Sleep and the Young Athlete

Abstract

Context:

Sleep plays a vital role in cognitive and physical performance. Teenage athletes (ages 13-19 years) are considered especially at risk for disordered sleep and associated negative cognitive, physical, and psychosomatic effects. However, there is a paucity of evidence-based recommendations to promote sleep quality and quantity in athletes who fall within this age range. We performed a review of the literature to reveal evidence-based findings and recommendations to help sports instructors, athletic trainers, physical therapists, physicians, and other team members caring for young athletes provide guidance on sleep optimization for peak sports performance and injury risk reduction.

Methods:

PubMed, Scopus, and Cochrane CENTRAL were searched on May 11, 2016, and then again on September 1, 2020, for relevant articles published to date.

Study Design:

Narrative review.

Level of Evidence:

Level 4.

Results:

Few studies exist on the effects disordered sleep may have on teenage athletes. By optimizing sleep patterns in young athletes during training and competitions, physical and mental performance, and overall well-being, may be optimized. Adequate sleep has been shown to improve the performance of athletes, although further studies are needed.

Conclusion:

Twenty-five percent of total sleep time should be deep sleep, with a recommended sleep time of 8 to 9 hours for most young athletes. Screen and television use during athletes’ bedtime should be minimized to improve sleep quality and quantity. For young athletes who travel, jet lag can be minimized by allowing 1 day per time zone crossed for adjustment, limiting caffeine intake, planning meals and onboard sleeping to coincide with destination schedules, timing arrivals in the morning whenever possible, and using noise-canceling headphones and eyeshades.

Strength-of-Recommendation Taxonomy (SORT):

B.

Sleep plays a vital role in sports performance in children and adolescents. There are many factors that affect sleep quality and duration that bear consideration in athletes, especially in teenagers. For example, younger athletes may be more affected by travel and timing of scheduled training and competition than their adult counterparts. Altitude has adverse effects on sleep; therefore, it is beneficial for athletes to undergo acclimation before competitions, particularly adolescents. Improper diet and nutrition choices may also negatively influence sleep. ³⁰ Sleep deprivation in teenagers is associated with poor athletic performance, ¹⁸ increased risk of injuries, ⁶² increased pain scores, ⁵¹ persistent pain, ¹² and overall health. ¹⁷ This review explores factors affecting sleep duration and quality and discusses evidence-based recommendations that support healthy sleep habits in young athletes.

Methods

We conducted a review of medical literature to identify articles on sleep and sports. PubMed, Scopus, and Cochrane CENTRAL were first searched on May 11, 2016, with English-language limits, resulting in 2509 citations after eliminating duplicates. The search included subject headings and keywords such as “sleep,” “sports,” “injuries,” “athletes,” “teenager,” “performance,” and “sleep deprivation.” The search results were updated on September 1, 2020, resulting in an additional 243 citations after removing duplicates, for a total of 2752 articles. Further articles were identified by searching the reference lists of relevant publications. Four authors reviewed the abstracts identified through this process to determine eligibility for study inclusion. The narrative review included articles related to sleep in athletes of any age as there were not a lot of articles focused on children and adolescents. Articles focused on sleep in pediatric athletes and active youth were examined thoroughly. Articles unrelated to sleep in athletes or active individuals were excluded.

General Characteristics of Sleep

The basic structural organization of normal sleep includes 2 distinct phases: nonrapid eye movement, which usually comes first, followed by rapid eye movement. Nonrapid eye movement sleep is then subdivided into 4 stages: N1, N2, N3, and N4. ⁵⁵ The length of time it takes to transition from full wakefulness to the lightest of these stages, N1, is referred to as sleep-onset latency, ⁵⁵ which varies widely from person to person. An average of 40 minutes after falling asleep, humans enter N3 stage, which should comprise 25% of their total sleep time. During N3, the brain produces slow, long waves, called δ waves, corresponding to deep sleep. This stage is considered the most restful portion of the entire sleep cycle, as it plays a major role in helping clear the brain for learning the following day, and reverts the accumulated need for sleep that builds over a normal day of being awake. ⁵⁵

The recommended minimum amount of sleep for individuals between the ages of 7 and 19 years is 8 to 9 hours per night; 10 hours is the recommendation minimum for children 6 years old and younger. It has been suggested that a significant number of pediatric athletes do not meet this recommended minimum due to a variety of factors, such as having to train, compete, and travel, in addition to maintaining a regular academic load.

One study, evaluating 196 competitive athletes between the ages of 14.4 and 17 years, found that 14.8% of them slept 6 hours 59 minutes or less, 33.2% slept between 7 hours and 7 hours 59 minutes, and only 52% of the athletes slept 8 hours or more. ⁹² Research has demonstrated that sleep is paramount for athletes to be healthy in mind and body, and this is especially true in pediatric athletes whose minds and bodies are in the process of physically developing while trying to succeed with academic and athletic performance in school. ⁹² Normal sleep physiology and chronotypes in children and adolescents include later bedtimes and later morning wakening patterns than adults. ⁹¹ A child’s sleep patterns can be affected by their parents’ sleep habits, as well as their daily activity and behaviors, sleep environment, and psychosocial conditions. ¹⁵

Factors Affecting Sleep

Many factors affect a person’s sleep, and some are especially relevant to young athletes. Low quality or quantity of sleep can affect a person’s overall performance and even increase the chance of injury, ⁶⁹ so taking these factors into account may improve an athlete’s performance during training and competitions. Perhaps this becomes most evident when young athletes travel to a far location for competitions, where jet lag and changes in time zones, altitudes, oxygen levels, bed type, and environmental conditions (eg, noise, amount of light, distractions) are involved. The following are some factors that may affect sleep quantity and quality, which if taken into careful consideration, may help maximize the performance of young athletes.

Exercise

Exercise in general tends to have a positive effect on sleep in individuals compared with sedentary counterparts. Different types of exercise may influence participants in different ways. Elite individual-sport athletes, for example, tend to go to bed earlier and wake up earlier, yet obtain less sleep overall than those who participate in team sports. ⁴⁸ In a study comparing sedentary adolescent girls who began a physical activity program versus those who remained inactive, sleep quality only improved in the active group. ³⁶ Another study exploring how daily training load impacted the sleep-wake cycle of adolescent female basketball players during a 14-day training camp found that sleep onset and offset times were delayed and total sleep times were prolonged during rest days compared with training days. ⁴⁹ Gerber et al, ³¹ studying the effects of vigorous exercise in 42 late adolescent and collegiate students, demonstrated similar favorable effects on sleep quantity and quality (ie, increased total sleep time, more stage N4 and rapid eye movement sleep, more slow-wave sleep, and a lower percentage of light sleep). Furthermore, they found that vigorous exercise was associated with less stress, pain, subjective sleep complaints, and depressive symptoms. ³¹

A study evaluating quality of sleep in adolescent runners and football players compared with nonathlete controls showed favorable sleep patterns in the adolescent athletes, specifically, shortened sleep-onset latency, fewer awakenings after sleep onset, more N4 sleep, and less rapid eye movement sleep. ⁴⁰ Interestingly, these favorable sleeping patterns were sustained even on days without exercise. ¹¹ Conversely, a study comparing high-school swimmers who overreached (a term loosely defined as regularly training before your muscles have had time to recover from the previous workout) with those who did not overreach showed that overreaching was associated with decreased sleep efficiency. ⁹⁹ Thus, we can observe a trend suggesting that exercise is beneficial to sleep quantity and quality, so long as the person is not overreaching in their training.

Timing of Exercise

Recent studies have reported that vigorous exercise a few hours before bedtime does not disturb sleep quantity or quality. Vigorous or moderate late-night (ie, 2-3 hours before bedtime) exercise in teenagers did not negatively affect sleep-onset latency or wake time after sleep onset, but instead seemed to improve sleep-onset latency without disturbing sleep quality.^25,65 In addition, 1 study showed that early evening high-intensity training did not impact subsequent sleep quality or quantity in elite male youth soccer players. ⁷⁴ However, in the adult population, other studies concluded that sleep quality and quantity were impaired in elite soccer players (25.9 [SD 7.5] years of age) after night matches and in elite swimmers (22.5 [SD 1.7] years of age) who trained early in the morning.^28,78,79 However, in these cases, sleep disturbance may have been related to an overall decrease in available time to sleep due to sports scheduling.^28,78,79 Therefore, in general, contrary to popular belief, it is not detrimental to sleep quality for people to train 2 to 3 hours before bedtime.

Competition

Factors related to competition, such as anxiety, may result in altered sleep patterns and adversely affect performance.^26,47,81 Despite young athletes reporting increased nervousness and poorer sleep on nights before competition, sleep efficiency was paradoxically improved and sleep duration was increased from baseline by about 45 minutes on average during competition periods.^73,75 It is important to take these factors into consideration during competition seasons.

Travel and Jet Lag

Teenage athletes may be more affected by travel, timing of scheduled training, and competition than adult athletes. ¹³ Research suggests that different age groups perform best at different times of the day; for example, prepubescent children and preadolescents tend to perform best in the early morning, whereas pubescent and postpubescent adolescents appear to perform best in the afternoons. ¹³

Disturbances in the sleep-wake cycle following travel may cause sleep fragmentation, premature awakenings, difficulty initiating sleep, and overall sleep loss. ⁷ East-to-west air travel seems to have less effect on both sleep and jet lag compared with west-to-east flights.7

Recommendations to help minimize jet lag include (1) allowing 1 day per time zone crossed for adjustment, (2) limiting caffeine intake, (3) planning meals and onboard sleeping to coincide with the destination schedule, (4) timing arrivals in the morning whenever possible, (5) using noise-canceling headphones and eyeshades. ⁷ Light is thought to influence sleep by suppressing melatonin ⁶⁷ ; however, studies evaluating the effects of light on sleep in young athletes are limited.

Diet and Nutrition

A number of nutritional factors may affect sleep, including supplements (eg, valerian, melatonin, and tryptophan), composition of food ingested, and timing of meals. ³³ There are some general concerns in the pediatric population regarding nutrition and supplements, such as consumption of caffeine, sugars, and high calories from ingesting sports and energy drinks. ¹⁶ A large cross-sectional study involving 1032 adolescents aged 13 to 17 years reported that nearly two-thirds had consumed energy drinks at least once, and about 41% recently (within the past 3 months); so one can infer that consumption of energy drinks among adolescents is widespread despite current recommendations against use. ⁶³

Medications and Supplements

Imbalance of serotonin (5-hydroxytryptamine) affects sleep. Ingestion of tryptophan, melatonin, and high-glycemic-index foods affect serotonin balance, which in turn have different effects on the regulation of sleep. Tryptophan intake may improve sleep-onset latency and subjective sleep quality. ³³

Evidence of melatonin’s positive effects on sleep duration and quality is limited in healthy athletic populations. A double-blind study showed 5 mg of melatonin versus placebo did not have a statistically significant difference in subjective sleep quality or physical performance, and resulted in less than 1% difference in time to complete 4 km of cycling between both groups. ² Another study similarly suggested that standard doses of melatonin taken at bedtime have limited or no significant effect on quality and quantity of sleep or athletic performance in adult athletes. ⁵⁷ In children and adolescents, there is concern that exogenous intake of this pineal hormone may affect pubertal reproductive hormones, and it is therefore not recommended. ¹³

Caffeine is commonly used by adult athletes as a performance enhancement supplement. Although it can increase feelings of energy after its consumption, it may also negatively affect sleep.^10,76 Caffeine consumed within 2 hours of bedtime increases sleep-onset latency and decreases slow-wave sleep and total sleep time.^10,76 Consumption of any amount of caffeine is not recommended for pediatric athletes. ¹⁶

Performance-Enhancing Substances

Performance-enhancing substances, such as anabolic androgenic steroids, are not recommended for healthy adult or pediatric athletes for a myriad of reasons which fall outside the scope of this paper. In adult athletes, however, anabolic androgenic steroids have been associated with reduced sleep efficiency and alteration of sleep architecture. ⁹⁵

Meal Composition and Timing

There are few data regarding the relationship between the composition of meals and sleep quality in teenage athletes. However, a pediatric study comparing ingestion of high- and low-glycemic-index drinks 1 hour before bedtime demonstrated increased arousals in the high-glycemic-index group. ³⁷ The form of carbohydrate intake (ie, solid meal vs drink with high, normal, and low carbohydrate content) may also have effects on sleep quality. For example, a study comparing these different forms of intake demonstrated decreased sleep-onset latency up to 3 hours after ingestion of solid meals without effect on sleep quality or duration as compared with a liquid meal. ⁶⁸ They hypothesized that solid meals have a vagal afferent stimulation which contributes to the observed decrease in sleep-onset latency, which liquid meals do not. Another study, involving 18-year-old Brazilian basketball players, noted that as the total energy intake for the day increased, the quality of sleep decreased (lower sleep efficiency and wake after sleep onset) regardless of the last meal’s glycemic index; however, conclusions may be limited due to the number of study subjects involved (N = 9). Further research exploring the relationship between nutrition and sleep in teenage athletes is necessary.

Relaxation Training

A study involving young dancers (8-19 years old) in Australia found that implementation of a progressive muscle relaxation intervention led to a statistically significant decrease in sleep-onset latency. ⁵³ In addition, a systematic review of the efficacy of cognitive behavioral sleep interventions on 357 adolescents (mean age, 14 years) found that the interventions improved sleep-onset latency by 16.15 minutes (95% CI −26.13 to −6.17) and sleep efficacy by 2.82% (95% CI 0.58% to 5.07%), both measured by actigraphy. Furthermore, subjective global sleep quality, daytime sleepiness, depression, and anxiety also improved. ⁸

Altitude

Altitude is associated with more frequent sleep arousals, reduction in N4 sleep, decreased slow-wave sleep, decreased oxygen saturation, and increased periodic breathing (including increased central apneas and hypopneas), giving an overall feeling of poor sleep quality.^4,35,39

Adolescents competing at high altitude without adequate time for acclimation may be more sensitive to experiencing symptoms of overtraining and poor performance, including general fatigue, headaches, diminished appetite, and impaired sleep quality or quantity. ⁷ In the absence of jet lag, the more time athletes spend at high altitude, the less they experience sleep disturbances. ⁸⁰ On returning to low altitude, sleep behaviors return to baseline after 5 to 6 days. ⁴⁵ Acclimation at high altitude may improve sleep in young athletes. Fourteen days at a new time zone and altitude provided a suitable adaptation period for teen Australian football players.^45,80

Temperature

Current evidence suggests that as body temperature decreases, it becomes easier to fall asleep ⁸³ ; however, there are few studies of this in young athletes and findings are conflicting.

Electronic Media

Sleep behavior is influenced by use of electronic media, including televisions, computers, smartphones, and tablets. A study of 4th to 7th graders showed that shorter sleep duration and perceived insufficient rest were associated with increased screen use during bedtime and sleeping with a television in the room. ²⁴

Taking a Sleep History

The Pittsburgh Sleep Quality Index, a validated questionnaire inventory tool, is the most widely used psychometric sleep quality screening instrument successfully applied to adolescents and young adult athletes. ⁹³ This index includes questions regarding bedtime, sleep-onset latency, wake time, total sleep time, night-time awakenings and disturbances, sleep quality, sleep medication use, and daytime functioning. Samuels et al ⁷⁷ published the Athlete Sleep Screening Questionnaire, a novel, subjective, self-reported sleep-screening questionnaire for elite athletes. Common questions that reflect sleep disorder risk factors are listed in Table 1.

Table 1.

Key discussion topics when taking a thorough sleep history

1	Current sleep habits
2	Changes from baseline sleep habits (encourage the use of a sleep diary)
3	Past medical or family history of sleep disorders (eg, narcolepsy, insomnia, sleep apnea), psychiatric conditions (eg, depression, anxiety, attention-deficit/hyperactivity disorder), and other relevant health issues
4	Medication use (past and current), both prescription and over the counter
5	Sleep aid use and frequency
6	Caffeine or other stimulant substance intake
7	Recreational drug use history
8	Sleep habits (eg, bed times, time of awakening, nap history)
9	Subjective assessment of sleep quality (eg, average, better, worse than average, feel rested, presence of fatigue, daytime somnolence)

Sleep and Injury

Sleep deprivation in teenagers is associated with an increased risk of musculoskeletal injury, a situation which can be especially detrimental to young athletes. A systematic review evaluating a possible relationship between chronic lack of sleep and increased risk of sports and musculoskeletal injury found a statistically significant association.^18,29 Lack of sleep is not only associated with increased risk of musculoskeletal injuries but may also be linked to other forms of injury and injury-prone behaviors. ⁶⁹ Another study found that employed adolescent students who slept 5 hours or less per school night were 2.9 times more likely to experience an occupational injury than adolescents who slept at least 8 hours per night. ³² Likewise, drivers aged 17 to 19 years getting 6 hours of sleep or less per night demonstrated an increased risk of motor vehicle accidents compared with those getting more than 6 hours of sleep each night. ⁵⁸ Interestingly, high-school students who slept 7 hours or less per school night also displayed a significant increase in injury-related risk behaviors (eg, infrequent use of seat belt or bicycle helmet and driving under the influence of alcohol) compared with students who slept at least 9 hours per school night. ¹⁰¹ Sleep-deprived adolescents were more likely to experience a bicycle accident,^41,69 with the greatest risk noted in adolescents sleeping fewer than 5.5 hours per night. ⁸⁷

Milewski et al ⁶² found that adolescent athletes who slept less than 8 hours per night were 1.7 times more likely to sustain a sport-related injury than their peers who slept at least 8 hours. The increased injury rate is thought to be correlated with an association between sleep deprivation and decreased psychomotor performance, mood, motor, and cognitive function. ⁶² Similarly, Luke et al ⁵² found a relationship between sleeping 6 or fewer hours per night and fatigue-related injury in pediatric athletes. An increased risk of injury was also seen in elite adolescent athletes with suboptimal nutrition who slept fewer than 8 hours on weekdays and those with simultaneously increased training load and intensity and decreased sleep time. ⁹⁷ So, the importance of proper rest schedules that allow for ideal quality and quantity of sleep extend beyond optimizing athletic performance and will indeed decrease the overall risk of injury in athletes. Furthermore, lack of sleep has been associated with increased pain scores, increased perceived symptoms, and persistent pain in pediatric patients. ²³ The evidence suggesting that lack of adequate sleep places children and adolescents at increased risk of falls, accidents, and injuries, sport-related or otherwise, is overwhelming.

Obesity, Illness, Stress, Mood, and Disease

Poor sleep quality and quantity have been implicated as risk factors for morbidity in children, including obesity, mental illness, asthma, and other health problems. ²¹ Although we could not find studies evaluating the effects of sleep deprivation on illness in pediatric athletes, college freshmen and active adults with poor sleep quality and quantity (<7 hours per night) had elevated body mass index and lower performance in physical fitness tests.^14,50 A 1-year study had 65 female soccer players (age range, 13-18 years) recording their sleep duration in hours and rated their stress, mood, fatigue, and soreness. Findings suggested that increased sleep was significantly associated with improved fatigue, mood, and stress. ¹⁰⁰

Sleep and Mental Health

A study comparing sleep electroencephalogram patterns, sleep logs, and psychologic functioning in adolescents before and after a 3-week exercise program involving daily 30-minute runs concluded that the intervention group demonstrated improvements in objective sleep, subjective sleep quality, mood, concentration, and daytime sleepiness compared with controls. ⁴⁰

The implementation of a treatment algorithm enables a strategic approach to evaluate sleep hygiene (Table 2). In an interesting case study, a 14-year-old boy suffering from multiple academic and personal challenges was originally diagnosed with depression, schizotypal personality disorder, and learning disabilities. ¹⁰² However, further sleep evaluation revealed a non-24-hour sleep-wake pattern and melatonin rhythm dissociations. Despite that, routine melatonin use in healthy adolescents is discouraged. In this specific case in which a hormonal imbalance was present, treatment with oral melatonin restored a normal sleep-wake schedule, and subsequent psychiatric evaluations failed to substantiate any of the 3 previous diagnoses. ¹⁰² Thus, awareness and screening of sleep disorders may prevent psychiatric misdiagnoses and enable accurate diagnosis and treatment of sleep-wake schedule disorders (Table 3).^{2,20,24,27,32,44,58,67,79,82,95,101} Sleep problems are also connected with overall suicidality in adolescents, although aggressive behavior has not been concurrently associated. ¹⁰²

Table 2.

Recommendations for patients with PPCS symptoms related to mental health

1	All patients with PPCS should be screened for mental health disorders, including depression, anxiety, PTSD, personality disorders, substance abuse, and somatoform disorders
2	All patients with PPCS should be screened for sleep disorders
3	For severe or complex PCS, PPCS, or failed treatments, referral to a mental health specialist or team should be encouraged
4	Compensatory strategies, restorative approaches, and cognitive rehabilitation should be included in a goal-oriented, comprehensive treatment plan
5	Consider use of electronic external memory devices, such as computers, smart phones, or portable voice prompt devices, to promote daily functioning

PCS, postconcussion syndrome; PPCS, persistent postconcussion symptoms; PTSD, posttraumatic stress disorder.

Table 3.

Recommendations for practitioners to address postconcussion syndrome sleep disturbances

1	Educate on the importance of sleep hygiene.27,67
2	Advise that the primary goal of treatment is to improve the restorative quality and continuity of sleep rather than focus on the total duration of sleep, although sleep duration within age-appropriate recommendations is encouraged.24,32,58,79,101
3	Pharmacotherapy (eg, melatonin, zolpidem) may be prescribed for short-term or long-term sleep impairments but should only be used for a short duration and at the lowest effective dose.2,95 Concussed athletes presenting with sleep difficulties may be treated safely with melatonin.44,82

Sleep and Concussion

In general, studies have shown conflicting evidence regarding the effect of concussion on sleep.^60,70,88 In 1 study, patients with mild traumatic brain injuries reported more sleep disturbances including insomnia, difficulty falling asleep, and greater sleep impairment. However, sleep quantity, timing, and daytime sleepiness did not differ between these patients and close matched controls. ⁸⁸ In another study evaluating surveys of 158 people with a history of mild traumatic brain injury, 92% of the individuals reported poor subjective sleep quality. ⁹³

Recovery from concussions and neural remodeling has been shown to be hindered by sleep disruption.^70,82,88 High-school and college athletes who experienced low quality sleep the night before baseline neurocognitive ImPACT testing reported a greater number of symptoms on the Postconcussion Symptom Scale.^54,61,82 Ensuring that student athletes obtain at least 8 hours of sleep the night before taking the postinjury ImPACT test may reduce the likelihood that reported symptoms are due to sleep deprivation rather than concussion. ⁵⁴

Sleep and Performance

Cognitive Performance

Sleep deprivation has been associated with impaired emotional function, short-term memory, working memory, and attention in children; and improving sleep hygiene has been shown to improve cognitive performance.^13,98 A study of adolescents aged 8 to 12 years with weekly bedtime adjustments to either 1 hour earlier (sleep optimization) or 1 hour later (sleep deprivation) found that when sleep was restricted, children showed poorer performance on memory tasks, supporting the ubiquitous need to promote healthy sleep habits in children. ⁹⁸

In a group of college-aged female soccer players, higher levels of global sleep dysfunction were significantly related to decreased vigor and increased tension, depression, anger, fatigue, somatic anxiety, worry, and concentration disruption. ⁶ In another study, a population of adolescents, who reported reduced sleep duration and other sleep-related symptoms on the Postconcussion Symptom Scale, scored lower results on the neurocognitive ImPACT testing (ImPACT Applications Inc.) when compared with asymptomatic optimally rested individuals. This difference was most pronounced in high-school girls.^82,87 Other studies of ultra-endurance and extreme sport athletes have shown that prolonged exercise and its associated lack of sleep may negatively affect cognitive performance; however, the subjects studied in these investigations were adult athletes.^22,36

Athletic Performance

In teenage athletes, numerous studies have consistently implicated sleep deprivation in delayed reaction time, mood disturbance, reduced time to exhaustion, increased perceived effort, fatigue, and reduced time to task failure without impacting physiologic markers of anaerobic, aerobic, or power output.^9,38,90,94 Interestingly, even the type of bed in which athletes sleep may affect their performance. One study compared 74 young athletes aged 10 to 19 years who slept on either a high-rebound or a low-rebound mattress topper, or a spring mattress with no topper for 6 to 8 weeks. ⁵⁹ The authors found that sleeping on high-rebound mattress toppers resulted in statistically significant improvements on some athletic performance measures (eg, 40-meter sprint) compared with sleeping on low-rebound toppers or spring mattresses without a topper. ⁵⁹ Another study carried out in Italy with 12 karate athletes between 16 and 18 years of age showed that after a single night of sleep deprivation, selective attention, maximal force, and maximal force time (isometric strength) of brachial biceps was decreased, which highlights the importance of a proper sleep regimen for athletes in combat sport. ⁵

Psychomotor Performance

High-school student athletes often experience diminished sleep duration during the school week compared with weekends. Psychomotor vigilance test performance, a standard measure of reaction time, was found progressively to decrease throughout the week, with the worst results on Fridays. ⁸⁹ Improving sleep duration in a small sample of collegiate basketball players was shown significantly to improve psychomotor vigilance test reaction times and performance in sport-specific tasks, such as shooting accuracy and sprint times. ⁵⁶ A cross-sectional study assessing a connection between quality of sleep and quality of life in 272 healthy adolescent athletes between the ages of 13 and 18 years found a significant association between poor sleep quality and worse physical function/mobility, greater self-reported anxiety, depressive symptoms, fatigue, and pain interference. ⁷² These findings suggest that teaching otherwise healthy adolescent athletes ways to improve sleep quality through proper sleep hygiene may have great potential to improve these measured outcomes.

Cardiopulmonary Function

In a study that examined sleep deprivation in younger athletes, 17- to 18-year-old male volleyball players and runners in the sleep-deprived cohort demonstrated shorter time to exhaustion and decreased exercise ventilation, but no cardiac function changes compared with controls. ³ Other studies, performed using adult athletes as samples, suggest that sleep deprivation associated with endurance events increases athletes’ perceived exertion and impairs cognitive performance, mood, and general wellbeing, but does not alter physiologic performance.^22,36,46

Recovery

There is little information in the literature regarding the biochemical and physiologic processes of recovery in the pediatric population; however, within the adult medical literature, sleep is known to play a critical role in the regenerative process during recovery. ⁹⁶ Without adequate sleep after exertion, athletes may experience impaired muscle recovery, decreased glycogen storage, decreased power and endurance, and increased soreness.^23,66,84 Interestingly, sleep deprivation secondary to early morning rising may cause greater detriment to anaerobic performance than late bedtime.^85,86 In addition, a positive association was found between subjective recovery and total sleep time, sleep-wake patterns, and time off from exercise. ⁴³

Interventions

Napping

One study reported that positive performance gains were found in simple gross motor skill acquisition after napping. ⁶⁴ However, napping has not been found to be advantageous in offsetting the performance effects of jet lag or in endurance racing, running economy, or complex gross motor skill acquisition.^34,42,71 Data regarding napping as an intervention for sleep deprived teenage athletes are scarce.

Sleep Extension

Extending sleep hours above habitual baseline levels may improve athletic motor performance and decrease perceived sleepines.^56,84 Sleep extension may counter the effects of sleep deprivation if used either before the deprivation event or after to facilitate recovery. ¹ Nevertheless, tapering exertion before a competition may decrease sleep quality (slow-wave sleep) and have a negative effect on an athlete’s mood, which may affect overall performance; therefore, conclusions should be carefully drawn.

Summary and Future Directions in Sleep Research

Exercise is associated with improved sleep by altering many factors; for example, by shortening sleep-onset latency. Interestingly, recent studies have demonstrated moderate exercise 2 to 3 hours before bedtime in teenagers seemed to improve sleep-onset latency without disturbing quality of sleep.^25,65 Solid meals at dinner time demonstrated superior sleep-onset latency compared with liquids with equivalent carbohydrate content, with low-glycemic-index content showing fewer night time arousals than high-glycemic-index consumption.^37,68 Sleep-promoting medications, such as standard doses of melatonin, compared with placebo, had no statistically significant effect on quality or quantity of sleep or physical performance ² ; however, this has only been demonstrated in adults. Regular use of melatonin, or stimulants such as coffee, is not currently recommended in healthy teenagers. Muscle relaxation and limiting screen time demonstrated a statistically significant decrease in sleep-onset latency in children, ⁵³ emphasizing the importance of sleep hygiene over pharmaceutical agents. Allowing adequate time for acclimation to altitude and time zone changes before competition is also important for optimal performance. At least 8 hours of sleep per night is associated with injury risk reduction in teenage athletes. ⁶² It is important for healthcare providers to take an adequate sleep history (Tables 1 and 2) and provide education on healthy sleep guidelines. If a sleep disorder is suspected or identified in a pediatric patient, referral to a sleep specialist for further evaluation and treatment may be warranted (Table 3).

Educators, trainers, physical therapists, parents, and clinicians must be a part of the effort to optimize sleep in teenage athletes. Sports camps, traveling teams, and academies must ensure that children’s academic and athletic development are supported by adequate rest. Monitoring mechanisms should be in place to help implement and ensure athlete adherence to good sleep practices. Teenage athletes with sleep problems must be identified and treated as these conditions may persist into adulthood and are associated with a variety of comorbid physical and mental health conditions. ¹⁹

Limitations

Part of the available data and conclusions regarding athletes and sleep are drawn from adult studies. Furthermore, there is a general lack of rigor in available pediatric studies, as most were nonrandomized, lacked control groups, were case studies, or had small sample sizes, and were therefore difficult to generalize to children and adolescents, let alone teenage athletes. Many subjects surrounding lack of sleep and sleep improvement in teenage athletes have not been thoroughly studied and, therefore leave room for future research.