I haven't seen any evidence, even anecdotal, that you can _damage_ yourself from too much meditation, in a way analogous to an elite athlete.

Bad technique can lead to problems like depersonalization, and people can get something like an addiction to jhanas - but as far as I know elite meditators simply get more and more "enlightened". In some cases this may lead them to join a monastery or become a hermit, but whether this is problematic depends on your point of view.