1. I think we should first rule out non-scientific factors (for example, The Romance of the Three Kingdoms says that Monroe was chased by Guan Yu). The living and medical conditions in ancient times were worse than those in modern times, and the average life expectancy was not long. Death in middle age is very common.
2. The career of Commander-in-Chief is a hard job, which involves both military affairs and politics, especially facing two major rivals. Overwork is easy to damage health.
3. At that time, the development of Jiangnan was low, the economy was backward compared with the north, and the climate was hot and humid, which was not conducive to people's health from a medical point of view.
In fact, to put it simply, in the troubled times of the Three Kingdoms, everyone is nothing more than a way to die: being killed (including dying in battle), dying of illness and starving to death. It is impossible for senior officials to starve to death. Since you haven't been killed, you should die of illness, hehe. Not only the three of them, but also Lu Xun died of illness, hehe.