Middle age usually means the forties through mid-sixties
Middle age sits halfway between young adulthood and old age, and the usual bracket runs from 40 to 64. Other definitions stretch it from about 40 or 45 to 65 or 70, and most people now reportedly think it only starts at 55, so no single boundary commands agreement.
Common physical markers include grey hair and a sharp fall in fertility. From around 40 a pregnant woman is classed as being of advanced maternal age, and fertility keeps declining until menopause, which typically arrives between 45 and 55 and ends natural conception. Skin changes, aerobic capacity and maximum heart rate drop, hair thins, and sensory sensitivity reaches one of its lowest points, though people vary widely in when these shifts appear. Visible ageing can come faster for women with osteoporosis, yet the capacity to handle complex tasks stays intact.
Death rates start to rise, chiefly from heart disease, cancer, high blood pressure and diabetes, but most middle-aged people in industrialised countries can still expect to reach old age. One study linked frailty and poverty among middle-aged city dwellers to greater oxidative DNA damage from hydrogen peroxide.
Erik Erikson called this his seventh stage, generativity versus stagnation, when adults care about future generations and want to build things that outlast them. Some mental sharpness may fade, but experience and learned strategies usually hide the loss.
Socially, ties between grown children and ageing parents keep shifting, and community work and career growth are typical. Job satisfaction leans toward inner contentment over ambition, though career changes are frequent. The popular idea of a midlife crisis is largely mistaken: personality stays stable through these years, and relationships tend to settle into steady bonds.
Source: Middle age
