Remember those days when you could make back to back plans with your gang? Be it a late-night movie, a party, or a study session, you could just do it all without breaking your back or suffering from a sore neck the next day. If you must have noticed as you grew older, nearing your late 20s, sleeping well before midnight is what keeps you on track – energetic, motivated, and most importantly not tired. Well, chances are that is your circadian rhythm at work! 

The study of circadian rhythm is attributed to the field of chronobiology. Chronobiology is the study of biological rhythms and is heavily based on the effects of time on internal events and internal biological clocks. 

The National Cancer Institute defines Circadian Rhythm as, ‘the natural cycle of physical, mental, and behavior changes that the body goes through in a 24-hour cycle. Circadian rhythms are mostly affected by light and darkness and are controlled by a small area in the middle of the brain. They can affect sleep, body temperature, hormones, appetite, and other body functions. Abnormal circadian rhythms may be linked to obesity, diabetes, depression, bipolar disorder, seasonal affective disorder, and sleep disorders such as insomnia. Circadian rhythm is sometimes called the “body’s clock” 

Healthline states that ‘your circadian rhythm helps control your daily schedule for sleep and wakefulness. This rhythm is tied to your 24-hour body clock, and most living things have one. Your circadian rhythm is influenced by outside things like light and dark, as well as other factors. Your brain receives signals based on your environment and activates certain hormones, alters your body temperature, and regulates your metabolism to keep you alert or draw you to sleep’ 

National Institute Of General Medical Sciences explains, ‘circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. These natural processes respond primarily to light and dark and affect most living things, including animals, plants, and microbes. Chronobiology is the study of circadian rhythms. One example of a light-related circadian rhythm is sleeping at night and being awake during the day’

The study of circadian rhythms has been conducted over a long period of time, just under different terms and conditions. But just like all phenomena related to Chronobiology, there is certainly crucial information and guidelines that one must know about, pertaining to why and how it affects people of all ages. 

1. In 2017, 3 researchers funded by the National Institute of General Medical Sciences won the Nobel prize for researching circadian rhythms by studying, observing, and analyzing fruit flies. Fruit flies share similar genetic makeup to that of human beings, wherein they isolate a gene to control the body’s clock. The 3 scientists proved that this gene produces protein overnight and then breaks down the next day. This process in turn affects normal bodily functions of the body – sleeping, sharpness of the brain, hunger, and so on. 
2. Many bodily parts and components make up an individual’s biological rhythms and the circadian rhythm is one of such biological rhythms. The prime example being their brain cells responding light and dark, letting the eyes capture environmental changes in the surroundings. That is exactly how your body knows when it is time to be awake and fall asleep. 
3. Hormones like Melatonin and Cortisol are one of the key elements of a person’s circadian rhythm. Their levels may vary. Cortisol is produced extensively during the day and melatonin is released in large amounts at night facilitating a feeling of sleepiness. 
4. Metabolism, body temperature is also based quite a lot on the circadian rhythm. Temperature decreases when we are not awake and metabolism keeps changing during the course of the day. Thus metabolism and body temperature form a vital part of an individual’s circadian rhythm. 
5. Other factors like working hours, lifestyle choices, surroundings, and habits also influence circadian rhythms. It is of extreme importance to live a life in a balance of physical and mental activities to achieve the optimum benefits of one’s circadian cycles. 
6. Newborns do not develop a circadian rhythm till they reach to be a few months old, as a result, their sleeping schedules are quite disruptive in the very first few weeks of their life. This may also result in crying, being cranky, and moody at times. Healthline says that ‘toddlers and children have a fairly regulated sleep schedule once their circadian rhythm and corresponding body functions mature. Children need about 9 or 10 hours of sleep a night’
7. Adults face tiredness the most between 2 AM to 4 AM and 1 PM to 3 PM during the day. Melatonin is released every night in a fully grown adult’s body and hence, it is advised to get at least 7 to 9 hours of sleep during night time, especially for this particular hormonal release to be entirely fruitful. Though with age, the levels keep decreasing and increasing at great lengths, causing aged persons to sleep earlier during night time. 

It is of vital importance to be responsive to one’s circadian rhythms to lead a hale and hearty life, devoid of fatal complications. It has a direct effect on our sleep cycles, which are crucial to our normal bodily functions.