Most of the literature on sleep is regarding restriction and its impact on health and performance. However, there is a growing body of research on sleep extension and the potential implications on athletic performance. It’s relatively understood that sleep is a primary contributor to recovery and performance.
Despite this, it’s estimated over one-third of the American population is underslept.1 The American Academy Of Sleep Medicine recommends individuals aged 18-60 sleep a minimum of seven hours a day.1
Why Sleep Is Important
Failing to meet this requirement has been associated with various chronic conditions such as heart disease, stroke, diabetes, high blood pressure, and various other deleterious health and performance outcomes.
One paper looking at the effects of sleep deprivation on resistance training performance found significant reductions in strength in the bench press, deadlift, and leg press. Additionally, the researchers observed2 increased subjective feelings of difficulty and increased sleepiness scores. Reductions in strength were preserved until the fourth consecutive night of sleep restriction. Still, mood, fatigue, and other subjective sleep deprivation levels increased after just one night of nocturnal sleep restriction.2
Sleep Restrictions Have Detrimental Effects
A study3 looking at the cardiovascular, respiratory, and metabolic responses to sleep restriction in endurance-trained athletes found:
“After partial sleep deprivation, there were statistically significant increases in heart rate (P less than 0.05) and ventilation (P less than 0.05) at submaximal exercise compared with results obtained after the baseline night. Both variables were also significantly enhanced at maximal exercise, while the peak oxygen consumption (VO2) dropped (P less than 0.05) even though the maximal sustained exercise intensity was not different.”3
Sleep restriction reduces alertness, coordination, and other psychomotor characteristics, as was found in a 2009 paper4 by Edwards et al. whereby participants in the sleep-restricted group saw an associative decrease in performance of throwing darts.4
Sleep is known to play an important role in cognitive restitution, and research has consistently found impeded attentional mechanisms such as reaction time and coordination when sleep is restricted.5
Sleep restriction of varying degrees has also been shown to augment the time course to return to baseline performance.6
Chronic sleep restriction having a longer refractory period than acute restriction before returning to baseline.
One paper7 looking at the effects of sleep restriction on sprint performance and muscle glycogen content found:
“Sleep loss and associated reductions in muscle glycogen and perceptual stress reduced sprint performance and slowed pacing strategies during intermittent-sprint exercise for male team-sport athletes.”7
Various other studies have demonstrated a strong association between sleep deprivation and reduced muscular performance.8,9
There are also considerable inter-individual differences in resilience about sleep deprivation, with some individuals experiencing greater performance dropoff than others under similar conditions.10
Body Composition and Performance
Also relevant but maybe less obvious is the role of body composition in performance.
This is likely more relevant to sports where weight classes exist and where the power-to-weight ratios are critical determinants of performance.
Sleep deprivation has been shown to have significant deleterious results on body composition, with one study11 finding:
“Sleep curtailment decreased the proportion of weight lost as fat by 55% (1.4 vs. 0.6 kg with 8.5 vs. 5.5 hours of sleep opportunity, respectively; P = 0.043) and increased the loss of fat-free body mass by 60% (1.5 vs. 2.4 kg; P = 0.002). This was accompanied by markers of enhanced neuroendocrine adaptation to caloric restriction, increased hunger, and a shift in relative substrate utilization toward oxidation of less fat.”11
Thus poor sleep can have an unfavorable impact on your body composition.
Sleep Extension's Implications on Athletic Performance
Now that we’ve covered several of the potential consequences of sleep restriction, let's shift gears and discuss the antithesis.
A 2011 paper12 aimed to investigate the effects of sleep extension on various metrics of athletic performance and other cognitive measurements. The researchers found:
“Total objective nightly sleep time increased during sleep extension compared to baseline by 110.9 ± 79.7 min (P < 0.001). Subjects demonstrated a faster timed sprint following sleep extension (16.2 ± 0.61 sec at baseline vs. 15.5 ± 0.54 sec at end of sleep extension, P < 0.001). Shooting accuracy improved, with free throw percentage increasing by 9% and 3-point field goal percentage increasing by 9.2% (P < 0.001). Mean PVT reaction time and Epworth Sleepiness Scale scores decreased following sleep extension (P < 0.01). POMS scores improved with increased vigor and decreased fatigue subscales (P < 0.001). Subjects also reported improved overall ratings of physical and mental well-being during practices and games.”12
As you can see, there were significant increases in performance from baseline.
Subjects initially were sleeping between 6-9 hours per night, but during the intervention were instructed to record a minimum of 10 hours in bed each night.
It’s important to note that 10 hours in bed is not the same as 10 hours of sleep.
Due to obvious limitations, the study's objective was to measure time in bed, a decent proxy for total sleep. However, it may not always be practical to adopt a10 hr nocturnal sleeping schedule.
A fragmented sleep pattern characterizes a bi-phasic (2 phases) or polyphasic (3+ phases) approach to sleep. This approach has demonstrated beneficial effects in subjects with sleep disorders.13
Napping has also been shown to improve cognitive performance14,15 meaningfully.
Since total cumulative sleep throughout the day is a reasonable metric for recovery and athletic performance, utilizing naps can be an effective strategy to bolster total sleep, enhance recovery and athletic performance if extending nocturnal sleep is not a practical option.
One study found that just a 10-minute nap was enough to improve alertness and cognitive performance16 significantly. Longer naps of +30 minutes also have been shown to have significant benefits.
However, longer naps may lead to a phenomenon called sleep inertia. Essentially this is a period of cognitive impairment following arising from a longer duration nap (+30 minutes.)16
Sleep inertia does not persist throughout the day, but it may be beneficial to structure longer naps away from cognitively demanding tasks like work or training.
The national institute of health outlines an additional resource to enhance the quality of your sleep.
- Set a schedule: go to bed and wake up at the same time each day.
- Exercise 20 to 30 minutes a day but no later than a few hours before going to bed.
- Avoid caffeine and nicotine late in the day and alcoholic drinks before bed.
- Relax before bed: try a warm bath, reading, or another relaxing routine.
- Create a room for sleep: avoid bright lights and loud sounds, keep the room at a comfortable temperature, and don’t watch TV or have a computer in your bedroom.
- Don’t lie in bed awake. If you can’t get to sleep, do something else, like reading or listening to music, until you feel tired.
- See a doctor if you have a problem sleeping or if you feel exhausted during the day.
There appears to be good evidence of sleep extension performance-enhancing effects up to 10 hours per night.
However, the benefit it confers may vary since recovery requirements are individual in nature.
1. "1 in 3 adults don't get enough sleep." CDC Newsroom, Media Relations Press Release, Feb 18, 2016. Accessed March 24, 2021. 
2. Thomas Reilly & Mark Piercy (1994). "The effect of partial sleep deprivation on weight-lifting performance." Ergonomics, 37:1, 107-115. 
3. Mougin F, Simon-Rigaud ML, Davenne D, Renaud A, Garnier A, Kantelip JP, Magnin P. "Effects of sleep disturbances on subsequent physical performance." Eur J Appl Physiol Occup Physiol. 1991;63(2):77-82. 
4. Edwards BJ, Waterhouse J. "Effects of one night of partial sleep deprivation upon diurnal rhythms of accuracy and consistency in throwing darts." Chronobiol Int. 2009 May;26(4):756-68. 
5. Morteza Taheri, and Elaheh Arabameri. "The Effect of Sleep Deprivation on Choice Reaction Time and Anaerobic Power of College Student-Athletes." Asian J Sports Med. 2012, Mar; 3(1):15-20.
6. Belenky G, Wesensten NJ, Thorne DR, Thomas ML, Sing HC, Redmond DP, Russo MB, Balkin TJ. "Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: a sleep dose-response study." J Sleep Res. 2003 Mar;12(1):1-12.
7. Skein M, Duffield R, Edge J, Short MJ, Mündel T. "Intermittent-sprint performance and muscle glycogen after 30 h of sleep deprivation." Med Sci Sports Exerc. 2011 Jul;43(7):1301-11.
8. Bulbulian R, Heaney JH, Leake CN, Sucec AA, Sjoholm NT. "The effect of sleep deprivation and exercise load on isokinetic leg strength and endurance." Eur J Appl Physiol Occup Physiol. 1996;73(3-4):273-7.
9. Takeuchi L, Davis GM, Plyley M, Goode R, Shephard RJ. 'Sleep deprivation, chronic exercise, and muscular performance." Ergonomics. 1985 Mar;28(3):591-601.
10. Money I, Waterhouse J, Atkinson G, Reilly T, Davenne D. "The effect of one night's sleep deprivation on temperature, mood, and physical performance in subjects with different amounts of habitual physical activity." Chronobiol Int. 1998 Jul;15(4):349-63.
11. Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. "Insufficient sleep undermines dietary efforts to reduce adiposity." Ann Intern Med. 2010 Oct 5;153(7):435-41.
12. Cheri D. Mah, MS, Kenneth E. Mah, MD, MS, Eric J. Kezirian, MD, MPH, and William C. Dement, MD, Ph.D. "The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players." Sleep. 2011 Jul 1; 34(7):943–950. Published online 2011 Jul 1. Accessed March 24, 2021.
13. MasayaTakahashif. "The role of prescribed napping in sleep medicine," Science Direct. Sleep Medicine Reviews, Volume 7, Issue 3, June 2003, Pages 227-235. Accessed March 24, 2021.
14. Smith, S.S., Kilby, S., Jorgensen, G. et al. "Napping and nightshift work: Effects of a short nap on psychomotor vigilance and subjective sleepiness in health workers." Sleep Biol. Rhythms 5, 117–125 (2007).
15. Mats Gillberg. "The effects of two alternative timings of a one-hour nap on early morning performance." Biological Psychology. Volume 19, Issue 1, August 1984, Pages 45-54
16. Tietzel AJ, Lack LC. "The recuperative value of brief and ultra-brief naps on alertness and cognitive performance." J Sleep Res. 2002 Sep;11(3):213-8.