The second reason is that they began to believe in western medicine, and they realized that some diseases can be cured faster with western medicine, especially those emergencies. When Kangxi was in office, it became a common practice to stay up late every day because of the heavy workload. Kangxi also realized that his physical condition began to decline, so Kangxi began to pay attention to health, eat on time every day, stay up as little as possible, and pay attention to rest.

At the same time, he gave up many unnecessary drugs and bad habits, and later he started vaccination, which greatly reduced the fate of premature death due to smallpox.

The third reason is that they begin to believe in science, respect the laws of nature, and no longer believe in the concept of immortality. In ancient times, many emperors tried their best to live forever. Most emperors found some people to help him make elixir of life.

There is no way to live forever. The best way to live forever is to believe in science and get the right treatment when you are sick. No matter whether this method is Chinese or western, as long as it is cured, I think it is the best method. Kangxi made the greatest contribution to the introduction of western medicine. Without Kangxi's consent, many people in our country might have died of chickenpox.

The fourth reason is that both Kangxi and Qianlong have a normal mind, and they can correctly face the fact that they are getting old. At the same time, they also understand that birth and death are natural laws, as long as they let nature take its course.