As early as the Spring and Autumn Period and the Warring States Period, people have recognized the important role of mental conditioning in medical care, and put forward many specific methods of conditioning. For example, Lao Tzu put forward the views of "simplicity but not simplicity, less thinking and less thinking" and "virtual but motionless, static and unchanged" Zhuangzi pointed out that "if you are simply indifferent, you can't be worried, and evil spirits can't attack, then your morality is complete and God doesn't lose". Confucius believed that "benevolent people live long" and "virtuous people live long", and emphasized the importance of moral cultivation for providing for the aged. Neijing systematically established the theory and method of mental conditioning on the basis of inheriting the thought of health preservation of pre-Qin philosophers. Since then, it has been continuously enriched and improved. Sun Simiao in the Tang Dynasty put forward twelve principles of "thinking less, thinking less, wanting less, talking less, laughing less, worrying less, being happy less, being angry less, being good less and being evil less". Important documents in the past dynasties include Tao Hongjing's Record of Nourishing and Prolonging Life in the Liang Dynasty, Chen Zhi's Letter of Supporting the Aged in the Song Dynasty, and Wang Jue's Taiding Health-keeping Theory in the Yuan Dynasty. There are also Peng Zu's theory of keeping in good health and keeping in good health, the secret of longevity in history, needless to say, Shen Jiashu's recuperation in Qing Dynasty, and You Cheng's compilation of Shou, etc.