How old are you really?


“Old Age” (1936) by Dorothea Lange | Library of Congress

Today’s blog post begins with a confession of sorts: as someone belonging to the millennial generation, I am perhaps unusually preoccupied with age.  And if we’re searching for some underlying explanation, it probably makes the most sense to take a look back at my parents.  For starters, my mom is nearly 3 decades younger than my dad, whose physical fitness and mental acuity continue to defy the machinations of Father Time.  And it would seem that the apple doesn’t fall too far from the metaphorical tree because as I progress into my late twenties, I find myself commonly — and often frustratingly — mistaken for a precocious teen.  For me and certainly both my parents, age is really just a number, but how does this truism check out scientifically?  I’m inclined to think how we look and feel is more important than the year we were born, but I’ll pose my question to the experts.  Is chronological age all that important in understanding a person’s overall health?

If you ask the competitors at this year’s National Senior Games, the answer would be a resounding no.  These athletes — 50 years and older — set records in swimming, cycling, and a host of 17 other sports.  Clearly, not your average retirees.  Indeed, according to The New York Times, when 4,200 of them calculated their so-called “fitness age,” many were as much as 25 years younger than their chronological age.  The scientist who engineered the fitness calculator, Dr. Ulrik Wisløf of the Norwegian University of Science and Technology, was equal parts nonplussed and delighted by the disparity.  “I had expected a big difference since these people have trained for years,” he tells The Times.  “However, I was surprised that it was this big.”

Earlier in the month, the importance of chronological age was again thrown into question when an international team of researchers published a paper in Proceedings of the National Academy of Sciences.  Confirming what many of us have long suspected, they discovered that among nearly a thousand young adults, the pace of aging varies significantly.  More specifically, by examining changes in their cardiovascular, metabolic, and immune systems, along with the health of their kidneys, livers, lungs, teeth, and DNA, researchers found that a number of the study’s participants seemed decades older than their actual age, while others showed few signs of aging, if any at all.  So, while chronologically they were all the same age, biologically speaking, there was great variation from one person to the next.

To most of us, this variability seems fInterveneairly obvious.  Even as a late twenty-something, I’ve begun to see differences in how my peers and myself are weathering adulthood.  But what sets this study apart is that it tracks the pace of aging in young adults — not seniors, the traditional subjects of age-related research.  Daniel Belsky, an assistant professor at Duke University School of Medicine and one of the leading scientists involved with the project, underlines the importance of changing approach.  “One reason to study aging in young people,” Belsky tells me, “is that they are largely free of age-related disease.”  In this way, he explains, scientists can more easily “identify mechanisms of aging as something separate from disease processes.”

Another reason, says Terrie Moffitt, the paper’s senior author, is early intervention may one day translate into more effective treatments for ailments that typically crop up later in life.  “It has recently been shown that interventions administered to healthy animals can slow their aging in the laboratory,” says Moffitt.  “Likewise,” she continues, “interventions to slow human aging will most likely need to be applied to healthy young people.”  And it should go without saying — though the paper addresses the matter anyhow — that if people stay healthier for longer, ultimately the costs associated with poor health and disability will go down.

But few of us are actually concerned about potentially becoming a burden to the economy at some point in the distant future.  I imagine I’m not alone in wondering first and foremost what accounts for these vast differences in the pace of aging and what might someone who falls outside of, say, the Dorian Gray subset do to slow it down.  Unfortunately, the study conducted by Belsky and Moffitt hasn’t yet addressed these queries.

“Our first step was to determine if we could actually track and measure biological aging in young people,” Moffitt tells me.  “Now that we can, our research turns to uncovering what factors in early life can predict rapid aging.”

So far, they have come up with the usual list of offenders, smoking being chief among them.  But perhaps what was more unexpected is the correlation researchers observed between intelligence and aging.  According to Moffitt, study members who as children received high scores on aptitude tests, aged more slowly than their peers.  She and her team are also considering a number of more obvious predictors like diet, exercise, and sun exposure, as well as mental health, experiences of physical and/or emotional trauma, job-related stress, relationships, and personality traits.

And for those of you blessed with younger-looking parents, don’t go hanging your hat on genetics.  According to Belsky, our genes may have as little as 20% to do with the overall aging puzzle.  And Moffitt agrees, adding, “[a] key piece of information is how very rapidly the human lifespan has increased in just the past two generations.  This is far too quickly for genetic change.”

“Different people under the same environmental conditions will age at different rates, and genetically identical twins under different environments will also age at different rates, highlighting the importance of both factors,” says Juan Carlos Izpisua Belmonte, a professor in the Gene Expression Laboratory at the Salk Institute.


Belmonte is not involved in this particular study, but he along with researchers at the Salk Institute and Chinese Academy of Science made headlines back in May for a groundbreaking study of their own.  In hopes of better understanding what drives the aging process on the cellular level, they directed their attention to Werner syndrome, a disorder that leads to accelerated aging.  Sufferers often develop ailments like cataracts, diabetes, osteoporosis, and cancer as young people and rarely make it into their fifties.  Over the course of Belmonte’s study, he and his colleagues found that the gene mutation responsible for Werner syndrome causes bundles of DNA called heterochromatin to deteriorate — a discovery, says Belmonte, with far wider implications.

“[W]e discovered that the same type of alterations in heterochromatin that we observed in our Werner syndrome model was also present when analyzing adult stem cells from normal young and old individuals,” he explains.  In other words, the same mechanism behind Werner syndrome is at work in people aging normally.  And now that it has been identified, scientists may one day be able to slow down or altogether reverse aging, what Belmonte describes as “one of the most complex processes that we observe in nature.”  That might be so, but he and his team are certainly working to unpack the complexity.

But what if the mystery of aging weren’t such a mystery after all?  What if the signs of it were written all over our faces?  Well, in the study conducted by Belsky and Moffitt, it isn’t simply a question of what if.  They have indeed found a positive correlation between older-looking faces and faster rates of aging.  “[W]hat this means,” says Moffitt, “is that if your friends and family have the impression that your face is beginning to look older for your age group, there may also be accelerated deterioration of your organ systems inside,” adding, “this internal aging will show on the skin of your face.”

Curious to know how old I appear to others, I followed Moffitt’s suggestion and submitted my photo to, a free site engineered to guess a person’s age.  However fun, this software could use a bit of tweaking if you ask me.  As alluded to above, I more easily pass for a teenager than the twenty-something that I am.  So, I wasn’t entirely convinced when the site pegged me for 39 and my mother, a sprightly 36-year-old.

However faulty the site, another study out of the Max Planck Partner Institute and Chinese Academy of Sciences suggests there is indeed a link between older-looking faces and faster rates of aging.  In fact, our faces can be as good an indicator of biological age as blood samples, says Jing-Dong Han, the study’s senior researcher.  Using high-resolution 3D facial images, she and her team developed a method for tracking patterns in how faces change over time, and after taking scans of over 300 volunteers, they found that participants who looked old for their age also had accelerated aging blood profiles — a finding that surprised Han herself.

“At the time I did not expect to see such remarkable changes with age, nor did I expect the 3D images to be such an accurate biomarker for biological age,” Han tells me.

So, where does that leaves us?  Well, I suspect we can go on lying about our chronological age, but as far our biological age is concerned, we can’t easily escape it…as it’s literally written on our faces.