The Oldest Old Have Been Very Old for a Long Time

On life expectancy, healthspan, lifespan, and ancient centenarians

If you glance at my Medium posts from time to time, you’ll have noticed that I’ve been keeping an eye on aging research (among other things) the past few years. It has left me skeptically intrigued.

Skeptical because a lot of claims don’t live up to the hype (yet?) and when it comes to the extremes of human longevity the dials haven’t moved much (see below).

Intrigued because a lot of very smart people have found their way to the study of aging in itself. Not just age-related conditions, but aging on its own has become a burgeoning research topic. Add to that the fact that billionaires don’t want to die, and suddenly there’s a ton of funding for investigations into the roots of aging (Altos labs, Calico,…). Scientists are - step by step - unraveling the tapestry of biological pathways involved in the decline that accompanies old age.

Long live the children

What do I mean when I write that we haven’t moved the longevity dials much? Aren’t we growing older all the time? As population average, sure. As individuals, not so much.

Life expectancy (the mean number of years of life remaining at a given age) at birth has indeed risen dramatically in the last two centuries. If we compare today to the early 1900s, it has doubled to a bit over 70 as the global average.

(Keep in mind that data is never perfect or complete. A lot of what I will use in this section is based on Our World in Data’s excellent entry on life expectancy.)

The reason for this remarkable jump, however, is not that the oldest old are getting older, but that the youngest are dying less. A big chunk of the rise in life expectancy can be explained by the drastic drop in child mortality. And because life expectancy is an average, a reduction in child mortality can give it a big boost. It’s difficult to get good data on this, but several estimates suggest that roughly a third to half of children died before the age of five in the 19th century. Today, the global average hovers a tad below 4%.

It’s not all about child mortality, of course. Pushing back infectious diseases has been another big factor (which sounds a bit ironic two years into a global pandemic). Better healthcare, doctors who started washing their hands (thanks, Ignaz)… All in all, we’re more likely to survive into old age.

Long live the elders

Yes, life expectancy has improved greatly. No, maximum lifespan has not. It has barely budged since ancient times. The current officially verified longevity record is held by Jeanne Calment who lived to be 122 years and 164 days old at her death in 1997. (Claims that she was actually her daughter have been discredited, so her record stands.)

How do the longest-lived people in ancient cultures stack up? After a cursory search, a few interesting ones waved their hands at me from across the river of time. (I’d be very interested in other historical, non-mythical figures’ semi-verified lifespans. If you know a good one, leave a comment below!)

A few millennia ago, Assyrian priestess Adad-guppi supposedly lived to be 104. Ancient Greeks liked dates and numbers, so we have a few good ones here as well. Plato lived to be 80. Theophrastus kicked the proverbial bucket around 83/84. Playwright Sophocles made it to somewhere between 90 and 92, as did Diogenes. (In Diogenes’ case this was quite an achievement. As the spiritual grandfather of cynics, Diogenes lived in poverty, slept in ceramic jars on the marketplace, was captured and sold into slavery, and made a sport out of insulting powerful men who could have his head on a stake if they so chose.) Democritus, who presaged the atomic era, also reached - at least - 90. Some writers have him living to 104, or even 109.

For the Roman period, we have a great resource thanks to Pliny the Elder. In his monumental Natural History, he devoted a chapter to ‘The Greatest Length of Life’. He mentions several consuls and censors in their late nineties. However, we all know women are the longevity champs, and this seems to have been true among the Romans too:

Among women also, Livia, the wife of Rutilius, exceeded her ninety-sixth year; during the reign of Claudius, Statilia, a member of a noble family, died at the age of ninety-nine; Terentia, the wife of Cicero, lived one hundred and three years, and Clodia, the wife of Ofilius, one hundred and fifteen; she had fifteen children.

Even if we grant an error of a few years, or even a decade (several ancient cultures were pretty good with calendars, though), that’s impressive. Even today, that would be impressive. And that’s the point. We may have bumped up life expectancy significantly, but when it comes to the upper limit, the extreme of longevity… That has barely moved.

Long live healthy lives

Another distinction to make is the one between lifespan and healthspan. The first one is about living as long as possible, the second one is about living as healthy as possible for as long as possible. Not the same thing. If we take a rough global estimate, the difference between these two metrics is around 9 years. Because I’m not exactly an optimistic person, let’s make that a decade. Very roughly, then, people - on average - spend the last decade of their lives dealing with various health issues that have a negative impact on their quality of life.

Doesn’t sound like a good deal.

So imagine that, somehow, we can extend lifespan by over a century, but not healthspan. Who wants to live to be 200 years old if you have to spend 130+ years of that in bad health?

Closing that gap is, in my opinion, where the great value of current longevity research lies. To truly push (healthy) lifespan ahead, we will need to intervene in more fundamental ways than what a lot of longevity research is doing now. (That statement is - also - purely my own opinion, which may be wildly off the mark. Might be good stuff for a spin-off post, though. Let me know if this sounds interesting.)

However, a lot of the pharmacological and lifestyle interventions that are being put together in labs around the world could be invaluable tools to close the healthspan gap. Cutting that decade down to a few years will result in a tremendous amount of quality-adjusted life years (QALYs) gained, not to mention the positive impact on both a personal and societal level. That alone is worth the investment.

Closing the healthspan gap will also give more people the chance (depending, of course, on the distribution and cost of the needed interventions) to reach longevity escape velocity. This is the idea that, at some undefined future point, the progress in science and technology will add years to (healthy) life expectancy faster than we can live them. Immortality, quoi? To be fair, it’s one of those things that always seems to be a few decades away. We’re not there yet. Not even close.

If it would happen, the conquest of aging, would you join?

---