Let your mind wander, don’t retire and stop worrying: surprising ways to help save your brain from the cognitive cliff

You write that “changing the way you think about the brain cliff can literally change the way you think and remember”. How?

Dr Norman Swan: There are three things you need to know which are not widely known.

Think cognitive change not cognitive decline: one way people think about our cognitive function is by comparing it to what it was like when we were in our 20s and it’s not a valid comparison. It leads to an assumption that we’ve declined into deficit. That’s not actually what’s happened, especially when we’re in midlife (40s and 50s). Our brains have changed, not deteriorated. Focusing on what that “change” looks like can make the task of maintaining cognitive function and perhaps even improving it, much clearer. Sure, our fluid intelligence – which is about speed and problem-solving – peaks in our 20s, but unless you’re a maths whiz or a gun lab researcher, that is less important than what’s called your crystallised intelligence which can actually improve with age. It’s the wisdom of knowledge and experience.

Secondly, as the years pass, our thoughts move address.

This is about a phenomenon in the brain called scaffolding. To protect our cognitive abilities and perhaps even enhance them as the years pass, our brains build out networks of nerves which act pretty much like the scaffolding inside a skyscraper. It’s the infrastructure around which the brain works. The more successfully we scaffold, the further away we push the brain cliff. This scaffolding initially moves across the brain then into the frontal lobes – the all-important prefrontal cortex which brings our thoughts and memories together and is involved with judgment, decision-making and emotional control.

The third idea is that we should do as much as possible to encourage the scaffolding and as little as possible to get in its way.

I interviewed seven cognitive super-agers, who are as different as you could imagine – from the illiterate 95-year-old shoemaker to the woman who taught Mick Jagger statistics and the 94-year-old woman who still works in McDonald’s in Kyushu, Japan. But underneath, they’re remarkably similar and they’re all protecting their scaffolding in several ways. One example is how they respond to stress. They get over it. They problem-solve. They don’t ruminate. And where do you think we ruminate? Yes, in our prefrontal cortex. So you’re occupying valuable brain space for cognitive function with unproductive circular thoughts. As we move through life, the prefrontal cortex becomes more and more important and anything that distracts or damages it potentially brings the brain cliff closer. Depression affects the prefrontal cortex. Alcohol does too.

You mention that the time to start helping our brains adapt is in our 40s and 50s. What should you be doing at that age and is it ever too late to start?

It’s never too late to start.

Exercise enhances our brain plasticity, which in turn encourages brain scaffolding. An anti-inflammatory diet – with low amounts of red meat, high diversity of vegetables including leafy greens, fermented foods such as yoghurt and fruits such as berries – can change the microbiome and aid direct absorption of bioactive compounds, both of which support brain scaffolding.

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What’s also thought to be part of scaffold building is what’s called the default mode network – what our brain gets up to when it’s supposedly at rest. When the default mode network fires up, parts of the brain that don’t normally talk to each other make connections. How do you know if your default network is at work? Your mind wanders. Mind wandering looks as though it’s good for your brain.

An associated activity is mental time travel: reliving the past, being well anchored in the present and imagining the future. When you’re in midlife you’re in a good place when it comes to mental time travel. When you’re young, there’s not much past; when you’re much older, the past tends to dominate. Mental time travel and mind wandering seem to encourage our scaffolding.

What was the thing about cognitive super-agers which most surprised you, having interviewed so many of them?

One of the important findings from research has been that genes don’t play a large role in whether we’re on a journey to the brain cliff or when we might reach it. That means the environment and how we live matter hugely and that’s what the cognitive super-agers I interviewed illustrated.

There was only one of them where you could convince yourself that his family history mattered, and even he – a neuropsychiatrist from New Jersey aged 100 – was doing the things that maintain your brain. He had learned a new skill – pencil drawing – and through the classes had made new friends and was well connected with other people beyond his family.

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What have you changed in your own life or daily habits since going on this deep dive into cognitive decline?

I’ve become much more aware of when I might be ruminating and how I respond to stress. I work hard at problem solving and “getting over it”. I’ve really cut back my alcohol intake – not that it was ever high. I’m much more assiduous about my coronary risk factors like cholesterol and blood pressure. Leafy greens, berries and yoghurt are more prominent in my diet, and moderate to vigorous exercise is not an optional extra in my life. Oh … and I’ve no intention of retiring. Retirement is bad for your brain. So the ABC will have to sack me.

You say that rumination and stress may accelerate cognitive change. How, and how can people best try to counteract this?

For some people these are disabling and it’s hard to change by yourself. There are variations on cognitive behavioural therapy which can help in the hands of a well-trained clinical psychologist.

You have a chapter titled “Don’t Retire”. Should we all be working until we drop?

Work is mostly good for our brains. The evidence is strong that cognitive decline speeds up after retirement. Now some people with hard physical jobs simply can’t keep them up. The point here is what retirement means. If you move from your job to other work such as volunteering, new leisure activities, learning new and complex skills, then that’s actually not retirement. You’re still at work. Retirement to the couch and Netflix is a bad idea.