Old age is the stage of life that starts at age 60 in developing countries and at age 65 in developed countries, according to the World Health Organization (WHO).
The third age is characterized by physical changes throughout the individual's body, altering their functions and behaviors, perceptions, feelings, thoughts, actions and reactions.
There are also changes in social roles that result from bio-psychological changes related to advancing age.
The Brazilian Federal Constitution mentions the third age starting at 65 years of age, while the Brazilian Penal Code refers to the age of 70 years. Both are inconsistent with the 60-year limit set out in the National Policy for the Elderly.
Geriatricians, from a biological point of view, divide the ages into:
- first age: 0 - 20 years;
- old age: 21 - 49 years;
- Third Age: 50 - 77 years;
- fourth age: 78 - 105 years.
There is yet another classification that divides the elderly into 3 branches:
- old young: 66 - 74 years;
- Old elderly: 75 - 85 years;
- personal maintenance: 86 years onwards.
The term "Third Ages" was created by the French gerontologist Huet, whose chronological beginning coincides with retirement (between 60 and 65 years old).
Several terminologies have been used to designate the third age, although, for most scholars, this diversity of expressions is euphemisms.
Aging occurs in different dimensions (biological, social, psychological, economic, legal, political) and depends on various factors that occurred in earlier stages of life, such as experiences in the family, school or other institutions.
Thus, old age or old age does not comprise a single concept, since the chronological age may not be identical to the biological and social age of the individual.
See also the meaning of Young age.