age range typically considered middle aged
For other uses, see Middle Ages (disambiguation) . Middle age is the period of age beyond young adulthood but before the onset of old age. Various attempts have been made to define this age, which is around the third quarter of the average life span of human beings.he Diagnostic and Statistical Manual of Mental Disorders, the standard diagnostic manual of the American Psychiatric Association, used to define middle age as 40â60, but as of Edition IV (1994) revised the definition upwards to 45â65.