Natural one maybe. Humans are biological machines. We know how to replace hearts with artificial ones that can last years. Soon they may start lasting decades.

Natural one maybe. Humans are biological machines. We know how to replace hearts with artificial ones that can last years. Soon they may start lasting decades. We can replace many hormones with artificial ones. I do not see any reason we can’t learn how to replace other organs and systems. And in this case you may as well live 200+ years