Why does health and longevity become an important symbol of a well-off society?

National fitness is the foundation and guarantee for all people to enhance their physique and live a healthy life. People's health is an important connotation of building a well-off society in an all-round way and an important foundation for everyone to grow up and realize a happy life. The World Health Organization puts forward that "health is a good state of physical, mental and social adaptation, not just the absence of disease and weakness". Among the top ten new health standards, two are obviously related to people's mental health. One is "optimistic, positive, willing to take responsibility, no matter big or small, not picky", pointing to people's emotional health; The other is "strong adaptability to various changes in the external environment", that is, people have good social adaptability.