[wtetzner]

> Because evolution trends toward living long enough to reproduce.

I'm not sure it's that simple. Given that humans tended to live in tribes, it was in the tribe's best interest if people were healthy and vital beyond reproduction, for hunting, protection, care of young, passing on wisdom, etc.

> People often die of heart disease once they're old enough they weren't having kids (although exceptions certainly exist).

There are cultures where heart disease is nearly unheard of. So I don't think this explanation is very satisfying.