The Holy Quran and the Circadian Rhythms and Shift Work


أَلَمْ يَرَوْا أَنَّا جَعَلْنَا اللَّيْلَ لِيَسْكُنُوا فِيهِ وَالنَّهَارَ مُبْصِرًا ۚ إِنَّ فِي ذَٰلِكَ لَآيَاتٍ لِّقَوْمٍ يُؤْمِنُونَ

“Do they not see that We made the night that they may rest therein and the day sight giving? Indeed in that are signs for a people who believe.” (Al Quran 27:86/87)

Written and collected by Zia H Shah MD, Chief Editor of the Muslim Times

In 1802, Sir Humphry DavyPresident of the Royal Society (1820-1827), invented the first electric light. He experimented with electricity and invented an electric battery. When he connected wires to his battery and a piece of carbon, the carbon glowed, producing light. His invention was known as the Electric Arc lamp. And while it produced light, it didn’t produce it for long and was much too bright for practical use.  The electric bulb, one of the everyday conveniences that most affects our lives, was not “invented” in the traditional sense until 1879 by Thomas Alva Edison, he could be said to have created the first commercially practical incandescent light.

Devoting nights completely to work was not possible until the electric bulbs became common place.

The alternation of day and night is mentioned in 37 places in the Quran, and several instances consider the succession of night and day to be a sign of the greatness of the Creator and a subject to be studied by those who believe or are given wisdom. One verse says: “Do they not see that We made the night that they may rest therein and the day sight giving? Indeed in that are signs for a people who believe.” (Al Quran 27:86/87)

The Quran emphatically claimed that the night was for rest and day for work and could have simply become outdated in the 20th century if a large human population had conveniently chosen to work at night without any negative consequences, but, it was not to be, for the Quran is the word of All Knowing God.

The holy Quran claimed that in the study of the alternation between night and day are signs for the men and women of wisdom, which in modern expressions we will say the insightful scientists and the study will be called circadian rhythm science.

A circadian rhythm is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria, which are primitive bacteria and don’t have a nucleus.[1]

The term circadian comes from the Latin circa, meaning “around” (or “approximately”), and diēm, meaning “day”. The formal study of biological temporal rhythms, such as daily, tidal, weekly, seasonal, and annual rhythms, is called chronobiology. Processes with 24-hour oscillations are more generally called diurnal rhythms; strictly speaking, they should not be called circadian rhythms unless their endogenous nature is confirmed.[2]

Although circadian rhythms are endogenous (“built-in”, self-sustained), they are adjusted (entrained) to the local environment by external cues called zeitgebers (from German, “time giver”), which include light, temperature and redox cycles. In medical science, an abnormal circadian rhythm in humans is known as circadian rhythm disorder.[3]

In 2017, the Nobel Prize in Physiology or Medicine was awarded to Jeffrey C. Hall, Michael Rosbash and Michael W. Young “for their discoveries of molecular mechanisms controlling the circadian rhythm” in fruit flies.[4]

Those who work at night and sleep during the day, a large majority of them suffer from what has been described as shift work sleep disorder.

The symptoms of shift work sleep disorder include:

  • Excessive sleepiness when you need to be awake, alert, and productive.
  • Insomnia, or the inability to sleep when you need to. This can mean trouble falling asleep, or waking up before you’ve slept sufficiently.
  • Sleep that feels unrefreshing or insufficient
  • Difficulty concentrating
  • Lack of energy
  • Irritability or depression
  • Difficulty with personal relationships

In the U.S., about 8.6 million people perform shift work, whether they have a night job or rotate shifts during the week. For many, it’s a rite of passage in their careers; for others, it’s a financial necessity. But there’s a growing sense that shift work could be taking a serious toll on their health.”There is strong evidence that shift work is related to a number of serious health conditions, like cardiovascular disease, diabetes, and obesity,” says Frank Scheer PhD, a neuroscientist at Harvard Medical School and Brigham and Women’s Hospital in Boston. “These differences we’re seeing can’t just be explained by lifestyle or socioeconomic status.” Shift work is also linked to stomach problems and ulcers, depression, and an increased risk of accidents or injury.

The Quranic expression of night for rest and day for work is for humans, otherwise there is a long list of animals that are nocturnal and for whom converse is applicable. The list is reproduced from Wikipedia in the references.

In conclusion I want to quote a couple of other verses of the Quran about night and day phenomena or circadian issues:

And He it is Who has made the night a covering for you, and Who has made sleep for rest, and has made the day for rising up. (Al Quran 25:47/48)

And among His Signs is your sleep by night, and day for your seeking of His bounty. In that surely are Signs for a people who hear. (Al Quran 30:23/24)

Indeed in the alternation of night and day, and in all that Allah has created in the heavens and the earth there are Signs for a God-fearing people. (Al Quran 10:6/7)

And He has also subjected to you the sun and the moon, both performing their work constantly. And He has subjected to you the night as well as the day. (Al Quran 14:33/34)

The prophet Muhammad, may peace be on him, said that the best among you is the one who learns the holy Quran and teaches it. If you like what you read please go ahead and share with the friends and family or on the social media.

Additional Reading

Cataloging 750 verses of the Holy Quran inspiring believers to study nature


Known nocturnal animals

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