The dual nature of Sleep

THE DUAL NATURE OF SLEEP: QURANIC SYMBOLISM AND SCIENTIFIC UNDERSTANDING

 

INTRODUCTION

Sleep has long fascinated both theologians and scientists, serving as a vital function for human health while also carrying profound spiritual significance. In the Quran, sleep is described as a temporary withdrawal of the soul, likened to death, and a sign of divine power and mercy. This perspective contrasts yet harmonizes with scientific explanations, which define sleep as a crucial biological process essential for cognitive function, cellular repair, and overall well-being. The aim of the essay is to analyse religious belief associated with sleep and to justify it from both an ethical and scientific perspective. Scientific and Quranic definitions of sleep will be discussed to figure out the similarities and differences in understandings. Examining the Quranic verses alongside modern sleep science, this essay explores the dual nature of sleep—as both a necessary physical function and a profound metaphor for death—offering insights into its deeper meanings and significance in human life.

 

METHODOLOGY

This essay is based on Literature review from the verses of the Quran and text from medical books and articles. Qualitative Content Analysis and Quranic Hermeneutics is used to review the data collected. Verses relating to ‘sleep’ are collected and analysed in light of exegesis and interpretations from prominent Islamic scholars. Hermeneutics method of analysis not only helps with understanding the text but also context and contextualisation. Furthermore, it also helps with understanding the literal meaning of the Quranic text [1]. Research from medical experts, relating to sleep, were also analysed to understand the established scientific descriptions of ‘sleep’ and its impact on humans. Since the focus of this essay was to understand the dual nature of ‘sleep’ from Secondary Data obtained from Quranic interpretations and scientific evidence and there was no data collected from subjects via questionnaires or interviews, Quantitative Analysis techniques was not used.

 

SCIENTIFIC DEFINITIONS OF SLEEP

National Institute of Neurological Disorders and Stroke defines sleep as; “Sleep is a complex biological process that helps the body and mind restore, regulate, and function properly. It is essential for overall health, impacting brain function, mood, and physical well-being.” [2]

The American Academy of Sleep Medicine defines sleep as; “Sleep is a naturally recurring state of mind and body, characterized by altered consciousness, reduced sensory activity, inhibition of nearly all voluntary muscles, and decreased interactions with the environment.” [3]

National Sleep Foundation (NSF) defines sleep as; “Sleep is a vital, reversible state of reduced awareness and responsiveness, essential for cognitive function, memory consolidation, and overall health. [4]

The definitions above from reputable sources show that sleep is not what it normally looks like which is someone just feeling tired and falling asleep. There are complex processes involved during sleep which are vital for healthy operation of the human body. The work of our brain doesn’t stop during sleep but in fact the brain works to fulfil other needs of the human body, which are not possible to be done while someone is awake. It can also be understood from the definitions that sleep is a vital function to refresh the state of human body. Without sleep or without good quality of sleep there are impacts on overall wellbeing of individuals and their productivity. It can also be observed that following a natural process, the consciousness levels, function of the senses and intentional use of muscles are reduced. This ultimately reduces the relationship between human body and external environment, however there are other interactions taking place within the body and activities like dreaming. In addition, it can also be understood that without sleep it wont be possible to process and store information collected during the awake period. Let’s now have a look at the stage of sleep known by medical science.

The human body cycles through two phases of sleep, the Non Rapid Eye Movement (NREM) sleep, which is divided into 3 stages N1, N2 and N3 and Rapid Eye Movement (REM). Sleep starts from Stage N1 of NREM sleep. This is the lightest state as soon as someone falls asleep and last for short period only. Then you move to Stage N2 of NREM sleep. This is when the brain starts to slow down. This time is also associated with the brain’s activity to organise memories from the time one spent while being awake. This is the longest part of your sleep. Then you move into the final stage of NREM sleep, Stage 3, also called ‘deep sleep’. During this stage the brain is believed to be helping with repair of injuries and strengthening of the immune system. According to medical experts this stage is the one required for one to feel rested when they wake up. During this stage its not easy to wake someone up and if they do, sleep inertia can be observed, which is a state of confusion waking after deep sleep. It is also possible to go into REM sleep after Stage 2 of NREM sleep. This is where someone starts to dream, and their brain activity is similar to when you are awake. During REM, the eyes move behind the eyelids as you are dreaming. [5]

 

QURANIC DEFINITIONS OF SLEEP

Sleep as Resting

وَهُوَ ٱلَّذِى جَعَلَ لَكُمُ ٱلَّيْلَ لِبَاسًۭا وَٱلنَّوْمَ سُبَاتًۭا وَجَعَلَ ٱلنَّهَارَ نُشُورًۭا

It is He who made for you the night as a covering and sleep for rest and He made the day a recall to life. (Furqan 25:47)

وَمِنْ آيَاتِهِ مَنَامُكُم بِاللَّيْلِ وَالنَّهَارِ وَابْتِغَاؤُكُم مِّن فَضْلِهِ ۚ إِنَّ فِي ذَٰلِكَ لَآيَاتٍ لِّقَوْمٍ يَسْمَعُونَ

And of His signs is your sleep by night and day, and your pursuit of His bounty. There are indeed signs in that for a people who listen. (Rum 30:23)

In this verse sleep وَٱلنَّوْمَ has been referred as a time for rest سُبَاتًۭا. ‘Sabt’ in Arabic is associated with Saturday or Yawn Sabt. This is the day set for resting after all week of hard work. Similarly after the hard work of all day, sleep is meant for resting. This is the time when you wind down and reduce your voluntary activities to gain energy. When you are relaxing or sleeping, parts of the body get refreshed. During sleep, apart from heart beating and breathing other functions of the body are slowed down.

In the second verse, sleep is referred to as a sign of God during day and night مَنَامُكُم بِاللَّيْلِ وَالنَّهَارِ. Whenever signs of God are mentioned, it highlights the need to find more about God and the system he has created. Nasir Makarim Shirazi says in his exegesis works, Tafseer Namoona, that what happens in sleep is still unknown to scholars. Some say that when a person sleeps, the flow of blood is directed to other parts of the body by the brain. This has also been experimented with some devices. Some say there are chemical changes in the body which causes sleep. When someone works hard, some sort of poison is created which numbs a part of the brain, cause the person to sleep. When the poison dilutes, this person wakes up. It has also been said that we can decide when to wake up for example when a mother is fast asleep, she will wake up only upon her infant crying and no other situations or when we have something important in the morning, we wake up in, or even before, time [6]

 

Sleep as Temporary Death

اللَّهُ يَتَوَفَّى الْأَنفُسَ حِينَ مَوْتِهَا وَالَّتِي لَمْ تَمُتْ فِي مَنَامِهَا

ۖ فَيُمْسِكُ الَّتِي قَضَىٰ عَلَيْهَا الْمَوْتَ وَيُرْسِلُ الْأُخْرَىٰ إِلَىٰ أَجَلٍ مُّسَمًّى

Allah takes the souls at the time of their death, and those who have not died, in their sleep. Then He retains those for whom He has ordained death and releases the others until a specified time. (Zumar 39:42)

وَهُوَ الَّذِي يَتَوَفَّاكُم بِاللَّيْلِ وَيَعْلَمُ مَا جَرَحْتُم بِالنَّهَارِ ثُمَّ يَبْعَثُكُمْ فِيهِ لِيُقْضَىٰ أَجَلٌ مُّسَمًّى ۖ ثُمَّ إِلَيْهِ مَرْجِعُكُمْ ثُمَّ يُنَبِّئُكُم بِمَا كُنتُمْ تَعْمَلُونَ

It is He who takes your souls by night, and He knows what you do by day, then He awakens you therein so that a specified term may be completed. Then to Him will be your return, whereat He will inform you concerning what you used to do. (Anaam 6:60)

In these verses two more words have been introduced in addition to وَٱلنَّوْمَ. These are يَتَوَفَّى and تَمُتْ. In Majma Al-Bayan, al-Tabrisi writes that Tawaffa, (to take) means to receive something completely and in full. Allama Tabatabai, in his famous exegesis of the Quran, Al-Mizaan, says that when we look at the term يَتَوَفَّى along side other verses in the Quran which says: You are taken by the angel of death (32:11), or when death approached you, our messengers take him away (6:61), we understand that it is God who takes away the soul الْأَنفُسَ via his assistants. The verse doesn’t mention body as we know that the time of death, soul is separated from the body. Arabic grammar analysis shows that the meaning of the verse is that God takes those souls who did not die while they were asleep. Here a distinction is being made of souls that have died and that have not died. God retains the ones which have died. For those souls that are released they, the process repeats, until they are meant to die.

In the second verse, God use the same term يَتَوَفَّاكُم in the meaning of taking away the soul from the body, partially in the case of sleep and fully in the case of death. This verse shows God power and decree while someone is asleep, and he know what someone has been doing during the day. Then for some he decides to wake up i.e delays death and other do not wake up. This is based on the usual pattern of humans which is sleeping in the night and being awake in the day. Allama Tabatabai says that the soul has been regarded as the essence of the human being and not the body. Hence when there is a discussion that how will people return to life when they have died, its not the bodies being referred to here but it’s the soul which is preserved by God and will just be sent back. In both verses أَجَلٌ مُّسَمًّى is mentioned which means that all souls will be taken away at a specified time only known by God. [7]

 

The connection of body and brain during sleep

The Quranic explanation of sleep is comparable to the scientific understanding to some extent Table 1 [8]. The first stage is Al-Wafat, which is similar to NREM stage of sleep. You are starting to fall asleep, then you become more unaware of the surroundings and finally get into the deep sleep mode. After this point Al-Noum occurs, which is similar to REM sleep but from a Quranic perspective is of two types. Either the person rests well, is completely unaware of their surroundings and may dream as well, or the soul is taken away by God and death occurs Al-Mout. During REM stage of sleep the blood pressure increases, and heart rate and breathing speed up to daytime levels. Hence, depending on the type of dream, sometimes we may wake up suddenly and find ourselves sweating or the heart beating very fast. The person may also talk during the dream of which they are completely unaware about. Blood pressure and heart rate are at their lowest point during deep sleep. Due to advances in medical science, it is now possible to put someone to sleep via anaesthesia or induced coma during which the body doesn’t react to operations carried out on it. Meanwhile during deep sleep, the brain’s housekeeping system — a series of channels called the glymphatic system, which drains cerebrospinal fluid — flushes away toxins, including beta-amyloid and other proteins linked to Alzheimer’s disease. When people don’t get sufficient amounts of deep sleep, blood pressure may not decline as it should. This can trigger activity in cells in blood vessel walls and activate damaging inflammation [9].

Zurarah asked from both the fifth and the sixth Imams (peace be upon them), “What invalidates the wudu?” They answered, “Whatever comes out from both of your lower organs like stool, urine, semen or wind; or the sleep which prevents the functioning of the mind. [10]. This statement shows that from a jurisprudential perspective, the state of ritual purity that a person entered into when they perform ablution (wudhu) is broken when a person sleeps, but not all kinds of sleep. It’s the sleep in which the person becomes unconscious to the level that the mind stops functioning. The mind only stops functioning when there is no input from the 5 senses (sight, sound, touch, taste and smell). For example, during deep sleep, the eyes remain closed, and visual processing is largely inactive because the brain’s occipital lobe (responsible for vision) reduces activity. Similarly, the sense of taste is closely linked to smell, so it remains largely inactive during deep sleep due to reduced olfactory function. Additionally, saliva production decreases, which can lead to a dry mouth upon waking [11].

 

Sleep and Worship

The Prophet Muhammad (PBUH) said: “Sleep is a comfort for the body and a gift from Allah. The believer should sleep with the remembrance of Allah so that his soul may rest in peace.”

The job and responsibility of the final messenger of God, Prophet Muhammad (pbuh) was to recite the verses of the Quran to people, purify them from evil desires and action, teach Quran to them with the ultimate objective of gaining wisdom (Jumma 62:2) . His words are of immense significance as some of them has been designated to become part of the Quran and the others become part of Islamic law or highly recommended advice and guidance. Narrations from Prophet Muhammad are meant to make humanity do wise actions in line with natural instinct and God’s will. In the above narration he defines sleep as a comfort for the body and a gift of God. As God is all wise and the creator of humans, he knows the importance of ensuring how the human body can work at optimum levels and what is needed for the body. The body has been equipped with all the necessary functions by God which are all his blessings. We can recognise these blessings from the fact that we are not able to control any of them. We are not able to save ourselves from illnesses of the body which can impact food intake, processing, digestions, excretion etc similarly what causes us to fall asleep, how all the body parts are rested and how energy is stored while sleeping is all not in our control. So, the fact that sleep has been designated for our comfort can be classed as nothing but a gift from the all-Merciful God who has not created us to be left alone but our good care has been planned in advance. This kindness of God demands that we thank and remember him on a regular basis. If the remembrance is straight after or before the act of kindness it has more value. So, in the second part of the narration, Prophet Muhammad (pbuh) advises us to remember God before going to sleep. Lots of recommended actions have been suggested by the Prophet himself, the Imams and members of his household. If these actions are performed with the right actions than peace will be acquired by the soul whether God decides to return it to the body or keep it. The narration also highlights that God’s mercy is all encompassing. First, he created sleep for our comfort, then he guided us on what to do before sleeping and when those actions were performed, God make our soul rest in peace.

 

SLEEP FROM THE DIVINE PERSPECTIVE

ٱللَّهُ لَآ إِلَـٰهَ إِلَّا هُوَ ٱلْحَىُّ ٱلْقَيُّومُ ۚ لَا تَأْخُذُهُۥ سِنَةٌۭ وَلَا نَوْمٌۭ

Allah—there is no god except Him—is the Living One, the Ever-Living. Neither drowsiness befalls Him nor sleep (2:255)

After having discussed the scientific and spiritual dimensions of sleep, we can now discuss sleep with reference to God, the Creator of everything. The beginning of the verse confirms the fundamental belief in Islam which is that there is only one God, he is life, and he is the only one who has been giving life. Second part of the verse identifies more characteristics of God, explaining that he doesn’t even get drowsy, let alone fall asleep. The Cambridge Dictionary defines ‘drowsy’ as being in a state between sleeping and being awake [12]. If God is meant to be life and be able to give life on a continuous basis, along with being the only one who gives life, there is no option of God to be drowsy or fall asleep, as this will impact himself and the process of life. Furthermore, drowsiness or sleep requires some changes inside the body which achieves some specific purposes like memory organisation, cellular rebuilding, muscle refresh etc. All of these activities are associated with a human or animal body. This verse can help in understanding that God is not limited to a body, which will be in need of these activities as a result of sleep or before sleeping when one is in the state of drowsiness. In fact, as he is the one who is life, all life is dependent on him and he is continuously giving life, God is the one responsible to creating the system when bodies get tired and are re-energised via drowsiness or sleep. Another thing we can understand about God from this verse is that if for any reason God, gets into a drowsy state, he will not be able to take decisions with full consciousness and if he falls asleep then he won’t be able to take decisions at all. When humans or animals get drowsy or sleep, the rest of the world continues to function however if God gets drowsy or falls asleep all systems in the world will stop as the one who is responsible for them ceases to be available.

فَضَرَبْنَا عَلَىٰ آذَانِهِمْ فِي الْكَهْفِ سِنِينَ عَدَدًا

We sealed their ears in the cave for a number of years – Shakir OR We put them to sleep in the Cave for several years – Qarai (Kahf 18:11)

In Chapter 18 of the Quran, which is about the People of the Cave, according to the exegesis compiled by Ali Abdur-Rasheed, God tells the story of some people who didn’t accept the government of their time in terms of their beliefs. They prayed to God and their prayers were answered in the form of ‘sealing of ears’ which is also regarded as deep sleep. However, this prevention of hearing is a clear indication that the people of the Cave are not dead. The next verses of this chapter talk about God waking them up to calculate how long they slept for and then they were put back to sleep. This illustrates the fact that sleep is something that can be initiated by God, in addition to the brain or other chemical changes that happen within the body following tiredness or some other influence. Not just putting someone to sleep (cessation of hearing in this example) but waking up someone as well to their full potential and senses can be managed by God. Other factors that are vital to the life of human being like energy from inside the body and external factors like air, have to be assumed to be provided by God during their sleep [14].

 

CONCLUSION

Having looked at the stages of sleep from a scientific perspective and the verses of the Quran relating to sleep, it can be concluded that resting and repair of human body most likely occurs during sleep. The Islamic belief is that God has designed the body in this way so that it can function to its optimum level. When there is less sleep, or quality of sleep is not good, or there are other deficiencies that affect sleep, certain disorders happen, and human health is impacted. According to the Sleep Foundation, sleeping disorders include Insomnia which is an ongoing difficulty to fall or remain asleep despite wanting to sleep and having enough time to sleep or Sleep Apnea which is a common sleep-related breathing disorder that disrupts breathing at night, or Narcolepsy which is a sleep disorder that makes people feel excessively tired during the day despite getting an adequate amount of sleep, or Excessive Daytime Sleepiness (EDS) which is described as extreme grogginess occurring almost every day, among others. [15]. These disorders can be prevented by following good sleep hygiene practices and the practices advised by Islamic scholars in the light of Quranic verses and narrations from Prophet Muhammad and the Imams (peace be upon all of them) [16].

However, Quran goes further in explaining that sleep is not just a function of human body that needs attention from a medical viewpoint. Sleep is considered as a blessing of God, among numerous other blessings. Sleep has been created specifically, among other functions of the body like input from senses to make decisions, food and drink to gain energy, digestive system and others, as God has knowledge of all things, and he is All-Wise. Sleep and what happens during sleep is something dependant on God. Every time we fall asleep there is a chance that we will not awake up if the time of death has arrived. Therefore, one must be careful of all actions during the day, which God is aware of and before falling asleep, remember God so the sleep results in the outcomes it has been created for. In his book, Fadhlallah Haeri quotes the Prophet saying that “My eyes sleep but my heart does not”. What this means is that one must think of their weakness and incapability while they are asleep and the fact that it is not in their will to either go to sleep or wake up from it. Whoever sleeps in the state that they have been headless with their obligations is at loss. Whoever sleeps after he has discharged his duties concerning obligatory and recommended prayers, and has carried out his responsibilities, sleeps a praiseworthy sleep [17].

 

REFERENCES

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2. National Institute of Child Health and Human Development (2019). About Sleep. [online] https://www.nichd.nih.gov/. Available at: https://www.nichd.nih.gov/health/topics/sleep/conditioninfo.
3. American Academy of Sleep Medicine, 2022
4. National Sleep Foundation, 2021
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8. Table 1 – Ismail, H. (2004). C Brief Communication Consciousness, sleep and death. A Quranic perspective. [online] Available at: https://nsj.org.sa/content/nsj/9/3/221.full.pdf [Accessed 30 Mar. 2025].
9. Publishing, H.H. (2024). Sleep stages and memory. [online] Harvard Health. Available at: https://www.health.harvard.edu/healthbeat/sleep-stages-and-memory.
10. Wasa’il, vol. 1, p. 177
11. Carskadon, M. A., & Dement, W. C. (2011). “Normal Human Sleep: An Overview.” Principles and Practice of Sleep Medicine.
12. Cambridge Dictionary (2025). drowsy. [online] @CambridgeWords. Available at: https://dictionary.cambridge.org/dictionary/english/drowsy [Accessed 30 Mar. 2025].
13. Commentary on Chapter 18 of Quran. al-islam.org/sites/default/files/singles/631-kahf.pdf
14. Bihar al-Anwar, Vol. 76, Hadith 20
15. Pacheco, D. (2024). Sleep Disorders | National Sleep Foundation. [online] Sleepfoundation.org. Available at: https://www.sleepfoundation.org/sleep-disorders.
16. Al-Hilli, M. (2024). Ten Islamic Recommendations Before Sleep. [online] Al-Islam.org. Available at: https://al-islam.org/media/ten-islamic-recommendations-sleep [Accessed 30 Mar. 2025].
17. Imam As-Sadiq (2017). Lantern of the Path. Ansariyan. Chapter on Sleep

Table 1

Ali Jaffri

March 2025 – London