High exercise levels are related to favorable sleep patterns and psychological functioning in adolescents: a comparison of athletes and controls. The longitudinal course, risk factors, and impact of sleep disturbances in children with traumatic brain injury. Impaired Sleep Mediates the Negative Effects of Training Load on Subjective Well-Being in Female Youth Athletes Sleep patterns and injury occurrence in elite Australian footballers. Cognitive Performance, Sleepiness, and Mood in Partially Sleep Deprived Adolescents: The Need for Sleep Study. Effects of a Short Daytime Nap on Shooting and Sprint Performance in High-level Adolescent Athletes. Risk factors of acute and overuse musculoskeletal injuries among young conscripts: a population-based cohort study Evidence of disturbed sleep and increased illness in overreached endurance athletes. Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers Sleep in athletes undertaking protocols of exposure to nocturnal simulated altitude at 2650 m. The mediating effect of sleep quality on the relationship between PTSD and physical activity. Sleep restriction worsens mood and emotion regulation in adolescents. A novel sleep optimisation programme to improve athletes’ well-being and performance Physical inactivity is a risk factor for physical activity-related injuries in children The New Zealand rugby injury and performance project. VI. A prospective cohort study of risk factors for injury in rugby union football EEG Changes across Multiple Nights of Sleep Restriction and Recovery in Adolescents: The Need for Sleep Study. Sleep disturbances, pain and analgesia in adults hospitalized for burn injuries.
PURPOSE To investigate whether chronic vigorous exercising is related to improved sleep and psychological functioning , and whether this association varies with gender . Both lay and scientific opinions hold that physical activity is an efficient remedy and preventative measure for poor sleep . However , empirical evidence on adolescents is very limited . METHODS A total of 434 adolescents ( 258 athletes , 176 controls ; mean age 17.2 years ) took part in the study . Weekly hours spent exercising were 17.69 hours and 4.69 hours , respectively . To assess sleep patterns and psychological functioning , participants completed a sleep log for 7 consecutive days and several self-rating question naires . RESULTS Compared with controls , athletes reported better sleep patterns including higher sleep quality , shortened sleep onset latency , and fewer awakenings after sleep onset , as well as less tiredness and increased concentration during the day . Athletes reported significantly lower anxiety and fewer depressive symptoms . Compared with males , females reported fewer variations in sleep . Male controls had particularly unfavorable scores related to sleep and psychological functioning . CONCLUSIONS Findings suggest that chronic vigorous exercising is positively related to  adolescents '  sleep and psychological functioning . Results also indicate that males with low exercise levels are at risk for increased sleep complaints and poorer psychological functioning This study aim ed to examine the prevalence and trajectory of sleep disturbances and their associated risk factors in children up to 24 months following a traumatic brain injury ( TBI ) . In addition , the longitudinal association between sleep disturbances and children 's functional outcomes was assessed . This was a prospect i ve study of a cohort of children with TBI and a comparison cohort of children with orthopedic injury ( OI ) . Parental reports of pre-injury sleep disturbances were compared to reports of post-injury changes at 3 , 12 , and 24 months . Risk factors for sleep disturbances were examined , including severity of TBI , presence of psychosocial problems , and pain . Sleep disturbances were also examined as a predictor of children 's functional outcomes in the areas of adaptive behavior skills and activity participation . Both cohorts ( children with TBI and OI ) displayed increased sleep disturbances after injury . However , children with TBI experienced higher severity and more prolonged duration of sleep disturbances compared to children with OI . Risk factors for disturbed sleep included mild TBI , psychosocial problems , and frequent pain . Sleep disturbances emerged as significant predictors of poorer functional outcomes in children with moderate or severe TBI . Children with TBI experienced persistent sleep disturbances over 24 months . Findings suggest a potential negative impact of disturbed sleep on children 's functional outcomes , highlighting the need for further research on sleep in children with TBI Background : Although increased training load ( TL ) and impaired sleep are associated with decreases in subjective well-being in adult athletes , these relationships among female youth athletes are unclear . It is unknown whether the effects of sleep and TL on well-being are independent or whether alterations in sleep mediate the effects of TL on subjective well-being . Hypothesis : Sleep and TL exert independent effects on subjective well-being among youth athletes , although alterations in sleep mediate a significant portion of the effect of TL on well-being in female youth athletes . Study Design : Prospect i ve cohort study . Level of Evidence : Level 4 . Methods : A total of 65 female soccer athletes ( age range , 13 - 18 years ) were monitored for 1 year . Daily TL was determined by session rating of perceived exertion and converted to z-scores . Every morning , participants recorded sleep duration in hours and rated stress , mood , fatigue , and soreness on a scale from −3 to + 3 ( worst to best ) . Linear mixed-effects models and mediation analysis were used to evaluate the independent effects of TL and sleep on well-being . Results : Average sleep duration was 7.9 ± 1.4 hours during the study period . In the multivariable model , TL and sleep duration were independently associated with fatigue ( TL : β = −0.19 , P < 0.001 ; sleep : β = 0.15 , P < 0.001 ) , mood ( TL : β = −0.030 , P = 0.014 ; sleep : β = 0.13 , P < 0.001 ) , stress ( TL : β = −0.055 , P = 0.001 ; sleep : β = 0.13 , P < 0.001 ) , and soreness ( TL : β = −0.31 , P < 0.001 ; sleep : β = 0.022 , P = 0.042 ) . Sleep duration mediated a significant portion of the effect of TL on mood ( 26.8 % , P < 0.001 ) , fatigue ( 12.6 % , P < 0.001 ) , and stress ( 24.5 % , P < 0.001 ) . Conclusion : Among female youth athletes , decreased sleep duration and increased TL are independently associated with impairments of subjective well-being . In addition , decreased sleep mediates a significant portion of the negative effect of increases in TL on subjective well-being . Clinical Relevance : Monitoring and promoting sleep among female adolescent athletes may significantly improve subjective well-being , particularly during periods of increased TL OBJECTIVES To examine the potential relationship between sleep duration and efficiency and injury incidence in elite Australian footballers . DESIGN Prospect i ve cohort study . METHODS Australian footballers ( n=22 ) from one AFL club were studied across the 2013 competitive season . In each week sleep duration and efficiency were recorded via actigraphy for 5 nights ( the 3 nights preceding a game , the night of the game and the night after the game ) . Injury incidence was monitored and matched with sleep data : n=9 players suffered an injury that caused them to miss a game . Sleep in the week of the injury ( T2 ) was compared to the average of the previous 2 weeks ( T1 ) . A two-way repeated measures ANOVA was used to determine any effect of sleep duration and efficiency on injury . Significance was accepted at p<0.05 . RESULTS Injury incidence was not significantly affected by sleep duration , sleep efficiency or a combination of these factors . Analysis of individual nights for T2 versus T1 also showed no differences in sleep quality or efficiency . However , a main effect for time was found for sleep duration and efficiency , with these being slightly , but significantly greater ( p<0.05 ) at T2 ( 437±61min and 82±7 % ) than T1 ( 414±64min and 79±7 % ) . CONCLUSIONS No significant effect of sleep duration and efficiency on injury occurrence was found in elite Australian footballers STUDY OBJECTIVES To investigate the effects of sleep restriction ( 7 nights of 5 h time in bed [ TIB ] ) on cognitive performance , subjective sleepiness , and mood in adolescents . METHODS A parallel-group design was adopted in the Need for Sleep Study . Fifty-six healthy adolescents ( 25 males , age = 15 - 19 y ) who studied in top high schools and were not habitual short sleepers were r and omly assigned to Sleep Restriction ( SR ) or Control groups . Participants underwent a 2-w protocol consisting of 3 baseline nights ( TIB = 9 h ) , 7 nights of sleep opportunity manipulation ( TIB = 5 h for the SR and 9 h for the control groups ) , and 3 nights of recovery sleep ( TIB = 9 h ) at a boarding school . A cognitive test battery was administered three times each day . RESULTS During the manipulation period , the SR group demonstrated incremental deterioration in sustained attention , working memory and executive function , increase in subjective sleepiness , and decrease in positive mood . Subjective sleepiness and sustained attention did not return to baseline levels even after 2 recovery nights . In contrast , the control group maintained baseline levels of cognitive performance , subjective sleepiness , and mood throughout the study . Incremental improvement in speed of processing , as a result of repeated testing and learning , was observed in the control group but was attenuated in the sleep-restricted participants , who , despite two recovery sleep episodes , continued to perform worse than the control participants . CONCLUSIONS A week of partial sleep deprivation impairs a wide range of cognitive functions , subjective alertness , and mood even in high-performing high school adolescents . Some measures do not recover fully even after 2 nights of recovery sleep . COMMENTARY A commentary on this article appears in this issue on page 497 PURPOSE The purpose of the research was to investigate the sport-specific performance effect of a brief afternoon nap on high-level Asian adolescent student-athletes that were habitually short sleepers . METHODS In the studies , participants were r and omly assigned to a nap or non-nap ( reading ) condition . In the first study , 12 male shooters ( 13.8 ± 1.0 yrs ) performed a shooting assessment ( 20 competition shots ) with heart rate variability monitored during the assessment . In the second study , 19 male track & field athletes ( 14.8 ± 1.1 yrs ) performed a 20 m sprint performance assessment . Subjective measures of sleepiness and alertness were obtained in both studies . RESULTS The brief nap had no effect on any measure of shooting performance ( p > 0.05 ) and autonomic function ( p > 0.05 ) in shooters . However , fastest 20 m sprint times increased significantly ( p < 0.05 ) from 3.385 ± 0.128 sec to 3.411 ± 0.143 sec , with mean 2 m times trending towards significance ( p < 0.1 ) amongst the track & field athletes . No significant differences were observed in any other measures . CONCLUSIONS The results of the research indicate varying effects of naps between sport-specific performance measures . Napping had no effect on shooting performance while a negative effect existed in 20-m sprint performance , potentially due to sleep inertia . Considering these findings , some caution is warranted when advocating naps for adolescent athletes Background Military service in Finl and is compulsory for all male citizens and annually about 80 % of 19-year-old men enter into the service . The elevated risk for many chronic diseases and loss of function among those who are inactive and unfit can be often detected already in youth . On the other h and , activity-induced injuries among young are true public health issue . The purpose of the present prospect i ve cohort follow-up study was to evaluate predictive associations between acute or overuse injuries and their various intrinsic risk factors . Methods Four successive cohorts of conscripts who formed a representative sample of Finnish young men were followed for 6 months . At the beginning of the service , the risk factors of injuries were measured and recorded and then the acute and overuse injuries treated at the garrison clinic were identified . Predictive associations between injuries and their risk factors were examined by multivariate Cox ’s proportional hazard models . Results Of the 1411 participants , 27 % sustained an acute injury and 51 % suffered from overuse injury . Concerning acute injuries , highest risk for severe injuries were detected among conscripts with low fitness level in both the st and ing long-jump and push-up tests ( hazard rate , HR=5.9 ; 95 % CI : 1.6‒21.3 ) . A history of good degree in school sports was not a protective factor against acute injuries . High waist circumference and , on the other h and , being underweight according to BMI increased the HR for overuse injuries . Brisk leisure time physical activity before military entry was a protective factor against overuse injuries . Poor result in Cooper ’s test was a warning signal of elevated risk of overuse injuries . Conclusion We confirmed previous findings that low level of physical fitness is predictor for musculoskeletal injuries during intensive physical training . The U-shaped relationship between body composition and overuse injuries was noticed indicating that both obesity and underweight are risk factors for overuse injuries . Persons with excellent sports skills according to their earlier degrees in school sports had similar HR for acute injuries than those with poorer degrees . This indicates that school-age sports skills and fitness do not carry far and therefore preventive programmes are needed to prevent activity-induced injuries PURPOSE This study aim ed to examine whether ( i ) objective markers of sleep quantity and quality are altered in endurance athletes experiencing overreaching in response to an overload training program and ( ii ) potential reduced sleep quality would be accompanied with a higher prevalence of upper respiratory tract infections in this population . METHODS Twenty-seven trained male triathletes were r and omly assigned to either overload ( n = 18 ) or normal ( CTL , n = 9 ) training groups . Respective training programs included a 1-wk moderate training phase followed by a 3-wk period of overload or normal training , respectively , and then a subsequent 2-wk taper .  Maximal aerobic power and oxygen uptake ( VO2max ) from incremental cycle ergometry were measured after each phase , whereas mood states and incidences of illness were determined from question naires . Sleep was monitored every night of the 6 wk using wristwatch actigraphy . RESULTS Of the 18 overload training group subjects , 9 were diagnosed as functionally overreached ( F-OR ) after the overload period , as based on declines in performance and VO2max with concomitant high perceived fatigue ( P < 0.05 ) , whereas the other 9 overload subjects showed no decline in performance ( AF , P > 0.05 ) . There was a significant time-group interaction for sleep duration ( SD ) , sleep efficiency ( SE ) , and immobile time ( IT ) . Only the F-OR group demonstrated a decrease in these three parameters ( -7.9 % ± 6.7 % , -1.6 % ± 0.7 % , and -7.6 % ± 6.6 % for SD , SE , and IT , respectively , P < 0.05 ) , which was reversed during the subsequent taper phase . Higher prevalence of upper respiratory tract infections were also reported in F-OR ( 67 % , 22 % , and 11 % incidence rate for F-OR , AF , and CTL , respectively ) . CONCLUSION This study confirms sleep disturbances and increased illness in endurance athletes who present with symptoms of F-OR during periods of high volume training Background : Shoulder strength and motion deficits in high school baseball pitchers have been implicated in injury risk . Purpose /Hypothesis : To prospect ively determine if preseason strength and range of motion ( ROM ) are predictive of injury in high school baseball pitchers . It was hypothesized that ROM asymmetries and weakness would be predictive of injury . Study Design : Case-control study ; Level of evidence , 3 . Methods : Preseason strength and ROM measurements  were made on 101 pitchers from 4 different high schools over 4 seasons ( total 166 pitcher-seasons : 25 freshman , 46 junior varsity , and 95 varsity player-seasons ) .  Glenohumeral internal rotation ( IR ) , glenohumeral external rotation , and posterior shoulder ROM  were measured bilaterally . Strength in IR , external rotation , supraspinatus ( empty-can test ) , and scapular retraction  was measured bilaterally ( h and held dynamometer ) . Injury incidence ( injuries per 1000 pitches ) was computed for players categorized as above normal ( ≥1 SD above the mean ) , normal ( within 1 st and ard deviation of the mean ) , and below normal ( ≤1 SD below the mean ) for each potential risk factor . Injury was defined as a missed game or practice because of shoulder or elbow problem . Results : There were 28 upper extremity injuries ( 19 shoulder , 9 elbow ; incidence , 0.58 injuries/1000 pitches ) . There was a trend for supraspinatus weakness to be associated with increased injury risk ( relative risk [ RR ] , 3.60 ; 95 % CI , 0.75 - 17.32 ; P = .09 ) . When analyzing major injuries only ( > 3 missed games ) , preseason supraspinatus weakness was significantly associated with increased injury risk ( RR , 4.58 ; 95 % CI , 1.40 - 15.01 ; P = .02 ) . Paradoxically , pitchers with no IR loss were at increased risk compared with pitchers with ≥20 ° loss ( RR , 4.85 ; 95 % CI , 1.01 - 23.29 ; P = .04 ) . Other ROM and strength measures were unrelated to injury risk . Conclusion : Although excessive loss of IR ROM is thought to be a risk factor for injury , the opposite was the case in this study . The absence of IR ROM loss  in high school pitchers may indicate inadequate prior exposure to pitching , result ing in increased injury risk . Preseason supraspinatus weakness was associated with increased risk for a major injury , and preventative supraspinatus strengthening may be beneficial A popular method to attempt to enhance performance is for athletes to sleep at natural or simulated moderate altitude ( SMA ) when training daily near sea level . Based on our previous observation of periodic breathing in athletes sleeping at SMA , we hypothesised that athletes ' sleep quality would also suffer with hypoxia . Using two typical protocol s of nocturnal SMA ( 2650 m ) , we examined the effect on the sleep physiology of 14 male endurance-trained athletes . The selected protocol s were Consecutive ( 15 successive exposure nights ) and Intermittent ( 3x 5 successive exposure nights , interspersed with 2 normoxic nights ) and athletes were r and omly assigned to follow either one . We monitored sleep for two successive nights under baseline conditions ( B ; normoxia , 600 m ) and then at weekly intervals ( nights 1 , 8 and 15 ( N1 , N8 and N15 , respectively ) ) of the protocol s. Since there was no significant difference in response between the protocol s being followed ( based on n=7 , for each group ) we are unable to support a preference for either one , although the likelihood of a Type II error must be acknowledged . For all athletes ( n=14 ) , respiratory disturbance and arousal responses between B and N1 , although large in magnitude , were highly individual and not statistically significant . However , SpO2 decreased at N1 versus B ( p<0.001 ) and remained lower on N8 ( p<0.001 ) and N15 ( p<0.001 ) , not returning to baseline level . Compared to B , arousals were more frequent on N8 ( p=0.02 ) and N15 ( p=0.01 ) . The percent of rapid eye movement sleep ( REM ) increased from N1 to N8 ( p=0.03 ) and N15 ( p=0.01 ) . Overall , sleeping at 2650 m causes sleep disturbance in susceptible athletes , yet there was some improvement in REM sleep over the study duration STUDY OBJECTIVES Physical inactivity is linked to health outcomes such as obesity , diabetes , and psychiatric disorders . Sleep disturbance has been linked to the same adverse outcomes . We examine the influence of sleep on physical activity  as a novel approach to underst and these relationships . Specifically , our objective was to determine whether low sleep quality predicts low physical activity in posttraumatic stress disorder ( PTSD ) , a disorder associated with sleep disturbance , physical inactivity , and poor health outcomes . METHODS We used data from the Mind Your Heart Study , a prospect i ve cohort study of 736 out patients recruited from two Department of Veterans Affairs ( VA ) medical centers . We assessed PTSD with the  Clinician Administered PTSD Scale , sleep quality  using an item from the Pittsburgh Sleep Quality Index  , and physical activity by self-report at baseline and again one year later . Hierarchical multiple regression models and structural equation modeling were used to examine the relationships among PTSD , sleep , and physical activity . RESULTS Sleep quality but not PTSD status was prospect ively associated with lower physical activity in a model adjusting for age , sex , apnea probability , depression , body mass index , and baseline physical activity ( β = 0.129 , SE = 0.072 , p < 0.01 ) . Structural equation modeling indicated that the results were consistent with sleep quality statistically mediating the relationship between PTSD status at baseline and physical activity one year later . CONCLUSIONS Worse sleep quality predicts lower physical activity in PTSD , providing possible evidence for a behavioral pathway from disturbed sleep to poor physical health outcomes BACKGROUND The relationship between inadequate sleep and mood has been well-established in adults and is supported primarily by correlational data in younger population s. Given that adolescents often experience shortened sleep on school nights , we sought to better underst and the effect of experimentally induced chronic sleep restriction on adolescents ' mood and mood regulation . METHODS Fifty healthy adolescents , ages 14 - 17 , completed a 3-week sleep manipulation protocol involving a baseline week , followed by a sleep restriction ( SR ) condition ( 6.5 hr in bed per night for five nights ) and healthy sleep duration ( HS ) condition ( 10 hr in bed per night for five nights ) . The study used a r and omized , counterbalanced , crossover experimental design . Participants ' sleep was monitored at home via self-report and actigraphy . At the end of each condition , participants and their parents completed question naires of mood and mood regulation . To assess for expectancy effects , we also analyzed parent and teen ratings of hyperactivity/impulsivity , which prior research suggests is not sensitive to SR in adolescents . Wilcoxon Signed Rank tests compared question naire outcomes across the two conditions . RESULTS Participants averaged 2.5 more hours of sleep per night during HS relative to SR . Compared with HS , adolescents rated themselves as significantly more tense/anxious , angry/hostile , confused , and fatigued , and as less vigorous ( p = .001-.01 ) during SR . Parents and adolescents also reported greater oppositionality/irritability and poorer emotional regulation during SR compared with HS ( p < .05 ) . There were no cross-condition differences in depression or hyperactivity/impulsivity ( p > .05 ) . CONCLUSIONS Findings complement prior correlational study results to show that after only a few days of shortened sleep , at a level of severity that is experienced regularly by millions of adolescents on school nights , adolescents have worsened mood and decreased ability to regulate negative emotions Abstract Objectives : To improve well-being and performance indicators in a group of Australian Football League ( AFL ) players via a six-week sleep optimisation programme . Design : Prospect i ve intervention study following observations suggestive of reduced sleep and excessive daytime sleepiness in an AFL group . Methods : Athletes from the Adelaide Football Club were invited to participate if they had played AFL senior-level football for 1–5 years , or if they had excessive daytime sleepiness ( Epworth Sleepiness Scale [ ESS ] > 10 ) , measured via ESS . An initial education session explained normal sleep needs , and how to achieve increased sleep duration and quality . Participants ( n = 25 ) received ongoing feedback on their sleep , and a mid-programme education and feedback session .  Sleep duration , quality and related outcomes were measured during week one and at the conclusion of the six-week intervention period using sleep diaries , actigraphy , ESS , Pittsburgh Sleep Quality Index , Profile of Mood States , Training Distress Scale , Perceived Stress Scale and the Psychomotor Vigilance Task . Results : Sleep diaries demonstrated an increase in total sleep time of approximately 20 min ( 498.8 ± 53.8 to 518.7 ± 34.3 ; p < .05 ) and a 2 % increase in sleep efficiency ( p < 0.05 ) . There was a corresponding increase in vigour ( p < 0.001 ) and decrease in fatigue ( p < 0.05 ) . Conclusions : Improvements in measures of sleep efficiency , fatigue and vigour indicate that a sleep optimisation programme may improve athletes ’ well-being . More research is required into the effects of sleep optimisation on athletic performance Objectives To describe the risk factors associated with injuries result ing from physical education ( PE ) , leisure time physical activity ( leisure time PA ) and sports in 9–12-year-old children . Design Prospect i ve cohort study . Setting Primary schools . Participants Nine hundred and ninety-five children aged 9–12 years . Main outcome measures Injuries occurring during either PE class  , leisure time PA or sports , and caused the child to at least stop the current activity were recorded prospect ively . Individual weekly exposure was estimated from baseline and follow-up question naires . Potential risk factors were gender , age , socioeconomic status , ethnicity , habitual level of PA , body mass index and a motor fitness . A multivariate Cox proportional hazard regression model was developed , accounting for clustering within schools . Results Gender , age and level of PA were independent significant risk factors for injury . Different modalities of PA had different injury risk factors . Most importantly , the low levels of habitual PA  significantly increased injury risk . Conclusions The children at highest injury risk are the target audience of the contemporary PA promotion efforts . PA promotion should also focus on injury prevention Objectives —Although the nature of rugby injury has been well documented , little is known about key risk factors . A prospect i ve cohort study was undertaken to examine the association between potential risk factors and injury risk , measured both as an injury incidence rate and as a proportion of the playing season missed . The latter measure incorporates a measure of injury severity . Methods —A cohort of 258 male players ( mean ( SD ) age 20.6 ( 3.7 ) years ) were followed through a full competitive season . At a preseason assessment , basic characteristics , health and lifestyle patterns , playing experience , injury experience , training patterns , and anthropometric characteristics were recorded , and then a battery of fitness tests were carried out . Results —A multiple regression model identified grade and previous injury experience as risk factors for in season injury , measured as an injury incidence rate . A second model identified previous injury experience , hours of strenuous physical activity a week , playing position , cigarette smoking status , body mass index , years of rugby participation , stress , aerobic and anaerobic performance , and number of push ups as risk factors for in season injury , measured as proportion of season missed . Conclusions —The findings emphasise the importance of previous injury as a predictor of injury incidence and of missing play . They also show the importance of considering both the incidence rate and severity of injury when identifying risk factors for injury in sport STUDY OBJECTIVES To investigate sleep EEG changes in adolescents across 7 nights of sleep restriction  to 5 h time in bed [ TIB ] ) and 3 recovery nights of 9 h TIB . METHODS A parallel-group design , quasi-laboratory study was conducted in a boarding school . Fifty-five healthy adolescents ( 25 males , age = 15 - 19 y ) who reported habitual TIBs of approximately 6 h on week nights ( group average ) but extended their sleep on weekends were r and omly assigned to Sleep Restriction ( SR ) or Control groups .  Participants underwent a 2-week protocol comprising 3 baseline nights ( TIB = 9 h ) , 7 nights of sleep opportunity manipulation ( TIB = 5 h for the SR and 9 h for the Control group ) , and 3 nights of recovery sleep ( TIB = 9 h ) .  Polysomnography  was obtained on two baseline , three manipulation , and two recovery nights . RESULTS Across the sleep restriction nights , total SWS duration was preserved relative to the 9 h baseline sleep opportunity , while other sleep stages were reduced . Considering only the first 5 h of sleep opportunity , SR participants had reduced N1 duration and wake after sleep onset ( WASO ) , and increased total sleep time ( TST ) , rapid eye movement ( REM ) sleep , and slow wave sleep ( SWS ) relative to baseline . Total REM sleep , N2 , and TST duration remained above baseline levels by the third recovery sleep episode . CONCLUSIONS In spite of preservation of SWS duration over multiple nights of sleep restriction , adolescents accustomed to curtailing nocturnal sleep on school day nights evidence residual effects on sleep macro-structure , even after three nights of recovery sleep . Older teenagers may not be as resilient to successive nights of sleep restriction as is commonly believed BACKGROUND AND PURPOSE Sleep disturbances are frequently reported in hospitalized patients . We have recently shown significant daily relationships between poor sleep and acute burn pain during the first week of hospitalization , where poor sleep leads to reports of higher pain intensity and in return , greater pain affects quality of sleep . This prospect i ve study was design ed to objective ly evaluate sleep disturbances in hospitalized burn patients and further evaluate their relationships with pain intensity and administered medication . PATIENTS AND METHODS Sixteen non-ventilated burn patients wore an actigraph ( Ambulatory Monitoring , Inc. )  during hospitalization ( N of 24-h observations 164 ) . Sleep measures included duration and fragmentation ( # of awakenings , mean duration of awakenings , mean duration of sleep episodes ( MDAW ) ) . Pain intensity was assessed at rest ( nighttime , morning , during the day ) and following therapeutic procedures known to be painful ( e.g. dressing changes ) . RESULTS Although sleep duration was extremely variable , patients slept an average of 5.5 h a night with numerous awakenings . During the day , patients often took naps , bringing their total sleep time ( TST ) to 8 h. Regression analyses showed significant temporal relationships between sleep , pain and analgesic medication such that a night of poor sleep was followed by a significantly more painful day and higher analgesic intake . Further , high levels of pain and analgesic medication during the day were both significant predictors of poor sleep on the following night . CONCLUSIONS These results obtained with objective measures support previous findings that subjective sleep quality following burn injuries is poor , and strengthen the evidence of a relationship between sleep and sensitivity to pain . Nonetheless , further analyses are necessary to determine and dissociate the effects of pain intensity and analgesic medication on sleep
Conclusions : Chronic lack of sleep in adolescents is associated with greater risk of sports and musculoskeletal injuries .
Current evidence can not yet definitively determine the effect of acute lack of sleep on injury rates .
Background : Although sleep has been identified as an important modifiable risk factor for injury , the effect of decreased sleep on sports injuries in adolescents is poorly studied .
The objective of this study was to quantitatively and qualitatively review published literature to examine if a lack of sleep is associated with sports injuries in adolescents and to delineate the effects of chronic versus acute lack of sleep .