New research on the aging process has me recalling an oft-quoted conversation in Ernest Hemingway’s The Sun Also Rises, in which a couple of guys discuss financial disaster:
“How did you go bankrupt?” Bill asked.
“Two ways,” Mike said. “Gradually and then suddenly.”
We tend to think of growing old in a similar way. You may occasionally notice yourself slowing down over the course of several years — maybe a lingering soreness after a softball game or a surprising need to rest after an hour or two of yardwork — and think nothing of it until you awaken one morning in your 70s shocked to realize you’re not 28 anymore.
But that’s not how the body ages, according to a study published last month in the journal Nature Aging. Stanford University researchers argue that aging is not a linear process; cellular activity at specific ages plays an outsized role in our ability to thrive in our dotage.
“Obviously you change throughout your entire life,” study coauthor Michael Snyder, PhD, tells The Washington Post. “But there are two major periods when there are lots of changes: One is when people hit their mid-40s, and one is when they hit their 60s.”
“[There] are two major periods when there are lots of changes: One is when people hit their mid-40s, and one is when they hit their 60s.”
Over the course of about two years, Snyder and his colleagues periodically took blood and stool samples, as well as oral, nasal, and skin swabs, from 108 healthy study participants ranging in age from 25 to 75. Those samples yielded more than 135,000 different molecules and microbes, some of which are known to affect metabolism, cardiovascular function, immune response, and other age-related mechanisms. Their analysis revealed that the vast majority of these molecules remained relatively stable in number except among participants in their mid-40s and 60s.
In the younger cohort, researchers found significant changes in the number of molecules affecting the metabolism of alcohol and fats (lipids). Among the older group, the fluctuating molecules were responsible for immune regulation, kidney function, and carbohydrate metabolism. The latter finding was not surprising, Snyder notes, because many age-related diseases tend to arise when we reach our 60s. But researchers were initially surprised by the molecular shifts among those in their mid-40s, wondering whether their results may have been skewed by the onset of menopausal or perimenopausal conditions in the female participants.
After looking deeper into the data, though, they found that the same molecular shifts occurred in the men. “In hindsight, it makes intuitive sense,” Snyder says. “People who do a lot of exercise realize when they hit their 40s that they’re not quite the same as they were in their 20s.”
And when people hit that plateau, he believes clinicians could design specific lifestyle interventions — diet, exercise, stress management, and such — to help them neutralize the molecular mischief that can accelerate the aging process.
It may be awhile before we’ll see such a treatment approach, though. Snyder and his colleagues can’t say with any certainty whether the clustering of these troublesome molecules at particular points in the lifespan is the result of some aging-related mechanism or whether it has more to do with lifestyle patterns common to folks in their mid-40s and 60s. Maybe, for instance, people at those points in their lives simply tend to drink more alcohol, thus sparking the metabolic issues revealed in the study. Longer-term research involving a larger group of participants could support — or refute — Snyder’s findings.
While we await further reminders of the obstacles lying in wait on our journey from younger to older, however, it’s probably not a bad idea to do whatever we can to maintain some semblance of a healthy lifestyle. It may come in handy when you suddenly realize you’re not 28 anymore.