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Sleep

Also called sleep and training, sleep loss, sleep deprivation, sleep restriction, sleep extension, napping, naps

What studies found on sleep and training. How research measures sleep in athletes, what sleep loss did to performance and muscle, how sleep relates to injury, and where the evidence is thin or split.

Region
Across the body
Updated
October 6, 2026
Reviewed
October 6, 2026 · how entries are checked

What it is

An 18-member expert panel convened by the National Sleep Foundation set out the sleep durations it considered appropriate at each age7. The panel noted that its figures apply to healthy people without a sleep disorder7. It also noted that sleep need varies from person to person7. Rest between sets, rest days and deloads are on the rest page.

Age groupHours of sleep the panel considered appropriate
Teenagers8 to 107
Young adults and adults7 to 97
Older adults7 to 87

How studies define sleep loss

Two reviews of sleep and exercise use these terms for too little sleep2,8:

  • Sleep loss. One meta-analysis, a study that pools the results of several earlier studies, defined it as 6 hours or less of sleep in 24 hours2.
  • Sleep deprivation. A systematic review of resistance exercise used this term for no sleep, and set it apart from consecutive nights of restricted sleep8.
  • Late restriction. The same meta-analysis used this term for waking earlier than normal2.

How it is measured

A 2019 review lists the ways sleep is assessed in athletes9:

  • questionnaires9;
  • sleep diaries9;
  • consumer sleep technology9;
  • activity monitoring9;
  • polysomnography9.

The review says no guidelines exist for standardising sleep assessment in athletes9.

Polysomnography records brain activity, eye movements and muscle activity, among other signals10. A 2023 paper on sleep tracking in sport calls it the gold standard for measuring sleep10. The paper notes that it can be intrusive and expensive10. It says a limited number of studies have used it in athletes10.

What studies found

How athletes sleep

In a study of 175 elite athletes, they said they needed 8.3 hours of sleep to feel rested and averaged 6.7 hours1. The athletes came from 12 sports and wore wrist activity monitors for about 12 nights of normal training1. Of them, 3% got enough sleep to meet their self-assessed need1. Another 71% fell short by an hour or more1.

Hours a nightSleep they said they needed8.3 Sleep they averaged6.7
Hours a night. Bars start at zero; the table below gives each value with its source.
Measure in 175 elite athletesHours a night
Sleep they said they needed8.31
Sleep they averaged6.71

How training affects sleep

A systematic review covered 54 observational studies that objectively measured sleep in elite athletes11. A systematic review searches for all the research on a question in a set, checkable way and sums it up. An observational study watches what happens to people without the researchers choosing who gets what. The review found that five things impaired sleep11:

  • training that started before 07:0011;
  • rises in training load of more than 25%11;
  • travel that departed late at night or early in the morning11;
  • air travel eastward11;
  • ascent to altitude11.

A 2024 meta-analysis of overreaching from endurance-based training found a 2.0% reduction in sleep efficiency measured by actigraphy (a worn movement sensor)12.

A systematic review of 13 studies found that regular resistance exercise improved all aspects of sleep, most of all sleep quality13.

Sleep loss and performance

A meta-analysis covered 69 publications on sleep loss, and 89% of the participants were male2. Sleep of 6 hours or less in 24 hours reduced exercise performance by a mean of 7.56%2. The 95% confidence interval ran from 3.13% to 11.9%2. A confidence interval is a range around a study’s result that shows how precise it is. Effects were significant in each exercise category the authors examined2.

The same analysis compared patterns of sleep loss and times of day2. Consistent negative effects were seen only after sleep deprivation and after late restriction2. Tasks done in the afternoon or evening were consistently affected, while morning tasks were largely unaffected2.

For strength, a systematic review covered 17 studies, each rated moderate or weak in quality8. It found that going without sleep barely changed muscle strength during resistance exercise8. Consecutive nights of restricted sleep could reduce force in multi-joint movements but not in single-joint ones8.

Sleep loss and muscle

Three studies of 10 to 24 people looked at muscle more directly3,14,15.

  • One night without sleep. A randomised crossover study, in which each person tries every option in turn, tested 13 healthy young adults3. One night without sleep reduced muscle protein synthesis by 18%3. It raised the hormone cortisol in blood plasma by 21% and lowered the hormone testosterone by 24%3.
  • Five short nights. In 24 healthy young men in three matched groups, one group spent five nights with 4 hours in bed14. The data suggest this acutely reduces myofibrillar protein synthesis compared with 8 hours in bed14. A myofibril is one of the contracting strands inside a muscle fibre. The data also suggest that three sessions of high-intensity interval exercise during the short nights can maintain it14.
  • Two days without sleep after muscle-damaging exercise. In a randomised crossover study, 10 men did 240 eccentric contractions of the muscles that straighten the knee15. Eccentric means muscle work done while the muscle lengthens. Going without sleep for the next 48 hours did not delay the recovery of muscle strength15. It did change inflammatory and hormonal responses15.

One trial added sleep education to a training programme16. Untrained healthy men did 10 weeks of whole-body resistance training twice a week, and 23 were in the final analysis16. They were randomly assigned to exercise alone or to exercise with sleep health education16. The two groups gained a similar amount of lean body mass, which is body weight that isn’t fat16. The education group lost significantly more fat mass16.

Sleep and injury

Findings on sleep and injury differ by the group studied4,5.

  • Adolescents, one school. A study of 112 adolescent athletes at one combined middle and high school matched survey answers to past injury records17. Those averaging less than 8 hours a night were 1.7 times more likely to have had an injury17. The 95% confidence interval ran from 1.0 to 3.017.
  • Adolescents, pooled. A meta-analysis of 7 studies in people aged 19 or younger found chronic poor sleepers more likely to be injured than good sleepers4. The odds ratio, how many times higher the odds are in one group, was 1.584. Its 95% confidence interval ran from 1.05 to 2.374.
  • Military personnel. A systematic review covered 8 studies18. Three were cohort studies, which follow a group of people over time, and 5 were cross-sectional, looking at a group once18. Of the 8, 5 supported an association between sleep quality or duration and musculoskeletal injury, meaning injury to muscles, bones or joints18. The authors describe the research as limited18.
  • Adult athletes. A systematic review covered 12 prospective cohort studies in adult athletic populations5. It found limited evidence of an association between poor sleep and injury5.

Longer nights and naps

A 2023 systematic review of 25 intervention studies in athletes acknowledged the limited amount of high-quality evidence19. It concluded that more sleep, at night or through naps, appeared to be the most effective way to improve physical or cognitive performance19. Three other approaches showed no effect in the few studies available19. They were sleep hygiene (habits meant to help sleep), taking electronic devices away at night, and immersion in cold water19.

One study of longer nights followed 11 male university basketball players, each compared with his own baseline20. For 5 to 7 weeks they aimed for at least 10 hours in bed each night20. Nightly sleep rose by about 111 minutes20. Afterwards timed sprints were faster, at 15.5 seconds against 16.220. Free-throw and three-point shooting percentages were each about 9% higher20.

For naps, a meta-analysis pooled 22 randomised controlled trials, all in men aged 18 to 3521. A randomised controlled trial assigns people to groups by chance, then compares the groups. The 291 participants were trained athletes and physically active adults21. A nap taken between 12:30 and 16:50 after a normal night improved cognitive and physical performance and reduced perceived fatigue21. The positive effects were also confirmed after partial sleep deprivation21.

What is disputed

How much sleep athletes need

A 2021 expert consensus states that one fixed figure, such as 7 to 9 hours a night, is unlikely to be ideal for athletes6. It recommends an approach that considers each athlete’s perceived sleep needs6. It also calls for research into the benefits of napping and of extending sleep6.

How strong the research is

The same paper sets out limits of the research6. It states that a night or more without sleep reduces athletic performance6. The effect of partial sleep restriction over 1 to 3 nights, it says, remains unclear6. It adds that studies of sleep in athletes often have inadequate experimental control, few female participants and assessment tools of questioned validity6.

The muscle studies here cut sleep for one night in 13 adults, five nights in 24 men, and 48 hours in 10 men3,14,15. The 10-week trial added sleep education and had 23 men in its final analysis16.

The review of resistance exercise and sleep also reports a gap13. It found that the effects of a single session on sleep remain poorly studied and inconsistent13.

Whether poor sleep goes with injury

The reviews above disagree4,5. The adolescent meta-analysis concluded that chronic lack of sleep is associated with a greater risk of sports and musculoskeletal injuries4. Its authors added that the effect of acute lack of sleep could not yet be determined4. The review in adult athletes concluded that evidence so far does not back poor sleep as a risk factor for injury in its own right5. The military and adult reviews drew on cohort or cross-sectional studies5,18.

A prospective study, which follows people forward in time, enrolled 434 high school cross country runners and analysed 16122. Week-to-week changes in self-reported sleep duration and quality were not associated with running-related injuries22.

Connections

The rest page covers rest between sets, rest days and deloads. A 2018 statement by international experts calls a balance between stress and recovery essential for athletes to keep performing at a high level23. The overtraining page covers recovery that falls short, including the meta-analysis of sleep during overreaching12.

Two reviews on this page concern resistance training8,13. One looked at what regular resistance exercise does to sleep, the other at what lost sleep does to strength8,13.

The studies of protein synthesis bear on muscle tissue3,14.

Sleep is related to

Sources

  1. Sargent C, Lastella M, Halson SL, Roach GD (2021). How Much Sleep Does an Elite Athlete Need?. International journal of sports physiology and performance. doi:10.1123/ijspp.2020-0896 PMID 34021090
  2. Craven J, McCartney D, Desbrow B, Sabapathy S, Bellinger P, Roberts L, et al (2022). Effects of Acute Sleep Loss on Physical Performance: A Systematic and Meta-Analytical Review.. Sports medicine (Auckland, N.Z.). doi:10.1007/s40279-022-01706-y PMID 35708888
  3. Lamon S, Morabito A, Arentson-Lantz E, Knowles O, Vincent GE, Condo D, et al (2021). The effect of acute sleep deprivation on skeletal muscle protein synthesis and the hormonal environment.. Physiological reports. doi:10.14814/phy2.14660 PMID 33400856
  4. Gao B, Dwivedi S, Milewski MD, Cruz AI (2019). Lack of Sleep and Sports Injuries in Adolescents: A Systematic Review and Meta-analysis.. Journal of pediatric orthopedics. doi:10.1097/BPO.0000000000001306 PMID 30888337
  5. Dobrosielski DA, Sweeney L, Lisman PJ (2021). The Association Between Poor Sleep and the Incidence of Sport and Physical Training-Related Injuries in Adult Athletic Populations: A Systematic Review.. Sports medicine (Auckland, N.Z.). doi:10.1007/s40279-020-01416-3 PMID 33560506
  6. Walsh NP, Halson SL, Sargent C, Roach GD, Nédélec M, Gupta L, et al (2020). Sleep and the athlete: narrative review and 2021 expert consensus recommendations.. British journal of sports medicine. doi:10.1136/bjsports-2020-102025 PMID 33144349
  7. Hirshkowitz M, Whiton K, Albert SM, Alessi C, Bruni O, DonCarlos L, et al (2015). National Sleep Foundation's sleep time duration recommendations: methodology and results summary.. Sleep health. doi:10.1016/j.sleh.2014.12.010 PMID 29073412
  8. Knowles OE, Drinkwater EJ, Urwin CS, Lamon S, Aisbett B (2018). Inadequate sleep and muscle strength: Implications for resistance training.. Journal of science and medicine in sport. doi:10.1016/j.jsams.2018.01.012 PMID 29422383
  9. Halson SL (2019). Sleep Monitoring in Athletes: Motivation, Methods, Miscalculations and Why it Matters.. Sports medicine (Auckland, N.Z.). doi:10.1007/s40279-019-01119-4 PMID 31093921
  10. Driller MW, Dunican IC, Omond SET, Boukhris O, Stevenson S, Lambing K, et al (2023). Pyjamas, Polysomnography and Professional Athletes: The Role of Sleep Tracking Technology in Sport.. Sports (Basel, Switzerland). doi:10.3390/sports11010014 PMID 36668718
  11. Roberts SSH, Teo WP, Warmington SA (2019). Effects of training and competition on the sleep of elite athletes: a systematic review and meta-analysis.. British journal of sports medicine. doi:10.1136/bjsports-2018-099322 PMID 30217831
  12. Murphy C, Svansdottir SA, Dupuy O, Louis J (2024). Does overreaching from endurance-based training impair sleep: A systematic review and meta-analysis.. PloS one. doi:10.1371/journal.pone.0303748 PMID 38809828
  13. Kovacevic A, Mavros Y, Heisz JJ, Fiatarone Singh MA (2018). The effect of resistance exercise on sleep: A systematic review of randomized controlled trials.. Sleep medicine reviews. doi:10.1016/j.smrv.2017.07.002 PMID 28919335
  14. Saner NJ, Lee MJ, Pitchford NW, Kuang J, Roach GD, Garnham A, et al (2020). The effect of sleep restriction, with or without high-intensity interval exercise, on myofibrillar protein synthesis in healthy young men.. The Journal of physiology. doi:10.1113/JP278828 PMID 32078168
  15. Dáttilo M, Antunes HKM, Galbes NMN, Mônico-Neto M, DE Sá Souza H, Dos Santos Quaresma MVL, et al (2020). Effects of Sleep Deprivation on Acute Skeletal Muscle Recovery after Exercise.. Medicine and science in sports and exercise. doi:10.1249/MSS.0000000000002137 PMID 31469710
  16. Jåbekk P, Jensen RM, Sandell MB, Haugen E, Katralen LM, Bjorvatn B (2020). A randomized controlled pilot trial of sleep health education on body composition changes following 10 weeks' resistance exercise.. The Journal of sports medicine and physical fitness. doi:10.23736/S0022-4707.20.10136-1 PMID 32141273
  17. Milewski MD, Skaggs DL, Bishop GA, Pace JL, Ibrahim DA, Wren TA, et al (2014). Chronic lack of sleep is associated with increased sports injuries in adolescent athletes.. Journal of pediatric orthopedics. doi:10.1097/BPO.0000000000000151 PMID 25028798
  18. Lisman P, Ritland BM, Burke TM, Sweeney L, Dobrosielski DA (2022). The Association Between Sleep and Musculoskeletal Injuries in Military Personnel: A Systematic Review.. Military medicine. doi:10.1093/milmed/usac118 PMID 35544342
  19. Cunha LA, Costa JA, Marques EA, Brito J, Lastella M, Figueiredo P (2023). The Impact of Sleep Interventions on Athletic Performance: A Systematic Review.. Sports medicine - open. doi:10.1186/s40798-023-00599-z PMID 37462808
  20. Mah CD, Mah KE, Kezirian EJ, Dement WC (2011). The effects of sleep extension on the athletic performance of collegiate basketball players.. Sleep. doi:10.5665/SLEEP.1132 PMID 21731144
  21. Mesas AE, Núñez de Arenas-Arroyo S, Martinez-Vizcaino V, Garrido-Miguel M, Fernández-Rodríguez R, Bizzozero-Peroni B, et al (2023). Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials.. British journal of sports medicine. doi:10.1136/bjsports-2022-106355 PMID 36690376
  22. Joachim MR, Heiderscheit BC, Kliethermes SA (2024). Changes in Sleep, Stress, and Fatigue Were Not Prospectively Associated With Running-Related Injuries Among High School Cross Country Runners.. Sports health. doi:10.1177/19417381231217347 PMID 38148661
  23. Kellmann M, Bertollo M, Bosquet L, Brink M, Coutts AJ, Duffield R, et al (2018). Recovery and Performance in Sport: Consensus Statement.. International journal of sports physiology and performance. doi:10.1123/ijspp.2017-0759 PMID 29345524

Every source the library cites

Changes

  • First published.