Arthritis affects nearly half of people 65 and older, but experts say you mitigate its effects by moving. Head to Alexandria’s Chinquapin pool any Tuesday or Thursday morning and you will see a group of mostly older women chatting and laughing. They’re in the Aquatic Exercise for Seniors class, and some have arthritis or joint pain. Arthritis affects nearly half of all people 65 and older, according to the Centers for Disease Control and Prevention.