The term "aging" refers to the physical and psychological changes that occur with maturation. While this term technically refers to the changes that occur at any stage of life, it is most commonly used to refer to the changes that occur in midlife and into old age. These include the physical and mental decline that normally occurs as a part of growing old': intellectual decline, loss of physical strength and dexterity, and health problems that are associated with aging.
With modern medical technology and knowledge many of these symptoms can be reduced and ameliorated in the attempt to provided continued health and independence. People are living longer and healthier lives than any other time in history and research into aging and its effects has had much to do with that.