Breathing is accompanied by a person's life. In people's life, not only food is important, but also qi is very important to our life. The earliest existing medical literature in China, Huangdi Neijing, said: "Qi is the foundation of human beings, and people will be born if they get qi, sick if they get qi, and dead if they lose qi." Qi, called Qi in ancient times, is the most basic energy and physiological function that constitutes the human body and maintains life activities. The "essence, qi and spirit" of human body is based on the cultivation of "qi", and through the correct breathing method, we can adjust our body, breath and heart, improve and strengthen the operation of qi in human body, and eliminate turbid qi, so as to achieve the purpose of strengthening our body and prolonging our life.

Huangdi Neijing analyzes the concept of nourishing qi and breathing with life as the core from the viewpoint of "the universe of heaven and earth is big and the universe of human body is small". Neijing said: "Yin and Yang are the way of heaven and earth, the rules of all things, and the parents of change." The book talks about the relationship between heaven and man, taking yin and yang as the main axis, and points out that the general principle of health preservation lies in "using yin and yang as the method and using skill numbers." Then, in order to thoroughly understand respiratory health, we must further explore the true meaning of yin and yang. Because, from the evolution of heaven and earth to the changes of the four seasons; The rise and fall of qi and blood and the length of life are all manifestations of the rise and fall of yin and yang.

Now the medical community believes that the key to human health lies in maintaining "internal balance". The steady state of human internal environment is a necessary condition for cell survival, and spirit, physical strength, sleep and appetite are signs of human health. Therefore, we must adjust the human body's steady state from these four aspects, which is the fundamental way out for the recovery of chronic diseases and sub-health status. In other words, the key to the "steady state" of life and health lies in the balance of yin and yang inside and outside the body. However, the adaptive adjustment of life homeostasis, all medical means are not omnipotent, and the real cure of diseases depends on our own self-regulation ability. Neijing says that "hyperactivity is harmful, heredity is controlled, and control is biochemical", which means that the yin-yang and five elements must restrict each other in order to maintain the balance between them, neither too much nor too little, otherwise it will be harmful. As the saying goes, "life is tangible and inseparable from yin and yang." If the yin and yang in the body are out of balance, the vitality on which the human body depends will be chaotic, which will eventually damage our health.

What is the essence of yin and yang? Huangdi Neijing said: "Yang turns into Qi and Yin." This is the most basic attribute of yin and yang. Let me talk about it first: negative molding. Yin, this kind of energy, often turns into material form, and the form of everything in the world is formed by Yin, including the human body. Yin dominates quietness, and its basic attribute is "solidity". Based on the principle of opposition between Yin and Yang, Yang takes the initiative, and its basic attribute is "gasification", which tends to change into ethereal energy. The combination of "solidified yin" and "vaporized yang" is the combination of static and dynamic, thus creating a state of balance between yin and yang. Neijing said: "Yang in Yang is also the heart, Yin in Yang is also the lung, Yin in Yin is also the kidney, Yang in Yin is also the liver, and Yin in Yin is also the spleen." This is the reason why yin and yang correspond. "Yin Pingyang is the secret, God is the rule, Yin and Yang are separated and refined." Yin and Yang are energy of opposite nature. In our healthy state, Yin and Yang are interdependent, mutually restricted and in a stable state of mutual balance. The essence of human existence is composed of yin and yang. If yin and yang are separated, the structural balance of essence and qi is broken and the balance relationship is destroyed, then diseases will follow.