"Su Wen's Theory of Regulating Qi and Spirit" says: "In winter and March, you must go to bed early and get up late, and you must hold the sun." Going to bed early nourishes the human yang and keeps the body warm; Get up late to fix yin essence, work at sunrise, avoid cold and seek warmth. In winter, most animals go out less and hibernate. Therefore, in winter, we should work and rest regularly, sleep more, stay up less, improve the yang, help the healthy qi and prevent the occurrence of "fever" in spring.

Tibet in spring, summer, autumn and winter is the natural law of the four seasons. Living in nature, human beings must adapt to the changes of the four seasons and adjust their spiritual activities in order to achieve the harmony between the human body and the surrounding environment, as well as people's mental and physical functions, so as to achieve the purpose of health preservation. Su Wen's Theory of Four Qi Tunes and Ginseng points out the way of keeping in good health between the four seasons, that is, "spring, heaven and earth are born, and everything is glorious." People should lie down at night and get up early, so that they have ambition. This is called keeping in good health. In summer, everything is gorgeous, so people should lie down at night and get up early, and never get tired of the sun, so that they will be lifeless. This is called raising longevity. The weather is urgent in autumn. People should go to bed early and get up early, and have fun with chickens. This is called harvesting: in winter, there is water and ice on the ground, which does not interfere with the sun. People should go to bed early and get up late, and their ambitions will be subdued only when the sun comes out. This is called "nourishing Tibet", which embodies the principle of "nourishing Yang in spring and summer and nourishing Yin in autumn and winter".