'Physical activity is like Miracle-Gro': Simple steps to boost your brain as you age

From taking on a new challenge to connecting with friends, exercising daily and switching to a Mediterranean diet, there are a lot of simple steps you can take to protect your brain as you age, experts tell Helen O'Callaghan  
'Physical activity is like Miracle-Gro': Simple steps to boost your brain as you age

Picture: iStock 

Old age is no barrier to creativity. This is the view of Professor Denis O’Mahony, consultant geriatrician at Cork University Hospital (CUH), who has met many people who have “remarkably high cognition” right into their 90s.

“I’ve met people who are publishing books and doing all sorts of creative things in their 90s. And you can think of any number of great artists who’ve produced some of their best work at the end of their life,” he says, citing Leonard Cohen, Johnny Cash and Seamus Heaney. “Many are doing terrific work in older age, not just in the arts but through engagement in society at large.”

 O’Mahony, who is also associate professor in the Department of Medicine, UCC, says research consistently tells us that people with healthy lifestyle habits in young and middle adulthood usually retain these into old age, to their benefit. “They tend to have better health, less chronic illness when they come into their older years, retain their functional physical and cognitive independence into advanced old age and they tend to live longer.” 

The lifestyle habits he’s referring to include avoiding smoking, moderating alcohol intake, daily exercise, habitual social engagement and diet close to or fully Mediterranean. “These give the brain the best shot of staying dementia-free,” he says, adding that, while ideally you’d develop these in youth and middle-age and bring them with you into old age, it’s never too early or too late to start.

In fact, it’s estimated that between one-third and 40% of all dementia cases result from modifiable – preventable – risk factors, and O’Mahony says that in 2020 three new modifiable risk factors (excessive alcohol consumption, head injury and air pollution) were added to the 2017 Lancet Commission’s existing nine. These are less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and infrequent social contact.

Prof Denis O'Mahony, consultant in geriatric medicine, CUH. Picture Denis Minihane.
Prof Denis O'Mahony, consultant in geriatric medicine, CUH. Picture Denis Minihane.

Stretch your mind

Health psychologist and neuroscientist Dr Sabina Brennan’s first book, 100 Days to a Younger Brain, has the subtitle ‘Maximise your memory, boost your brain health and defy dementia’. 

Brennan says the human brain is quite resilient and ages relatively well.  “We experience a general sort of slowing, no different to not being able to run as fast, or get up off the floor, as quickly as we used to. It may take a little longer than before to access information, but the information’s there – just as accurate as when we were younger. We experience a small decline in memory for recent events, which could be more to do with failures in attention – paying attention is the first step in memory-making.” 

While we don’t get off scot free when it comes to the fortunes of our brain as we age, it’s not all downhill. “Disease is the cause of most brain decline, but a lot of the decline in brain function isn’t inevitable,” says Brennan.

Brain ageing doesn’t start at 60, she says: research finds our brain starts to atrophy/shrink from around age 30. And many of the so-called ‘age-related’ changes are in fact lifestyle related. 

Brennan says a lot of the healthy lifestyle things we stop doing at about the age of 30 would actually keep our brain healthy. “We stop exercising, learning new things, exploring the world, seeking new opportunities.” This, she says, is because we reach a comfortable point in life and stop stretching ourselves. “Yet, the lifestyle factors that we stop doing would help prevent brain shrinkage and keep our brain resilient.” 

Even if you develop Alzheimer’s disease, research shows healthy lifestyle habits make you more resilient to it. Brennan points to 1980s research that looked – after death – for the difference between the brain of a person diagnosed with Alzheimer’s disease and the brain of a similarly-aged person without that diagnosis. “Alzheimer’s is characterised by plaques and tangles in the brain. The researchers made the amazing discovery that 10 people in the control group – with no diagnosis – had sufficient disease in their brain for a diagnosis, yet they’d never manifested any symptoms.” 

The discovery exploded scientific interest in the question: why were these people resilient to Alzheimer’s disease? “The news is quite good but it’s not a get-out-free card,” says Brennan, explaining that the symptom-less people had built up resilience, by making and maintaining simple but effective lifestyle habits, enabling them to withstand the disease in their brain.

 “They had reserves in their brain that allowed continued function despite the disease present in their brain. So it comes down to – not how much disease you have in your brain – but how much healthy brain you have.” 

There’s a caveat though. Brennan says such people – because Alzheimer's is progressive – do reach a tipping point when there’s too much disease for the brain to cope and the person then gets symptoms.

But it’s still a positive message. “The person with resilience – higher reserve levels – gets to hold onto their cognitive function and live independently for longer than they would have. And this reserve is linked to lifestyle factors, which means we can build ourselves up by making brain-healthy lifestyle choices.”

 Making healthy choices

Brennan divides these brain-healthy choices into three groups:

Activity: Physical, mental and social. All are critical for encouraging neuroplasticity (brain ability to adapt to change and to grow new connections between brain cells). “We’ve 86 billion brain cells, all communicating with each other and the rest of our body’s cells by electrical and chemical signals. Your brain’s constantly communicating to operate you.”

 While the brain’s just two per cent of body weight, it consumes about 25% of our nutritional intake. “It’s a really high-energy organ. And this fuel, including oxygen, is delivered by our cardiovascular system. So what’s good for our heart is good for our brain – the more physically active we are, the better our cardiovascular system can service our brain. On top of that, physical activity releases a chemical – like Miracle-Gro - in our brain encouraging growth of new brain cells and connections between them.” 

Social activity is also critical – no surprise lockdown has been particularly damaging for older people. “Social interaction and engagement are complex activities that keep the brain active. Social isolation and loneliness are as detrimental to physical, mental and brain health as smoking and obesity.”

Lifelong learning is vital for brain health.  Dr Michael Merzenich, Kavli prizewinning neuroscientist, chief scientific officer of California-based Posit Science and described as the ‘godfather of brain plasticity’, strongly advocates that change benefits the brain. 

“See life as an expanding process, not as a contracting process. Engage with the world again. Look for the surprises in it. Continuous learning and living life in a lively vital way are two of the strongest things for improving your brain,” he said in a 2020 interview with late US broadcaster Larry King.

Brennan also urges pushing beyond your comfort zone, seeking novelty. “If you play a musical instrument, push to learn a new piece or technique. Listen to a different genre of music. Read in a different genre. Try a different food. The brain has to pay a lot of attention when it’s first learning something, it has to sit up and take notice – and it gets the benefit of neuroplasticity.”

 Attitude: Over-50s with more positive perceptions of ageing live 7.5 years longer, says Brennan. “Attitudes are powerful – simply switching older adults’ perceptions of ageing to more positive perceptions improves physical function to the same level as a six-month exercise programme.

Dr Joanne Feeney, senior research fellow with the Irish Longitudinal Study on Ageing (TILDA), says the majority of older people – asked to rate their own perception of their memory and cognitive ability – say it’s quite good. “The proportion saying ‘fair’ or ‘poor’ increases with age. Among 75s and over, 30% rate their memory as ‘fair’ or ‘poor’, compared with 15% of those aged 58-64.” 

Brennan says older adults taking memory tests – if told beforehand that ‘memory declines with age’ – perform more poorly than those not told this. “Giving talks to older adults, I urge them never to say ‘senior moments’ or ‘my memory’s going’. It’s a self-fulfilling prophecy – you become what you say,” she says, adding that while one in three describes older people as dependent/sick/frail, in reality only 5% of over 65s live in nursing homes/assisted living.

Lifestyle: sufficient good quality sleep’s critical for brain health. “The brain’s a high-energy organ. It produces a lot of metabolic waste, which can only be cleared when you sleep. Your brain has a job of work to do at night, sorting out memory, clearing out so as to take in more information during the day,” says Brennan.

The sleep cycle shifts with age – you tend to wake earlier, so need to go to bed earlier. “Many people ignore this. They always went to bed at 11pm so they still do, even though they’re waking at 5am.” Recommended sleep for 18-64-year-olds is seven to nine hours; for 65 and over, it’s seven to eight. Balance and regularity around mealtimes and hydration are also important for maintaining brain-sharpness – as well as balance between work and play, time spent in front of screens and being in nature and between exercise and recovery time.

It seems that keeping your brain sharp as you age comes down simply to living a full life.

  • Dr Sabina Brennan’s new book, Beating Brain Fog: Your 30-Day Plan to Think Faster, Sharper, Better (€16.99), addresses multiple causes of brain fog from hormonal changes and chemotherapy, to childbirth, medications, ill health and stress. Visit superbrain.ie.

Boost your brain

Siobhan Cahill, community dementia care coordinator with HSE in Cork, has these brain-boosting tips:

Physical activity: Movement helps to boost production of feel-good neurotransmitters (endorphins). Any moderate aerobic activity that raises a gentle sweat – for example, game of tennis, hike or swim can create feel-good endorphins. Get your body moving – walking, gardening, housework – as long as it’s aerobic, it all counts towards boosting brain-health.

Diet: Like the heart, the brain benefits from a diet low in saturated fats and high in brightly-coloured fruits and green vegetables. Eating oily fish lubricates our brain – rich in omega-3 fats, it appears to dampen inflammation in the brain and bump up the creation of new brain cells. A Mediterranean diet includes high consumption of fruit, veg, beans, peas and complex carbs, with moderate amounts of fish. Olive oil is the main fat source of fat. Drinking a small glass of red wine during dinner is part of it.

Be socially connected: Just 10 minutes of social interaction can greatly increase brain performance. Any simple social interaction with others can be more beneficial than more widely practised brain workouts (playing chess, solving difficult crossword puzzles). Join a book/film club, community group, choir or sports team. Social interaction is a tonic for your brain, stimulating brain cells to grow new connections and strengthening those already formed.

Use your mind: Mental stimulation is a vital ingredient to staying brain-sharp. Challenge/stretch yourself. Avoid getting stuck in a rut, always doing the same thing. Try more complex Sudoku/crosswords. Learn new skill/new language/bridge/new hobby. Develop computer skills. Learning anything new boosts brain connections and builds cognitive reserves.

Sleep: Your brain needs it to run smoothly. While we sleep, memories are sorted and embedded into brain circuits. Sleep can boost powers of recall.

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