Nap

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A man napping in a hammock, on a patio in Costa Rica Hammock nap on patio.jpg
A man napping in a hammock, on a patio in Costa Rica

A nap is a short period of sleep, typically taken during daytime hours as an adjunct to the usual nocturnal sleep period. Naps are most often taken as a response to drowsiness during waking hours. A nap is a form of biphasic or polyphasic sleep, where the latter terms also include longer periods of sleep in addition to one period. For years, scientists have been investigating the benefits of napping, including the 30-minute nap as well as sleep durations of 1–2 hours. Performance across a wide range of cognitive processes has been tested. [1]

Contents

Benefits

Sara Mednick conducted a study experimenting on the effects of napping, caffeine, and a placebo. Her results showed that a 60–90-minute nap is more effective than caffeine in memory and cognition. [2]

Power nap

A power nap, also known as a Stage 2 nap, is a short slumber of 20 minutes or less which terminates before the occurrence of deep slow-wave sleep, intended to quickly revitalize the napper. The power nap is meant to maximize the benefits of sleep versus time. It is used to supplement normal sleep, especially when a sleeper has accumulated a sleep deficit. The greater the sleep deficit, however, the more effective the nap. [3]

Prescribed napping for sleep disorders

It has been shown that excessive daytime sleepiness (EDS) can be improved by prescribed napping in narcolepsy. [4] Apart from narcolepsy, it has not been demonstrated that naps are beneficial for EDS in other sleep disorders. [4]

Learning and memory

Research suggests that shorter, habitual naps after instruction offer the most benefits to learning. [5] [6] The benefits to alertness show no change based on duration of the nap for combating post-lunch dip, even for naps as short as 10 minutes. [7] Napping enhances alertness in young adults and adolescents during afternoons’ performances, which affect efficiency. [8] Additionally, pre-teens who nap regularly during the day demonstrate better sleep at night. In younger children, napping increased drowsiness even while improving memory recall. [9]

For students of all ages, napping during the school day showed benefits to reaction time and recall of declarative memory of new information, especially if the naps remain in slow-wave sleep, i.e. less than an hour in length. [10] [6]

Cognitive capacity

In adults, a causal association has been found between habitual daytime napping and larger brain volume. [11] Brain volume normally declines with age, and is associated with neurodegenerative disease. [11] Earlier studies have shown benefits of napping for cognitive performance for healthy adults. [11]

Alertness and fatigue

The circadian cycle plays a role in the rising demand for daytime naps: sleepiness rises towards the mid-afternoon, hence the best timing for naps is early afternoon [12] [ citation not found ] Twenty- to thirty-minute naps are recommended for adults, while young children and elderly people may need longer naps. [13] [14] Research, on the other hand, has shown that the benefits of napping depend on sleep onset and sleep phases rather than time and duration. [15]

Negative effects

Sleep inertia

The state of grogginess, impaired cognition and disorientation experienced when awakening from sleep is known as sleep inertia. [16] This state reduces the speed of cognitive tasks but has no effects on the accuracy of task performance. [4] The effects of sleep inertia rarely last longer than 30 minutes in the absence of prior sleep deprivation. [17]

Potential health risks

A 2016 meta-analysis showed that naps longer than an hour may be associated with an increased risk for cardiovascular disease, diabetes, metabolic syndrome or death. [18] There was no effect of napping for as long as 40  minutes per day, but a sharp increase in risk of disease occurred at longer nap times. [18]

Habitual naps are also an indicator of neurological degradation such as dementia in the elderly, as reduction in brain function causes more sleepiness. [19]

On sleep disorders

For idiopathic hypersomnia, patients typically experience sleep inertia and are unrefreshed after napping. [20]

Best practices

How long and when a person naps affects sleep inertia and sleep latency: a person is more likely to benefit in terms of those two points when they sleep moderately in the afternoon. According to research, the degree to which a person experiences sleep inertia differs in different durations of nap. Because sleep inertia is possibly resulting from awakening from slow-wave sleep, it is more likely to happen when one has a longer nap. [21] Sleep inertia is less intense after short naps. [22] Sleep latency is shorter when a nap is taken between 3 and 5 pm, compared with a nap taken between 7 and 9 pm. [23]

According to The Sleep Foundation, Psychology Today and Harvard Health Publishing, these are the best practices for napping: [13] [24] [14]

See also

Related Research Articles

<span class="mw-page-title-main">Sleep</span> Naturally recurring resting state of mind and body

Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.

<span class="mw-page-title-main">Sleep disorder</span> Medical disorder of a persons sleep patterns

A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Sleep disorders are frequent and can have serious consequences on patients' health and quality of life. Polysomnography and actigraphy are tests commonly ordered for diagnosing sleep disorders.

<span class="mw-page-title-main">Stimulant</span> Drug that increases activity of central nervous system

Stimulants are a class of drugs that increase the activity of the brain. They are used for various purposes, such as enhancing alertness, attention, motivation, cognition, mood, and physical performance. Some of the most common stimulants are caffeine, nicotine, amphetamines, cocaine, methylphenidate, modafinil.

<span class="mw-page-title-main">Power nap</span> Short sleep

A power nap or cat nap is a short sleep that terminates before deep sleep. A power nap is intended to quickly revitalize the sleeper.

Somnolence is a state of strong desire for sleep, or sleeping for unusually long periods. It has distinct meanings and causes. It can refer to the usual state preceding falling asleep, the condition of being in a drowsy state due to circadian rhythm disorders, or a symptom of other health problems. It can be accompanied by lethargy, weakness and lack of mental agility.

<span class="mw-page-title-main">Nootropic</span> Compound intended to improve cognitive function

Nootropics, colloquially brain supplements, smart drugs and cognitive enhancers, are natural, semisynthetic or synthetic compounds which purportedly improve cognitive functions, such as executive functions, attention or memory.

Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders.

Sleep inertia is a physiological state of impaired cognitive and sensory-motor performance that is present immediately after awakening. It persists during the transition of sleep to wakefulness, where an individual will experience feelings of drowsiness, disorientation and a decline in motor dexterity. Impairment from sleep inertia may take several hours to dissipate. In the majority of cases, morning sleep inertia is experienced for 15 to 30 minutes after waking.

<span class="mw-page-title-main">Slow-wave sleep</span> Period of sleep in humans and other animals

Slow-wave sleep (SWS), often referred to as deep sleep, is the third stage of non-rapid eye movement sleep (NREM), where electroencephalography activity is characterised by slow delta waves.

Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep or to wake up before the individual has slept enough. About 20% of the working population participates in shift work. SWSD commonly goes undiagnosed, so it's estimated that 10–40% of shift workers have SWSD. The excessive sleepiness appears when the individual has to be productive, awake and alert. Both symptoms are predominant in SWSD. There are numerous shift work schedules, and they may be permanent, intermittent, or rotating; consequently, the manifestations of SWSD are quite variable. Most people with different schedules than the ordinary one might have these symptoms but the difference is that SWSD is continual, long-term, and starts to interfere with the individual's life.

Alertness is a state of active attention characterized by high sensory awareness. Someone who is alert is vigilant and promptly meets danger or emergency, or is quick to perceive and act. Alertness is a psychological and physiological state.

Caffeine-induced sleep disorder is a psychiatric disorder that results from overconsumption of the stimulant caffeine. Caffeine is one of the most widely consumed psychoactive drugs: almost 90% of Americans in a survey consume some type of caffeine each day. "When caffeine is consumed immediately before bedtime or .... throughout the day, sleep onset may be delayed, total sleep time reduced, normal stages of sleep altered, and the quality of sleep decreased." Caffeine reduces slow-wave sleep in the early part of the sleep cycle and can reduce rapid eye movement sleep later in the cycle. Caffeine increases episodes of wakefulness, and high doses in the late evening can increase sleep onset latency. In elderly people, there is an association between use of medication containing caffeine and difficulty in falling asleep.

<span class="mw-page-title-main">Sleep deprivation</span> Condition of not having enough sleep

Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity. All known animals sleep or exhibit some form of sleep behavior, and the importance of sleep is self-evident for humans, as nearly a third of a person's life is spent sleeping.

<span class="mw-page-title-main">Narcolepsy</span> Human sleep disorder

Narcolepsy is a chronic neurological disorder that impairs the ability to regulate sleep–wake cycles, and specifically impacts REM sleep. The pentad symptoms of narcolepsy include excessive daytime sleepiness (EDS), sleep related hallucinations, sleep paralysis, disturbed nocturnal sleep (DNS) and cataplexy. There are two recognized forms of narcolepsy, narcolepsy type 1 and type 2. Narcolepsy type 1 (NT1) can be clinically characterized by symptoms of EDS and cataplexy, and/or will have CSF orexin levels of less than 110 pg/ml. Cataplexy are transient episodes of aberrant tone, most typically loss of tone, that can be associated with strong emotion. In pediatric onset narcolepsy, active motor phenomena are not uncommon. Cataplexy may be mistaken for syncope, tic disorder or seizures. Narcolepsy type 2 (NT2) does not have features of cataplexy and CSF orexin levels are normal. Sleep related hallucinations, also known as hypnogogic and hypnopompic are vivid hallucinations that can be auditory, visual or tactile and may occur independent of or in combination with an inability to move. People with narcolepsy tend to sleep about the same number of hours per day as people without it, but the quality of sleep is typically compromised. Narcolepsy is a clinical syndrome of hypothalamic disorder, but the exact cause of narcolepsy is unknown, with potentially several causes. A leading consideration for the cause of narcolepsy type 1 is that it is an autoimmune disorder. Proposed pathophysiology as an autoimmune disease suggest antigen presentation by DQ0602 to specific CD4+ T cells resulting in CD8+ T-cell activation and consequent injury to orexin producing neurons. Familial trends of narcolepsy are suggested to be higher than previously appreciated. Familial risk of narcolepsy among first degree relatives is high. Relative risk for narcolepsy in a first degree relative has been reported to be 361.8. However, it is important to note that there is a spectrum of symptoms found in this study, including asymptomatic abnormal sleep test findings to significantly symptomatic.

Idiopathic hypersomnia(IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). Idiopathic hypersomnia was first described by Bedrich Roth in 1976, and it can be divided into two forms: polysymptomatic and monosymptomatic. The condition typically becomes evident in early adulthood and most patients diagnosed with IH will have had the disorder for many years prior to their diagnosis. As of August 2021, an FDA-approved medication exists for IH called Xywav, which is oral solution of calcium, magnesium, potassium, and sodium oxybates; in addition to several off-label treatments (primarily FDA-approved narcolepsy medications).

The effects of sleep deprivation on cognitive performance are a broad range of impairments resulting from inadequate sleep, impacting attention, executive function and memory. An estimated 20% of adults or more have some form of sleep deprivation. It may come with insomnia or major depressive disorder, or indicate other mental disorders. The consequences can negatively affect the health, cognition, energy level and mood of a person and anyone around. It increases the risk of human error, especially with technology.

Neuroenhancement or cognitive enhancement is the experimental use of pharmacological or non-pharmacological methods intended to improve cognitive and affective abilities in healthy people who do not have a mental illness. Agents or methods of neuroenhancement are intended to affect cognitive, social, psychological, mood, or motor benefits beyond normal functioning.

<span class="mw-page-title-main">Sleep deprivation in higher education</span> Health issue in students

Sleep deprivation – the condition of not having enough sleep – is a common health issue for students in higher education. This issue has several underlying and negative consequences, but there are a few helpful improvements that students can make to reduce its frequency and severity.

Adolescent sleep is typically poor in duration and quality. Sleep duration and quality reduce to suboptimal levels, and sleep duration variability and latency increases during adolescence. Sleep recommendations suggest that adolescents should obtain 8–10 hours of sleep per night. Additionally, there is a shift in the body's circadian rhythm such that sleep and wake timings become later during adolescence. Technology, social factors, and physical development are thought to contribute to poor sleep during this time. Poor sleep duration and quality in adolescents has been linked with altered brain functioning and development, poor mental and physical health, as well as higher rates of disease and mortality. The concerns surrounding poor sleep during adolescence has garnered significant public attention, especially concerning policies related to school start times. Many evidences suggest that sleep contributes positively to attention, behavior, and academic achievement for adolescents.

<span class="mw-page-title-main">Behavioral sleep medicine</span>

Behavioral sleep medicine (BSM) is a field within sleep medicine that encompasses scientific inquiry and clinical treatment of sleep-related disorders, with a focus on the psychological, physiological, behavioral, cognitive, social, and cultural factors that affect sleep, as well as the impact of sleep on those factors. The clinical practice of BSM is an evidence-based behavioral health discipline that uses primarily non-pharmacological treatments. BSM interventions are typically problem-focused and oriented towards specific sleep complaints, but can be integrated with other medical or mental health treatments. The primary techniques used in BSM interventions involve education and systematic changes to the behaviors, thoughts, and environmental factors that initiate and maintain sleep-related difficulties.

References

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  6. 1 2 Ji X, Li J, Liu J (February 2018). "The Relationship Between Midday Napping And Neurocognitive Function in Early Adolescents". Behavioral Sleep Medicine. 17 (5): 537–551. doi:10.1080/15402002.2018.1425868. PMC   6669094 . PMID   29388804.
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  11. 1 2 3 Paz V, Dashti HS, Garfield V (2023). "Is there an association between daytime napping, cognitive function, and brain volume? A Mendelian randomization study in the UK Biobank". Sleep Health . 9 (5): 786–793. doi:10.1016/j.sleh.2023.05.002. PMID   37344293.
  12. ↑ Stampi 1992 ; Bertisch as cited in Bilodeau 2021 .
  13. 1 2 "Napping May Not Be Such a No-No". Harvard Health. 1 November 2009. Retrieved 18 February 2023.
  14. 1 2 Chan OY, Phoon WH, Gan SL, Ngui SJ (October 1989). "Sleep-wake patterns and subjective sleep quality of day and night workers: interaction between napping and main sleep episodes". Sleep. 12 (5): 439–448. doi: 10.1093/sleep/12.5.439 . PMID   2799217.
  15. ↑ Jones BJ, Spencer RM (December 2020). "Role of Napping for Learning across the Lifespan". Current Sleep Medicine Reports. 6 (4): 290–297. doi:10.1007/s40675-020-00193-9. PMC   8011550 . PMID   33816064.
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  18. 1 2 Yamada T, Shojima N, Yamauchi T, Kadowaki T (December 2016). "J-curve relation between daytime nap duration and type 2 diabetes or metabolic syndrome: A dose-response meta-analysis". Scientific Reports. 6 (1): 38075. doi:10.1038/srep38075. PMC   5133463 . PMID   27909305.
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  21. ↑ Milner CE, Cote KA (June 2009). "Benefits of napping in healthy adults: impact of nap length, time of day, age, and experience with napping". Journal of Sleep Research. 18 (2): 272–281. doi:10.1111/j.1365-2869.2008.00718.x. PMID   19645971. S2CID   22815227.
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  24. ↑ Andrews LW (5 June 2010). "Ultimate Napping: A How-To Guide". Psychology Today. Retrieved 18 February 2023.
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