I do not understand someone who will go to all the money and time of making their house handicapped accessible but they won’t spend the same amount of money and time on making their body less likely to become handicapped. Sure, there are accidents that happen but generally the biggest reason that people become disabled is because they stop taking care of themselves.
Being infirm is not a natural part of becoming older. It is a natural result of stopping taking care of yourself. If you don’t use it you will indeed lose it.
There is no reason that older means less fit. Less active means less healthy, yes. Being active shouldn’t be something that just young people do. Being active is something that people should do. If you stop working, it doesn’t mean you stop moving. You don’t have a reason to anymore – so you have to make up reasons. Volunteer. Go to the Y. Garden. Stay active, or you’ll become immobile.