A nap is almost customary in many nations, particularly the warm countries. It is very common in countries such as Greek, Italy, and Spain in the Mediterranean region and is known as siesta, while the same is not significant in other regions like North America and Northern Europe.

The idea of a nap is rooted in the culture of the Islamic world. It stems from the Sunnah of our prophet Muhammad (peace be upon him). He (peace be upon him) practiced the nap and recommended it, Anas Bin Malik (may Allah be pleased with him) narrated that the prophet (peace be upon him) said, "We should nap because the Satan does not nap." (Declared sound by Al Albani). A nap is mentioned in the Holy Quran, where Allah has said, "How many towns have we destroyed (for their sins)? Our punishment took them on a sudden by night or while they slept for their afternoon rest" (Al-Araf, verse 4).

The Internet carries plenty of articles about naps and its benefits, but most of the information is not scientifically proved or backed with any research. Moreover, it does not examine a nap from the medical perspective.

In this article, we have tried to include references to researches published in authorized scientific magazines. Here we will also avoid the theories and assumptions that have not been proved scientifically. We aim to study the nap from a purely medical perspective.

Naps are natural phenomena seen in newborns, infants, and young children and disappear after that (for children during schooling). However, the same reappears as adults and stays for the elderly (more than 65 years).

Various published studies from different countries suggest that, 36 to 80% of adults indulge in a nap. Some research foundations in the Kingdom have shown that 80% of the adults and 20-40% of other age people have a nap.

An earlier research conducted in Riyadh claimed that 40% of primary school children also take a nap after returning from school. Although it is well known that primary school going children do not require a nap, they might indulge in one because they suffer from a lack of sleep during night and try to compensate the lost sleep during the day.

This leads us to make the following nap divisions.

Researchers classify naps into three types:

• Compensation nap: People with lack of sleep during night try to compensate with the nap during the day. This is a common phenomenon in the Kingdom.
• Preventive nap: It is the nap a person takes to stay awake for a long period afterwards. This is usually seen among people working in shifts or driving at night.
• Usual nap: The regular habitual nap that some people enjoying during the day.

Nap benefits:

Before speaking about the benefits of a nap, I would like to mention that the benefits of a nap vary as per individual elements such as the body’s need for sleep, the biological clock, duration, and time of the day, emergence of sleep laziness symptoms after nap (discussed later) and other factors such as age, sex, etc.

Recent researches have shown several benefits of a daily nap. These include effects like improvement of the person’s mood, reducing sleepiness and tiredness, stimulating mental abilities such as logical analysis, arithmetic, etc.

The research also showed that, the best therapy to avoid feeling sleepy is to get a little nap! The effect of a nap far exceeds those of other stimulants such as coffee or other medication. Also, unlike stimulants, a nap develops the mental abilities too.

Nap timing:

Nap timing depends upon the person's wakening and sleeping schedules. The ideal nap time for a person who wakes up at dawn and sleeps after dinner differs from a person who wakes up late and sleeps even later. This is a result of the body's biological clock effect, when a person feels sleepy; the body temperature drops a little. Based on their wakening and sleeping schedule, this happens two times a day - once during the actual sleep time (night) and during the noon (from 12 o'clock noon till 5 o'clock).

The period of 2-4 hours prior to the night sleep time is known as the prohibited region because it is difficult and uncomfortable to sleep during this time. Most people find it difficult to identify their nap times because this largely depends on their waking and sleeping times, their biological clock and the quality of their previous night’s sleep.

Length of the nap:

The length of the nap depends on its purpose. If the person wants to sleep because he has a long travel or a stressful work shift coming up, then he should sleep for long hours. However, for daily life routine, published research suggested that the ideal duration for a nap is 10-20 minutes because this length of time provided the best results for overcoming sleepiness, stimulating the mental abilities and improving memory.

But doesn’t longer sleep give best results? This hypothesis about naps is actually incorrect. A longer nap may result in laziness or inability to sleep during night-time. The reason for that is that the sleeper reaches the deep sleep stage approximately 30 minutes after getting sleep and if he has to wake up during this phase, he might show symptoms like sleep laziness. A study conducted on a group of volunteers and published in JAMA in 2006, highlighted that the ability to understand and comprehend is hampered after waking up from deep sleep.

Sleep laziness is a normal physiological stage one passes though after being suddenly woken up. It feels like vertigo, with lack of concentration and confusion. This phase can last for as long as 30 minutes. Other factors that could escalate this state are wakening up from the deep sleep stage (third and fourth stage of sleep) before the mind gets adequate rest. This could happen due to a nap during late afternoon (sunset time).

The brain, as mentioned earlier, gets into a deep sleep stage 30 minute after the onset of sleep, so it is preferable to limit the nap to less than 30 minutes so that you feel fresh and energetic.

Nap in the elderly:

It is known that the elderly (over 65 years of age) nap frequently during the daytime. This is to compensate for the lack of sleep at night. We know that as the age increases, the ability to get quality sleep reduces, but research on the benefits of naps in the elderly have produced contradictory results.

A nap study conducted in 2007 (published in the internal medicine achieves), included the findings from the supervision of the health of 23,681 Greek volunteers for six years. The study concluded that men who took a daily nap, regardless of the length or the time of the nap, were less affected by diseases like arteriosclerosis and even lived longer.

I hope this article has succeeded in providing the reader with some critical insights about nap and the scientific researches that are conducted around it. I would like to add here that a nap is not necessary because while some people might feel comfortable and relaxed after their usual nap, others might not prefer it and feel nervous and anxious after a nap. It is also believed that people who do not prefer naps get into the deep sleep faster than the others do.

This is an ongoing subject for research.

Ahmed BaHammam, FACP, FCCP
Professor of Medicine
Director, University Sleep Disorders Center
College ofMedicine, King Saud University