nav-left cat-right

The Difference Between Lifespan and Life Expectancy

Did people in the ancient world ever live past 30? Actually, people in the ancient world could live as long as people today. Only, in the ancient world only a handful of people got to old age, whereas today most people expect to. It is the difference between lifespan and life expectancy. Life expectancy is the average expected of a child at birth, and is heavily influenced by things like infant mortality. If 50 out of every 100 infants die, and all the rest live to 50 years old, then the life expectancy of any one of those infants is 25 years. But none of them died at 25; they either died as an infant, or lived to 50. So in pre-industrial societies, the life expectancy may have been 25 or 30, but that was because of high infant mortality, combined with war, the risks of childbirth, etc. An individual who avoided becoming seriously ill could make it to 90, and there are more than a few cases of individuals exceeding 100.

As to the role of nutrition, I we may not have better nutrition today than before if we look at the quality of available foodstuffs. But we have both more consistent nutrition, and we have vastly better hygiene. And the improvements in hygiene is the primary reason why people in the 20th century lived longer than any previous era. Now in the 21st century the longevity trends are starting to reverse. But that is a whole other discussion.


Leave a Reply

Your email address will not be published. Required fields are marked *