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.
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“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 problem-solving 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.
The function of the brain is to help us do things that aid our survival. The more you do, the more you need to process information.
Moving about is simply a very large subset of doing, of interacting with the outside world. Before the evolution of speech, art and tool-making, it was nearly all of it. Swallowing food, ejaculating gametes, eliminating wastes and biting attackers made up the rest.
Correlation, causation: the disabled have plenty of reasons to be cranky. Sessile creatures are mindless because they can afford to be, but they’re not chronically out of sorts.
Boredom is a sign that we are insufficiently engaged actively with the world. It is the painful death by starvation of consciousness.
I had always thought of walking as a way of clearing the mind, i.e. helping to shut down stressful thoughts that then allow us to think more clearly about individual topics. So less brain activation rather than more. Maybe I’ve been thinking about it in the wrong way, and its more activation in the areas of the brain that are responsible for walking that swamps areas that usually think stressful things.
Years ago I worked with a man who used to go to the local medical practice for anti-depressant tablets. Trouble was for him there were two doctors at the practice and it was a case of ‘who’s next.?’ No one had a say which of the doctors was available. The older doctor would simply say to this man ‘I’m not giving you any tablets. just go for a walk.’ The younger one would write whatever prescription was demanded.
The man hated seeing the older doctor and would ‘pass’ to allow someone else to see the older doctor. He wanted the tablets so bad, yet they never did him any good.
I distrust the very idea of getting rid of stressful thoughts by any means other than addressing the cause. A stressful thought is the awareness of a problem to be solved. It is a mental pain signal. Solve the problem and move on.
Depression is a symptom, not an illness. Any sensible and effective treatment must focus on identifying and fixing the cause. If the cause is proven – not merely assumed – to be some chemical imbalance, then figure out why there’s a chemical imbalance. If the cause is an actual life problem, then address the actual life problem.
The only antidepressant I believe in is getting rid of depressants. Whatever brings you down has got to go.
To contrast with the kinda new-age crystal energy tone of this posting, how ’bout “walking” on steroids: Jump on your motorcycle and crank it up.
Ride to live. Live to ride. Hey, it’s good for your brain!
Harry Jones: I’ve recently come to the same conclusion about depression, it’s a symptom. Barring injuries or congenital factors, in my opinion, depression in an otherwise healthy person is a symptom of chronic cognitive dissonance. For whatever reason the depressed person has by habit or ideology decided to ignore some aspect of reality. The ‘natural brain’ is still processing reality while the depressed person willfully ignores the normal promptings. The resulting stress of supressing reality eventually takes its toll.
No kindle?
:-(
Matches my priors well enough to explore further
The towering Werner Herzog makes two life recommendations to those who would be great:
1. To read constantly — thousands and thousands of books; and
2. To travel by foot.
Sauce: https://youtube.com/watch?v=Eua5iPUKw6Y
I can’t walk as much, as well, or as fast as I used to but I should still do more. I well remember how good it has always felt. It was, to spin off what Jon Davies said, both mind clearing/relaxing and mind-engaging/energizing for me. Perhaps not the only thing that can fill both roles, but it did both for me.
Should probably do more, again. These days it’s mostly point A to point B.
Harry Jones makes a useful distinction, at least I find it so. Depression can certainly be both chemical and life-problem, though I’m not sure they are always so easy to separate. Worth keeping in mind, though, since solving a problem if you can is far better than enduring it. Stoicism is a fall-back position, not a primary solution.
I’m intrigued by though not so sure of your point, Wang Wei Lin. I’ve had it in the back of my head a few days now. I’m keeping an open mind to it because it is a striking way to think about it, but I still doubt. The shortest way I can express my doubt is that depression for me has more often seemed like a function of the recognition of unhappy reality and the inability to see past it.
there’s something existentialist not to say even Nietzschean about the notion that only failure to accept reality could produce depression, insofar as it implied that a healthy person should be happy in recognizing and experiencing any reality. I can almost praise this but it seems unrealistic, to coin a phrase.