I have to quibble with some text from Matt Ridley's otherwise awesome book Genome (1999). On page 201 he writes
Natural selection cannot weed out genes that damage the body in post-reproductive age, because there is no reproduction of the successful in old age.
The idea behind this is that natural selection works through gene propagation by those most able to reproduce. The phrase "survival of the fittest" (not Darwin's, by the way) is a bit misleading-- it doesn't really matter how well or how long you survive, only how much you reproduce. So if a person can no longer reproduce, then having great lungs in old age, or having crappy lungs in old age, it doesn't matter; it can't affect evolution.
So goes my thinking, anyway. Note that I am not an evolutionary biologist.
Pictured is Simon, the Ocelot who out-competed Alexander's genetic ass!
Ridley, M. (1999) Genome. The Autobiography of a Species in 23 Chapters. HarperCollins.