Conventionally considered to occur between ages 40 and 60–65 years and primarily defined by psychosocial rather than by physiological events.
An imprecise term that refers to the period of life that begins roughly at age 40 and ends at about age 64. During middle age in Western societies, many medical problems begin to increase in frequency, including degenerative arthritis, cancer, diabetes mellitus, high blood pressure, myocardial ischemia and infarction, obesity, and visual accommodative disorders.