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When it comes to retirement, experts recommend that everyone do some hard thinking. By this, they mean you should plan your finances responsibly, consider carefully where to live, and decide what colour beach chair to sit in all day as you sip strawberry daiquiris in the sun. But there’s another reason to think hard about these details: hard thinking by itself – a strenuous mental workout – is good for your ageing brain.
My collaborators and I at Massachusetts General hospital and Northeastern University in Boston study people over 65 who have incredible memories for their age, on a par with healthy 25-year-olds. Scientists call them “superagers” (a term coined by neurologist Marsel Mesulam at Northwestern University in Chicago). While nobody knows exactly why some people are superagers, we believe that one common factor is that they engage in demanding mental exercise. They continually challenge themselves to learn new things outside of their comfort zone.
Beginning in middle age, research shows, many people take steps to avoid unpleasantness: they quit their irritating jobs; take relaxing holidays instead of vigorous ones; they pursue happiness. Scientists call this phenomenon the“positivity effect”.
Nobody wants a life filled with stress, so it’s reasonable to indulge the positivity effect and divest yourself of negative things. In fact, stress that continues for a long time, a condition known as chronic stress, is toxic to your brain – it literally eats away at critical brain regions.
Not all stress is bad, however. Research suggests that you need some amount of stress in your life if you want to stay mentally sharp – in particular, the momentary stress that comes with hard work. Your nervous system evolved so that occasional bouts of stress, where you tax your body and brain for a short time, is necessary to keep your brain healthy as you age.
To understand why this is the case, consider how your memory works. Whenever you remember something, like where you left your car keys, you aren’t retrieving a memory wholesale from some distinct crevice in your brain; instead, you construct memories in the moment, out of bits and pieces gathered from around your brain. This construction process is launched by an ensemble of brain regions that, according to our research, are thicker and better connected in superagers. Perhaps you’ve heard of some of these regions, which include the hippocampus, the anterior insula, the midcingulate cortex, and the medial prefrontal cortex, among others.
The same “superager ensemble” of brain regions also assembles your thoughts, emotions, decisions, dreams, sights, sounds, smells, and everything else you perceive, using the same construction process that makes your memories. Anytime you feel happy or afraid, for example, your brain constructs those emotions out of bits and pieces of your past experience in similar situations, led by your brain’s superager ensemble.
In addition, the superager ensemble performs the vital task of regulating your organs, hormones and immune system. These brain regions are responsible for predicting your body’s energy needs in advance, to keep you alive and healthy. If you’re getting the idea that they are hugely important, you’re right: they are major hubs that coordinate communication throughout your brain. They show up in thousands of neuroscience studies on diverse topics. I’m calling them the superager ensemble only as a convenient shorthand.
All in all, when the key regions of your superager ensemble are thick and well connected, your brain can regulate your body and construct your experiences faster and more efficiently. But it’s not always easy to keep these regions in good shape, because they also create the stressful feelings that you have when exerting yourself. Thinking hard can make you feel unpleasant in the moment, just as strenuous physical exercise can make you ache for a time. These unpleasant feelings invite you to stop working hard. Based on research in my lab, however, if you want to realise the brain benefits of superageing, you must push past the momentary discomfort. In many cases, the unpleasant feeling is a false alarm, and you actually do have the mental or physical resources to continue exerting yourself.
What enables superagers to persevere in the face of unpleasantness? That’s an open question, but scientists have found that if they electrically stimulate one of the regions of the superager ensemble – the midcingulate cortex – subjects report a feeling of motivationto overcome difficult challenges. The psychologist and author Angela Duckworth calls this feeling “grit”.
In the past, some researchers have described grit as the ability to regulate your emotions by thinking rationally. Modern neuroscience, however, has established that the human brain has no dedicated areas for thinking versus feeling. Our research suggests that grit is not so much a grand battle between cognition and emotion; it’s more the ability to use your unpleasant feelings as fuel rather than as a reason to apply the brakes. Superagers, and other people who regularly cultivate grit, treat their unpleasant feeling as a signal to keep going.
So, what can you do to increase your chances of being a superager? While there are no guarantees, here are some tips.
First, engage in strenuous mental activity on a regular basis, enough to make you feel unpleasant in the moment. Pick a topic that has always interested you, whether it’s chemistry or gardening or sports statistics, and dive into it until your brain hurts. Take classes that you find challenging, or work on a project that’s difficult. Learn to play a musical instrument, or study a foreign language. If you fail at your task, don’t fret, just try something else. The key is to push past the discomfort that comes with learning a new subject or skill.
The head of my daughter’s karate school, Grandmaster Joe Esposito, has a saying about pushing past discomfort, when he speaks to his nervous students before their black belt test: “Make your butterflies fly in formation.” I suspect that superagers keep their butterflies exceptionally well trained.
Second, if you aren’t exercising regularly, begin doing so if you can. Studies show that vigorous physical effort, again past the point of unpleasantness, may have similar effects on your brain as hard mental effort. The mechanisms are not yet known, but demanding exercise appears to improve the thickness and connectivity of the same brain regions. For example, in one study, people who exercised regularly in their 60s were more likely to be mentally fit in their 90s. (Of course, check with your GP before beginning any new programme of physical exercise, especially if you’re near or past retirement age. Superageing is much less satisfying when accompanied by pulled muscles or broken bones.)
Third, eat healthy food and get enough sleep. Several studies have shown that a Mediterranean diet, rich in vegetables, fruits, fish and healthy fats like olive oil, is associated with better memory, less cognitive decline, and less brain atrophy in general. Sufficient sleep is known to be important for a healthy memory, and it even clears out certain “wastes” from your brain, known as beta-amyloid plaques, that are linked to dementia.
I’ll also offer some non-advice. You may hear that you can exercise your brain by playing sudoku and visiting “brain game” websites. These relatively mild activities are not likely to increase your odds of becoming a superager, because the level of difficulty is too low. You have to work hard enough to feel the strain of effort.