Dramatically Longer Average Lifespans: Fact, Myth, or Something Else?

People in our great-grandparents' era lived to about age 45, so the advances in medicine that now allow us to live to well over 75 have created middle age where there was once no such thing. And extrapolating these trends, our children can expect to live to 150.

Or are accurate statistics leading to false conclusions?

While average life expectancy continues to increase, the benefits of modern medicine -- while substantial -- have not been dramatic for the middle aged.

In the U.S. in 1901, forty year olds were expected to live another 28 years, on average, for a total lifespan of 68 (source: United States Life Tables, 1890, 1901, 1910, and 1901-1910, Table 1. link to pdf).

Now, forty year olds can expect to live 39 more years. The eleven extra years added in the last century are no doubt important ... but not as remarkable as many would expect.

After all, over the same period, life expectancy increased from 50 to 77 years. Given that, there should have been few middle-aged (by today's definitions) or old people. How can these facts be reconciled?

The problem is with the use of averages. Yes, the average life expectancy a century ago was low, but it was dragged down by an astounding -- by our standards -- number of childhood deaths. Fifteen percent of children died before age three, and over twenty percent before age eight. Now 99%+ make it to their fifteenth birthday, and we don't lose 20% of a given year's children until they're ... over 65.

There are many examples of average lifespans in the sixties or older from centuries past.

The book Expectations of Life (summarized here) shows that members of the English aristocracy could, if they lived to twenty, expect to live into their sixties. Remarkably, this is true for any time after the thirteenth century (with the exception of plague years).

Our own analysis of the signers of the Declaration of Independence shows an average lifespan of 66 years, with many living into their seventies and longer. Their average age at the signing was 45. Top heavy with merchants, lawyers, and wealthy planters, they were not a valid socio-economical sample of American society. But given that medicine at the time may have done more harm than good, their health may have been more representative of the norm.

Noted aging researchers Leonid Gavrilov and Natalia Gavrilova looked at over 6,000 women born into European aristocracy in the 1800s and found that those that survived to age 30 lived until their mid-60's (born in the early 1800s) to almost 80 (later in the 1800s).

A sampling of Cape Cod gravestones of the early 1700s finds many marking the final resting place of people who died in their sixties, seventies, or even eighties. Of those who died past the age of twenty, 20 of 58 died in their seventies or eighties (the average age at death for this group was 58). The poor, of course, could not afford a stone marker ... but again we see plenty of people living to 60+.

The best data is the 68 year expected lifespan for forty year olds from the 1901 U.S. data above.

So living past 60 was not unusual.

It is true that medicine isn't only benefitting the very young. People who hit 80 can expect to live longer than in the past. In 1901 an 80 year old was expected to live to about 85; now it's 89. In 1901 only 13,500 out of 100,000 born were expected to see their 80th birthday; now it's almost 53,000. About 40% of the improvement is from lower infant / toddler mortality, with the balance from lower year-in, year-out deaths at every age.

We also don't have a good measure of the quality of life back then. How many 70 year olds play tennis on artificial knees? Once they would have been in a walker or had a cane.

But plenty of people lived through middle age in centuries gone by; middle age, at least as a chronological construct, wasn't invented in the twentieth century.

Some abuse the average longevity figures to "show" nearly twofold increases in human lifespan. This site uses accurate charts of average lifespan to ask whether it can double again, to (say) 150 or so. As you can tell from the data here, it's not going to happen any time soon.

More of us will live longer. More of us will live to "old age" -- whatever that is. But we won't be the first.