As our body gets older it starts to work less efficiently - the same is true for cats. Your cat's heart or kidneys may not work as well as they once did or your cat may develop an overactive thyroid gland (hyperthyroidism). Your vet will be able to help you manage these conditions as long as they see your cat before the disease becomes too advanced. If you are concerned about the health of an older cat make an appointment to see your vet as soon as possible.