Liu Gongdu, the cousin of the Tang Dynasty calligrapher Liu Zongyuan, lived to be over 80 years old. At that time, the average age was only 40 years old, which was definitely a long life! Therefore, his health care experience is recorded in the Book of the Old Tang Dynasty: "I am good at recuperating my body. I am over eighty years old and have light steps. Or pray for it. I didn't have any skills at first ... my ears were at room temperature. In short, his secret of health preservation is: Qihai point must keep warm.

Qihai point is located at 1.5 inch below the navel, and the adjacent Guanyuan point, Shenque point on the navel and Mingmen point on the back corresponding to the navel are four important points related to Yang. The heat preservation of these parts is the maintenance of human yang.

Yang Qi in TCM refers to the function of the whole body. People who are weak and older have weak yang because of the decline of organ function. On the other hand, if you can keep your yang full, people will be less sick and more energetic.

"Qi Hai", "Guanyuan" and "Shenque" are all located in the abdomen and pelvis of human body. From the point of view of western medicine, this is the place with the richest blood vessels and the slowest blood flow. If you catch cold, the blood flow in the pelvic cavity will become slower, which will not only affect the function of organs in the pelvic cavity, including uterus, ovaries, intestines and kidneys, but also affect the smooth blood circulation of the whole body. This is also the reason why Liu Gongdu can live a long life as soon as he protects the "Qihai point", because he has grasped the key to TCM health preservation-protecting Yang.