Experts tell us that the essence of health preservation lies in balance, that is, promoting the body's balance and harmony with the external environment. Traditional health preservation has existed since ancient times. There are common sayings widely known and practiced by the public, such as "keep warm in spring and keep cool in autumn" and "eat radish in winter and ginger in summer." Therefore, to fulfill the service function of this section, today we invite experts to provide readers with specific practices for scientific health preservation in terms of eating, drinking, sleeping, and exercise.
Traditional health preservation is an important part of China's 5,000-year cultural tradition. Drawing knowledge from the treasure trove of traditional health preservation helps in scientifically maintaining a healthy body.
In fact, traditional health preservation is in our daily diet and daily routine. As long as the correct methods are mastered, every aspect of diet and routine can be a form of health preservation.
Here, we focus on the health preservation methods of eating, drinking, sleeping, and exercise.
Eating: Lightness and the Five Properties
Diet should be moderate and light. The *Huangdi Neijing* (The Yellow Emperor's Inner Canon) explains a principle: eating in moderation replenishes qi (vital energy), while overeating damages it; rich flavors damage qi, while light flavors replenish it. Laozi also said in the *Tao Te Ching*: overindulging in delicious food harms the stomach. Second, one must consider the properties of food and the body's needs. All edible things have a nature, which can be classified into five properties: cold, hot, warm, cool, and neutral. When the body is hot, one should eat cooling foods; when the body is cool, one should eat warming foods. For example, if the stomach is hot, one should eat cooling bananas; if the stomach is cool, one should drink warming ginger soup. Eating against these principles can lead to illness. For instance, from the Start of Autumn to the Autumn Equinox, the climate is dry and hot, and it is not advisable to eat pungent foods, as this can easily cause dryness and heat in the stomach and intestines, leading to symptoms like deafness and tinnitus.
Eating fruit appropriately provides nutrition, while eating it improperly can harm the body. When the spleen and stomach are weak with loose stools, do not eat fruit. When qi is abundant with dry stools, eat more fruit.
Drinking: Moderate Alcohol, Different Teas
Drinking alcohol should follow rules: first, moderation. Excessive alcohol that cannot be metabolized in time will damage internal organs. Second, be cautious about drinking baijiu (white liquor) from the Start of Spring to the Spring Equinox and from the Start of Autumn to the Autumn Equinox. Drinking baijiu during these two periods can easily cause internal dryness and heat.
Drinking tea is beneficial to health. One major function of tea is to remove impure qi. Drinking tea often can remove body odor. However, tea also comes in different varieties with different properties.
Green Tea: Cool in nature, suitable for people with a hot stomach.
Scented Tea: Tea scented with jasmine and other flowers. Jasmine is warm in nature, so drinking jasmine tea can warm the stomach for those with a cold stomach.
Black Tea: Warm in nature and aids digestion. Drinking it can help warm the stomach for those with a cold stomach. Oolong Tea: Combines the characteristics of green and black tea and is neutral in nature.
Sleep: Following the Rhythms of the Seasons
Traditional health preservation considers sleep to be the greatest form of nourishment. There are many common sayings: "A good night's sleep makes one full of spirit; a sleepless night leaves one exhausted." "A good night's sleep is like eating a hen." Why is sleep so important? It is what Laozi called "the interaction of yin and yang is the Tao." Nighttime sleep is for rest and recovery, conserving essence and strength; daytime work and study are the release of energy. Yin and yang are equally important, and neither can be missing.
The timing for both sleeping and waking should be scientifically determined. The first principle of health preservation in the *Huangdi Neijing* is "one must follow the four seasons and adapt to the cold and heat." Only by adapting to the changes of the four seasons in a year and living in harmony with the changing time and space can one benefit for life and health. The same applies to sleep and waking.
A year has four seasons, and so does a day. A year has twelve months and twenty-four solar terms; a day has twelve two-hour periods and twenty-four hours. A day is a microcosm of a year. Therefore, a person's daily rhythm should conform to the "spring, summer, autumn, winter" of a day. 9 PM to 3 AM is the winter of the day, called "Day Winter." 3 AM to 9 AM is the spring of the day, called "Day Spring." 9 AM to 3 PM is the summer of the day, called "Day Summer." 3 PM to 9 PM is the autumn of the day, called "Day Autumn."
9 PM marks the "Start of Winter" for the day. At 9 PM, heaven and earth sleep. If a person does not sleep, it is like playing a "tug-of-war" with heaven and earth. "Human strength cannot match heavenly power," and the result is that heaven will always win. Only when the body's rhythm aligns with the rhythm of heaven and earth can one "borrow heavenly power to supplement human power."
There are two situations for sleeping too late at night: one is being unable to fall asleep, and the other is being sleepy but forcing oneself to stay awake. Being unable to fall asleep is due to not allowing the yang qi to recede when it should. Autumn is about reaping; from 3 PM to 9 PM is "Day Autumn," and a person should gradually enter a state of reaping. "When yang qi is abundant, the eyes are open; when yin qi is abundant, the eyes are closed." If one engages in stimulating activities in the evening, the yang qi cannot recede, and yin qi cannot become dominant, making it difficult to fall asleep. The second situation is forcing oneself to stay awake, which is a misconception, not understanding the principle of "Day Winter" or the need to conform to the laws of nature.
Sleeping too late at night damages the qi of the gallbladder. In severe cases, it can lead to depression. The *Huangdi Neijing* states: "Qi strengthens the gallbladder." "The twelve organs all depend on the gallbladder." The period from 11 PM to 1 AM is the Zi hour, when the gallbladder meridian is most active. A person's gallbladder qi is replenished during sleep. If one does not sleep, the gallbladder qi is consumed, and in severe cases, it can lead to "timidity," which is what modern medicine calls depression.
9 PM to 3 AM is the optimal time for sleep for humans. Sleep during other periods cannot replace "Day Winter."
The time for waking up should also follow the seasons.
3 AM is the "Start of Spring" for the day, and 6 AM is the "Spring Equinox." Heaven and earth awaken at 3 AM, and the body's cells also wake up under the influence of this time and space. Waking up between 3 AM and 5 AM requires no further sleep; sometimes, trying to sleep again can make one more tired. If heaven is awake and a person does not get up, it is also a "tug-of-war," and a person cannot outlast heaven and earth. If one has not gotten up by 5 AM, by 6 AM ("Spring Equinox"), the spirit cannot emerge, leaving one feeling listless.
Some public officials often stay up late for work, which affects their health over time. This is because sleeping late at night consumes yang qi, and getting up late in the morning suppresses yang qi. This is called the "double suppression." Therefore, even if you sleep late, you should get up before 5 AM and take a nap at noon to prevent the "double suppression."
Furthermore, the bedroom for sleeping should not be too large, mainly to gather yang qi. Traditional health preservation emphasizes that doors and windows must be closed during sleep. Even in summer, do not sleep with a fan or air conditioner on. When a person falls asleep, a protective layer of yang qi forms on the body's surface. If wind blows this layer away, the body will replenish it. This cycle can drain the yang qi, leaving one feeling weak in the morning, with a sallow complexion and a head feeling wrapped in cloth. If it is too hot in summer, you can close the bedroom door and use the air conditioner to cool the room, then take a quick shower and go to sleep immediately. The cool air can last for over an hour, by which time you will be asleep. If you wake up feeling hot in the middle of the night, you can repeat this process.
Exercise: Moderate Movement and Morning Walks
Walking should also be dialectical. When walking, one should focus all one's energy on the legs. The spirit can mobilize qi; qi can mobilize essence and infuse it into the leg joints. The fluid flowing in the human body is called jin-ye. Jin is thin and permeates the skin; when the body is warm, it is excreted as sweat; when the body is cool, it is excreted through the urinary tract. Ye is thick and permeates the sinews and bones, lubricating the joints. If a person's energy is not on their legs while walking, the "human bearings"—the hip, knee, and ankle joints—do not get sufficient lubrication, and over time, the joints can be worn out.
Walking also requires managing intensity. "Life is in motion" is a common saying. If you add two more words, "moderation," making it "life is in moderate exercise," the saying becomes scientific. Walk when your legs feel light; rest when your legs are tired. Because tired legs are like a hot car engine; starting it again will wear out the components.
The best time for walking is in the morning. Morning is spring, and spring is about activity; the liver governs activity and corresponds to spring, controlling the sinews and meridians. Morning activity keeps the sinews and meridians supple.
It is not advisable to go for a walk after dinner. "Go out early and return late" is a familiar saying. Late is winter, and winter is about storage. Without savings, there is no capital to spend.
Spiritual Health Preservation
In winter, yin qi flourishes to its extreme, and yang qi wanes to its minimum before beginning to stir again. In winter, one should follow the changes of nature, keeping the spirit and emotions calm, tranquil, and free from desire, so that the qi and spirit are gathered inward. Because winter is a time of withered trees, fading grass, and falling snow, it can often make people feel melancholy. The best way to change this negative emotion is to participate in more recreational activities, such as dancing, playing chess, painting, practicing calligraphy, enjoying music, and visiting friends and relatives. This can eliminate the low spirits of winter, boost morale, and arouse people's passion for and yearning for life.