But the life milestone can be a stressful one—and, thus, “a potential trigger for cognitive aging,” according to a 2021 piece in The Journals of Gerontology, authored by researchers at the University of Cologne in Germany, and the University of California at San Francisco.

Researchers interviewed nearly 9,000 European retirees ages 50 and older, from 17 countries. Each completed six memory assessments over the course of 13 years. 

Their findings: Retirement was generally associated with a moderate decrease in word recall, and memory decline “accelerated after retirement.” This was true in all countries involved—even in those with more generous welfare systems and higher pension benefits—like Germany, Austria, France, and Belgium—versus those with low public pensions, like Portugal, Greece, Israel, Estonia, Poland, and Slovenia.

Studies have shown that postponing retirement can protect against cognitive decline, especially among the more highly educated. But let’s face it—life is short. For those who can and wish to retire on time, here are four tips for staying mentally sharp during what should be the most joyous season of life.

Keep (or get) connected.

A quarter of Americans ages 65 and older are socially isolated, according to a 2020 report from the National Academies of Sciences, Engineering, and Medicine. While loneliness is miserable, it’s also more: It poses a health risk as deadly as smoking a dozen cigarettes a daily, U.S. Surgeon General Dr. Vivek Murthy recently told attendees of Fortune’s Brainstorm Health conference. Retirement often means loss of the community you worked in, perhaps for decades. Keep connected to others by taking classes, volunteering, hanging out with friends, or picking up a sport.

Keep active.

It’s never too late to begin an exercise routine—even if you didn’t pre-retirement, or if you fell off the wagon at some point. Having been physically active at any point in adulthood, “to any extent,” is associated with better cognition later in life—though those with a lifelong habit of exercising see optimal results, according to a recent article in the Journal of Neurology, Neurosurgery, and Psychiatry.

Aim for at least 150 minutes of moderate-intensity activity—or 75 minutes of vigorous activity—a week, per the recommendation of the U.S. Centers for Disease Control and Prevention. 

Keep stress to a minimum.

There are myriad ways to keep stress at bay. A few of them:

• Sexual activity. Studies show that those who have sex less frequently report higher levels of stress. Of note: masturbation counts as sex; no partner required.
• Sleep. It’s well known that quality sleep is protective against cognitive decline—and a host of other health issues like depression and obesity. Aim for seven to nine hours a night, according to the National Institute on Aging. If sleep is a struggle for you, talk to your doctor—a sleep study may be in order to get to the root of the issue.
• Budget. Do your best not to introduce any new stressors in your life. For the vast majority, this will require keeping a budget. If you don’t have one, you’re not alone—and it’s never too late. A financial advisor can help you establish one and determine how much money you truly need to live on—not just how much you think you need.

Keep working.

Hear us out: Ideally, you’re in a situation where you don’t have the financial need for a typical 9-to-5. But you have just as much to contribute to society as the day before you retired. If it brings you joy, consider volunteering, contract work, or a part-time job in a field you love—regardless, perhaps, of pay. You’ll reap the benefits of connectedness and cognitive acuity and typically accompany work—hopefully without all the stress.