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Research · Daily life

Napping

In pooled trials, an afternoon nap improved memory, alertness and test performance against no nap, with small to medium effects. In pooled cohorts, naps under an hour were not linked to heart disease or death, while naps of an hour or more were linked to more deaths, heart disease and type 2 diabetes. Grogginess after waking was reported.

Checked 2026-11-13
Status
A daily life factor, not a product.
Also called
nap, naps, daytime nap, daytime napping, power nap, siesta, afternoon nap, catnap, short nap, long nap, nap length, napping at work, napping on night shift
Studied for
alertness, focus, memory, energy, less fatigue, athletic performance, recovery, heart health, living longer, staying sharp on night shifts

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help4

Reported risks7

What it was studied for, and what was found

Shown to help4

Strong

Memory and thinking after a nap

Shown to improve memory and overall test performance after an afternoon nap, a small to medium effect in three meta-analyses, similar across ages and nap lengths.

Compared with control conditions the abstract does not describe [1]; a no-nap control condition, and the same people before the nap [2]; a no-nap condition in randomized trials [3]

The numbers and sources
Effect
Across 60 samples, naps improved the aggregate of cognitive tests (Cohen's d 0.379, 95% CI 0.296 to 0.462), declarative memory (d 0.376), procedural memory (d 0.494) and speed of processing (d 0.211). Age, nap length, nap start time, habitual napping and prior sleep loss did not change the effect [1]. In working-age adults, overall cognitive performance improved after a nap (effect size 0.18, 95% CI 0.09 to 0.27), mainly up to 120 minutes after waking [2]. In young athletes and active men, a nap after a normal night improved cognitive performance (SMD 0.69, 95% CI 0.37 to 1.00) [3].
Population
60 samples from 54 studies [1]. 381 participants in 11 studies, almost all in laboratories, mean nap 55.4 minutes [2]. 291 males aged 18 to 35 in 22 randomized trials [3].
Sources
[1], [2], [3]
Caveats
Short laboratory studies of single naps. Heterogeneity was high in the athlete trials (I² 71.5%) [3]. Results in real workplaces are scarce [2].
Strong

Alertness and fatigue after a nap

Shown to raise vigilance and alertness and to reduce felt fatigue after a nap, in three meta-analyses of nap studies.

Compared with control conditions the abstract does not describe [1]; a no-nap control condition, and the same people before the nap [2]; a no-nap condition in randomized trials [3]

The numbers and sources
Effect
Naps improved vigilance (Cohen's d 0.610, 95% CI 0.291 to 0.929) [1]. Alertness improved after a nap (effect size 0.29, 95% CI 0.10 to 0.48), with better results for naps before 1 p.m. [2]. Perceived fatigue fell after a nap following a normal night (SMD -0.76, 95% CI -1.24 to -0.28), and benefits were also seen after partial sleep deprivation [3].
Population
60 samples from 54 studies [1]. 381 working-age adults in 11 studies [2]. 291 young males in 22 randomized trials [3].
Sources
[1], [2], [3]
Caveats
Most studies were in laboratories, short and small. Fatigue was self-rated, and heterogeneity was high (I² 89.5%) [3].
Moderate

Naps during night shifts

Shown to improve cognitive performance during night shifts after a nap, mostly from 30 minutes after waking, in one meta-analysis. Memory dipped right after waking.

Compared with control conditions without a nap [4]

The numbers and sources
Effect
Performance improved after a night-shift nap against no nap (effect size 0.25, 95% CI 0.10 to 0.41). Gains were seen mainly 30 minutes after waking. Memory got worse immediately after waking, with no overall change in global performance at that point. Earlier naps in the night tended to help more [4].
Population
494 participants in 18 studies, 6 in real work settings and 12 in laboratories. Mean nap 41.6 minutes, at a mean time of 2:12 a.m. [4].
Sources
[4]
Caveats
One meta-analysis with few real-work studies. Safety, health and economic outcomes were not measured [4].
Strong

Physical performance after a nap

Shown to improve physical test performance after an afternoon nap in two meta-analyses of athletes and active adults. Muscle force did not change.

Compared with a no-nap condition in randomized trials [3]; no-nap conditions [5]

The numbers and sources
Effect
After a normal night, a nap improved physical performance (SMD 0.99, 95% CI 0.67 to 1.31), with larger benefits for naps of 30 to under 60 minutes and when testing came more than an hour after waking [3]. In the 5-m shuttle run test, napping raised highest distance (effect size 1.026) and total distance (0.737) and lowered the fatigue index (0.839). Muscle force did not change (effect size 0.175, p = 0.267) [5].
Population
291 males aged 18 to 35, 164 trained athletes and 127 active adults, in 22 trials [3]. Physically active people and athletes in 18 studies after 7 to 9 hours of night sleep [5].
Sources
[3], [5]
Caveats
Small crossover studies, mostly in young men. Heterogeneity was high (I² 89.1%) [3]. Sprint, jump and endurance results rested on one to three studies each [5].

Not shown to help1

Strong

Short naps and heart disease and death

Not linked to heart disease or death for naps under an hour in two pooled cohort analyses. One Swiss cohort linked napping once or twice weekly to fewer heart events.

Compared with people who did not nap [6][7][8]

The numbers and sources
Effect
Naps under 60 minutes a day were not linked to cardiovascular disease (p = 0.98) or death from any cause (p = 0.08). The dose-response curve for heart disease was J-shaped: risk dipped from 0 to 30 minutes, rose slightly to about 45 minutes and rose sharply after that [6]. Naps under an hour were not linked to death (HR 1.00, 95% CI 0.90 to 1.11) or cardiovascular disease (HR 1.03) [7]. In one cohort, napping 1 to 2 times a week was linked to fewer cardiovascular events (HR 0.52, 95% CI 0.28 to 0.95), and nap length was not linked to events [8].
Population
151,588 participants in 11 cohorts, mean follow-up 11 years [6]. 371,306 participants in 21 studies [7]. 3,462 Swiss adults without heart disease followed 5.3 years, 155 events [8].
Sources
[6], [7], [8]
Caveats
Observational, with naps self-reported. The dip near 30 minutes was not tested against a trial. The Swiss finding rests on few events with a wide interval [8].

Amounts studied

Trials gave one afternoon nap, most often starting near 2 p.m. and between 12:30 and 4:50 p.m. [3]. Mean nap length was 55.4 minutes in working-age adults [2] and 41.6 minutes in night-shift studies, where naps fell between midnight and 4:10 a.m. [4]. The athlete trials found larger gains for naps of 30 to under 60 minutes [3], while a larger review found effects of similar size across nap lengths [1].

Cohorts asked people whether and how long they napped, and most split nappers at 60 minutes a day [6][7]. The heart disease curve was J-shaped with its lowest point near 30 minutes, and death from any cause rose in a straight line with nap time [6].

Risks

Reported risks6

StrongHow often is not known

Long naps linked to death from any cause

Linked to about 15% to 28% more deaths in nappers in four meta-analyses of cohorts, mainly with naps of an hour or more, rising in a straight line.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Naps of 60 minutes or more were linked to more deaths (RR 1.27, 95% CI 1.11 to 1.45), with a linear rise as nap time grew [6]. Nappers had higher death rates than non-nappers (HR 1.22, 95% CI 1.14 to 1.31) [9]. Nappers had a 15% higher risk (RR 1.15, 95% CI 1.07 to 1.24), significant for naps over 60 minutes (RR 1.15) and not for shorter naps (RR 1.10, 95% CI 0.92 to 1.32) [10]. Nappers had higher mortality (HR 1.28, 95% CI 1.18 to 1.38), as did those napping an hour or more (HR 1.22, 95% CI 1.12 to 1.33) [7].
Population
151,588 participants in 11 cohorts [6]. 130,068 participants with 19,059 deaths in 12 studies [9]. 98,163 participants in 7 studies [10]. 371,306 participants in 21 studies [7].
Sources
[6], [9], [10], [7]
Caveats
Observational. Long naps often follow poor night sleep, sleep apnea, depression or early illness, so reverse causation and confounding may explain much of the link. The reviews draw on overlapping cohorts.
StrongHow often is not known

Long naps linked to heart disease

Linked to about 37% to 82% more cardiovascular disease with naps of an hour or more in two meta-analyses. Two other reviews found no clear link with cardiovascular death.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Naps of 60 minutes or more a day were linked to more cardiovascular disease (RR 1.82, 95% CI 1.22 to 2.71) than no nap [6]. Napping an hour or more was linked to a 1.37-fold risk (HR 1.37, 95% CI 1.09 to 1.71) [7]. Napping was not significantly linked to cardiovascular death in two reviews (HR 1.20, 95% CI 0.96 to 1.50 [9], and RR 1.19, 95% CI 0.97 to 1.48 [10]).
Population
151,588 participants with 5,276 cardiovascular events [6]. 371,306 participants in 21 studies [7]. 130,068 participants [9]. 98,163 participants [10].
Sources
[6], [7], [9], [10]
Caveats
Observational. Heterogeneity was high in the newer review (I² 68.3% for long naps) [7]. Sleep apnea, which raises both daytime sleepiness and heart risk, may confound the link.
StrongHow often is not known

Long naps linked to type 2 diabetes

Linked to more type 2 diabetes with naps over an hour in four meta-analyses, a J-shaped curve flat up to about 40 minutes a day.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
A long nap of 60 minutes or more was linked to diabetes (OR 1.46, 95% CI 1.23 to 1.74), and a shorter nap was not (p = 0.75). The curve showed no change up to about 40 minutes a day, then a sharp rise [11]. Habitual nappers had a 17% higher risk (RR 1.17, 95% CI 1.08 to 1.27), and each extra 30 minutes a day 11% more [12]. Naps over an hour were linked to a 31% higher risk of new diabetes in cohorts [13]. Naps under 30 minutes were not linked (OR 1.05, 95% CI 0.97 to 1.14), and naps over 60 minutes were (OR 1.31, 95% CI 1.20 to 1.44). In people with diabetes, napping was linked to poorer glucose control (OR 2.05) [14].
Population
288,883 Asian and Western participants [11]. 249,077 participants with 13,237 cases in 7 cohorts [12]. 304,885 people in 10 studies [13]. 40 observational studies [14].
Sources
[11], [12], [13], [14]
Caveats
Observational, and several reviews mixed cross-sectional with cohort data [13][14]. Early diabetes, poor night sleep and sleep apnea can all lengthen naps, which is reverse causation and confounding.
ModerateHow often is not known

Napping linked to obesity

Linked to 22% higher odds of obesity in nappers in one meta-analysis, significant for naps over an hour and not for shorter naps.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Nappers had higher odds of obesity than non-nappers (OR 1.22, 95% CI 1.10 to 1.35, I² 87%). The link was significant for naps over an hour and not clear below an hour, and it was not significant in Chinese studies (OR 1.05) [15].
Population
170,134 participants in 12 studies from the UK, Spain, the USA and China [15].
Sources
[15]
Caveats
Observational, mostly cross-sectional, with very high heterogeneity. Weight gain and sleep apnea can cause daytime sleepiness and napping, which is reverse causation.
ModerateHow often is not known

Napping linked to high blood pressure

Linked to 19% more high blood pressure in daytime nappers in one meta-analysis. Across all nappers, including night-shift workers, the link was not significant.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Across all nappers, the pooled risk of hypertension was not significant (RR 1.13, 95% CI 0.98 to 1.30). Limited to daytime nappers, it was (RR 1.19, 95% CI 1.06 to 1.35). One study found less hypertension in night-shift workers who napped at night (OR 0.79, 95% CI 0.63 to 1.00) [16].
Population
112,267 people in 9 observational studies [16].
Sources
[16]
Caveats
Observational, with few studies. Nap length was not analyzed in the abstract.
LimitedHow often is not known

Grogginess after waking from a nap

Limited evidence: grogginess and poorer performance just after waking, called sleep inertia, were reported after naps, including some naps of 30 minutes or less.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Studies of naps of 30 minutes or less gave mixed results on whether deep sleep and sleep inertia occurred, depending on prior sleep and time of day [19]. During the sleep inertia period after daytime naps, results were conflicting [2]. After night-shift naps, memory got worse immediately after waking [4]. In athlete trials, benefits were larger when testing came more than an hour after waking [3].
Population
Nap studies reviewed in [19]. 381 adults [2]. 494 participants on night shifts [4]. 291 young males [3].
Sources
[19], [2], [4], [3]
Caveats
The review pooled no data and gave no rate [19]. Sleep inertia usually lasts minutes, and few studies measured how long.

Mixed results1

ModerateHow often is not known

Napping and cognitive impairment or dementia

Mixed results: one meta-analysis linked napping, especially over 30 minutes, to more cognitive impairment and dementia. Another found no link over time with global cognition or memory in older adults.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Napping was linked to dementia (OR 1.14, 95% CI 1.07 to 1.21). Naps longer than 30, 45 and 60 minutes a day were linked to 35%, 41% and 40% higher odds of cognitive impairment [17]. In longitudinal studies of adults over 60, napping was not linked to global cognition (OR 1.00, 95% CI 0.85 to 1.18) or memory (OR 1.08, 95% CI 0.98 to 1.19) [18].
Population
20 reports [17]. 95,719 participants over 60 in 25 studies, 7 longitudinal [18].
Sources
[17], [18]
Caveats
Observational. Dementia disturbs the sleep and wake rhythm years before diagnosis, so long daytime sleep may be an early sign rather than a cause.

Claims tested and not found

  1. That a nap increases muscle force. In pooled studies of athletes and active adults, napping did not change muscle force (effect size 0.175, p = 0.267) [5].
  2. That only short naps improve thinking. In 54 studies, nap length did not change the size of the cognitive benefit [1].
  3. That naps of 30 minutes or less reliably avoid grogginess. A review found mixed results on deep sleep and sleep inertia after such naps [19].
  4. That habitual napping is linked to memory decline in older adults. Longitudinal studies of adults over 60 found no link with global cognition (OR 1.00) or memory (OR 1.08, 95% CI 0.98 to 1.19) [18].

Related

Sleep durationShift work

Sources

  1. Leong RLF, Lo JC, Chee MWL. Systematic review and meta-analyses on the effects of afternoon napping on cognition. Sleep Medicine Reviews. 2022. https://doi.org/10.1016/j.smrv.2022.101666
  2. Dutheil F, Danini B, Bagheri R, et al. Effects of a Short Daytime Nap on the Cognitive Performance: A Systematic Review and Meta-Analysis. International Journal of Environmental Research and Public Health. 2021. https://doi.org/10.3390/ijerph181910212
  3. Mesas AE, Núñez de Arenas-Arroyo S, Martinez-Vizcaino V, et al. 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. 2023. https://doi.org/10.1136/bjsports-2022-106355
  4. Dutheil F, Bessonnat B, Pereira B, et al. Napping and cognitive performance during night shifts: a systematic review and meta-analysis. Sleep. 2020. https://doi.org/10.1093/sleep/zsaa109
  5. Boukhris O, Trabelsi K, Suppiah H, et al. The Impact of Daytime Napping Following Normal Night-Time Sleep on Physical Performance: A Systematic Review, Meta-analysis and Meta-regression. Sports Medicine. 2024. https://doi.org/10.1007/s40279-023-01920-2
  6. Yamada T, Hara K, Shojima N, Yamauchi T, Kadowaki T. Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis. Sleep. 2015. https://doi.org/10.5665/sleep.5246
  7. Wang M, Xiang X, Zhao Z, et al. Association between self-reported napping and risk of cardiovascular disease and all-cause mortality: A meta-analysis of cohort studies. PLOS ONE. 2024. https://doi.org/10.1371/journal.pone.0311266
  8. Häusler N, Haba-Rubio J, Heinzer R, Marques-Vidal P. Association of napping with incident cardiovascular events in a prospective cohort study. Heart. 2019. https://doi.org/10.1136/heartjnl-2019-314999
  9. Zhong G, Wang Y, Tao T, Ying J, Zhao Y. Daytime napping and mortality from all causes, cardiovascular disease, and cancer: a meta-analysis of prospective cohort studies. Sleep Medicine. 2015. https://doi.org/10.1016/j.sleep.2015.01.025
  10. Liu X, Zhang Q, Shang X. Meta-analysis of self-reported daytime napping and risk of cardiovascular or all-cause mortality. Medical Science Monitor. 2015. https://doi.org/10.12659/MSM.893186
  11. Yamada T, Shojima N, Yamauchi T, Kadowaki T. J-curve relation between daytime nap duration and type 2 diabetes or metabolic syndrome: A dose-response meta-analysis. Scientific Reports. 2016. https://doi.org/10.1038/srep38075
  12. Chen GC, Liu MM, Chen LH, et al. Daytime napping and risk of type 2 diabetes: a meta-analysis of prospective studies. Sleep and Breathing. 2018. https://doi.org/10.1007/s11325-017-1528-z
  13. Guo VY, Cao B, Wong CKH, Yu EYT. The association between daytime napping and risk of diabetes: a systematic review and meta-analysis of observational studies. Sleep Medicine. 2017. https://doi.org/10.1016/j.sleep.2017.01.018
  14. Liu M, Liu M, Wang S, et al. Relationship between daytime napping with the occurrence and development of diabetes: a systematic review and meta-analysis. BMJ Open. 2023. https://doi.org/10.1136/bmjopen-2022-068554
  15. Cai Z, Yang Y, Zhang J, Liu Y. The relationship between daytime napping and obesity: a systematic review and meta-analysis. Scientific Reports. 2023. https://doi.org/10.1038/s41598-023-37883-7
  16. Cheungpasitporn W, Thongprayoon C, Srivali N, et al. The effects of napping on the risk of hypertension: a systematic review and meta-analysis. Journal of Evidence-Based Medicine. 2016. https://doi.org/10.1111/jebm.12211
  17. Fang W, Le S, Han W, et al. Association between napping and cognitive impairment: A systematic review and meta-analysis. Sleep Medicine. 2023. https://doi.org/10.1016/j.sleep.2023.09.022
  18. Álvarez-Bueno C, Mesas AE, Reina-Gutierrez S, et al. Napping and cognitive decline: a systematic review and meta-analysis of observational studies. BMC Geriatrics. 2022. https://doi.org/10.1186/s12877-022-03436-2
  19. Hilditch CJ, Dorrian J, Banks S. A review of short naps and sleep inertia: do naps of 30 min or less really avoid sleep inertia and slow-wave sleep? Sleep Medicine. 2017. https://doi.org/10.1016/j.sleep.2016.12.016

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