Follow your body’s daily cycle for good health

The Body Clock According to TCM

One should sleep and function following the seasonal changes in the length of day and night for optimal health. This idea is written in The Inner Canon of the Yellow Emperor (黄帝内经), a classic text of the Traditional Chinese Medicine (TCM), dated over 2000 years ago.  Another classic text for acupuncture, the Midnight-noon and Ebb-flow Doctrine (子午流注), describes how the body’s Qi (氣) affects the different organ system during the different time of the day.

The Chinese Biological Clock (Image source: Pinterest)

For example, during sleep, Qi flows inward to restore the body starting from the gall bladder from 11 pm to 1 am; in deep sleep, Qi is detoxing the blood in the liver from 1 am to 3 am; Qi is strengthening the lung between 3 am to 5 am to prepare one from getting up fresh in the morning. Between 5 to 7 am, our large intestine become active, and it is always a good idea to drink a glass of warm water upon waking to aim bowel movement [1]. As such, TCM always stresses on following the natural daily cycle of the body to maintain good health.

Circadian Rhythms: Modern Understanding of The Body Clock

The idea of a daily cycle that affects one’s physical, mental, and behavioural activities is no longer an abstract or mythical concept. Research of the past 30 years has found scientific evidence of biological clocks not only within the body but also within every cells, tissues, and organ that regulate their innate natural rhythms. Such rhythms are called “circadian rhythms” [2]. In fact, the discoveries of the working of biological clocks in plants, animals and humans, allowing them to adapt their inner rhythm to synchronize with the Earth’s revolutions has led to the award of the Nobel Prize in Physiology or Medicine to three American scientists, Jeffrey C. Hall, Michael Rosbash and Michael W. Young in 2017 [3].

The following diagram illustrates the typical circadian rhythm of a person.

Biological clock human
The human circadian rhythm example.

The circadian rhythm closely follows the light-dark cycles of the Earth’s revolutions and is associated closely with the fluctuation of the various hormones in the body. For example, melatonin, the sleep hormone, is triggered by darkness to induce sleep at night and stop producing in the morning. Cortisol, the stress hormone is the highest in the morning, around 7 am–8 am, to prepare the body for the stress associated with waking, Secretion of insulin which regulates the uptake of glucose is at its peak at 5 pm and decline to its lowest at about 4 am This is to facilitate the energy storage during active hours [4].   

Melatonin is triggered by darkness to induce sleep at night and stop producing in the morning.

Disruption of circadian rhythms can have negative health impacts. For instance, shift work that interrupts the normal sleep pattern is known to induce sleep deficiency, nervous system and hormonal imbalance, inflammation, impaired glucose metabolism, as well as dysregulated cell cycles [5]. Alcohol, jet lag, and stress are some other modern disruptors of circadian rhythms. Long-term disrupted circadian rhythms can lead to obesity, metabolic syndrome, type II diabetes, gastrointestinal dysfunction, compromised immune function, cardiovascular disease, excessive sleepiness, mood and social disorders, and increased cancer risk [5].

Working late can disturb your circadian rhythms leading to health problems.

Modern medicine is only starting to realise the power of the body’s circadian rhythms. In one study, patients with colon cancers are found to be more responsive to treatment when the chemotherapy is synchronised with their circadian rhythms. Whereas another study found that the risk of sustaining major post-surgery heart damage can be halved if the surgery is performed in the afternoon when one’s cardiovascular efficiency is high [6]. Chronotherapy, the study of the best time-of-the-day for the application of specific medicine, has shown promising results in many clinical trials but not yet widely applied. [7].

Chronotherapy is the study of the best time-of-the-day for the application of specific medicine.

Healthy Living Following Circadian Rhythms

How can we apply the knowledge of circadian rhythms to maintain good health? The first thing we need to do is to examine our lifestyle. Here are some important aspects of our lifestyle that needs to be in synchronisation with nature:

Maintaining a lifestyle in accordance to your circadian rhythm is the way to good health.

Sleep – maintaining a regular sleep-wake pattern following the daily light-dark cycle is important to keep the body healthy.  When sleep times are out of alignment, one may experience physical and social difficulties and have a higher risk of emotional distress [8].

Eat – eating meals in accordance to the circadian rhythms is a good way to maintain weight and glucose metabolism. One should eat at regular timing during the day and avoid taking food at night. Breakfast and lunch should provide higher energy than dinner [8]. In fact, over-night fasting for more than 12 hours is an ideal way to keep a healthy weight, improve insulin control, and achieve better cholesterol level [9].  

Avoid overeating at night. Dinner should be light and zesty.

Drink – keep the body adequately hydrated is important for health. Taking a large glass of warm water at wake according to TCM, sustain hydration during the day, while reducing water intake in the evening are definitely good ideas. The kidney is known to work at its best during our active hours [10].  Avoid alcohol drinking.

Work – avoid night-shift-work, burning mid-night oil, frequent jet-lag, and irregular work pattern that alternate between day work and night work. All these working patterns will create undue stress for the body and severely disrupt the circadian rhythms.    

Playing computer games late into the night is not the way to maintain good health.

Leisure – late-night partying, excessive indulge in computer games, and recreational drug uses are examples of leisure activities that may severely disrupt the circadian rhythms. In other words, anything fun that keeps you up all night is not good for your health.


The body operates optimally when the internal clock is in sync with the external environment. This ancient Chinese wisdom was expounded over 2000 years ago, only to be validated by science in terms of circadian rhythms in recent decades. Disruption of circadian rhythms can lead to many modern diseases including metabolic syndrome, type II diabetes, gastrointestinal dysfunction, compromised immune function, cardiovascular disease, and even cancer. Hence, it is wise to maintain a lifestyle in harmony with the body’s natural rhythms.

It is wise to maintain a lifestyle in harmony with the body’s natural rhythms.


[1]        为何下午3点要喝水?中医十二时辰养生法 | 脏腑 | 大纪元, (n.d.). (accessed March 27, 2019).

[2]        W. Huang, B. Marcheva, J. Bass, W. Huang, K.M. Ramsey, B. Marcheva, J. Bass, Circadian rhythms , sleep , and metabolism, J. Clin. Invest. 121 (2011) 2133–2141. doi:10.1172/JCI46043.rons.

[3]        2017 Nobel Prize in Physiology or Medicine, (n.d.). (accessed March 27, 2019).

[4]        D. Gnocchi, G. Bruscalupi, Circadian Rhythms and Hormonal Homeostasis: Pathophysiological Implications, Biology (Basel). 6 (2017) 10. doi:10.3390/biology6010010.

[5]        S.M. James, K.A. Honn, S. Gaddameedhi, H.P.A. Van Dongen, Shift Work: Disrupted Circadian Rhythms and Sleep-Implications for Health and Well-Being, Curr. Sleep Med. Reports. 3 (2017) 104–112. doi:10.1007/s40675-017-0071-6.

[6]        L. Peeples, Medicine’s secret ingredient — it’s in the timing, Nature. 556 (2018) 290–292. doi:10.1038/d41586-018-04600-8.

[7]        J.M. Selfridge, T. Gotoh, S. Schiffhauer, J. Liu, P.E. Stauffer, A. Li, D.G.S. Capelluto, C. V Finkielstein, Chronotherapy: Intuitive, Sound, Founded…But Not Broadly Applied, Drugs. 76 (2016) 1507–1521. doi:10.1007/s40265-016-0646-4.

[8]        S.M. Abbott, K.J. Reid, P.C. Zee, Circadian Rhythm Sleep-Wake Disorders, Psychiatr. Clin. North Am. 38 (2015) 805–823. doi:

[9]        R.E. Patterson, D.D. Sears, Metabolic Effects of Intermittent Fasting, Annu. Rev. Nutr. 37 (2017) 371–393. doi:10.1146/annurev-nutr-071816-064634.

[10]      D. Firsov, O. Bonny, Circadian rhythms and the kidney, Nat. Rev. Nephrol. 14 (2018) 626–635. doi:10.1038/s41581-018-0048-9.

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