Ancient Life expectancy
Throughout the ancient and medieval worlds, people died much younger
on average than they do in North America or Europe or Australia or Japan
today (though they lived longer than some people in Africa or Asia do
today). The average age at death today in the United States is about
82, while in the Roman
Empire it was probably about 35. Now that seems like an enormous
difference, but mostly the average is low because a lot of babies died
soon after they were born.
(Here's a little project to do with averages
to help you see why this is true).
A lot of babies died before they were a year old. This was partly from inherited diseases or birth defects like bad heart valves or cystic fibrosis. Also it was partly from being so small and weak that if they caught ordinary illnesses like dysentery (diarrhea) they were more likely to die of them than bigger people. Historians think that maybe a quarter of all babies born died before they were a year old (one out of four babies).
Then a lot of kids died too. We think that about half of all the babies born died before they turned ten. Again this was mostly from being smaller and weaker, and more likely to die from diseases that everybody caught, like measles or malaria.
Probably hardly anyone died of disease between about 10 and 40; at this age people are strong and healthy and even if they catch diseases they generally live through them. Some men did die at this age because they were killed in war, and some women died in childbirth (while they were having babies). But recent studies suggest that these were not usually as important as disease.
After the age of 40, more people began dying of diseases and of things like cancer, heart attacks, and strokes, as they do today. Without medicines, most people died in their forties and fifties. Because of this, most people did not ever know their grandparents, who died about the time they were born, and many kids lost one or both parents before they grew up. About a third of Roman boys seem to have lost their father before they were grown up.
Still, it was not very unusual for people to live into their eighties,
and we know of some people who lived to be about a hundred years old.