Daytime sleep: benefits for recovery
Daytime sleep is one of the most accessible recovery tools: it requires neither equipment nor supplements. Many professional teams officially include it in the schedule of training camps. The editorial team looked into when daytime sleep helps, how many minutes to sleep, and how not to spoil your night’s rest.
Why an athlete needs daytime sleep
The main function of daytime sleep for an athlete is to compensate for night-time sleep deprivation. Early training, evening matches, flights and pre-event nervousness often prevent getting the needed 8–9 hours at night. A short daytime sleep makes it possible to partly repay the debt and reduce its effect on attention, reaction and well-being.
The second function is support between two training sessions in a day. When there are several hours between the morning and evening session, sleep in that interval helps to restore concentration, reduce the feeling of fatigue and get ready for the next load. That is exactly why daytime rest is included in the schedule of many training camps.
The third function is connected with biological rhythms. In most people, at the start of the afternoon there is a natural dip in alertness — the so-called postprandial, or post-lunch, dip. It exists independently of food and is part of the circadian rhythm. A short sleep during this period ‘fits into’ natural physiology and usually comes easily.
Finally, daytime sleep is useful for learning: some studies indicate that sleep after practising a new motor skill helps to consolidate it. For technical sports this is an additional argument in favour of a pause after lunch.
What the studies show
In the study by Waterhouse and co-authors (2007), young men, after night sleep shortened to 4 hours, either rested or slept for about 30 minutes after lunch. The short sleep improved subjective alertness, some indicators of short-term memory and 20-metre sprint time compared with no sleep. The authors concluded that daytime sleep is beneficial precisely against a background of partial deprivation.
The systematic review by Lastella and co-authors (2021), devoted to athletes’ daytime sleep, reached a similar general conclusion: daytime sleep of roughly 20 to 90 minutes generally improves cognitive indicators and some aspects of physical work capacity, and also reduces subjective fatigue. At the same time the quality of the studies is heterogeneous, the samples are small, and the protocols differ greatly.
The effect is more pronounced in those who are sleep-deprived. If an athlete sleeps well at night, daytime sleep gives a smaller gain — there is simply nothing to ‘compensate’ for. Therefore daytime sleep should be regarded as a tool, not a mandatory ritual for everyone.
The expert consensus on athletes’ sleep (Walsh and co-authors, 2021) also mentions daytime sleep as a useful strategy, especially with early training and after travel, but advises making sure that it does not interfere with falling asleep at night.
Duration and sleep inertia
The key concept to know is sleep inertia. This is a state of drowsiness, disorientation and reduced work capacity immediately after waking. It is strongest when a person wakes from deep slow-wave sleep, and can last from a few minutes to half an hour and longer.
Brooks and Lack (2006) compared daytime sleep of different durations after night-time sleep restriction. A ten-minute sleep gave a quick improvement in alertness with practically no inertia. Twenty- and thirty-minute sleeps gave an effect, but after thirty minutes noticeable inertia was observed. A five-minute sleep hardly helped at all.
Another option is a full sleep cycle of about 90 minutes. A person goes through the stages of light, deep and rapid sleep and usually wakes from a lighter stage, so inertia is less pronounced than after 40–60 minutes. Such sleep is appropriate after a very short night or on a competition day with an evening start, when there is time to fully ‘wake up’.
| Duration | Advantages | Limitations | When appropriate |
|---|---|---|---|
| 10–20 min | Quick gain in alertness, minimal inertia | Small contribution to repaying sleep debt | Before training, during the workday |
| 30–60 min | More deep sleep | Pronounced inertia after waking | If there are at least 30–60 min before the load |
| ~90 min | A full cycle, greater compensation of the debt | May interfere with night sleep | After a short night, a flight, competitions |
A practical rule: the less time between waking and the load, the shorter the sleep should be. If training is in an hour, 15–20 minutes is enough; if there are still several hours until the start, you can allow yourself a longer sleep.
When and how to nap correctly
The optimal time for daytime sleep in most people is roughly between 13:00 and 16:00, that is, during the period of the natural dip in alertness. Sleep later than 16:00–17:00 more often interferes with falling asleep at night, especially if it is long.
Conditions matter just as much as at night: darkness (an eye mask), silence or earplugs, coolness, a comfortable position. Even if you did not manage to fall asleep, 20 minutes of lying quietly with your eyes closed provides some rest.
A well-known technique is the ‘coffee nap’. A person drinks coffee and lies down immediately for 15–20 minutes. Caffeine begins to act roughly when they wake up and helps to get rid of inertia faster. Reyner and Horne (1997) showed that the combination of caffeine and a short sleep reduced sleepiness in drivers on a simulator more effectively than either measure separately. However, this technique should not be used in the afternoon by those in whom caffeine worsens night sleep.
- Set an alarm so as not to ‘sink’ into deep sleep.
- After waking — light, water, a light warm-up.
- Plan daytime sleep on a schedule, not only when you ‘just can’t any more’.
- Watch how daytime sleep affects falling asleep in the evening, and adjust the duration.
For teams at training camps it is useful to build a 60–90-minute ‘quiet window’ into the schedule after lunch. Not all athletes will sleep, but the opportunity to rest without irritants is beneficial in itself.
Whom daytime sleep may harm
Daytime sleep is not suitable for everyone. People with insomnia often worsen their night sleep if they nap during the day: the ‘sleep pressure’ decreases, and in the evening it becomes even harder to fall asleep. In such cases sleep physicians usually advise giving up daytime sleep at least for the duration of treatment.
Some people tolerate even a short sleep poorly: after waking they feel worn out, with a headache. If this happens regularly, it may be worth shortening the duration to 10 minutes or replacing sleep with quiet rest without a phone.
A constant need to sleep during the day in a person who supposedly gets enough sleep at night is a reason to think about the quality of night sleep. Snoring, awakenings and morning headaches may indicate sleep apnoea; daytime sleepiness can also be a manifestation of other conditions, in particular anaemia or thyroid disorders.
Finally, daytime sleep is not a substitute for night sleep. It helps to soften the consequences of sleep deprivation, but does not remove them completely, and regularly ‘patching’ the deficit during the day is not equivalent to sufficient night rest.
Editorial conclusions
Daytime sleep is an effective and free recovery tool, especially for athletes who are sleep-deprived at night or train twice a day.
The most universal format is 10–20 minutes in the interval from 13:00 to 16:00: it quickly increases alertness and almost never causes inertia. A longer sleep is appropriate if enough time remains before the load.
Daytime sleep does not replace night sleep and may interfere for those who have problems falling asleep. Listen to your body and watch the quality of your night rest.
The editorial team advises reading also our materials on how much an athlete should sleep, on sleep and muscle growth, and on active recovery.
References
- Lastella M, Halson SL, Vitale JA, Memon AR, Vincent GE. To nap or not to nap? A systematic review evaluating napping behavior in athletes and the impact on various measures of athletic performance. Nat Sci Sleep. 2021;13:841–862.
- Waterhouse J, Atkinson G, Edwards B, Reilly T. The role of a short post-lunch nap in improving cognitive, motor, and sprint performance in participants with partial sleep deprivation. J Sports Sci. 2007;25(14):1557–1566.
- Brooks A, Lack L. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep. 2006;29(6):831–840.
- Reyner LA, Horne JA. Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology. 1997;34(6):721–725.
- Walsh NP, Halson SL, Sargent C, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2021;55(7):356–368.
- Tietzel AJ, Lack LC. The recuperative value of brief and ultra-brief naps on alertness and cognitive performance. J Sleep Res. 2002;11(3):213–218.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
