‘It’s a superpower’: how walking makes us healthier, happier and brainier
Taking a stroll with Shane O’Mara is a risky endeavour. The neuroscientist is so passionate about walking, and our collective right to go for walks, that he is determined not to let the slightest unfortunate aspect of urban design break his stride. So much so, that he has a habit of darting across busy roads as the lights change. “One of life’s great horrors as you’re walking is waiting for permission to cross the street,” he tells me, when we are forced to stop for traffic – a rude interruption when, as he says, “the experience of synchrony when walking together is one of life’s great pleasures”. He knows this not only through personal experience, but from cold, hard data – walking makes us healthier, happier and brainier.
We are wandering the streets of Dublin discussing O’Mara’s new book, In Praise of Walking, a backstage tour of what happens in our brains while we perambulate. Our jaunt begins at the grand old gates of his workplace, Trinity College, and takes in the Irish famine memorial at St Stephen’s Green, the Georgian mile, the birthplace of Francis Bacon, the site of Facebook’s new European mega-HQ and the salubrious seaside dwellings of Sandymount.
O’Mara, 53, is in his element striding through urban landscapes – from epic hikes across London’s sprawl to more sedate ambles in Oxford, where he received his DPhil – and waxing lyrical about science, nature, architecture and literature. He favours what he calls a “motor-centric” view of the brain – that it evolved to support movement and, therefore, if we stop moving about, it won’t work as well.
This is neatly illustrated by the life cycle of the humble sea squirt which,
in its adult form, is a marine invertebrate found clinging to rocks or boat hulls. It has no brain because it has eaten it. During its larval stage, it had a backbone, a single eye and a basic brain to enable it to swim about hunting like “a small, water-dwelling, vertebrate cyclops”, as O’Mara puts it. The larval sea squirt knew when it was hungry and how to move about, and it could tell up from down. But, when it fused on to a rock to start its new vegetative existence, it consumed its redundant eye, brain and spinal cord. Certain species of jellyfish, conversely, start out as brainless polyps on rocks, only developing complicated nerves that might be considered semi-brains as they become swimmers.
Sitting at a desk all day, it’s easy to start feeling like a brainless polyp, whereas walking and talking, as we are this morning, while admiring the Great Sugar Loaf mountain rising beyond the city and a Huguenot cemetery formed in 1693, our minds are fizzing. “Our sensory systems work at their best when they’re moving about the world,” says O’Mara. He cites a 2018 study that tracked participants’ activity levels and personality traits over 20 years, and found that those who moved the least showed malign personality changes, scoring lower in the positive traits: openness, extraversion and agreeableness. There is substantial data showing that walkers have lower rates of depression, too. And we know, says O’Mara, “from the scientific literature, that getting people to engage in physical activity before they engage in a creative act is very powerful. My notion – and we need to test this – is that the activation that occurs across the whole of the brain during problemsolving becomes much greater almost as an accident of walking demanding lots of neural resources.”
O’Mara’s enthusiasm for walking ties in with both of his main interests as a professor of experimental brain research: stress, depression and anxiety; and learning, memory and cognition. “It turns out that the brain systems that support learning, memory and cognition are the same ones that are very badly affected by stress and depression,” he says. “And by a quirk of evolution, these brain systems also support functions such as cognitive mapping,” by which he means our internal GPS system. But these aren’t the only overlaps between movement and mental and cognitive health that neuroscience has identified.
I witnessed the brain-healing effects of walking when my partner was recovering from an acute brain injury. His mind was often unsettled, but during our evening strolls through east London, things started to make more sense and conversation flowed easily. O’Mara nods knowingly. “You’re walking rhythmically together,” he says, “and there are all sorts of rhythms happening in the brain as a result of engaging in that kind of activity, and they’re absent when you’re sitting. One of the great overlooked superpowers we have is that, when we get up and walk, our senses are sharpened. Rhythms that would previously be quiet suddenly come to life, and the way our brain interacts with our body changes.”
From the scant data available on walking and brain injury, says O’Mara, “it is reasonable to surmise that supervised walking may help with acquired brain injury, depending on the nature, type and extent of injury – perhaps by promoting blood flow, and perhaps also through the effect of entraining various electrical rhythms in the brain. And perhaps by engaging in systematic dual tasking, such as talking and walking.”
One such rhythm, he says, is that of theta brainwaves. Theta is a pulse or frequency (seven to eight hertz, to be precise) which, says O’Mara, “you can detect all over the brain during the course of movement, and it has all sorts of wonderful effects in terms of assisting learning and memory, and those kinds of things”. Theta cranks up when we move around because it is needed for spatial learning, and O’Mara suspects that walking is the best movement for such learning. “The timescales that walking affords us are the ones we evolved with,” he writes, “and in which information pickup from the environment most easily occurs.”
Essential brain-nourishing molecules are produced by aerobically demanding activity, too. You’ll get raised levels of brain-derived neurotrophic factor (BDNF) which, writes O’Mara, “could be thought of as a kind of a molecular fertiliser produced within the brain because it supports structural remodelling and growth of synapses after learning … BDNF increases resilience to ageing, and damage caused by trauma or infection.” Then there’s vascular endothelial growth factor (VEGF), which helps to grow the network of blood vessels carrying oxygen and nutrients to brain cells.
Some people, I point out, don’t think walking counts as proper exercise. “This is a terrible mistake,” he says. “What we need to be is much more generally active over the course of the day than we are.” And often, an hour at the gym doesn’t cut it. “What you see if you get people to wear activity monitors is that because they engage in an hour of really intense activity, they engage in much less activity afterwards.”
But you don’t get the endorphin high from walking, I say. “The same hit you get from running is what you’d get from taking morphine? We simply don’t know that’s true,” he says. “People who study this area don’t go on about endorphins and there may be a reason for that.” Not that he is opposed to vigorous exercise, but walking is much more accessible and easily woven into everyday life: “You don’t need to bring any
thing other than comfy shoes and a rain jacket. You don’t have to engage in lots of preparation; stretching, warmup, warm-down …” O’Mara gets off his commuter train a stop early so that he can clock up more steps on his pedometer. To get the maximum health benefits, he recommends that “speed should be consistently high over a reasonable distance – say consistently over 5km/h, sustained for at least 30 minutes, at least four or five times a week.”
Twice during our circuitous route, he asks me to point to where I think our starting point of Trinity College is, and my estimates are pretty close. “That just shows you how good your GPS is,” he says. “You have never been here before, but you have a very good sense of where you need to go.” This is reassuring, I say, because, of course, Google Maps is enfeebling our innate abilities to find our way. “That’s absolute garbage,” says O’Mara. “We really have to get a grip. If you hire a car and drive around a country you’ve never been in, taking a route into a city you’ve