Washing our hands has become one major way to protect ourselves from Covid-19. However, ablutions have always had a central place in the practices and beliefs of many religious traditions. Christians perform baptism with water, in amounts varying from small sprinkles to larger vessels, to bring about purification, cleanliness, revival, and rebirth. Jesus’ washing the feet of his disciples as narrated in the Gospel makes the washing of feet an important practice in Christianity to promote cleanliness and is still carried out to this day. The Jewish tradition also has many instances of ablution where water is specifically used to promote cleanliness, including washing hands to reclaim or preserve purity and mikveh in which the feet or whole body is immersed in water.

The Islamic ablution, also known as “wudhu,” contains 24 washing movements to be carried out several times a day for the five daily prayers. If performed for all five prayers, it would consist of about 120 repeated actions as Muslims washed parts of their body.

A lover must undertake the required preparation to cleanse and beautify oneself before meeting with their Beloved. Likewise, a believer is required to wash specified parts of their body to stand before God in supplication, as instructed in Chapter Maidah of the Qur’an, verse 6: “O believers, when you stand for prayer, wash your faces, and your hands up to the elbows, and wipe your heads, and wash your feet up to the ankles. If you are unclean, bathe and purify your bodies fully. But if you are ill or in the middle of travelling or … you cannot find water, then take wholesome dust and wipe your faces and hands with that. For God does not wish to burden you, rather He desires to purify you and to complete His blessing and favor upon you so that, perhaps, you may be grateful” [5:6].

The spiritual cleansing that the act of wudhu provides is highlighted by the Prophet Muhammad (pbuh) in numerous hadiths, or prophetic sayings, which has been collected under The Book of Purification. While water literally cleans the face and limbs, with every pure intention to do wudhu, the water droplets that meet the body also wash away the minor sins that were committed by the hands, mouth, face, ears, and feet. The famous hadith that “cleanliness is half of faith” [Sahih Muslim, 223] can be interpreted as applying primarily to doing wudhu in one translation [Wudhu: Fiqh, Rules, Purification and Blessings, Qadri]. Therefore, to perfect the faith, to be cleansed of our mistakes continuously, God has given us a simple mechanism through which to be purified and recalibrated countless times in a day.

Many of us perform this pattern of washing with little thought. It has become a routine that we seldom consider a medical protection that we apply to our body. Besides its effects on the soul, washing also has wonderful effects on the body. Over fourteen hundred years ago, the Prophet (pbuh) advised ablution before going to bed. Interestingly, yoga experts in recent years have also started to encourage the washing of the legs, hands, arms, eyes, and the mouth before sleep with cool water for a deeper undisturbed sleep. This is not surprising considering the relief that comes with the touch of water on a busy day.

Three of our principal systems benefit from wudhu; the circulatory system, the immune system, and the electrostatic balance of the body. In this way, the health benefits from the ritual of washing are threefold…

Circulatory system

The circulatory system is a magnificent circuit of blood vessels between the heart and the tissues that make up every other system of the body. The systemic circulatory system circulates oxygenated blood from the heart to the tissues around the body and back to the heart, whilst the pulmonary circulatory system transports deoxygenated blood to the lungs for detoxification and returns clean blood to the heart. The correct functioning of the blood vessels, which act as wires that connect our major organs, are essential to the efficiency of this circuit. These vessels divide into thinner branches called arterioles which in turn split into smaller capillaries which surround the cells of the body. The vascular resistance generated by blood vessels is overcome by the blood pressure generated by the heart to enable blood flow. Over time (due to ageing, or a diet high in fat), our blood vessels often harden and become constricted meaning that the heart has to work harder to overcome increased vascular resistance to maintain steady blood flow. The vessels in the limbs are the most peripheral to the heart and thus the most vulnerable to the process of hardening and narrowing over a long period.

The application of water in our daily routine “exercises” these blood vessels by alternately contracting and dilating them. Water can act as an agent of temperature gradients, thereby affecting the thermoregulatory response of the cutaneous circulation. When hot, water ensures that vessels in the limbs dilate, and when cold, that they contract. In this way, water ensures the flexibility of vessels distant from the heart, forcing nutrients deposited in tissues as a result of poor circulation back into the bloodstream through a temperature gradient.

Lymphatic system

The lymphatic system, on the other hand, is probably not the first to come to mind when we think of the body’s organ systems. Yet without this quietly working system our cardiovascular system would collapse and our immune system would be impaired. Our lymphatic vessels transport “leaked” blood fluids into our capillaries to prevent the accumulation of fluid in the interstitial spaces and eventual tissue damage. The vessels of the lymphatic system are much thinner than those of the cardiovascular system, ensuring the circulation of white blood cells which have an essential role in protecting the body against invaders and resisting disease. It is this fluid that we see oozing out when we have a cut or wound.

The optimal functioning of this system and its thin vessels, like those of the circulatory system, can be said to be closely linked with the effect of washing. The phagocytes and lymphocytes, which make up the immune system are housed by our lymphoid tissues and organs, are supported by the act of wudhu. The nasopharyngeal region behind the nose leads to the tonsils, which are small masses of lymphoid tissue that trap and remove pathogens that are entering the throat. Washing the mouth and nose three times with every wudhu therefore helps to remove the bacteria that builds up in the region of the body most exposed to the external environment. Moreover, the act of washing both sides of the neck during wudhu stimulates our cervical lymph nodes – a specialized mass of tissue which houses lymphocytes and particularly helps to protect the body by removing bacteria and tumor cells from lymphatic circulation. Our lymphocytes are arguably the most important component of our immune system, patrolling every point of the body many times a day and destroying cancer cells and pathogens along the way. Considering that the act of wudhu enhances the filtration effect of our lymphoid circulation, one can see the blessings that come with the divine command to “wash…and purify your bodies fully….”

Electrostatic balance

Our physiology is also closely related to the electrostatic balance of the body. While many psychosomatic diseases result from electrostatic imbalance, the most pronounced effect of static electricity is exerted on the subcutaneous muscles located under the skin, mitigating their function and inducing the onset of wrinkles which often start in the face. Maintaining the regular habit of washing the skin – particularly the face which is most frequently exposed to ultraviolet radiation – protects the surface and internal layer of our skin cells by constantly dampening the skin surface with clean water. It is a much simpler alternative to spending hundreds and hundreds of dollars on expensive skin care and makeup products to maintain a healthy complexion.

In regards to how wudhu can benefit our electrostatic balance, the part of the verse which sheds light to tayammum, “if you cannot find water, then take wholesome dust and wipe your faces and hands with that” highlights that the water substitute for wudhu significantly reduces static electricity, like water. This is why when wudhu is performed calmly with care, it often leaves one feeling refreshed and discharged.

The Quran is a grand source containing many prescriptions for good health. While every civilized person may wash their face and hands throughout the day, wudhu ensures that cleanliness and a sense of well-being is sustained by virtue of its association with worship. The worth and significance of wudhu is not limited to the medical benefits discussed here. However, for anyone else wondering why taking a pause on a busy day with wudhu feels so rejuvenating, I hope this humble article sheds some light to a grand prescription from among the many medicines revealed in the Qur’an.

By examining the heart of a crocodile, researchers have discovered how it is that an air-breathing land animal can manage to glide through murky waters for several hours without the need to surface.

There is that one scene in documentaries that we often come across on television: Crocodiles gliding gracefully inside the water, waiting for hours for the perfect time to pounce and snatch their prey from their necks and into the water. But how do these animals manage to stay underwater for almost two hours without surfacing for air even though they, just like human beings and other land animals, live on pulmonary respiration and are in need of the free oxygen in the air?

A member of the reptiles class, crocodiles do not have gill nor can they have skin respiration since their skin is covered with a thick and airtight keratin armor. Just as every living organism are provided with a suitable anatomic and physiological character for their survival, crocodiles are also granted with a system that facilitates their long stay in the water.

Crocodiles are bestowed with a special heart anatomy different to other reptiles like lizards, tortoises, and snakes. The hearts of other reptiles are designed to contain three sections including two atriums and one ventricle. The right atrium, which collects the returned oxygen-deprived (deoxygenated) blood and the left atrium which collects the oxygen-rich (oxygenated) blood retrieved from pulmonary arteries of the lung, transports the blood to one common ventricle. Because there is only one ventricle to receive and combine oxygenated and deoxygenated blood, a mixture of less oxygenated blood is pumped to their body. Depending on outside temperature, the body temperature of a reptile increases or decreases. Their metabolism slows down, almost to a halt, while their body temperature decreases when outside temperature drops near or beyond freezing conditions. Hibernation begins as a result. Frogs and reptiles stop hibernating as soon as their body temperature increases depending on the outside temperature when the weather gets warm. These organisms are called cold blooded animals (with variable body temperatures) because of this feature.

The heart of a crocodile is different to other reptiles in that it has four chambers just like birds and mammals. Blood is sent to the lungs for gas exchange from the right, and from the left ventricle it is pumped to the body. Thus the two types of blood do not mix in the heart. However, what is interesting is that blood is mixed as soon as it leaves the heart via a valve (foramen of panizza) placed in between the right and left aorta.

What could be the purpose of blood, which does not normally mix in the heart, mixing through the medium of a hole? Does this opening in between two aortas indicate a flaw? It is understood after some research that this hole in fact is not a flaw or an anomaly; on the contrary, it is a necessity for a metabolism suited perfectly to the lifestyle of the crocodile.

Warm blooded vertebrates like birds and mammals with a four chamber heart have faster metabolic speeds and higher blood pressures. For these organisms can only supply the energy they consume during their daily activities via such a fast metabolism and a high level of oxygen provided with oxygenated blood.

If the metabolism of a crocodile was fast like mammals all throughout the year, it would have to continuously be nourished and use oxygen. Furthermore, because crocodiles do not have much predators, they could have also lead to the extinctions of some species by overpopulating if they featured a faster metabolism. The low ratio of heart-body mass in crocodiles (0.15%) compared to mammals and birds (0.40%-0.50%) cause the movements of crocodiles to be relatively slower. The Almighty, who creates everything with his wisdom, lowers the blood oxygen ratio and the metabolic speed of crocodiles by creating a valve that combines the two aortas. Thus eliminating the possibility of crocodile overpopulation.

Crocodiles have two aortic arches whereas mammals only have a left, and birds have one right aortic arch. The left aortic arch, despite some contact with the returned blood via foramen of panizza, delivers the oxygenated blood towards intestines, stomach, spleen and the liver after receiving it from the left ventricle of the heart. This is because the digestive system of a crocodile requires oxygen-rich blood. Deoxygenated blood while exiting the right ventricle goes towards the pulmonary arteries of the lung for exchange and mixes with oxygenated blood coming from the right aorta, feeding other organs that are instrumental for its slow metabolism.

Under the water, separated oxygen-rich and oxygen-poor blood mixes when exiting the heart and switches route, thus making oxygenated blood vessels start to carry oxygen poor blood. So what is the reason behind this switch in the direction of the bloodstream under the water? See at this point, the extraordinary features of the crocodile blood circulation system kick in. The two anatomical features belonging only to only crocodile hearts is what enables them to stay under water without breathing. Because of little or no lung use under the water, a big portion of the blood stream is diverted away from lungs; therefore oxygen poor blood is pumped back to the body. As one feature of the two, foramen of panizza restricts (does not close) upon signals coming from nostril sensors under the water but expands and remains open on land. The two aortic arches connects with each other via foramen of panizza as soon as they leave the heart but merge completely in the lower parts of the body away from the heart (anastomosis).

The second feature stems from a serrated valve. Refilling of pumped blood is stopped via a passive, thin leaf-shaped valve which is located at the tip of the pulmonary artery exiting the right ventricle. Thus, one-way direction of blood flow in the heart is maintained. These valves, which carry nodules made of connective tissue, constrict during the dive and blood flow to the lungs is reduced greatly. Therefore blood rejoins the systemic circulation from the right aortic arch.

The blood circulation of crocodiles is similar to birds, mammals, and humans while they are active on land. Oxygen-deprived blood is sent to lungs for gas exchange. The only difference is the turning of the right aorta to the left and the left aorta to the right. Oxygen rich blood not only flows through the left aorta but also through the right aorta via foramen of the panizza as well causing distribution via two channels into the body. However, the foramen of the panizza being open is not sufficient for these two channels to be used. At the same time, the pressure of the blood within the left ventricle needs to be higher as well. This way, high pressure oxygenated blood flows into the right aorta through the opening of the panizza, applying pressure to the valve at the tip of the right aorta to close it in order to prevent the mixing of the oxygen-poor blood into this route. As a result, oxygenated blood gets distributed quickly by each aortic arch without mixing with the used blood. Thus, oxygen-poor and oxygen-rich blood follows the following route on land

* Deoxygenated blood: Body – superior and inferior pulmonary veins – right atrium – right ventricle – lung pulmonary artery – lungs.

* Oxygenated blood: Lung pulmonary vein – left atrium – left ventricle – right aorta and left aorta via panizza valve (both aortas are active) and body.

The opening of the panizza narrows with the help of signals coming from the nostrils when crocodiles submerge. At the same time serrated valves at the tip of pulmonary artery that transports the blood to the lungs also constrict. While this serrated valve is at work, a majority of the blood returning from the body is not sent to the lungs because they are not functioning at the time. This serrated valve also increases the pressure of the right ventricle. This pressure, along with elevated resistance in pulmonary circulation and lowered pressure of systemic circulation, leads to the opening of normal valves at the tip of the left aorta. In the end, the left aorta which normally carries oxygenated blood on land starts carrying oxygen deprived blood, and there is a route switch.

The most beneficial part of this switch is to re-route the deprived blood back to the body via a different route, that is, the left aorta. This by-passes the lungs and prevents time loss. Despite the fact that blood of the left aorta mixes with the oxygenated blood of the right aorta to some degree via the panizza valve, the main function of this opening while submerged is to supply blood flow to the arteries feeding the heart and brain through the transfer of some poor blood from the left aorta into the right aorta; this way vital organs are not left without blood.

Blood returning from the body is not sent to the lungs for gas exchange when crocodiles are under the water. However, existing oxygen in the blood can be delivered to the tissues quickly by a route switch. The amount of bicarbonate ions that is important in the transport of CO2 in the blood increases when oxygen pressure in the tissues drop. Anaerobic respiration of tissues increases. This leads to an increase in lactic acid levels and reduces pH. Eventually, it facilitates the release of oxygen carried by hemoglobin. In the end, oxygen that is bonded with hemoglobin is used more efficiently. In the meantime, the body temperature of a crocodile submerged under water decreases and slows down its metabolism, reducing the need for oxygen. Oxygen stored in the blood can be sufficient up to two hours under the water. However when these reserves are consumed, crocodiles have to resurface to breathe even though it may cost a prey to escape.

Crocodiles can live on land and in the water and adapt to their environments with ease and efficiency thanks to the ponderous working of their mechanisms under water, the change in blood circulation, slow blood flow, reduced body temperature and metabolic speed bestowed upon them. Just like humans in sleep, crocodiles can remain submerged for long periods (4-6 minutes in usual dives; up to 2 hours when pressed) with this perfect system granted to them. Crocodiles use these mechanisms not only when under water, but also while resting or for periods after heavy feeding.

O believers, when you stand for prayer, wash your faces, and your hands up to the elbows, and wipe your heads, and wash your feet up to the ankles. If you are unclean, bathe and purify your bodies fully. But if you are ill or in the middle of travelling or … you cannot find water, then take wholesome dust and wipe your faces and hands with that. For Allah does not wish to burden you, rather He desires to purify you and to complete His blessing and favour upon you so that, perhaps, you may he grateful.[5:6]

Here is a grand prescription from among the many marvels of the Qur’an. The day will come when even non-Muslims will imitate the Muslim wudu or washing before prayer, a privilege and favour Muslims have enjoyed for more than fourteen hundred years. And they have done so, more or less, unawares, as it is only through the discoveries of biologists in the last twenty years that we have come to understand fully the wonderful effects of wudu. The three principal benefits that human health derives from washing are related to the circulatory system, the immune system, and the electrostatic balance of the body.

a) The circulatory system

The circulatory system is twofold. First, the heart pumps blood out to the tissue cells in every part of the body. Second, it collects back the biologically used blood. If this reverse circulation in particular is disturbed, diastolic blood pressure increases and ageing, even the onset of death, may be precipitated.

The healthful condition and functioning of the blood vessels is essential to this twofold circulatory system. Blood vessels resemble flexible tubing, dividing into thinner branches as the distance from the heart increases. If the thinner tubes in particular become hardened and lose their elasticity, pressure and workload upon the heart are increased. This is known in medical jargon as arteriosclerosis.

Various aspects of our lives cause the blood vessels to harden and become constricted. This problem, considered to be the basis of ageing and bodily deterioration, is now a distinct field of medicine on its own. Improper nutrition and nervous reactions can have a serious effect on the condition of the blood vessels. If sclerotic development is observed in a blood vessel, what practical measure can be taken against it?

The hardening and narrowing of blood vessels does not happen all at once, but over a long period. The vessels furthest from the heart, such as those in the brain, feet and hands, are more vulnerable to the process which begins slowly in these locations and goes on continuously with the passage of time. However, there is an application in our daily routine which, in a sense exercises blood vessels by alternately contracting and dilating them. Its agent is water, which gives rise to temperature gradients. Water ensures flexibility and visor of vessels distant from the heart by dilating them when hot and contracting them when cold. It also forces nutrients, deposited in tissues as a result of sluggish circulation, back into the bloodstream by virtue of the temperature difference.

In view of these facts, is it possible to understand the verse commanding Muslims to wash the hands, feet and face in the wudu rite as anything short of a marvel, particularly in the light of the conclusion of the verse: He desires to…. complete His blessing and favour upon you. Circulation of the blood is a favour to us from the Creator. The command to do wudu completes that favour by maintaining the blood vessels and the circulatory system generally in a healthy state. This is the first of the many blessings of wudu. It is impossible to deny the fact that washing protects against senility which is the way the hardening of blood vessels reflects on the circulation in the brain of a person who has been doing wudu regularly since childhood.

b) The immune system (lymphatic circulation)

In addition to the circulation of red blood cells in the body, there is also the circulation of white blood cells or leucocytes. The vessels of this system are ten times thinner than those which conduct red blood cells. We sometimes see its colourless fluid oozing from the skin walls in some abrasions or wounds. It is this lymphatic circulation which keeps all points of the body within the protection of the immune system. Any bacterium, alien object, or cancer cell (the cause of which is not known), which may have invaded the body is destroyed by the warrior cells or leucocytes in the lymphatic circulation. The appearance of an infectious disease or cancer in the body is always contingent on the malfunctioning of the immune system.

Exactly how this system of vessels expands and contracts has not yet been fully clarified. It is known, however, that heat and cold influence the system. Catching an infectious disease such as a common cold is ascribed to the inability, due to contraction of these vessels, to dispatch leucocytes in sufficient numbers to the afflicted area. Now the proper functioning of this system and its thin vessels, like that of the circulatory system in general, is closely linked with the invigorating effect of washing. The structure of the immune system, which provides resistance against all diseases, is reinforced through the wudu, and the divine favour mentioned in the verse is realized.

Now someone might claim that, while the lymphatic system is indeed invigorated by washing, it is just a coincidental and unintended side effect. However, the precise form of the command to do wudu disposes of this incorrect claim. I would argue, on the contrary, that the way in which the wudu is commanded to be done specifically aims at the lymphatic system as well. The reasons are as follows:

1. For the lymphatic system to function properly, even a single point in the body must not he neglected, which is assured by the full ablution or ghusl.

2. The most important centre for stimulating the lymphatic system is the nasopharyngeal region behind the nose and tonsils, and washing these spots is especially enjoined.

3. Stimulation of both sides of the neck has great influence on the lymphatic system, and this is also present in the wudu.

The most formidable warrior cells of the body, the lymphocytes, are transported to the farthest reaches of the body and, after passing through intensive biological training, patrol each point in the body many times a day. If they meet a bacterium or a cancer cell, they destroy it. Is this not a divine blessing of the first quality? If a circulatory disorder occurs once in a while and you are able to avert or mitigate its effect by means of regular wudu, is it not proper to regard the command as the promised fulfilment of divine favour for which mankind are required to give thanks?

c) Static electricity

The body normally has a balance of static electricity, and the physiology of a healthy body is closely related to this electrostatic balance.

Atmospheric conditions, as well as plastic clothing and products common in our time can adversely affect this balance. Painful illnesses, irritability and facial wrinkles are the best-known results. Most of us have become aware of this electricity when climbing out of a car or after sitting in a plastic chair. Stormy weather has a comparable effect. Healing by acupuncture and, in certain respects, physiotherapy, can redress this imbalance of static electricity; but we can avoid the effect entirely, simply by doing the wudu several times a day.

There are many psychosomatic illnesses arising from electrostatic imbalance. I shall not dwell on these here. I shall address only the question of skin care, which has become such a fashionable subject now.

The worst influence of static electricity is exerted continually on the small subcutaneous muscles (under the skin), finally rendering them inoperative, which is why wrinkles set in, starting with the face, though the skin is affected over the whole body. At this point, many of my readers will have divined at least one of the reasons for the radiant appearance of those who have done wudu all their lives. Whoever maintains the habit of regular washing inevitably has the more healthy, and therefore the more beautiful, skin. How remarkable it is that in our time, when millions are spent on cosmetics, a tenfold increase in expenditure would still not properly substitute for simple washing.

Doubtless, the sceptic will ask, but does wudu really have anything to do with static electricity?

Of course it does. The part of the verse pertaining to tayyamum when water is not available for wudu, underlines the fact. For this substitute for wudu also disposes of static electricity to a significant extent. Indeed, the importance of it has hitherto gone unrecognized, and no-one has tried to explain why, tayyamum can take the place of wudu when the necessity arises.

As the verse clearly states, the sanitary aspect of wudu is a great blessing which we can now partially explain in medical terms. A person might well say: But I already wash my face and hands anyway. Let us recall, however, that as a widespread public habit, this practice has a very short history (barely seventy years or so) even amongst nations who have a tendency to claim to be the most civilized in the world. More important, cleanliness based on a sort of general good advice can never be sustained with the steadiness of discipline which, in Islam, it has by virtue of its association with worship.

To be sure, the worth and significance of wudu does not end with these medical observations the sense of well-being and dignity derived from wudu also contribute to the general health of the practising Muslim but here my aim has been to make widely known precisely those additional medical benefits.