Let Your Mind Wander and Skip Retirement: Surprising Ways to Keep Your Brain Sharp

A doctor named Norman Swan has written a new book called The Brain Cliff. In it, he explains how our brains change as we get older — and how we can slow down that process. Swan says that the choices we make every day, like what we eat and how we handle stress, can make a big difference. His findings might surprise you.

Swan says one of the first things people get wrong is how they think about aging and the brain. Many people compare their memory and thinking skills now to how sharp they were in their 20s. Swan says that is not a fair comparison. Our brains do not simply get worse — they change in different ways. In our 20s, we are fast problem-solvers. But as we age, we build up something called crystallised intelligence, which is wisdom gained from knowledge and life experience, and that kind of thinking can actually get better over time.

Swan also explains a process called scaffolding. Think of it like the metal framework builders put up around a skyscraper. As we age, our brains build new networks of nerves that support and protect how we think. The brain even shifts some of this scaffolding into the front part of the brain, called the prefrontal cortex. That area helps us make decisions, control our emotions, and bring our thoughts together.

Swan interviewed seven people he calls cognitive super-agers — people who stayed mentally sharp well into old age. They were very different from each other: one was a 95-year-old shoemaker who never learned to read, another taught statistics to rock star Mick Jagger, and a third was a 94-year-old woman still working at a McDonald's in Japan. Even so, Swan found that all of them shared certain habits that protected their brains.

One key habit was how they dealt with stress. These super-agers did not dwell on their problems — instead, they solved them and moved on. When people worry over and over about the same thing, a habit called rumination, they use up space in the prefrontal cortex that could be used for thinking and remembering. Swan says that depression and alcohol also hurt the prefrontal cortex, bringing the brain cliff closer.

Swan says it is never too late to start protecting your brain, but the best time to begin is in your 40s and 50s. Exercise helps the brain stay flexible and build new connections. Eating less red meat and more leafy greens, berries, yogurt, and fermented foods can improve gut health, which in turn supports the brain. Small, steady changes to daily habits can add up to a big difference over time.

Another surprising brain booster is letting your mind wander. When we daydream, a part of the brain called the default mode network switches on, connecting parts of the brain that do not usually work together. Swan says this is good for scaffolding. A related activity called mental time travel — thinking about the past, staying grounded in the present, and imagining the future — also seems to help the brain stay strong.

One of Swan's biggest findings was that genes do not play a large role in whether someone reaches the brain cliff. That means lifestyle choices matter much more than most people think. Even a 100-year-old neuropsychiatrist from New Jersey learned pencil drawing as a new skill, made new friends through art classes, and stayed socially connected — all habits that protect the brain.

Swan also has strong feelings about retirement. The evidence is clear that cognitive decline speeds up after people stop working. However, he is not saying everyone must work a regular job forever — the key is to stay engaged through volunteering, learning new skills, or picking up complex hobbies. Simply sitting on the couch watching television, though, is bad for the brain, and Swan jokes that he has no plans to retire anytime soon.