2009 vs. 2019 Challenge Reveals a Strange Trend in the Biology of Aging

"We may be aging slower than our parents, our grandparents, our great-grandparents did."

The 2009-2019 challenge sweeping the internet may as well be renamed the “How Hard Did Aging Hit You?” meme. In the so-called #10YearChallenge, people post photos of themselves taken ten years apart, and for the most part, they show massive glow-ups from the decade past. It’s rough for people who didn’t age so gracefully in those ten years, who can’t help but ask: Why do some people age faster than others?

This is a question that aging experts like Daniel Belsky, Ph.D., an assistant professor of epidemiology at Columbia’s Robert N. Butler Columbia Aging Center are trying to answer. His research has shown there are no buts about it: Some people do actually age more slowly than others in terms of biological age, the rate at which bodies break down over time, which in turn is reflected in their looks. But on the whole, he adds, the rate of aging might be slowing for everyone.

“We all age one year at a time chronologically,” he tells Inverse, discussing the results of his 2015 PNAS study, showing that there are indeed differences in the rate that people age biologically. “So if we think about the average physiological change that occurs over the course of a 12-month interval as a biological year, some people were aging twice as fast as the norm.”

Has Pharrell even aged at all?

Some Individuals Age Faster Than Others

In that study, Belsky demonstrated that the pace of biological aging differs hugely between people by measuring 18 biomarkers (like gum health, total cholesterol, and cardiovascular fitness) in 954 participants who began the trial when they were 26 and concluded it when they were 38. Importantly, he found that those whose biological age was higher than their actual age looked older to a series of Duke undergrads who viewed their before and after headshots.

“Their pace of aging reflected two years of physiological change per 12-month interval,” says Belsky, “and some people’s bodies were changing much more slowly so that their bodies seemed not to change at all.”

Belsky has an idea of what goes into an “advanced” rate of biological aging thanks to established biomarkers of advanced age, like long telomeres. There’s a body of work indicating that some genes influence the rate at which someone ages, but there are other non-biological factors that play into how quickly biological age accumulates, like abuse and neglect during childhood.

But As a Society, We’re Aging Slower Than Ever

On an individual, adverse life experiences tend to cause people to age faster biologically, he says. But if you zoom out and look at a population level, there appears to be a different, more encouraging trend: As a society, we seem to be biologically aging slower than ever.

He points to a study published in Demography in 2018 that showed the biological ages of men between the ages of 20 and 39 were 0.63 of a year lower between 2007 and 2010 than they were between 1988 and 1994. For women of the same chronological age, biological ages were 1.27 years lower between 2007 and 2010.

The authors of that paper pinned those differences down, in part, to healthier lifestyles (for instance, a decline in smoking), though that didn’t explain the entirety of their findings. Belsky suspects they might come down to factors that impact the rate of biological aging in childhood, but for now, it’s too early to tell.

“We may be aging slower than our parents, our grandparents, our great-grandparents did,” he says. “At present, we don’t know if it’s the rate of biological aging that is changing or if there are different things that are happening earlier in life that affect the baseline integrity of the organism at adulthood.”

The ageless nature of people who partake in the 2009-2019 challenge probably has more to do with Instagram filters and careful photo selection than it does with biological aging. But still, results like this indicate that if this challenge had taken off 20 years ago, the photos might look a lot different.