Antisa Khvichava, 130 Years Old Woman

Old people have limited regenerative abilities and are more prone to disease, syndromes, and sickness than other adults. For the biology of ageing, see senescence. The medical study of the aging process is gerontology, and the study of diseases that afflict the elderly is geriatrics.
The boundary between middle age and old age cannot be defined exactly because it does not have the same meaning in all societies. People can be considered old because of certain changes in their activities or social roles. Examples: people may be considered old when they become grandparents, or when they begin to do less or different work — retirement.