sleep-related item as “somewhat true.” Of all cognitive variables, scores were most frequently impaired for SCT (30%). A higher level of sleep disturbance was associated with worse SCT and parent-rated attention problems. Associations between sleep and performance-based cognitive measures assessing attention and working memory were not statistically significant.

Conclusion

Findings of the current study highlight the importance of further investigation into the relationship between sleep and cognition in PBT survivors, which may assist efforts to maximize cognitive outcome and health-related quality of life in PBT survivors. The current study additionally suggests further investigation of SCT in this population is warranted, as it may be more sensitive to detecting possible associations with sleep disturbance relative to discrete measures that assess cognitive performance under ideal circumstances.

Sleep Restriction Reduces Cognitive but Not Physical Motivation

PURPOSE

Motivation is an important driver of behaviour, and several frameworks distinguish the willingness of individuals to invest cognitive versus physical effort to achieve a goal. One outstanding question is whether sleep loss lowers motivation within specific domains of effort, or has a global effect on motivation across multiple domains. Here, we investigated the effects of sleep restriction on the motivation to invest cognitive or physical effort in return for reward.

MATERIALS AND METHODS

24 healthy young adults (11 females) completed an effort-based decision-making task over two laboratory sessions - once while sleep restricted (three consecutive nights with a three-hour sleep opportunity), and the other while fully rested (nine-hour sleep opportunity on each night). In an initial reinforcement phase, participants were trained to ceiling performance across six levels of effort on separate cognitively and physically demanding tasks. Then, in the critical decision-making phase, participants revealed their preference for how much cognitive or physical effort they would be willing to invest for reward.

RESULTS

Sleep restriction reduced the willingness to exert cognitive effort, but spared motivation in the physical domain. Furthermore, the reduction in cognitive motivation appeared to be a primary motivational deficit, which could not be attributed to differences in reward-likelihood of different levels of effort or the temporal structure of the task.

CONCLUSION

The results suggest that sleep restriction has a selective effect on cognitive over physical motivation, which has significant implications for real-world settings in which individuals must maintain high levels of cognitive motivation in the face of chronic sleep loss.

Relationships Among Sleep Disturbance, Reward System Functioning, Anhedonia, and Depressive Symptoms

Recent models propose reward system dysfunction as a key mediator of the relationship between sleep and depression and anhedonia. This study explored interrelationships among sleep disturbance, depressive symptoms, anhedonia, and reward responsiveness. Two-hundred and sixty undergraduate students completed questionnaires and a daily diary paradigm assessing sleep, reward responsiveness, depression, anhedonia, and positive affect over 1 week. Baseline sleep disturbance was associated with depressive symptoms, anhedonia, and reward responsiveness. Daily diary sleep parameters showed differential associations with anticipatory versus consummatory reward responsiveness and positive affect. Poorer sleep quality, shorter sleep duration, and longer awakening after sleep onset predicted blunted anticipatory and consummatory reward responsiveness, while increased sleep onset latency and lower sleep efficiency predicted only decreased consummatory reward responsiveness. All sleep indices, except sleep onset latency, were associated with positive affect. Findings demonstrate unique associations between disparate sleep disturbance and reward responsiveness elements, highlighting new treatment mechanisms for anhedonia and depression.

Abnormal functional connectivity of the anterior cingulate cortex subregions mediates the association between anhedonia and sleep quality in major depressive disorder

BACKGROUND

The anterior cingulate cortex (ACC) is a crucial region in the pathophysiology of major depressive disorder (MDD). However, the relationship between functional alterations of the ACC subregions, anhedonia and sleep quality remains unclear in MDD patients.

METHODS

The resting-state functional connectivity (rsFC) of ACC subregions was measured in 41 first-episode medication-naïve MDD patients and 63 healthy controls who underwent functional magnetic resonance imaging. Between-group differences were examined using two-sample t-test. Furthermore, correlation and mediation analyses were carried out to investigate the relationships between the aberrant rsFC of ACC subregions, anhedonia and sleep quality in the patients and controls.

RESULTS

Compared to healthy controls, the MDD patients exhibited increased rsFC of ACC subregions to areas of the anterior default mode network (DMN) and showed decreased rsFC of the right subgenual ACC to left precuneus (PCUN), which belongs to the posterior DMN. In MDD group, the sleep quality and consummatory anhedonia are correlated with some rsFC, which involves the angular gyrus (ANG) and superior frontal gyrus (SFG). More importantly, the rsFC between the right perigenual ACC and left SPG mediates the association between anhedonia and sleep quality in MDD.

LIMITATIONS

The cross-sectional design and the subjective questionaries for assessment.

CONCLUSION

These findings confirm the functional alterations of the ACC subregions and reveal the mediating role of ACC subregions in sleep and reward dysfunction in MDD.

"The Competitive Season and Off-Season": Preliminary Research concerning the Sport-Specific Performance, Stress, and Sleep in Elite Male Adolescent Basketball Athletes

BACKGROUND

Through scholastic sports programs, adolescent athletes compete to represent their communities. However, few studies investigate the changes in physiological and mental profiles during varied sport periodization among this population. Therefore, the purpose of this study was to compare the changes in sports performance and stress-related biomarkers between the competitive season (CS) and off-season (OS) in elite adolescent basketball players.

METHOD

Nine elite Division I male basketball players (age: 15-18 years. old) participated in this study. Basketball-specific performance, salivary dehydroepiandrosterone sulfate (DHEA-S)/cortisol levels, mood state, and sleep quality were all accessed during the CS and OS periods.

RESULTS

The training load during OS was 26.0% lower than CS (p = 0.001). Muscle mass, aerobic capacity, 10 m sprint, and Abalakov jump (AJ) power during OS were greater than that during CS (+2.2-9.8%, p < 0.05), but planned agility was greater during CS (p = 0.003). The salivary DHEA-S/cortisol was greater during CS than during OS (p = 0.039). The overall mood state and sleep quality did not differ between periods, but the POMS-tension was higher during CS (p = 0.005).

CONCLUSION

The present study demonstrates that muscle mass, aerobic capacity, peak AJ power, and 10 m sprint performance, but not planned agility, were greater during OS compared to CS among elite adolescent basketball players. Furthermore, the stress-related responses reflected by the D/C ratio and mood tension were relatively lower during the OS in these athletes. Thus, this study suggests that coaches and sport science professionals should closely monitor athletes' training states across varied training/competition periods to better react to modifying training or recovery plans.

An Integrated Sleep and Reward Processing Model of Major Depressive Disorder

Major depressive disorder with comorbid sleep disturbance has been associated with negative outcomes, including lower rates of treatment response and a greater likelihood of depressive relapse compared to those without sleep disturbance. However, little, if any, research has been conducted to understand why such negative treatment outcomes occur when sleep disturbance is present. In this conceptual review, we argue that the relationship of sleep disturbance and negative treatment outcomes may be mediated by alterations in neural reward processing in individuals with blunted trait-level reward responsivity. We first briefly characterize sleep disturbance in depression, discuss the nature of reward processing impairments in depression, and summarize the sleep/reward relationship in healthy human subjects. We then introduce a novel Integrated Sleep and Reward model of the course and maintenance of major depressive disorder and present preliminary evidence of sleep and reward interaction in unipolar depression. Finally, we discuss limitations of the model and offer testable hypotheses and directions for future research.

Sleep deprivation, effort allocation and performance

Sleep deprivation causes physiological alterations (e.g., decreased arousal, intrusion of micro-sleeps), that negatively affect performance on a wide range of cognitive domains. These effects indicate that cognitive performance relies on a capacity-limited system that may be more challenged in the absence of sleep. Additionally, sleep loss can result in a lower willingness to exert effort in the pursuit of performance goals. Such deficits in motivation may interact with the effects of capacity limitations to further stifle cognitive performance. When sleep-deprived, cognitive performance is experienced as more effortful, and intrinsic motivation to perform dwindles. On the other hand, increasing motivation extrinsically (e.g., by monetary incentives) can inspire individuals to allocate more task-related effort, and can partially counter performance deficits associated with sleep deprivation. In this chapter, we review current research on the interplay between sleep deprivation, effort and performance. We integrate these findings into an effort-based decision-making framework in which sleep-related performance impairments may result from a voluntary decision to withdraw effort. We conclude with practical implications of this framework for performance in healthy populations (e.g., work productivity) and clinical conditions.

Sleeping hours: what is the ideal number and how does age impact this?

The objective of this narrative review paper is to discuss about sleep duration needed across the lifespan. Sleep duration varies widely across the lifespan and shows an inverse relationship with age. Sleep duration recommendations issued by public health authorities are important for surveillance and help to inform the population of interventions, policies, and healthy sleep behaviors. However, the ideal amount of sleep required each night can vary between different individuals due to genetic factors and other reasons, and it is important to adapt our recommendations on a case-by-case basis. Sleep duration recommendations (public health approach) are well suited to provide guidance at the population-level standpoint, while advice at the individual level (eg, in clinic) should be individualized to the reality of each person. A generally valid assumption is that individuals obtain the right amount of sleep if they wake up feeling well rested and perform well during the day. Beyond sleep quantity, other important sleep characteristics should be considered such as sleep quality and sleep timing (bedtime and wake-up time). In conclusion, the important inter-individual variability in sleep needs across the life cycle implies that there is no "magic number" for the ideal duration of sleep. However, it is important to continue to promote sleep health for all. Sleep is not a waste of time and should receive the same level of attention as nutrition and exercise in the package for good health.

Risk factors for precompetitive sleep behavior in elite female athletes

BACKGROUND

Sleep is of major importance for the athletes' short and long-term health, performance and recovery; however, published studies on athletes' sleep and even fewer before competition are scarce. This study evaluated the risk factors of sleep in young female gymnasts before an international competition.

METHODS

Sixty-seven rhythmic gymnasts (M=18.7, SD=2.9 years) of high performance (M=36.6, SD=7.6 h/week) were evaluated regarding training and sport practice, body composition, sleep duration, daytime sleepiness by the Epworth Sleepiness Scale, sleep quality by the Pittsburgh Sleep Quality Index, precompetitive anxiety by the Sport Competition Anxiety Test form A, and detailed dietary intake just prior to a world competition.

RESULTS

The majority of the participants (83.6%) presented reduced body fat levels (M=9.1, SD=2.1%) and low energy availability (EA, M=31.5, SD=11.9 kcal/kgFFM/day). They slept 8h10±1h30/night on weekdays and 8h40±00h40/night on weekends, 67% suffered from mild daytime sleepiness and 78% had a reduced sleep quality. Precompetitive anxiety was on average moderate (M=22.7, SD=3.2). The risk factors for short sleep duration were: 1.92 for a training volume>30 hours/week (95% CI 0.84-4.39), 4.57 for menstruation (95% CI 1.17-17.77), 6.62 for bedtime ≥11:00 PM (95% CI 1.74-25.10), 1.40 for BF<12% (95% CI 1.03-1.92), 2.19 for FFM<30 kg (95% IC 0.94-4.94), 2.37 for BMR<1100 kcal/day (95% CI 1.06-5.32), 1.90 for EEE≥700 kcal (95% CI 0.92-3.93) and 3.17 for EA<45 kcal/kg FFM/day (95% CI 0.84-6.59). Age, performance, sleep duration on weekdays and precompetitive stress were also predictors for a reduced sleep quality and/or abnormal daytime sleepiness.

CONCLUSIONS

Age, training regime, menstruation, individual preferences for bedtime, body composition and energy were important predictors of gymnasts' precompetitive sleep with consequences upon their sleep duration, SQ and DS.

Walking performance in adolescents and young adults with Down syndrome: the role of obesity and sleep problems

BACKGROUND

High prevalence of obesity and features of obstructive sleep apnea (OSA) are major health issues in individuals with Down syndrome (DS), and both may also affect adversely on their daily activities. Further, lower levels of physical work capacity (PWC) have been reported in this population compared to their peers with intellectual disabilities. However, no study examines the relationships between obesity and sleep problems with PWC in individuals with DS. Thus, this study investigated the influence of body mass index (BMI) and different types of sleep problems on PWC in adolescents and young adults with DS (14-31 years).

METHODS

The incremental treadmill walking trial was used to assess PWC.

RESULTS

The negative associations were indicated between BMI and walking steps (p = .03) as well as features with OSA and walking steps (p = .04). Thus, BMI and OSA were included in the regression analysis to estimate the walking steps achieved during walking trials. In addition, Bland-Altman plots demonstrated no overestimation and underestimation of variability in the difference between actual and estimated walking steps developed by using BMI and OSA.

CONCLUSIONS

Obesity and sleep problem are potentially detrimental to walking performance (i.e., fewer walking steps) in individuals with DS. Thus, individuals with DS may adopt a slow walk speed due to the increased balance deficits and physical fatigue that result from obesity and sleep fragmentation, respectively. Exercise interventions, which have the potential to reduce obesity and OSA, are recommended to improve the accomplishment of PWC in individuals with DS.

The role of sleep deprivation and fatigue in the perception of task difficulty and use of heuristics

This study investigated the effects of sleep deprivation on perception of task difficulty and use of heuristics (mental shortcuts) compared to naturally-experienced sleep at home. Methods: Undergraduate students were screened and assigned through block-random assignment to Naturally-Experienced Sleep (NES; n=19) or Total Sleep Deprivation (TSD; n=20). The next morning, reported fatigue, perception of task difficulty, and use of “what-is-beautiful-is-good,” “greedy algorithm,” and “speed-accuracy trade-off” heuristics were assessed. Results: NES slept for an average of 354.74 minutes (SD=72.84), or 5.91 hours. TSD rated a reading task as significantly more difficult and requiring more time than NES. TSD was significantly more likely to use the greedy algorithm heuristic by skipping instructions and the what-is-beautiful-is-good heuristic by rating an unattractive consumer item with a favorable review as poor quality. Those in Total Sleep Deprivation who chose more difficult math problems made this selection to finish the task more quickly in findings approaching significance, indicating use of the speed-accuracy trade-off heuristic. Collapsed across conditions, self-reported fatigue predicted greater perceived difficulty in both the reading task and a visuo-motor task, higher quality rating for the attractive consumer item, and lower quality rating for the unattractive consumer item. Conclusions: Findings indicate sleep deprivation and fatigue increase perceptions of task difficulty, promote skipping instructions, and impair systematic evaluation of unappealing stimuli compared to naturally-experienced sleep.

Past, present, and future: trends in sleep duration and implications for public health

Sleep is important for the physical, social and mental well-being of both children and adults. Over the years, there has been a general presumption that sleep will inevitably decline with the increase in technology and a busy 24-hour modern lifestyle. This narrative review discusses the empirical evidence for secular trends in sleep duration and the implications of these trends.

Relationship between Physical Function and Sleep Quality in African Americans

STUDY OBJECTIVES

There is a growing body of research examining the relationship between sleep and functional outcomes. However, little is known about sleep and physical functioning in older African Americans.

METHODS

Data for this project included 450 community-dwelling older African Americans (71.4 ± 9.2 years of age) who participated in the Baltimore Study of Black Aging. Overall sleep pattern and quality was measured by the Pittsburgh Sleep Quality Index (PSQI). Physical functioning was measured by the number of activities of daily living that each participant reported difficulty (ADL; e.g. eating, dressing, and bathing). Negative binomial regression models were conducted to estimate the association between sleep quality and physical functioning.

RESULTS

Seventy-two percent of the participants reported poor sleep quality. African Americans who reported poor sleep quality had a greater likelihood of an increase in the number of difficulties in ADLs that they reported even after accounting for demographic characteristics and health conditions. The relationship between sleep quality and physical functioning did not vary by gender.

CONCLUSIONS

Sleep may be an important factor to consider when seeking to improve physical functioning among community-dwelling older African Americans.

The effects of sleep loss on capacity and effort

Sleep loss appears to affect the capacity for performance and access to energetic resources. This paper reviews research examining the physical substrates referred to as resource capacity, the role of sleep in protecting that capacity and the reaction of the system as it attempts to respond with effort to overcome the limitations on capacity caused by sleep loss. Effort is the extent to which an organism will exert itself beyond basic levels of functioning or attempt alternative strategies to maintain performance. The purpose of this review is to bring together research across sleep disciplines to clarify the substrates that constitute and influence capacity for performance, consider how the loss of sleep influences access to those resources, examine cortical, physiological, perceptual, behavioral and subjective effort responses and consider how these responses reflect a system reacting to changes in the resource environment. When sleep deprived, the ability to perform tasks that require additional energy is impaired and the ability of the system to overcome the deficiencies caused by sleep loss is limited. Taking on tasks that require effort including school work, meal preparation, pulling off the road to nap when driving drowsy appear to be more challenging during sleep loss. Sleep loss impacts the effort-related choices we make and those choices may influence our health and safety.

Sleep/wake behaviours of elite athletes from individual and team sports

Sleep is an essential component for athlete recovery due to its physiological and psychological restorative effects, yet few studies have explored the habitual sleep/wake behaviour of elite athletes. The aims of the present study were to investigate the habitual sleep/wake behaviour of elite athletes, and to compare the differences in sleep between athletes from individual and team sports. A total of 124 (104 male, 20 female) elite athletes (mean ± s: age 22.2 ± 3.0 years) from five individual sports and four team sports participated in this study. Participants' sleep/wake behaviour was assessed using self-report sleep diaries and wrist activity monitors for a minimum of seven nights (range 7-28 nights) during a typical training phase. Mixed-effects analyses of variances were conducted to compare the differences in the sleep/wake behaviour of athletes from two sport types (i.e. individual and team). Overall, this sample of athletes went to bed at 22:59 ± 1.3, woke up at 07:15 ± 1.2 and obtained 6.8 ± 1.1 h of sleep per night. Athletes from individual sports went to bed earlier, woke up earlier and obtained less sleep (individual vs team; 6.5 vs 7.0 h) than athletes from team sports. These data indicate that athletes obtain well below the recommended 8 h of sleep per night, with shorter sleep durations existing among athletes from individual sports.

The complexities of defining optimal sleep: empirical and theoretical considerations with a special emphasis on children

The main aim of this paper is to consider relevant theoretical and empirical factors defining optimal sleep, and assess the relative importance of each in developing a working definition for, or guidelines about, optimal sleep, particularly in children. We consider whether optimal sleep is an issue of sleep quantity or of sleep quality. Sleep quantity is discussed in terms of duration, timing, variability and dose-response relationships. Sleep quality is explored in relation to continuity, sleepiness, sleep architecture and daytime behaviour. Potential limitations of sleep research in children are discussed, specifically the loss of research precision inherent in sleep deprivation protocols involving children. We discuss which outcomes are the most important to measure. We consider the notion that insufficient sleep may be a totally subjective finding, is impacted by the age of the reporter, driven by socio-cultural patterns and sleep-wake habits, and that, in some individuals, the driver for insufficient sleep can be viewed in terms of a cost-benefit relationship, curtailing sleep in order to perform better while awake. We conclude that defining optimal sleep is complex. The only method of capturing this elusive concept may be by somnotypology, taking into account duration, quality, age, gender, race, culture, the task at hand, and an individual's position in both sleep-alert and morningness-eveningness continuums. At the experimental level, a unified approach by researchers to establish standardized protocols to evaluate optimal sleep across paediatric age groups is required.

Sleep deprivation alters effort discounting but not delay discounting of monetary rewards

STUDY OBJECTIVES

To determine whether sleep deprivation would affect the discounting of delayed rewards, of rewards entailing the expense of effort, or both.

DESIGN

We measured rates of two types of reward discounting under conditions of rested wakefulness (RW) and sleep deprivation (SD). Delay discounting was defined as the willingness to accept smaller monetary rewards sooner rather than larger monetary rewards later. Effort discounting was defined as the willingness to accept smaller rewards that require less effort to obtain (e.g., typing a small number of letter strings backward) over larger but more effortful rewards (e.g., typing more letter strings to receive the reward). The first two experiments used a crossover design in which one session was conducted after a normal night of sleep (RW), and the other after a night without sleep (SD). The first experiment evaluated only temporal discounting whereas the second evaluated temporal and effort discounting. In the second experiment, the discounting tasks were repeatedly administered prior to the state comparisons to minimize the effects of order and/or repeated testing. In a third experiment, participants were studied only once in a between-subject evaluation of discounting across states.

SETTING

The study took place in a research laboratory.

PARTICIPANTS

Seventy-seven healthy young adult participants: 20 in Experiment 1, 27 in Experiment 2, and 30 in Experiment 3.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Sleep deprivation elicited increased effort discounting but did not affect delay discounting.

CONCLUSIONS

The dissociable effects of sleep deprivation on two forms of discounting behavior suggest that they may have differing underlying neural mechanisms.

Children's sleep needs: is there sufficient evidence to recommend optimal sleep for children?

It is widely recognized that sleep is important for children's health and well-being and that short sleep duration is associated with a wide range of negative health outcomes. Recently, there has been much interest in whether or not there are sufficient data to support the specific recommendations made for how much sleep children need. In this article we explore concepts related to children's sleep need, discuss the theory, rationale, and empirical evidence for contemporary sleep recommendations, and outline future research directions for sleep recommendations. If sleep is to be treated as a therapeutic intervention, then consensus guidelines, statements, and evidence-based best-practice documents are needed to underpin sleep recommendations for children.

Sleep in athletes and the effects of Ramadan

Sleep is now considered as a new frontier in performance enhancement. This article presents background content on sleep function, sleep needs and methods of sleep investigation along with data on the potential effects of Ramadan fasting on sleep in normal individuals and athletes. Accumulated sleep loss has negative impacts on cognitive function, mood, daytime sleepiness and performance. Sleep studies in athletes fasting during Ramadan are very rare. Most of them have demonstrated that during this month, sleep duration decreased and sleep timing shifted. But the direct relation between sleep changes and performance during Ramadan is not yet elucidated. Objective sleep patterns can be investigated using polysomnography, actigraphy, and standardised questionnaires and recorded in daily journals or sleep logs. The available data on sleep indicate that team doctors and coaches should consider planning sleep schedule and napping; implementing educational programmes focusing on the need for healthy sleep; and consider routine screening for sleep loss in athletes of all age groups and genders.

Diet and sleep in children with attention deficit hyperactivity disorder: preliminary data in Australian children

Sleep disturbances are common and consequential in children with attention deficit hyperactivity disorder (ADHD). Diet also influences ADHD symptoms. Interrelationships between diet, sleep and behaviour in children diagnosed with ADHD are little studied. We investigated, via parental report, the relationships between sleep and diet in 88 Australian children aged 6-13 years old (M = 8.94, SD = 1.78). This pilot data shows that 30 per cent of the children had sleep disturbance (≥ 2 standard deviations above the mean) with significant relationships between ADHD symptoms, sleep disturbance and diet. Parents who reported more sleep disturbance also reported a higher intake of carbohydrate, fats, and, most particularly, sugar which was also a significant predictor of night time sweating. These findings suggest an interrelationship between diet and sleep in children with ADHD. Given that both sleep and dietary intake are potentially modifiable behaviours within treatment regimes of children with ADHD, further investigation is needed.