Figure summarizes the major changes of aging and some key ways these changes affect pages. Though many changes occur with aging, under normal or resting conditions, there is usually very little functionally that is diminished solely on the basis of aging. The net effects are reductions in reserve capacity and placing geriatric patients at higher risk for adverse consequences related to medications and diseases. Interactions between lifestyle factors, such as exercise, diet, and environmental exposures, have a large impact on aging and lead to great individual variability. The interplay between these environmental factors, aging, and development of chronic diseases multiply the amount of variation seen as individual's age.