The Horary Cycle and our Body’s Natural Rhythms

The following article has been translated and adapted from a posting on 中国中医网.

In Ancient times, the Chinese separated the day into 12 periods of time based on the motion of the sun through the Heavens, each two hours in length. Each individual period became intimately associated with one of the 5 zang/6 fu organs, its corresponding meridian and its physiological functions. Below are further details of this system as it relates to human physiology and basic suggestions for promoting health through proper daily rhythm.

The Zi Period, 子时: Maintaining Yang Qi through Sleep
11pm to 1am is the period when Yin energy is at its height. Yin energy directly correlates to the physiological process of sleep. Therefore, we should be soundly asleep during this period. Just getting into bed during these hours, reading, watching television, or struggling to fall asleep is not an efficient use of this time.

The Gallbladder meridian is most active during the Zi period. According to the law of transformation of Yin and Yang (extreme Yin produces Yang; extreme Yang produces Yin), the gallbladder is responsible for giving birth to the first Yang energy of the 24 hour cycle. This Yang energy in its infantile state is highly vulnerable. Therefore, we must protect and allow it to grow through proper sleep.

The Niu Period, 丑时: Production of Blood by the Liver
1am to 3am is the period when the liver is most active. The liver, and its corresponding meridian, are responsible for stimulating new growth, further strengthening the Yang qi released by the gallbladder. The liver carries out its physiological functions of filtering toxins and producing blood during this time. Extensive clinical observation has shown that many patients who suffer from liver disease are fond of staying up late into the night. This deprives their liver of adequate opportunity to complete its tasks, and over time, leads to illness.

The Yin Period, 寅时: The Ideal Time for Measuring the Pulse
The morning from 3am to 5am is known as the “peaceful dawn”. During this time, the energy of the Heavens is approaching a state of equality; the relative state of Yin and Yang begin to come into balance. The lungs are most active during this period. As the day begins to break, the pulses most accurately reflect the state of the individual. One can note whether the pulse is stiff or tight. For those over 40 with a stiff pulse, there is a high correlation with high blood pressure; for those in their twenties or thirties with a tight pulse, it is likely that they are under a great deal of stress at work or suffering from a heightened level of general anxiety. A pulse that is both stiff and tight is known as a “wiry” pulse, often characteristic of high cholesterol and arteriosclerosis.

The Mao Period, 卯时: Drink a Glass of Water, Clear the Body of Toxins
The large intestine is most active during this period from 5am to 7am. It is important to begin the day at this time with a glass of warm water on an empty stomach. This is particularly effective for individuals who suffer from chronic constipation. As the energy of the large intestine begins to grow stronger, the water helps act as a catalyst to stimulate peristalsis, thus eliminating toxins from the body. The toxins contained within our stool compose about 50% of the total toxins of our entire body. The Mao period represents “the opening of the heavenly gate”, corresponds to the second month of the lunar calendar, when life, fueled by the growing force of Yang energy, emerges from the Earth, thus making it the ideal time for vacating the bowels.

The Chen Period, 辰时: Balancing the Nutrition of the Morning Meal
The stomach is most active during the Chen period, from 7am to 9am. We should take out morning meal at this time, thus making use of the abundant energy of the stomach. Breakfast should include some form of animal-based protein, including eggs or other breakfast meats.

The Si Period, 巳时: The First Optimal Period for Work or Study
9am to 11am is the time dominated by the spleen. The spleen is responsible for assimilation and transport of nutrients. This is the period of the day when brain activity is at its peak, making it the first ‘golden’ period of the day, ideal for study or work. However, this productivity and effectiveness is dependent upon having eaten a healthy breakfast. The spleen processes and assimilates food digested by the stomach, converting it to the energy that drives our various physical and mental activities. It is also the best time of the day for seniors to exercise.

The Wu Period, 午时: A Quick Nap to Fortify Yang Qi
The Heart channel is most active during this period from 11am to 1pm. During this time, we should follow lunch with a brief period of rest. According to the principles of transformation of Yin and Yang, Yang energy has reached its apex. The NeiJing tells us that Yin is associated with the interior and sleep, while Yang governs the exterior and waking hours. Therefore, by following the midday meal with a brief period of rest, we can further this transition of Yang to Yin. This is especially important for Yang deficient people to fortify their Yang energy with a longer period of sleep. For the rest of us, a half hour of rest should be sufficient to protect the Heart energy and Yang qi.

The Wei Period, 未时: Protect Blood Vessels by Drinking Water
1pm to 3pm is the time of the Small Intestine. At this time, the small intestine completes the absorption and assimilation of nutrients from digested food matter. The blood stream is now laden with the nutritional building blocks of life, a state somewhat analogous to the crowded streets of rush hour traffic. At this time, we should drink a glass of warm water or tea in order to help dilute the blood and promote circulation. This can help protect vessel walls from the excessive strain of nutrient-rich blood.

The Shen Period, 申时: The Second Optimal Period for Work or Study
The period from 3pm to 5pm is the second golden period for concentration of the day, when the urinary bladder is most active. The small intestine has completed its assimilation of nutrients and made them available for consumption by the brain, making it easier to carry out high-concentration oriented tasks.

The You Period, 酉时: The Best Time for Preventing Kidney Trouble
The kidneys are most active during the You period, from 5pm to 7pm. Drinking another glass of warm, clear fluids at this time assists the kidneys in filtering toxins from the body, helping prevent afflictions such as kidney stones and bladder infections.

The Xu Period, 戌时: The Third Optimal Period for Work or Study
The period from 7pm to 9pm is governed by the pericardium. At this time in the day, the heart energy relaxes into an eased flow, ushering in the third golden period for work or study of the day. It is also an ideal time to go for an after-dinner walk or get in some other form of exercise. As the pericardium hour draws to a close, finish it off with another glass of water or non-caffeinated tea to maintain proper circulation.

The Hai Period, 亥时: Preparing to Rest
The SanJiao, or triple burner, is most active during the hours of 9pm to 11pm. At this time, our day should slowly begin to draw to a close. Computers, TV’s and cell phones should slowly be retired for the day to allow the mind time to settle into a restive state. It is an ideal time for pleasure reading, enjoying some light music, quiet meditation, or sharing intimate time together with a partner.