Traditional Chinese medicine believes that qi is running on the human body surface, and qi is like a guardian outside the human body, called Wei Qi. Defending qi is the fixation of yang, which constantly transports and walks on the surface of human body. Stephy walks in the sun of the human body during the day; At night, you walk in the yin point, that is, you walk in the yin meridian. As soon as the yang enters the yin meridian, people want to sleep. Wei Qi walked through the Yin Meridian. When he left the Yin Meridian, people would wake up. This is the explanation of sleep mechanism by Chinese medicine.

Reference-Qu Limin talks about health from head to toe