1. Emperor asked: I have heard that many people in ancient times lived to a hundred without showing signs of aging. But today people look old at the age of fifty. Is it because times have changed or because people are not following proper ways of preserving health?

2. Qi Bo answered: People in ancient times were aware of the ways to preserve health. By following the ways of yin and yang, they were moderate in eating and drinking and scheduled time for work and rest. So both their body and spirit are healthy and they lived to a ripe old age. But people today are different. They have no set time for work and rest. They drink a lot, and after they get drunk they indulge in sexual intercourse. To frequently use your energy excessively and indulge in temporary pleasures transgress the ways of preserving health. Therefore, they get old at fifty. Learn more about the theory of Chinese medicine, please read TCM Theory of Prevention.