Middle age is a period of human life that immediately precedes the onset of old age. There is no universal consensus on what the exact definition of middle age is, but it is generally defined as being between the ages of 40 and 60. However, some definitions start later, at around age 45, such as those of Merriam-Webster and the Oxford English Dictionary, while others start as late as age 50. Some people consider middle age to begin sometime in their 40s to 50s, according to Dr. Katie Hill, while others believe that middle age spans from 40-60 (give or take 10 years). A 2012 survey of 1,000 UK adults aged 50-plus for the Love to Learn online learning website found that the average age at which the period of life was perceived to start was 54 years and 347 days old, and the average age at which middle age ends was 69 years and 277 days.

Middle age is better thought of as a social term rather than a medical one, according to Sonia Sehgal, M.D., F.A.C.P., geriatrician, UCI Health and clinical professor, department of internal medicine, UCI School of Medicine, since it’s mostly used to describe the transitional period between young adulthood and old age. It is a time of reflection for many people as they think back on their life lived so far and then plan for the years ahead. The physiological and psychological changes experienced by a middle-aged person center on the gradual decline of physical abilities and the awareness of mortality. In middle age, the relative potencies of past, present, and future are altered as the individual increasingly directs effort to the process of reminiscence and recollection of the past, rather than anticipation of the future. If approached constructively, middle age can prepare an individual for a satisfying and productive old age.