A nap is a short period of sleep.
It is 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 term includes longer periods of sleep in addition to one single period.
A 60–90-minute nap is more effective than caffeine in memory and cognition.
Excessive daytime sleepiness (EDS) can be improved by napping in narcolepsy.
Apart from narcolepsy, it has not been demonstrated that naps are beneficial for EDS in other sleep disorders.
The state of grogginess, impaired cognition and disorientation experienced when awakening from sleep is known as sleep inertia.
Sleep inertia 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.
Research suggests napping is a risk factor for morbidity and mortality in elderly people.
With idiopathic hypersomnia, patients experience sleep inertia and are unrefreshed after napping.
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.
A power nap is intended to quickly revitalize the napper, increase alertness and motor skills.
The short duration of a power nap prevents nappers from sleeping so long that they enter the slow wave portion of the normal sleep cycle without being able to complete the cycle.
When one enters deep, slow-wave sleep and fails to complete the normal sleep cycle, it can result in sleep inertia, where one feels groggy, disoriented, and even sleepier than before beginning the nap.
Optimal post-nap performance occurs at Stage 2 nap must be limited to the beginning of a sleep cycle, specifically sleep stages N1 and N2, typically 18–25 minutes.
Napping during the daytime could interfere with nighttime sleep.
The greatest immediate improvement in measures of alertness and cognitive performance comes after the 10 minutes of sleep.
The 20 and 30-minute naps show evidence of sleep inertia immediately after the naps and increased alertness more than 30 minutes later, but not to a greater level than after the 10 minutes of sleep.
Patients develop an understanding of the duration of their nap which works best for them, and the environment, and associated factors help produce the best results.
Naps improve mental performance, even after a full night’s sleep.
A short nap preceded by the intake of caffeine reduces subjective sleepiness.
Recovery Nap: compensates for sleep loss.
Prophylactic Nap: taken in preparation for sleep loss.
Appetitive Nap: taken for the enjoyment of napping, associated with relaxation, improved mood and energy level upon waking.
Fulfillment Nap: often scheduled into the days of infants and toddlers and can occur spontaneously in children of all ages.
Fulfillment naps in children should not be limited to 20 minutes, as children have a higher sleep requirement than adults.
Essential Nap: When sick, there is a greater need for sleep, as the immune system mounts a response to fight infection or promote healing, and that requires extra energy.
Five-minute naps are too short to provide sleep deep enough through sleep stages to produce a notable benefit.
Sleeping for 30 minutes or longer gives the body enough time to enter deep sleep.
Napping for too long or waking up from slow-wave sleep can cause grogginess for up to an hour, referred to as sleep inertia.
Naps lasting 10 to 20 minutes are considered the ideal length.
These power naps provide recovery benefits without leaving the napper feeling sleepy afterward.
Essential naps when sick, are often longer because our bodies require more sleep when dealing with an illness.
Homeostatic sleep drive refers the feeling of pressure to sleep.
It is synonymous with the hunger for food.
Homeostatic sleep drive is low after awakening from a good night”s sleep.
Homeostatic sleep drive pressure slowly increases throughout the day until bedtime, when sleepiness prevails.
Sleeping at night causes a decrease in sleep pressure, and then the cycle recurs the next day.
Napping diminishes homeostatic sleep drive, helping to be more awake and have better performance.
As a result, napping can:
Harms of Napping
Napping can interfere with the ability to fall asleep at bedtime.
Sleep inertia can be minimized or avoided by taking shorter naps.
The best nap length for most people is about 10-20 minutes,
which provides restorative sleep without drowsiness after waking.
Countering sleep inertia occurs by limiting the amount of time spent asleep.
Napping late in the day can affect your ability to fall asleep at bedtime.
Napping around the halfway point between the time one wakes up and the time one plans to go to bed.
It helps to nap in a comfortable space that is dark, cool, and quiet.
Children need more sleep than adults, and younger children need more sleep than older children.
The role of napping changes as we age.
Taking naps can help children get sufficient sleep, and sleep is important for a child’s physical, intellectual, and emotional development.
It is normal for infants to spend the majority of their time sleeping: They may take one to four naps14 per day, which can last between 30 minutes and two hours.
An extended nap after learning aids memory consolidation in infants.
Napping begins to decrease after one year of age.
Naps are important at 1-2 years of age and produce benefits.
Toddlers who nap have an increased ability to self-regulate their behavior and emotions compared with toddlers who don’t.
There is also evidence that napping improves language-learning in toddlers.
Children 3-5 years of age need 10 to 13 hours of sleep on a daily basis.
Some toddlers will start to get their adequate amount of sleep continuously throughout the night, while others will still need to nap during the day.
After age 5, some children may stop napping.
Teens 13-17 years old, have a number of challenges that interfere with them getting enough sleep at night, so that with a recovery nap they can maintain their cognitive performance.
However, teens that nap during the day get less sleep at night.
Napping in early adulthood can alleviate sleepiness and improve cognitive performance and emotion regulation.
In older adults, certain adverse health effects have been associated with very long, mid-day naps that are more than an hour in duration: linked with an increased risk for diabetes, heart disease and depression.
Long midday naps in adults, may indicate that nighttime sleep is of poor quality.