Retiring by Brain Age, Not Actual Age
A bucket-list trip to Europe. Time for volunteering or visiting the grandkids. Trading alarm clocks and meetings for unstructured days. While retirement may look different for each of us, it’s typical for most people to stop working sometime during their seventh decade. Age-based retirement has long been a societal norm.
But what if there was another way to decide the best time to retire? Imagine a world where our cognitive readiness—how our brain performs—tells us when the time is right to leave our job.
Research from Stanford Medicine has shed new light on the fact that chronological age doesn’t tell the full story when it comes to our brains. Researchers found that our organs, including the brain, can have a biological age that differs from our chronological age.
The researchers analyzed plasma proteomics data (including almost 3,000 proteins in the blood) from nearly 45,000 randomly selected participants in the UK Biobank, a collection of health data from more than a half-million participants.
They used these analyses to identify the “biological age” of participants’ brains and to understand how circulatory blood factors can modulate brain structure and function. The study, published in Nature Medicine in 2025, found evidence that “youthful brains and immune systems are uniquely predictive of longevity.”
Imagine how you might use information about your brain’s age to map your work life. A youthful brain could mean your cognitive skills would remain strong longer, giving you extra time in your profession. Conversely, a brain showing signs of age-related changes might help you decide it’s time to put your career behind you.
Still, the research isn’t quite there on using cognitive readiness as a determiner of retirement timing. Most retirement policies and the financial tools that help support retirees remain tied to chronological age.
On average, most retirements occur between age 62 and 67, according to Ross Andel, PhD, a professor in the Edson College of Nursing and Health Innovation at Arizona State University in Phoenix, who studies the role of work and retirement in cognitive change and cognitive impairment.
“Should that apply to everyone? Absolutely not,” he said. “There are people willing to work forever. If they’re productive and reasonably healthy, why not?”
As Good As You’ve Ever Been?
Some professional roles, such as commercial airline pilots and federal firefighters, have mandatory retirement ages based on the physical and cognitive demands of the positions. In health care, the cognitive capacity of late-career physicians has been discussed as a critical factor in patient safety.
Mark P. Mattson, PhD, 69, an adjunct professor in the Solomon H. Snyder Department of Neuroscience at Johns Hopkins University School of Medicine in Baltimore, is the former chief of the Laboratory of Neurosciences at the National Institute on Aging (NIA). At 62, he chose to retire from the NIA, where he oversaw a large laboratory that included postdoctoral fellows and graduate students.
Dr. Mattson said he decided to leave because he knew there would be a normal age-related progressive decline in his own brain performance, particularly in the areas of processing speed and working memory. He also wanted to make room for younger scientists in a field where jobs can be tough to find.
“There’s a lot of evidence that our brain’s functionality begins declining, even as early as our 30s,” he said. “It’s not really measured in ways other than your boss evaluating you or your ability to get tasks done. But if you were to test people by taxing their memory and pushing their ability to switch between tasks, you’d see that these abilities decline as they age.”
Interestingly, work itself can help protect cognitive health. This is especially true for people who work in complex jobs where they manage a lot of information.
Unlike athletes, where physical performance indicators like race times are easily measurable, cognitive performance is often less so, according to Dr. Mattson. Brain changes that affect job performance can be more subtle, he said.
“Now that we have the internet, I can go back and look at lectures I gave even 15 years ago,” he said. “When I compare myself presenting now to one of my lectures online, it’s pretty obvious. Most people recognize that our physical performance declines with age, but fewer people notice changes in their ability to grasp and explain concepts. You may think you’re as good as you’ve ever been unless someone tells you otherwise.”
Recognizing Cognitive Changes
The question of whether an individual can recognize that they’re not as cognitively sharp as they used to be is difficult to answer, according to Dr. Andel. Most people aren’t routinely undergoing cognitive tests and don’t have a baseline measure of their cognitive function that they can monitor for changes—unlike how you might keep an eye on shifts in health measures like blood pressure or cholesterol.
“There are instruments that are used to screen for dementia, such as the Montreal Cognitive Assessment,” Dr. Andel said. “Older adults may be given this screening test to see if they’re functioning normally. But most times, if you took that test, you’d ace it every time.”
Dr. Andel said he and his colleagues have worked on an individual cognitive test that is incorporated into Terrapino, an app designed to promote cognitive health through education and prevention. “We’ll see how it performs against a full cognitive assessment,” he said. “But it’s something people can take once or twice a year to follow their own cognitive performance.”
Use It or Lose It
Age-related changes in cognitive function are normal. The Baltimore Longitudinal Study of Aging noted that almost everyone experiences a steady rate of natural decline in their cognitive abilities.
As we get older, parts of our brain change and may shrink. Blood flow decreases and neurons don’t communicate as they once did. We may experience slowdowns in task switching and increases in time to master new concepts and technologies. We may have trouble remembering things as well as we used to.
Interestingly, work itself can help protect cognitive health. This is especially true for people who work in complex jobs where they manage a lot of information. Yet even jobs that aren’t intellectually stimulating can help prevent cognitive decline if they aren’t too stressful, according to Dr. Andel.
“‘Use it or lose it’ applies to just about everything, including brain health,” he said. “If you want to have a strong bicep, you do bicep curls. If you want to have a strong brain, you stay mentally engaged.”
The Responsibility of Retirement
Dr. Andel said people can help protect their brains by being intentional about how they spend their days in retirement. “Once you retire, it’s important to find something that mimics your work to foster intellectual engagement and give you routine and discipline,” he said. “Retirement is a new responsibility. Sure, we deserve to retire, but that doesn’t mean we can live a life without routine and engagement.”
A brain-healthy retirement requires a strategy for sustained cognitive stimulation, Dr. Mattson said. Although a post-retirement mountain biking accident has left him partially disabled, he stays active in the scientific world through teaching, writing and podcasting.
“I spend most mornings on scientific work,” he said.
He also studies the concept of “challenge, recover, repeat” to maintain his brain health.
“Physical exercise, intellectual problem-solving and intermittent fasting—followed by time to recover—create a cycle of stress and recovery that promotes neural resilience and may slow age-related decline,” he said. “You have to have a plan to keep yourself challenged and your brain engaged.”
