In the universe, human life activities are closely related to nature. This perspective, which examines the physiological phenomena of the human body in conjunction with the natural world, is a unique aspect of ancient Chinese culture known as the “Correspondence between Heaven and Man”. Therefore, the Huangdi Neijing states: “Between heaven and earth, within the six harmonies, the qi of the nine continents and the nine orifices, the five organs, and the twelve joints are all connected to the weather.” The so-called four seasons refer to spring, summer, autumn, and winter. Health preservation, also known as nurturing life or self-cultivation, is an important principle proposed under the guidance of the TCM thought of “Correspondence between Heaven and Man”. It is also a significant aspect of TCM preventive medicine. Seasonal health preservation involves nurturing life, growth, harvest, and storage throughout the four seasons. This means adjusting one’s daily activities, diet, and emotions according to the changes in the yin and yang of the seasonal climate, thereby aligning the human body with the changes in the natural environment to achieve health and longevity. Adjusting Daily Activities with the Seasons In nature, the four seasons exhibit characteristics of spring warmth, summer heat, autumn coolness, and winter coldness, and living organisms correspondingly undergo changes of spring birth, summer growth, autumn harvest, and winter storage. The human body should adjust its daily routines in accordance with the changes in nature. In spring, during the three months, yin diminishes and yang increases, and all things flourish. One’s daily activities should align with the springtime growth characteristics, which means “going to bed late and rising early” to nurture vitality; failing to do so may harm the liver, leading to summer heat. In summer, during the three months, the climate is hot, and yang energy is at its peak. One’s daily activities should be “going to bed late and rising early, without being weary of the sun” to nurture growth energy; failing to do so may harm the heart, leading to autumn fevers. In autumn, during the three months, yang diminishes and yin increases, all things mature, and the climate gradually turns cold. One’s daily activities should focus on nurturing harvest, thus one should “go to bed early and rise early, rising with the rooster”; failing to do so may harm the lungs, leading to winter diarrhea. In winter, during the three months, plants wither, and all things are stored away. Winter daily activities should focus on nurturing stored energy. Therefore, one should “go to bed early and rise late, waiting for the sunlight”, to dispel cold and preserve yang energy; failing to do so may harm the kidneys, leading to spring weakness. In summary, maintaining regular daily activities can preserve one’s spirit, as the saying goes, “Regular daily activities nurture the spirit.” Otherwise, it may affect health and longevity. Seasonal Dietary Adjustments According to the properties of food, preparing different foods for different seasons is called “seasonal diet”. “In spring, the air is warm, so it is advisable to eat more wheat to cool down; in summer, the air is hot, so it is advisable to eat legumes to counteract the heat; in autumn, the air is dry, so it is advisable to eat sesame to moisten; in winter, the air is cold, so it is advisable to eat millet to treat the cold with its warming properties.” In spring, when the climate is warm, one should eat light foods. It is customary to eat spring pancakes made of bean sprouts, eggs, and leeks on the day of the beginning of spring to align with the spring growth energy. On ordinary days, one should consume light foods such as glutinous rice, yellow beans, walnuts, sesame, eggs, black fungus, shiitake mushrooms, bok choy, and celery. One can also use mild herbs for nourishment, such as Taizi Shen (Pseudostellaria), Gan Cao (Licorice), and Feng Mi (Honey). In spring, the liver is emphasized, with sour flavors benefiting the liver and sweet flavors benefiting the spleen. One should eat less sour food, which benefits the liver’s dispersing function; excessive consumption can lead to excessive liver qi harming the spleen and stomach. It is advisable to eat more foods like yam and jujube, which are sweet and mild, to prevent the liver wood from overpowering the earth, hence “reduce sour and increase sweet in spring to nourish spleen qi”. In summer, when the climate is hot, one can eat light and easily digestible foods such as poultry, eggs, and dairy products. It is also good to consume yogurt to enhance appetite. Additionally, one should eat more vegetables and fruits, such as eggplant, tomatoes, cucumbers, winter melon, loofah, watermelon, lychee, and bayberry. “In summer, reduce bitter and increase pungent to nourish lung qi”. During summer, heart fire is at its peak, with bitter flavors entering the heart and pungent flavors entering the lungs. Excessive consumption of bitter flavors can exacerbate heart fire and suppress lung metal. It is advisable to eat more pungent foods like ginger and garlic to nourish lung qi, hence the saying, “Eat radishes in winter and ginger in summer, no need for a doctor’s prescription”. During the long summer (Xiao Shu, Da Shu), which is characterized by humidity and transformation, the climate is marked by continuous rain and pervasive dampness. Dampness affects the spleen, so one should focus on nourishing the spleen by eating foods that strengthen the spleen, such as mung beans, coix seeds, white lentils, lotus seeds, and lily bulbs. Vegetables and fruits should include winter melon, bok choy, loofah, asparagus, celery, tomatoes, cucumbers, apples, and bananas. One can use herbs like lotus seeds, lotus leaves, loofah, hawthorn, and sand ginger to awaken the spleen and aid digestion. “In long summer, reduce sweet and increase salty to nourish kidney qi”. Long summer belongs to earth, which is strong and overcomes water, so one should not overeat sweet foods to avoid harming kidney water. Salty flavors enter the kidneys, so it is beneficial to eat some salty foods to protect kidney qi. In autumn, the focus is on harvesting and dryness, which can easily damage body fluids, leading to symptoms like dry throat, dry nose, and cracked lips. Therefore, it is best to eat foods that generate fluids and moisten dryness, such as sesame, eggs, legumes, cabbage, apples, bananas, pineapples, and grapes. One can also use herbs like lily bulbs, radix adenophorae, polygonatum, and ophiopogon. “In autumn, reduce pungent and increase sour to nourish liver qi”. Pungent flavors enter the lungs, and sour flavors enter the liver. Excessive consumption of pungent foods can lead to liver disease. Therefore, it is important to control pungent foods like chili peppers and eat more sour foods to benefit liver qi. In winter, all things are stored and dormant, and the body’s qi and blood tend to close and store. The diet should focus on warming and nourishing, hence it is said that “food supplementation comes first in winter”. However, winter supplementation should be tailored to the individual. For those with yin deficiency, symptoms include soreness in the lower back and knees, and five hearts feeling hot. It is advisable to eat cooling and sweet foods such as rabbit meat, duck meat, sesame, white fungus, pears, and sugarcane. Herbs can include Sheng Di (Rehmannia), Bai Shao (White Peony), Tian Dong (Asparagus), Mai Dong (Ophiopogon), Sha Shen (Glehnia), Bai He (Lily), and Yu Zhu (Polygonatum). For those with yang deficiency, symptoms include cold extremities, pale complexion, and clear, prolonged urination. It is advisable to eat warming foods such as dog meat, lamb, deer meat, and longan. Herbs can include dried ginger, deer antler, aconite, cinnamon, and morinda. For those with qi deficiency, common symptoms include pale complexion and fatigue. It is advisable to eat qi-tonifying foods and herbs such as jujube, maltose, yam, ginseng, codonopsis, and Bai Zhu (White Atractylodes). For those with blood deficiency, symptoms include pale complexion, pale lips, palpitations, insomnia, and women experiencing scanty menstruation. It is advisable to eat longan, lotus seeds, and jujube. Alternatively, one can use Ejiao (Donkey-hide Gelatin), Shu Di (Rehmannia), Dang Gui (Angelica), He Shou Wu (Fo-Ti), Bai Shao (White Peony), and Ziheche (Cordyceps) to nourish blood. “In winter, eat more black foods”. Black is the color of water and corresponds to the kidneys. All black foods have a nourishing effect on the kidneys, such as black rice, black soybeans, black sesame, black dates, black fungus, black mushrooms, kelp, sea cucumber, nori, black-boned chicken, squid, turtle, and tortoise, which can be chosen for consumption in winter. “In winter, reduce salty and increase bitter to nourish heart qi”. Salty flavors enter the kidneys, and bitter flavors enter the heart. Excessive salty consumption can weaken heart yang, so it is advisable to reduce salt and increase bitterness, and to eat some bitter foods like kale and bitter tea to nourish heart qi. In summary, dietary choices must be made based on the seasonal climate changes, the different properties of foods, and individual physical conditions to be beneficial for health. Adjusting Emotions with the Seasons Emotions refer to anger, joy, thought, sadness, and fear, also known as the five emotions. Normal emotions are generated by the five organs; for example, the liver generates anger, the heart generates joy, the spleen generates thought, the lungs generate sadness, and the kidneys generate fear. Thus, the Neijing states: “Humans have five organs, which transform five qi, giving rise to joy, anger, sadness, worry, and fear.” Abnormal emotions are referred to as the seven emotions, which can affect qi dynamics and damage the five organs. For instance, anger can cause qi to rise and harm the liver, joy can cause qi to slow and harm the heart, worry and thought can cause qi to stagnate and harm the spleen, sadness can cause qi to dissipate and harm the lungs, and shock and fear can cause qi to descend and harm the kidneys. Therefore, one should adjust emotions according to the seasonal changes of yin and yang to maintain inner peace, vitality, and prevent disease. In spring, during the three months, this is a time of emergence, when the qi of heaven and earth is born, and all things flourish. One’s emotions should be kept inward; one should not become angry, and maintain a state of “do not kill, do not take, reward without punishment”, with thoughts and body relaxed to align with the spring growth energy. In summer, during the three months, this is a time of flourishing, when the qi of heaven and earth interacts, and all things blossom. One’s emotions should be joyful, avoiding impatience and anger, and one should think, “if what is loved is outside”, “do not be weary of the sun”; this way, one can keep emotions smooth to align with the summer growth energy. In autumn, during the three months, this is a time of balance, when the weather becomes urgent and the earth qi becomes clear, and the climate gradually turns dry, especially in late autumn when plants wither, creating a scene of desolation, which can easily lead to feelings of melancholy and irritability. Therefore, one should maintain a calm mind to alleviate the harshness of the season. In winter, during the three months, this is a time of closure and storage, when water freezes and the earth cracks, and one should keep emotions quiet and inward, thinking “as if there are private intentions, as if there are gains”; this way, one can avoid the invasion of cold qi. Adjusting to Cold and Warmth with the Seasons Throughout the year, as the climate changes between cold and warm, people should appropriately adjust their clothing, which is called adjusting to cold and warmth with the seasons. It is said, “In spring, cover up; in autumn, freeze, to avoid miscellaneous diseases”. “Spring covering” means that when the temperature just begins to warm in spring, one should not remove winter clothing too early; otherwise, if the temperature drops again, it will be difficult to adapt, easily leading to illness. It is especially important to cover the navel, as the navel belongs to the Ren meridian; for women, if wind and cold invade through this area, it can lead to menstrual pain and other gynecological diseases. Additionally, one should cover the back, as the back houses the Du meridian, which governs all yang energies; thus, protecting yang energy requires covering the back. Furthermore, one should cover the feet, as the feet have many acupoints and are the starting and ending points of the foot yang and foot yin meridians, which are connected to important organs like the liver, spleen, and kidneys; if the feet are cold, it can affect the function of these organs. “Autumn freezing” means that in autumn, when the temperature is slightly cool, one should not add clothing too early; appropriate cold stimulation can increase one’s ability to withstand cold. Moreover, as the season begins to change, the temperature is unstable; adding clothing too early can lead to sweating and catching a cold when the temperature rises again. Adjusting Yin and Yang with the Seasons Balancing yin and yang is a prerequisite for human health, hence it is said, “When yin is balanced and yang is secret, the spirit is treated.” Adjusting yin and yang according to the four seasons is key to maintaining the balance of yin and yang in the body. Therefore, one should nourish yang in spring and summer, and nourish yin in autumn and winter. Nourishing yin and yang encompasses many aspects. In terms of health preservation, nourishing yang in spring and summer means following the characteristics of the spring and summer climate to nurture life and growth; nourishing yin in autumn and winter means following the characteristics of the autumn and winter climate to nurture storage and concealment. For example, in seasonal diets, one increases sweet and pungent flavors in spring and summer, as sweet and pungent are yang, hence nourishing yang; in autumn and winter, one increases sour and bitter flavors, as sour and bitter are yin, hence nourishing yin. Furthermore, nourishing yang in spring and summer lays the foundation for nourishing yin in autumn and winter (yin is rooted in yang); nourishing yin in autumn and winter lays the foundation for nourishing yang in spring and summer (yang is rooted in yin). Nourishing yang in spring and summer utilizes the natural yang energy of growth in spring and summer to warm the body’s yang, known as “treating winter diseases in summer”. Nourishing yin in autumn and winter utilizes the natural yin energy of storage in autumn and winter to nourish the body’s yin, known as “preventing summer diseases in winter”. Thus, it is stated, “If one does not store essence in winter, one will surely fall ill in spring”, and “If one is harmed by cold in winter, one will surely fall ill in spring”, indicating that in autumn and winter, it is essential to preserve essence and qi. In summary, the changes of yin and yang through the four seasons are an eternal law of nature, and seasonal health preservation is a fundamental principle of health maintenance. “Therefore, the wise in health preservation must follow the four seasons, adapt to cold and heat, harmonize emotions, and adjust yin and yang; in this way, evil will not approach, and one will achieve longevity and vitality.”
