Chronic, work-related stress can accelerate your biological age—especially if your job is U.S. president

If you’ve experienced work-related chronic stress—physical and/or emotional tension that lasts for weeks, months, or longer—you know the havoc it can wreak on your body. Chronic stress can cause not only debilitating everyday symptoms from fatigue to forgetfulness, but also serious long-term conditions such as heart disease and high blood pressure.

You may have even felt that chronic stress has visibly aged you, which it’s indeed capable of doing. This phenomenon is perhaps most palpable in the faces of U.S. commanders-in-chief. Compare pictures of your favorite president on his inauguration day and final day in office. Whether he served an abbreviated term or, in the case of Franklin D. Roosevelt, three full terms and beyond, you might think he grew older faster than he may have under more relaxing circumstances.

Last summer, former President Barack Obama quipped about his older appearance in a keynote address at the Democratic National Convention in Chicago. “It’s been 16 years since I had the honor of accepting this party’s nomination for president,” he said. “And I know that’s hard to believe, because I have not aged a bit.”

Age, and the mental decline that comes with it, was a hot-button issue throughout the 2024 election. When President Joe Biden took office in 2021 at 78 years, 61 days old, he was the oldest person to begin leading the country. But on Jan. 20, that accolade will belong to President-elect Donald Trump, who will be 78 years, 220 days old. By comparison, former President Bill Clinton is the third-youngest person to be inaugurated at 46. Obama, 47 at his first inauguration, is the fifth-youngest.

All jobs can be stressful at times, and you’re not alone if yours has made you feel you were carrying the weight of the world on your shoulders. Our presidents, though, bear the burden and privilege of governing one of the world’s largest, wealthiest, and most populous countries, 24/7, at war and peace. It may be the most exclusive order of chronic stress, known to just five living men. If they look outlandishly older to you, it may be the case that their biological age—a measure of how well their body functions—is older than their chronological age—how long they’ve been alive.

From back left, former President Bill Clinton, former Secretary of State Hillary Clinton, former President George W. Bush, former first lady Laura Bush, former President Barack Obama, President-elect Donald Trump, former first lady Melania Trump; and from front left, President Joe Biden, first lady Jill Biden, Vice President Kamala Harris, and second gentleman Doug Emhoff are pictured during the funeral service of former President Jimmy Carter at the Washington National Cathedral in Washington, D.C., on Thursday, Jan. 9, 2025.

The scientific findings are mixed. A 2015 study in the journal the BMJ found that, compared to political runners-up, being elected to and serving in public office came with a 23% higher risk of premature death. The study, which assessed the survival of heads of state from 17 countries including the U.S., also showed world leaders lived almost three fewer years after their last election than the candidates they had bested. However, this research contradicted that published in 2011 in the Journal of the American Medical Association, which had found no evidence that U.S. presidents die sooner on average than other men. That’s not to say they don’t exhibit the demanding nature of their work on their faces.

“The graying of hair and wrinkling of skin seen in presidents while in office are normal elements of human aging; they occur for all men during this phase of life and can be accelerated by behavioral risk factors such as smoking and stress,” wrote study author S. Jay Olshansky, PhD, a professor of epidemiology and biostatistics at the University of Illinois Chicago School of Public Health. “Whether these outward changes occur faster for presidents relative to other men of the same age is unknown. Even if these signs of aging did appear at a faster rate for presidents, this study shows that this does not mean that their lives are shortened.”

While presidents may field stressors the general public can’t fathom—not to mention the classified pressures civilians will never know about—Olshansky highlights a critical advantage national leaders hold in stress management: access to elite medical care. Research published in 2023 in the journal Cell Metabolism showed that biological age fluctuates in humans, and such wear and tear caused by stress can be reversed through recovery. Well, maybe not completely undone, best doctors at your disposal or not, says Michael Snyder, PhD, chair of the genetics department at the Stanford University School of Medicine.

“I don’t know that it is reversible,” Snyder tells Fortune. “If you look at the presidents, it doesn’t look like they get younger after they leave office.”

From left, in this Friday, July 2, 2010, file photo, then-President Barack Obama, then-Vice President Joe Biden, and former President Bill Clinton chat before the start of a memorial service for Sen. Robert Byrd, D-W.Va., at the West Virginia State Capitol in Charleston.

How does chronic stress age the body?

A 2020 study in the journal Biomedicines put it simply: “People exposed to chronic stress age rapidly.” Eight years earlier, research published in the journal PLOS One had found that work-related exhaustion specifically accelerates the rate of biological aging. In the long term, sustained psychological battery can lead to mental maladies as well as physical ailments, such as major depressive disorder and autoimmune diseases.

“Chronic stress is probably most known for two things. One is increased inflammation,” Snyder tells Fortune. “The other would be oxidative stress, which generates a lot of free radicals, which itself is correlated with DNA damage, damage in general, and aging problems.”

Your body is designed to endure acute stress as a form of self-protection from dangerous situations. For example, you may have been stressed out by a looming work presentation but once it was over, the stress likely dissipated. If you’re under constant stress at work, stress morphs from protective to destructive, down to the cellular level.

“Your DNA can get modified, and your lifestyle affects that. So exercise, the food you eat, these affect your modifications on your DNA,” Snyder explains. “It’s called epigenetics and in general, those (modifications) are associated with more chronic conditions.”

Snyder uses himself as an example. He says he was genetically predisposed to diabetes and developed the disease several years ago following a viral infection. Though he managed to get his health under control to the point he was no longer diabetic, the disease eventually returned four years later.

“It was only partially reversible; I never got it all the way back, this DNA modification,” Snyder tells Fortune. “The bottom line is, I don’t think we fully know if it’s completely reversible or not, but there’s some evidence the effects of short-term change are reversible.”

The conditions researched in the Cell Metabolism study included pregnancy, major surgery, and severe COVID-19, all of which were shown to cause reversible increases in biological age. Could an employee struggling with work stress for years on end similarly decrease their biological age? Snyder isn’t sure.

“It might just mean that the cells that age got swapped out, whereas if you’re truly chronically aged, it’s sort of systemic across all your cells,” Snyder says. “That may not be as reversible. Hard to say.”

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This story was originally featured on Fortune.com