Life expectancy throughout most of human evolution was somewhere between 18 and 20 years. Life was short. By the mid-1800s life expectancy had reached the mid-30s in the United States, and in 1900 it was 47 years. By the end of the century, life expectancy had reached 77. It gained 30 years in one century—that’s unprecedented. More years were added to average life expectancy in the 20th century than all the years added in all prior millennia of human evolution combined. Most of the gains in the first half of the century resulted from reducing childhood mortality, but since 1950 life expectancy at 65 has been rising as well. In fact, life expectancy has increased by about three months a year for some time (see chart below).
I think most people are thinking about growth in longevity in terms of an aging population’s burden on society. But I think we have the opportunity to look at it another way— to reshape current models so that we live decades longer than our ancestors in a way that improves quality of life at all ages.
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