Circadian Rhythms are found everywhere, from humans to fungi and cyanobacteria. Circadian rhythms are physical, mental, and behavioural changes that follow a daily cycle. We might not know but a lot of common activities depend on these circadian rhythms. For instance, the reason that we sleep at night and are awake during the day is a light-related circadian rhythm.
A Class 11 student of National Public School, Koramangala, Samay Godika at the Breakthrough Junior Challenge this year brought back the ultimate INR 2.9 crore science prize on his explainer video on the science of circadian rhythms, called ‘the body clock’. Here is a deep dive into the science behind these biological clocks called circadian rhythms.
Are Circadian Rhythms Same As Biological Clocks?
Circadian rhythms are found in most living things except for a few exceptions, such as animals, plants, and many tiny microbes. The study of these systems is called chronobiology. Both, circadian rhythms and biological clocks are related, but they are not the same. Diverse biological processes, from global haemodynamics to intracellular protein levels depict distinct temporal oscillations with a period of 24 hours between one peak and the next. One of the most important differences is the timescale. Biological clocks may refer to different time scales from years to seconds, whereas circadian rhythms only refer to the 24 hour rhythms. They respond primarily to light and darkness in the living being’s, and are controlled in the brain structure called the suprachiasmatic nucleus (SCN), which is a master clock that controls and synchronises in the brain and is a group of around 20,000 brain selles in the hypothalamus. They are controlled by the fluctuating levels of different signal molecules in our cells and these are called biological clocks.
Why Are Circadian Rhythms Important?
In 1700’s, French scientist Jean-Jacques d’Ortous de Mairan recorded the first observation of an endogenous, or built-in, circadian oscillation in the leaves of the plant Mimosa pudica. Even in total darkness, the plant continued its daily rhythms. This led to the conclusion that the plant was not simply relying on external cues, or zeitgebers, but had its own internal biological clock to rely on.
Circadian rhythms are important in determining the sleeping and feeding patterns of all animals, including human beings. There are clear patterns of brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle. There has also been research suggesting lack of sleep and the consequent disruption of circadian rhythms in the development of obesity and depression, as well as most chronic diseases. Studies even show that a lack of sleep may have unexpected side-effects like not being able to read facial expressions. It is also one of the reasons that you experience jet lag. When there is a different time zone while travelling, the biological clocks will be different from the local time.
“Metabolism is impacted by the body’s circadian rhythm, the biological process that the body follows over a 24-hour cycle. So the time of day we eat can have a big impact on the way our body processes food,” says Professor Daniela Jakubowicz, MD, of TAU’s Sackler Faculty of Medicine had said. A research also suggest that these clocks are important for for regulation of the cardiovascular system.
Understanding what makes biological clocks tick may lead to treatments for sleep disorders, obesity, mental health disorders, jet lag, and other health problems. It can also improve ways for individuals to adjust to nighttime shift work. Learning more about the genes responsible for circadian rhythm will also help us understand biological systems and the human body. Bottomline is that these clocks contribute a lot to the human health and should hence be given more importance in studying.