The job of being the Avatar isn't an easy one, which means that the simple act of staying alive can very quickly become not that simple at all. Since the Avatars have such a target on their back and are often at the center of danger in the world, their lifespans are at risk of being cut short, and many died quite young. Being constantly put in perilous situations doesn't always lend itself to a long and happy life, and many of these heroes were well aware of that burden.
Even Aang, the lovable protagonist of Avatar: The Last Airbender, didn't live as long a life as he should have, passing away at the age of 66 due to complications from being frozen for 100 years. However, even that is a longer lifespan than a lot of the previous Avatars got, as Avatars like Kuruk or Wan died relatively young (in their 30s or 40s). However, there was one Avatar who lived an incredibly long life, becoming not only the oldest Avatar to ever live, but one of the oldest humans. This, of course, was Avatar Kyoshi, who not only lived a long life, but an interesting one.
What Is The Typical Avatar Lifespan?
Of the known Avatars that have had at least some information revealed about them in either The Last Airbender or The Legend of Korra, it seems that a majority of them die before they become elderly. The most common death age (again, mostly through educated guessing) appears to be somewhere in middle age. Roku is one of the few known Avatars who lived to be a bit older, about 70, and even Aang made it longer than some Avatars do, despite the fact that being trapped in the iceberg shortened his lifespan.
For a lot of the Avatars, like Wan and Yangchen, their exact ages when they died aren't known, but the generally accepted theory is that they made it to be middle-aged. It's not surprising that so many of these Avatars didn't get to live their life as fully as others might, as the stress of their position and the constant danger they would find themselves in would certainly take a toll on a person. The average lifespan of most non-Avatar citizens seems to be about the same as in real life - 80's or 90's, usually. There are, of course, people who lived for much longer, like King Bumi of Omashu who lived to be well over 100.
How Long Did Avatar Kyoshi Live For?
Avatar Kyoshi lived for significantly longer than any other Avatar, or even any other person, making it to age 230 before she died. This fact, of course, has led a lot of fans to wonder how she was able to live for so long. The answer is actually that Kyoshi was taught immortality. After Kyoshi was revealed to be the Avatar, she joined a group of criminals called the Flying Opera Company, the leader of which - Lao Ge, a famous assassin - taught her the secret to immortality, as well as the skills required for assassination. He taught her a lot about spirituality, which is how he was able to achieve immortality.
Lao Ge claimed that by keeping order in his body, he was able to extend his life, far past what a normal human would live for. According to him, the aging process was simply the body falling out of order as it began to break down, and so by repairing the damage, they could restore their body and live longer. Lao Ge did this through a specific type of concentrated meditation, looking over his body and putting every small part that needed it back into order. Essentially, he was able to stop the process of aging through pure mental force, though he could still be killed by other means, such as in battle. A person employing this method would also have their body stay in the same state, obviously, so they would retain a youthful appearance through all of their years until they either stopped the process or were killed by other means.
Kyoshi used this method herself, which is how she lived to be over 200 years old. There is no specific event that led to her death, and it seems that she just died peacefully. This, of course, would mean that she chose to stop her meditation and allow her body to age naturally once again. What would lead a person who had the secret to eternal life to give it up? Well, the biggest downside to immortality is the fact that not everyone has it, so Kyoshi would have had to watch all of her closest friends and family, including her daughter, Koko, age and pass on without her. It's possible that she got tired of this cycle and wanted to join them, deciding that her purpose had been served and she had lived for long enough already.