Longevity, also known as lifespan, is the length of time spent alive. Human longevity varies depending on numerous factors, including socioeconomic status, sex, gender, and lifestyle, but in the United States the average person lives to be about 79 years old.[1]
Healthy aging is the process of maintaining good health and functional ability during older age. A related concept is healthspan, a term defined as the number of years of life spent in good health, free of the chronic diseases and disabilities associated with aging.[2]