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19-479: A nap is a short period of sleep. Nap or NAP may also refer to: Nap 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
38-584: A battery of tests may be utilized, including: the psychomotor vigilance task , descending subtraction task (DST), auditory reaction time task , and the finger tapping task . There has been a great deal of research into potential methods to relieve the effects of sleep inertia. The demand for remedies is driven by the occupational hazards of sleep inertia for employees who work extended shifts such as medical professionals, emergency responders, or military personnel. The motor functioning and cognitive ability of these professionals who must immediately respond to
57-492: A call can pose a safety hazard in the workplace. Below are some of the various methods that have been suggested to combat sleep inertia. When a person is sleep deprived , re-entering sleep may provide a viable route to reduce mental and physical fatigue, but it can also induce sleep inertia. In order to limit sleep inertia, one should avoid waking from the deeper stages of slow-wave sleep . The onset of slow-wave sleep occurs approximately 30 minutes after falling asleep, therefore
76-443: A longer nap. Sleep inertia is less intense after short naps. Sleep latency is shorter when a nap is taken between 3 and 5 pm, compared with a nap taken between 7 and 9 pm. According to The Sleep Foundation, Psychology Today and Harvard Health Publishing, these are the best practices for napping: Sleep inertia Sleep inertia is a physiological state of impaired cognitive and sensory-motor performance that
95-431: A nap should be limited to under 30 minutes to prevent waking during slow-wave sleep and enhancing sleep inertia. Furthermore, self-awakening from a short nap was shown to relieve disorientation of sleep inertia as opposed to a forced awakening, but these results may warrant more research into the nature of arousal after sleep periods. Caffeine is a xanthine derivative that can cross the blood–brain barrier , as well as
114-408: 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
133-508: A role in the rising demand for daytime naps: sleepiness rises towards the mid-afternoon, hence the best timing for naps is early afternoon. Twenty- to thirty-minute naps are recommended for adults, while young children and elderly people may need longer naps. Research, on the other hand, has shown that the benefits of napping depend on sleep onset and sleep phases rather than time and duration. The state of grogginess, impaired cognition and disorientation experienced when awakening from sleep
152-420: A short nap, consuming caffeine prior to the nap can alleviate the effects of sleep inertia. Nonetheless, individual degree of consumption and tolerance to caffeine may be responsible for variation in its efficacy to reduce sleep inertia symptoms. The natural light provided by the sunrise may contribute to a reduction in sleep inertia effects. Research simulating increase of light at dawn was shown to potentiate
171-681: 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, the more effective the nap. It has been shown that excessive daytime sleepiness (EDS) can be improved by prescribed napping in narcolepsy . Apart from narcolepsy, it has not been demonstrated that naps are beneficial for EDS in other sleep disorders. Research suggests that shorter, habitual naps after instruction offer
190-461: Is known as sleep inertia. This state reduces the speed of cognitive tasks but has no effects on the accuracy of task performance. The effects of sleep inertia rarely last longer than 30 minutes in the absence of prior sleep deprivation. A 2016 meta-analysis showed that there may be a correlation between habitual napping for more than an hour, and having an increased risk for cardiovascular disease , diabetes , metabolic syndrome or death. There
209-467: 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. Sleep inertia is of concern with decision-making abilities, safety-critical tasks and
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#1732773369316228-479: The cortisol awakening response (CAR). The CAR is a spike in blood cortisol levels following awakening, and is associated with the return to an alert cognitive state. Some other interventions that could potentially minimize the effects of sleep inertia are sound and temperature. There is moderate evidence that the presence of mild sounds and a sharp decrease in the temperature of the extremities may independently reverse sleep inertia symptoms. Sound, especially music,
247-402: The ability to operate efficiently soon after awakening. In these situations, it poses an occupational hazard due to the cognitive and motor deficits that may be present. These symptoms are expressed with the greatest intensity immediately after waking, and dissipate following a period of extended wakefulness. The duration of symptoms varies on a conditional basis, with primary expression during
266-412: 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. 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. A power nap , also known as a Stage 2 nap,
285-402: The first 15–60 minutes after waking and potentially extending for several hours. Tasks that require more complex cognitive operations will feature greater deficits as compared to a simple motor task; the accuracy of sensory and motor functioning is more impaired by sleep inertia as compared to sheer speed. In order to measure the cognitive and motor deficiencies associated with sleep inertia,
304-513: The most benefits to learning. 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. Napping enhances alertness in young adults and adolescents during afternoons’ performances, which affect efficiency. 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. For students of all ages, napping during
323-480: The most widely-consumed stimulant compound, present in therapeutic quantities in a variety of food and drink, including tea , coffee , soft drinks and chocolate . The caffeine present in coffee or tea exerts its stimulating action by blocking adenosine receptors in the brain. By antagonizing the adenosine receptors, caffeine limits the effects of adenosine buildup in the brain and increases alertness and attentiveness. Previous research has shown that coupled with
342-516: 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. In adults, a causal association has been found between habitual daytime napping and larger brain volume. Brain volume normally declines with age, and is associated with neurodegenerative disease . Earlier studies have shown benefits of napping for cognitive performance for healthy adults. The circadian cycle plays
361-568: 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. No causal relationship was established: the link may be to do with people taking a longer nap in response to the pre-existence of other risk factors. Habitual naps are also an indicator of neurological degradation such as dementia in the elderly, as reduction in brain function causes more sleepiness. For idiopathic hypersomnia , patients typically experience sleep inertia and are unrefreshed after napping. How long and when
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