Main Move!: The New Science of Body Movement and How it Can Set Your Mind Free

Move!: The New Science of Body Movement and How it Can Set Your Mind Free

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Did you know that walking can improve your cognitive skills? That strengthening your muscular core reduces anxiety? That light stretching can combat a whole host of mental and bodily ailments, from stress to inflammation? We all know that exercise changes the way you think and feel. But scientists are just starting to discover exactly how it works.

In Move!, Caroline Williams explores the emerging science of how movement opens up a hotline to our minds. Interviewing researchers and practitioners around the world, she reveals how you can work your body to improve your mind. As lockdown throws us back on our own mental and physical resources, there is no better time to take control of how you think and feel.
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Also by Caroline Williams



The New Science of Body Over Mind


First published in Great Britain in 2021 by

Profile Books Ltd

29 Cloth Fair



Copyright © Caroline Williams, 2021

The moral right of the author has been asserted.

All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), without the prior written permission of both the copyright owner and the publisher of this book.

A CIP catalogue record for this book is available from the British Library.

ISBN 9781788164610

Export ISBN 9781788167284

eISBN 9781782836629

Audio ISBN 9781782838463

For Jon and Sam,

who keep me moving



1. Why We Move

2. The Joy of Steps

3. Fighting Fit

4. Slave to the Rhythm

5. Core Benefits

6. Stretch

7. Breathless

8. And … Stop

Summary: Move, Think, Feel

And Finally: A Movement Manifesto




‘Just come in and move however your body wants to …’

This is the moment I have been dreading all day. It’s 7.30 p.m. on a Wednesday and I have come to a village hall in Surrey, England, for what I’ve been told will be an evening of mind-altering free-form dance.

The young man on the door takes my money and encourages me inside. It’s dark, apart from a few candles and fairy lights, but I can just make out a middle-aged DJ with a bleached crew cut and harem pants, spinning what probably comes under the banner of gentle tribal beats. One woman is rolling on the floor, while another is wafting around chasing imaginary butterflies. Then two of them start hugging. At which point my body tells me very clearly that it would like to move, as quickly as possible, back through the door.

I don’t, and as the evening progresses, my body gives up ; the fight and starts to move. As the drums build towards a climax, the DJ murmurs ‘let go’ into the mic. Suddenly, as if he flicked a switch, I notice that I’m no longer moving my legs: they are moving me. My feet are hammering the floor at an alarming rate, as my head shakes from side to side and my arms flail in circles. I couldn’t stop if I wanted to, and I feel unleashed, alive, free.

It was my first foray into the world of how movement can radically affect the mind, and it was something of an eye-opener. I’ll be honest: getting high on life like this isn’t my usual kind of thing at all. My thing is more about sitting quietly, reading, thinking and writing about the peculiarities of the human mind – trying to get my head around why people think the way we do, and what science can tell us about how we might overcome the many mental and emotional glitches – from a lack of focus to anxiety and depression – that seem to come as part of the deal.

But then one day it occurred to me that my mind seems to work best when my body is on the move, and I started to wonder why. What is it about going for a long walk that unravels tricky scientific concepts in my head and helps a jumble of ideas finally coalesce into sentences? Why does an hour of yoga make me feel calm and in control, no matter what challenges the rest of the day holds? And why does jumping around to music in the kitchen make me feel so damn happy?

A spell of sitting and reading later, it transpired that I wasn’t the only one asking these questions. Scientists working across a huge variety of disciplines, from neuroscience to cell biology, from exercise physiology to evolutionary biology, have started to investigate how bodily movement affects the mind and are just beginning to tease apart the physiological mechanisms that explain why. What they are finding is potentially game-changing scientifically and, given the way most of us live our lives these days, profoundly important for our overall health and well-being.

It shouldn’t be news by now that most of us aren’t moving anywhere near enough, myself included. After walking the dog for an hour in the morning, my working day mostly involves sitting at a desk and moving no further than the kitchen for multiple cups of tea. If he’s lucky, the dog gets another wander through the woods, and on some days I do yoga, but more often than not weekday evenings involve yet more sitting, followed by eight hours in bed. Statistically, my life isn’t all that unusual. The average modern adult spends 70 per cent of their life sitting or lying completely still; we move around 30 per cent less than our counterparts in the 1960s. Children spend up to 50 per cent of their free time sitting around, and that’s before you factor all those hours bent over a school desk.1 Elderly people, unsurprisingly, clock up even more hours of stillness, spending up to 80 per cent of their waking day barely moving a muscle.2

There are good reasons why we, as a species, have chosen the way of the sloth. First, it’s comfortable. And second, we have spent most of the past century inventing technologies that make movement unnecessary. Unlike almost all of the other creatures on the planet, we are now in a position where we barely need to shift our bodies to find food, stay entertained or even find mates. Most of it can be done sitting down and occasionally moving our thumbs.

Yet while we (stiffly) pat ourselves on the back for having the brains to make this happen, we are missing something important. The brain evolved not for us to think but to allow us to move – away from danger and towards rewards. Everything else, from our senses to our memories, emotions and ability to plan ahead, was bolted on later to make these movements better informed. Moving is at the heart of the way we think and feel. If we stay still, our cognitive and emotional abilities become seriously compromised.

Sure enough, as we make ourselves comfortable, the cracks in our collective psyche are beginning to show. Our increasingly sedentary lifestyles have been linked to falling IQs,3 a vacuum in new creative ideas,4 a rise in antisocial behaviour5 and an epidemic of mental illness that is affecting people of all ages and from all walks of life.6

Studies suggest that both self-esteem and pro-social behaviour tend to be lower among people who spend more time sitting,7 and that sedentary time is linked to a greater risk of anxiety and depression. Although it isn’t clear which comes first, the sitting or the depression, physical activity is well known to be helpful in relieving symptoms of both conditions, so it stands to reason that a sedentary lifestyle is not ideal for anyone at risk of, or already dealing with, mental health issues.

Cognitive skills, too, take a hit when we sit. Being sedentary for long periods is the enemy of focused attention, memory and planning ability and puts an unnecessary lid on our creativity. A recent study of young Finnish schoolchildren found a significant relationship between the amount of time spent sitting and achievement in standardised maths and English tests over the course of two years, particularly among boys.8 The rot sets in at an early age, and if we do nothing about it, sitting still becomes a lifelong habit.9

It also makes us old before our time. In studies, middle-aged people who spent more than two or three hours per day sitting in the car or in front of the TV were found to lose their mental sharpness significantly faster than those who were more active. We also know that regular exercise can reduce the lifetime risk of dementia by 28 per cent.10 By one recent estimate, as many as 13 per cent of Alzheimer’s cases worldwide can be traced back to a sedentary lifestyle. By another, reducing sitting time by a quarter could prevent more than a million new diagnoses worldwide. It doesn’t matter how you cut the numbers, the message is the same: move more, and your brain will thank you in the long run.

Given our collective propensity for lolling around, it is perhaps more alarming than surprising that our sedentary ways may be affecting IQ at a population level, making humankind as a whole just a little bit less smart. IQ scores had, until recently, been rising by an average of 3 points per decade, for as long as people had been taking IQ tests and in countries all over the world. The trend is named the Flynn Effect, after the New Zealand-based psychologist James Flynn, who first documented it back in the 1980s.11

Soon afterwards, however, from the mid-1990s onwards, the Flynn Effect started to slow down, and by the early 2000s the trend was running in reverse, at the rate of a few points per decade.12 Some observers explained this with the controversial claim that less intelligent people tend to have more children, which over time could have diluted national averages.13 Others suggested that an increase in global migration was to blame, because incoming foreigners didn’t quite understand the questions.14 A recent study from Norway, though, shows quite clearly that neither of these – let’s be honest, offensive – explanations holds water. By tracking IQ scores of young men from the same family over several decades, researchers found that IQ scores were declining within families across different generations. This means that it can’t be down to changes in genetic fitness – evolution doesn’t work that fast, and certainly not for complex traits such as intelligence, where variation is explained not by one gene but many. It is much more likely that the changes can be explained by changes in the environment.

Or, perhaps, by the way we choose to use it.

A lack of movement isn’t the only change in our lifestyles in recent years, but there is no doubt that the descent to seatedness is an important social change that has been creeping up on us for some time, and not only in the pampered West. A study from 2012 compared the amount of physical activity involved in work, leisure, home life and travel in the US, UK, China, India and Brazil from the 1960s onwards. Everywhere they looked, physical activity was on a downturn – and not only in leisure time but all the time. The fastest declines were in China and Brazil during the 1990s. These were mostly accounted for by changes at work and home, as physical labour gave way to office work and home appliances made daily chores less of a workout. Only India seemed to be bucking the trend, at least in 2012, but sedentary time had already shown signs of rising there too.15

The gym is not enough

If you’re the kind of person who diligently hits the gym every day, you are probably feeling pretty smug right now. But there’s a catch: exercise – at least the way we currently think of it, as something to do in earnest between long periods of sitting – is not the way to turn things around. Brain imaging studies show that there is a correlation between the thickness of brain regions involved in memory and the amount of time a person spends sitting, regardless of whether or not they also do high-intensity exercise at some point during the day. And while mood and focus do spike briefly after a period of exercise, overall it doesn’t matter if you go for broke for an hour in your lunchtime spinning class. The effects of sitting still for the four hours either side of lunch don’t go away.

In fact, you could argue that binge-exercising is missing the point of movement entirely. In her book Move Your DNA, movement guru Katy Bowman makes exactly this point. She says that exercising in short bursts, or to target certain muscles, is a bit like taking vitamin supplements to try and offset an unhealthy diet. It may help, but it’s never going to make you truly healthy, and it will probably leave you hungry for what she calls ‘nutritious movement’. Bowman doesn’t delve all that deeply into how movement affects the mind, but I would argue that movement nutrition is at least as important for our mental, cognitive and emotional health as it is for our physical well-being. Moving our bodies in certain characteristically human ways connects us to the equally fundamentally human ways that we think, feel and make sense of the world that’s both around us and within.

This is a theme that I’ll return to in a few pages’ time. For now, though, the important thing to know is that, as a society, we’re not moving enough, and what little we are doing we are mostly doing wrong. That’s the bad news. And here comes the good: it doesn’t matter what you want to do with your mind. Whether you want to learn better, slow brain ageing, spark new ideas or just feel more in control of your mental health, there is almost nothing that moving more – and in particular ways – can’t help you to achieve. Body movements can serve as a short-cut to changing the ways we think and feel.

This is a big deal: contrary to received wisdom, thoughts don’t only come from inside our heads, and thoughts are not the only routes to emotions. Some kinds of body movement help to reduce inflammation – a modern-day scourge linked to everything from depression to chronic pain. Others hijack the brain–body stress pathways in ways that help dial down feelings of anxiety and instil a visceral sense of confidence. Others change the way that electrical information flows through the brain, directly affecting our mental state. Move right and the body becomes an extension to and an equal partner of the brain – not just the meat suit that carries it around.

I say this with confidence because many scientists are changing the way they think of the body and its relationship to the mind. After many years in which science cast the body as an understudy in the story of our mental lives, it has finally landed itself a starring role. For decades the mind has been thought of as being run exclusively by the brain, sitting high and dry in the head while the squelching, churning, pumping and filtering activities of the body managed the dirty business of keeping us alive. Now, though, we now know that, unglamorous as they may seem compared with the electrical fizzing and whizzing of the brain, our bodily functions are just as much of a key component in what makes us tick.

As we’ll see in the next section, the dirty business of keeping us alive actually involves a huge amount of communication between the body’s various organs, the pipes and wires joining them up and the bodily fluids that swoosh around and between them. This communication provides a constant backing track to our lives, directing our thoughts and colouring the way we feel.

In this new view the brain has a different, although no less important, role. According to the influential psychologist Guy Claxton, rather than being the master controller and arbiter of our every thought and decision, it instead acts as a kind of ‘chatroom’ that hosts the body–mind conversation that makes up our mental life. Here, he says, ‘swarms of factors can come together and, through communication, agree on a plan’.16 The brain is not so much the boss as a facilitator, bringing the key players to the table and allowing everyone to be heard and to come up with a collective plan of action.

‘Action’ is the important word here because that’s where the link to movement comes in. The power of movement is that it allows us to hack into this body–mind chatroom and changes the tone of the conversation for the better. The overall aim of this book is to reveal some of these emerging dials and levers and how they work, using the best, most up-to-date science that we have.

In the pages that follow I’ll meet not only the scientists who are investigating the physiological, neural and hormonal connections that link body and mind but also the many inspirational people who are putting the theory into practice and proving its worth in real life. From a psychologist who overcame illiteracy with the help of dance to an ultra-marathon runner who outpaced his demons, and from a neuroscientist who has found out he was wrong about Pilates to a stuntman who is helping kids backflip their way to better mind control, there is no shortage of people who are living proof of the movement solution. Science provides the data, but these people provide the inspiration to make a few simple changes that really can improve your life.

Ultimately, whether you are looking for more brain power, to feel more connected to others or just more in control of your life, the message from all corners of science is coming through loud and clear: this is no time to be sitting around.


Why We Move

That which we call thinking is the evolutionary internalisation of movement.

Rodolfo Llinás

Nothing in biology makes sense except in the light of evolution.

Theodosius Dobzhansky

Some days, the life of a sea squirt sounds almost idyllic. After a brief swim around the ocean while it’s young and still has the energy, the tadpole-like larva finds a rock with a view and settles down for a rest. Once attached, it sets about developing into its adult form, a blob with two tubes. There it will sit for the rest of its life, gently sucking in water through one tube and blowing it out of the other like a small, rubbery bagpipe.

There’s a high price to pay for this lifetime of relaxation. In its larval stage a sea squirt has a simple brain and a basic nerve cord that runs along the length of its tail. It uses these to swim around, searching for a good spot to live, and to coordinate its movements to get there. Once attached, though, glued firmly to the rock by its head, the sea squirt digests almost its entire nervous system, never to make a decision again.

The curious case of the disposable brain tells us something about why we have a nervous system at all. And, before we get to the ‘how to’ aspects of body movement over mind, it’s worth considering why the many body–brain pathways came to exist. The distinguished Colombian neuroscientist Rodolfo Llinás used the sea squirt to make the case that animals originally evolved brains not so that they could think but so that they could move – away from danger and towards where the living is easier, making informed decisions as they go. Movement, Llinás reasoned, is simply too dangerous to attempt without a plan.1

Sea squirts represent a snapshot of a time in evolution when life was experimenting with whether a nervous system was any more likely to make you survive the rigours of existence. Nervous systems are expensive to run – our own brains gobble up 20 per cent of our body’s entire energy budget despite accounting for only 2 per cent of our body weight. For the sea squirt, the answer was that the investment was worth it for as long as it was on the move, but thereafter, not so much. And when movement is no longer necessary, thinking is surplus to requirements, so the whole system goes in the recycling.

Since this period of evolutionary dithering, most species of animals have opted not only to keep a brain throughout the entirety of their lifespan but also to invest heavily in its architecture. Thinking and movement have been evolving in lockstep ever since. The human brain is by no means the pinnacle of the process of brain development – each creature’s brain is, after all, uniquely adapted to its own way of life – but in terms of investment it is certainly an extreme example. Our brains contain three times as many neurons as our closest living relatives the chimpanzees. In fact, with 86 billion neurons with over 100 trillion connections between them, the human brain is the most complicated object we have ever encountered.

Explanations of how we got this way generally concentrate on our cortex, the wrinkly outer layer of the brain, which is disproportionately large in humans compared with other apes. The wrinkles are actually a product of its size: as the cortex expanded, adding more and more processing power, the only way it could fit into the skull was to repeatedly fold in on itself. Other species with a smaller cortex, such as dogs, cats and chimpanzees, have far fewer folds and wrinkles than us. Some, including mice, rats and marmosets, don’t have any at all – their brains are as smooth as raw, skinned chicken.

Some think that our cortex enlarged to cope with the challenges of finding new ways to think – keeping track of our complex social lives, for example, or predicting where the next meal might show up and working out how to catch it. Then, once we used our big brains to work out how to cook, they got even bigger, because cooking allowed us to extract more calories from our food. All of this added up to an unusually large cortex that allows us to plan, to mentally travel back and forward in time and to come up with ideas for things that have never existed before.

That’s a good synopsis as far as it goes, yet it totally ignores the influence of movement. A new theory adds this vital detail into our origin story, linking the evolution of forward thinking not to abstract computations inside the head but to a growing evolutionary pressure to come up with new ways to move. In this view, the origin of our most impressive mental tricks can be traced even further back in our evolutionary history, to a time before humans existed, when our even more distant ancestors needed to find new ways to get around.

Twenty-five million years ago the common ancestor that we share with other apes split off the evolutionary tree from the monkeys. These early apes lived in the trees like their monkey cousins but were bigger, heavier and clumsier and were in constant danger of falling from the branches. Their solution to this problem was quite sensible: to spend more time bearing their weight on their hands, holding on tightly to branches above in situations where smaller monkeys might have been able to balance. This strategy worked well, and over millions of years (and some shoulder modifications) slowly evolved into an ability to brachiate – swinging arm over arm in the trees at speed, as gibbons do today.

Brachiation is a complicated way of moving. According to the evolutionary anthropologist Robert Barton, of Durham University, it requires more than just a vague plan of action to stand any chance of getting from A to B safely. Staying safe while swinging through the trees requires an ability to link movement to an understanding of the consequences of your actions at speed – I put my hand here, swing and reach … that one won’t hold my weight, so I’ll grab here and so on – which means being able to formulate and adapt a plan on the fly. In a paper published in 2014 Barton put forward his idea that the development of the extra brain circuitry needed to support this new skill not only led to an improvement in our ancestors’ physical gymnastic skills but also set the stage for our impressive mental gymnastics.2

The circuitry that is in charge of these kinds of super-fast movements is found not in the wrinkly cortex but in the cerebellum – the small, cauliflower-like region that, in diagrams at least, looks as if it’s dangling from the bottom of the rest of the brain. At about the time that the early apes started swinging through the trees, the cerebellum started expanding, becoming disproportionately large compared with the cortex. This trend continued through the evolution of the great apes and accelerated in the branch that led to us.

The way the cerebellum is built seems to have made this expansion a fairly straightforward process. While the rest of the brain’s wiring looks a bit like the organised chaos of an old-fashioned telephone exchange, the cerebellum is more like a well-kept vineyard, with neat rows of neurons linked with super-fast input and output wires. That means that another ‘module’ can be replicated and then bolted on fairly quickly, at least on an evolutionary timescale.

Until recently this finding would have raised a huge ‘so what?’ in evolutionary biology circles. The cerebellum had long been known to be specialised for fine-movement control. It shouldn’t have been terribly surprising that the cerebellum would expand to support a complex new movement skill.

Then in the late 1990s and early 2000s the view of the cerebellum started to change. It was gradually becoming clear that what the cerebellum does for movement it also does for thinking and emotional control. Brain imaging experiments and tracing of neurons throughout the brain revealed that many of the evolutionarily newer cerebellum ‘modules’ wire up to the frontal parts of the cortex, which are in charge of planning and forward thinking and help to fine-tune our emotional reactions. In fact, it turned out that only a small portion of the human cerebellum connects to the movement-generating parts of the rest of the brain. The rest specialises in thinking and feeling.

Barton’s theory is that, when brachiation tied together movement, forward planning and potentially fear of falling from a great height, it set us up for all manner of sequential thinking, from understanding the rules of language and numbers to building simple tools, telling stories and working out how to get to the moon and back. It’s tempting to speculate that it may also underlie the sensations that accompany some of our less successful social interactions: swinging and falling is certainly how it can feel when a conversation suddenly takes a turn for the worse.

The ability to think sequentially is particularly useful for skills that require not only fine sensory motor control but also a capacity to work out a sequence of actions that will lead you to your goal – central to the ability to knit a scarf or think through a series of moves in chess. It could also explain how chimpanzees can work out the sequence of movements that will allow them to adapt a twig to fish for termites. ‘Our capacity to work out how to achieve a goal by stringing together a sequence of actions is kind of the basis of our causal understanding of the world,’ says Barton.

Blame the ancestors

Twig technology aside, the other great apes haven’t done a great deal with their expanded forward-planning skills. Humans, though, took the ball and ran with it in a big way. One potential reason for this is that when our ancestors split off from the other apes, they started adopting a very different lifestyle, one in which they spent far less time in the trees and started roaming longer distances on the ground in search of food. The mental and physical demands of this new lifestyle brought about another crunch point in evolution, where new ways of moving and thinking came together and worked hand in hand to increase the species’ chances of survival. As a result, being physically active started to become non-negotiable to keep the brain working at peak capacity.

It’s worth a quick aside at this point to remember that evolution doesn’t work with an endgame in mind. Our minds and bodies didn’t get to be the way they are today because evolution had a plan to make us the cleverest, most self-aware species on the planet. We got here because the changes that brought us to this point must have provided some kind of survival advantage when they first appeared. Each of them had to be useful from the start, and they stuck around because they continued to supply benefits.

Use it or lose it, then, is a rule of evolution in general, but in terms of our physiological responses to movement it applies to us especially. It’s well known that our ability to exercise – our cardiovascular fitness, our muscle strength and so on – is directly linked to how much we as individuals have challenged those systems in the past. That isn’t the case for all species: bar-headed geese, for example, manage a 3,000-kilometre migration each year with no training at all. The physiological changes that build them stronger flight muscles and a bigger, more efficient heart are triggered not by months of intense training but by the change of season and a lot of extra food.3 It’s the stuff of dreams – imagine if the shortest day heralded not only the coming spring but also an increasingly fit and toned beach body, just in time for summer (but only if you ate enough pizza).

Unfortunately, our bodies aren’t built that way, and it seems that the same ‘use it or lose it’ rules apply to the brain. According to David Raichlen, who studies human evolution at the University of Southern California, this is a feature that can be traced to a point in time, around 4 million years ago, when our ancestors stopped being ape-like animals who sat around in the trees all day eating fruit, and started to explore.

At the time the climate in East Africa was becoming cooler and drier, and tropical forest was giving way to woodland and savannah. This made food more difficult to find and forced our ancestors to forage further afield. Under these circumstances, evolution would have favoured those who could stand up straighter to walk or run long distances in search of food.4

Those who were not only able to walk and run long distances but also to make intelligent decisions – finding their way to where the best forage is found, remembering the way back to base and so on – were even more likely to survive and pass on their genes. Around 2.6 million years ago, when hunting skills were added to gathering, thinking on our feet became yet more critical. Now our ancestors not only had to forage widely and wisely but also had to work together to outwit and bring down larger prey. And so these two selection pressures – to walk further and think better – were tied together in the unique evolutionary history of our species.

As a result, says Raichlen, our physiology became fixed so that, when we exercise, the brain responds by physically adding more capacity.5 The hippocampus, a part of the brain that is involved in spatial navigation and memory, responds to physical exercise by adding new cells – essentially adding capacity to the brain’s memory banks. If this new capacity is then called upon in future foraging or hunting bouts, it is more likely to be retained. New neurons are only part of this brain-boosting process. The extra capacity also requires more blood vessels, which allow for more fuel and oxygen to flow around the brain, helping it to do its job.

On the flip side, if the new memory banks are left idle, the brain will begin to make energy savings, removing any architecture that isn’t strictly necessary and trimming unused capacity to claw back some of its energy budget and divert it to where it’s needed.

The upshot of all this is that, while our closest relatives among the great apes get away with being couch potatoes, moving only if they can’t possibly avoid it and suffering no physical or mental repercussions for their laziness, we, like the sea squirt before us, can’t. The specific challenges of survival as a hunter–gatherer tied the nuts and bolts of our mental capacity to our levels of activity.

Sitting around is no longer an option for humankind if we want a healthy body and mind: that ship sailed when our ancestors gave up a life of fruit in the trees. As for how much we need to move, studies of the Hadza people, modern hunter–gatherers who live in northern Tanzania, have found that women walk almost 6 kilometres per day, while men cover 11.5 kilometres, the equivalent of 8,000–15,000 steps. If we take this as a rough guide to what our bodies evolved to do, it means that getting your steps in is non-negotiable for a fully functioning brain. If you don’t like it, take it up with Homo erectus, the species of ancient humans that started the whole sorry business.

On the upside, the evolutionary pressures that link moving and thinking are the very same ones that make moving feel good – including the well-known endorphin boost, which makes exercise feel effortless, even euphoric, and encourages us to keep going when we start to get tired. On the other hand, it raises the worrying possibility that, if our minds are there to help us move – and we don’t – perhaps we risk a future as a race of couch-bound filter-feeders, our hard-earned brains turned to mush.

It’s too soon to panic, though. Humans are nothing if not adaptable. What we need to do is use that adaptability to spring into action once again, to unglue ourselves from the sofa, get up and remember how good it feels to move.

Travelling without moving

The final part of our moving, thinking and feeling story is more difficult to pin down to a particular point in our evolutionary history, not least because we can’t see it happening in our own heads, let alone those of other species. But we do know that it must have happened, because at some point we became able to move not just physically but also virtually, inside our mind’s eye.

Whether other species can do this too is very much a moot point. There is some evidence of what looks a lot like thinking ahead in some species. In 2009 a captive chimpanzee called Santino was seen calmly piling up rocks in his compound at Furuvik Zoo in Sweden, which he would later hurl at visitors in what looked a lot like a premeditated attack.6 Similarly scrub jays, one of the cleverest members of the crow family, cache food to eat later. In experiments where they were fed boring kibble and then occasionally given something more exciting, they seemed to plan ahead and store more of the good stuff for later, when plain rations would presumably return.7 While some call this evidence of forward thinking, other scientists insist that it doesn’t prove that they are preparing for the needs of their future selves. Until we find a way to talk to the animals, we will never know for sure.

We do know, however, that humans definitely can relive the past and plan for the future. The ability to imagine things that have never been, mentally to travel back and forth in time to learn from the past and to plan for the future is very much a human speciality, and it all comes down to what Rodolfo Llinás calls the ‘evolutionary internalisation of movement’. From Llinás’s point of view, thinking and moving are basically the same kind of thing. The only difference is that movement has a final stage that makes it real to the outside world too.

The advantages of this ability are obvious. Unlike moving, thinking is invisible and risk-free, allowing us to explore the world in our own minds, trying things out for size and updating them based on new information before we risk life and limb. Something similar is true for emotions. The whole point of emotions is to stir us into action to change something that isn’t right in the world: the word ‘emotion’ comes from the Latin for ‘to move away’. It stands to reason that if the process of moving can begin mentally, before it shows on the outside, that gives an animal a huge advantage in terms of outwitting predators or rivals and navigating our complex social world.

Interestingly, experiments dating back to the 1960s showed that the body–brain–understanding system has to be trained on real-life movement if it is to work later in the virtual world of our minds. In a classic (but heart-breaking) experiment into visual perception two kittens were strapped into a kitten-sized carousel.8 There they would spend their days going round and round, each looking out at exactly the same laboratory-based view as the other. The only difference between them was that one kitten had its feet on the floor and could drive the carousel by walking forwards. The other was suspended in a box, with no contact with the ground or control over the carousel’s spin. After a few weeks like this the kittens were finally freed. The one that was allowed to drive the carousel with its feet was seemingly fine – able to see normally and move through the world with no problems at all. The other one was, to all intents and purposes, blind: it couldn’t avoid obstacles and couldn’t navigate the room safely. The scientists concluded that because the kitten hadn’t been able to link its body movements with the changing outside world in early life, it never learned to make sense of what its eyes could see.

What it’s like

Outside of the lab, of course, these connections between movement and internal experience happen automatically, and gradually build up to provide the basis for a rich understanding of our place in the world and how our actions affect what we experience.

This process may even explain a basic mystery of human consciousness: why we have such rich sensory experiences that exist only in our mind’s eye. How is it that we can so vividly imagine smelling a rose or seeing a sunset, for example, or conjure up the warm and fuzzy feeling of hugging someone we love? These imagined experiences feel like they are in our heads, but philosopher J. Kevin O’Regan of Paris Descartes University points out that these experiences begin with the way we move our bodies and physically interact with the environment.9 These sensations then get unhooked from bodily experiences and become amplified, going around and around in a mental loop, becoming more intense as they go. According to this theory, our rich imagination – the ability to ‘feel’ the sensations in a piece of writing or be ‘moved’ by a piece of art – comes from the way that our movements and interactions with the world can be detached from the world outside and sent undercover, where we can enjoy them privately.10

In sum, whether it’s our capacity to plan ahead, to remember where we are and what we are doing, to imagine the future or to feel deeply, the very experience of being human is intimately tied to our movements through the world. Vital, in fact, to the very concept of the mind.

Mind in body or body in mind?

This seems like a good point to acknowledge that the ideas in this book are tied up with some fairly hefty ongoing scientific and philosophical debates, the biggest being what – and where – the mind actually is.

In the view of cognitive scientists the mind is a construct of the brain. According to this argument, the brain functions as a kind of master computer, with the neurons and other cells of the nervous system acting as the hardware on which the software of the mind runs. From this point of view, the body is important, but mostly as a source of inputs into the system. It’s up to the brain’s clever algorithms to work out what’s going on and decide what to do about it.

The concept of the body doing the bidding of the all-powerful brain is probably how most people think about things. It’s even reflected in popular culture: in the classic 1990s film The Matrix intelligent machines grow humans in vats, keeping them busy with a fake version of reality directly projected into their brains. When Neo needs to learn Kung Fu – no problem, there’s an app for that.

People who work in embodied cognition don’t buy into this at all. They see the brain not as a master computer but as one node of a much larger network that spans not only the wider body but also the surrounding environment. In this view, it wouldn’t matter how much Neo’s brain knew about Kung Fu if he hadn’t learned the movements by actually doing them. Like the poor kitten on the carousel, he’d have no hope of putting what he’d learned into action.

The body certainly knows more than we generally give it credit for. Thanks to our sense of ‘proprioception’, the implicit knowledge of where our body is in space, we can move around without banging into things, adjust our balance without thinking about it or reflexively stick a hand out to catch a ball that is about to hit us in the face. Through proprioception we instinctively know where we are, how we are moving and where our body begins and ends.

Then there is the more mysterious sense, interoception: our ability to detect the internal physiological state of the body. All day and night the body busies itself tweaking countless physiological dials that keep our biology within a safe, liveable range. This constant tweaking, called homeostasis, is an ongoing effort with different systems managing their respective departments – heart rate, blood sugar level, water balance and so on – while keeping each other abreast of any news. Some of these changes we are conscious of (a racing heart, for example), and others we are not. Nevertheless, according to the Portuguese neuroscientist Antonio Damasio, of the University of Southern California, they influence our minds all the same.

For Damasio, the ongoing process of homeostasis, whether conscious or unconscious, is a central building block of our sense of self and of how that sense of ‘me’ experiences the here and now. Through homeostasis, and through our interoceptive sense of what is happening, we know whether we are on edge or relaxed, tired, thirsty or in need of a snack. Interoceptive ability varies, and the better a person is at sensing their internal state, the more likely they are to take action to put things back into balance – to seek out rest or to get away from someone who gives them a bad ‘gut feeling’, for example.

This isn’t to say that the brain isn’t involved – clearly it does play an important role in our mental lives. But in the embodied view the brain isn’t there to give orders: it’s there to pull together the strands of our internal experience so that the system as a whole can make sense of them. The insula, an area of cortex that is found deep in one of the folds of the brain, just above each ear, seems to play an especially important role in all of this, combining interoceptive messages with proprioceptive ones, and with information coming in through the senses, to come up with what the neuroscientist Bud Craig calls a ‘global emotional moment’ – a sense of ‘how I feel right now’.11

Where are you?

Of course, none of this helps to settle the argument about what the conscious mind is actually made of, where it is and what it would look like if you wanted to point and stare at it. Back in the seventeenth century the French philosopher René Descartes famously threw his hands up and declared that while the body (including the brain) is a physical thing, the mind is made of something else entirely, something that is both invisible and immeasurable. This general consensus has prevailed ever since, not least because if the mind is made of ‘stuff’, we’ve yet to find a way to quantify it.

Many neuroscientists and philosophers – and the Buddhist scholars who have in fact been saying it for the longest – believe that what we think of as the mind is actually an illusion that comes as an accidental side-effect of the binding together of messages flying around the body and brain into one ‘self’.

The embodied approach sees our conscious self as being grounded in, and bound together by, the sensory experiences of the body and its interactions with the world. In recent years neuroscientists have begun to put these things together and come up with a unified explanation: that the mind is the result of an ongoing process of predicting what is probably happening, both in the world outside and within our bodies, and then taking action to adjust the dials. Moving in the world and interacting with it are the best way to make sense of what the brain thinks is true.

And this is where the importance of movement comes in. Moving the body not only changes proprioception but can also have knock-on effects on information coming in from the senses, and on interoception, via changes in the internal state of the body. By changing the chemical and physical basis of how we feel, movement allows us to change the inputs to the ‘global emotional moment’, leaving us with a different sense of ‘how I feel now’.

This, in a nutshell, is what the rest of this book is all about. As we’ll see time and again, it is entirely possible to use the way we move as a form of self-management for better physical and mental functioning. And whether you believe that that you-ness of you lives in your head and looks out through your eyeballs, whether ‘you’ are distributed throughout your body, including the brain, or whether there is no you at all, it doesn’t matter. The truth is that brain, body and mind are part of the same beautiful system. And the whole thing works better when it’s on the move.


The Joy of Steps

All truly great thoughts are conceived by walking.

Friedrich Nietzsche, 1889

Charles Darwin had a lot of thinking to do. It was the summer of 1842, and already he’d been back from the voyages of the Beagle for more than five years. He had scribbled his first sketch of the tree of life almost as soon as he stepped ashore,1 but what with the noise and bustle of London and a growing family at home, he could barely hear himself think, let alone formulate a revolutionary new theory of biology.

His solution was to move – and in more ways than one. First, he relocated his family to a quiet corner of the English countryside where the kids could play somewhere other than just outside his study. Once there, he set about constructing what he came to call his ‘thinking path’ – a quarter-of-a-mile gravel path around the grounds of his home, which passed by a rolling meadow before looping back through a dark patch of woodland. It was there, on his daily four or five circuits of the path, that Darwin finally found the head-space to come up with his theory of evolution.

Walking the thinking path today with my son and his friend trailing behind, giggling about something they saw on YouTube, I feel Darwin’s pain. But the emerging science of movement suggests that it was more than just simple peace and quiet that helped Darwin think more clearly. Walking is proving to be a multi-use mental tool, which can affect both our psychology and our physiology in very specific ways. These changes can, in turn, transform the way we think and feel.

That walking and thinking are connected is hardly headline news. But while generations of geniuses, from Friedrich Nietzsche and Virginia Woolf to Bill Gates and Steve Jobs, have made the case for thinking on foot, we are only now discovering how and why it works so well. And, perhaps more importantly, science is beginning to reveal how different ways of doing it bring specific mental benefits, depending on what it is you are trying to achieve.

It might sound a little ridiculous: who actually needs to be told how to walk? But research coming from the fields of evolutionary biology, physiology and neuroscience is all pointing to the fact that walking a lot, and running a little, made our species what it is today. If we don’t do it enough, we risk losing our mental and emotional edge. And with researchers linking everything from falling IQ to a lack of creative ideas and failing mental health to our sedentary lifestyle, there are plenty of reasons to relearn what we think we already know.

Fittingly enough, given Darwin’s fondness for steps, the first evidence that walking and thinking are intimately connected comes from the story of the evolution of our species.

As we saw on p. 18, before the invention of hunting and gathering, our distant ancestors were basically layabouts who spent most of the day sitting around, munching fruit and perhaps the odd tuber. Like most of us today, they probably only averaged about 3,000–5,000 daily steps but, unlike us, they were none the worse for it because their physiology was fine-tuned to this level of fuel and activity.

Over time, though, the climate changed, woodlands turned to savannah and food became harder to find. Our ancestors had no choice but to roam further and wider to find enough to eat. Eventually some bright spark hit upon hunting and gathering as a way to gather enough calories to survive. In terms of survival this proved to be a good idea, which meant that evolution favoured those who were better adapted to walk and run long distances. We evolved to move and, like it or not, we all carry those genes today.

In 2017 David Raichlen, who studies human evolution at the University of Southern California, and his colleague Gene Alexander, at the University of Arizona, described this relationship with what they called the adaptive capacity model. It was the first time anyone had made the connection between our evolutionary history and the ‘use it or lose it’ plasticity of our adult brains. We’ve known for decades now that physical exercise is the best proven way to boost brain health and cognitive skills, including memory and attention, and to reduce the risk of depression and anxiety. Now there was a good reason why: we evolved to be, in Raichlen’s words, ‘cognitively engaged endurance athletes’.2

The ‘cognitive’ bit is important, because hunting and gathering is more than just physical work: you can’t simply put one foot in front of the other and hope that something tasty crosses your path and lies down to be eaten – and with our comparatively weedy physical frame we can’t rely on brute force to bring down big game. By necessity, human-style hunting is skilled mental work, which requires tracking and outwitting prey and predicting their next move, while working as a team, keeping an eye on the time, looking out for danger and remembering the way home. Gathering involves remembering where to find the good stuff and out-thinking other animals that want to eat you or steal your food.

As a result, our biological baseline is to be on our feet, moving and thinking at the same time. If we don’t do it, our brains make the sensible decision to save energy by cutting brain capacity. In better news, when we get on our feet and move, it primes the brain to be alert and to learn.

A well-oiled machine

Putting this to use isn’t actually all that hard. Evolution has built in several unique design features that link moving on our feet to a mental boost. And though most of us don’t need to hunt and gather any more, the system still works just as well whatever it is you want to achieve.

Among the human-tailored design features are, of course, the usual suspects: the feel-good hormones, the endorphins and endocannabinoids, that are linked to the runner’s high and the general feel-good factor that comes with exercise. Sure enough, studies have shown that we, along with other ‘athletic’ species, get a hit of the good stuff when we exercise. There are also Raichlen’s experiments: he compared humans with dogs, which clearly love running, and ferrets, which aren’t so keen. In terms of endocannabinoid signalling we have much more in common with dogs than with the more sedentary ferrets.3 The downside is that walking isn’t quite enough to bring on a high unless it leaves you seriously breathless. The feeling-great part only really kicks in after an intense run at a pace where it’s difficult to hold a conversation.

Endorphins, though, are easier to come by – they tend to appear after just twenty minutes of brisk walking. Likewise brain-derived neurotrophic factor, or BDNF, a growth factor that not only enhances the growth of new neurons in the hippocampus, which is important for memory, particularly spatial memory, but also increases the likelihood that the brain will make new connections, boosting our ability to learn. Meanwhile, another growth factor, vascular endothelial growth factor (VEGF), gets busy adding new blood vessels to support the expansion.

These links are pretty well understood and now count as run-of-the-mill in exercise physiology and mental health. But there are a few new kids on the block that are perhaps more surprising.

Who, knew, for example, that our feet come supplied with a set of inbuilt ‘pressure sensors’ that work with our beating heart to send more blood to the brain? This was the finding of an engineer called Dick Greene, who, having spent many years working in the oil fields of Texas, decided in the 1970s to turn his attention to the pipework of the human body. Back then the received wisdom was that, even when the heart rate rises to send more blood to working muscles, the brain as a whole gets no more than usual because our blood vessels adjust their diameter to keep blood flow constant and shield the brain from dips and surges. It does this for a good reason: too little blood at any one time and the tissue could be starved of oxygen and die; too much and the brain could swell, squashing delicate neural tissue against the skull.

Greene, though, suspected that there might be more leeway in the brain’s blood supply than conventional wisdom allowed. Using the technology of the time, however, it was only possible to measure blood flow to the brain while people were lying still, often with measurements being taken directly from the arteries and veins, so it was impossible to know whether moving changed anything. Then Greene worked out a way to measure blood flow in the carotid artery of the neck using non-invasive ultrasound mounted on a headset that allowed measurements to be taken continuously, even while his subjects were up on their feet and moving. As he suspected, he and others found that any form of aerobic exercise will increase blood flow to the brain by around 20–25 per cent, at least in the short term.

Crucially, though, he recently found that putting your full body weight on your feet while you are exercising provides an added boost. In 2017 Greene reported that putting weight on your feet compresses the major arteries of the feet, increasing turbulence in the blood and increasing blood flow to the brain by a further 10–15 per cent.

Whether this extra blood makes the brain work better in the moment or whether it’s more of a long-term, oiling-of-the-cogs kind of effect is something Greene and his team are still working on. The studies he had planned for 2020, to measure blood pressure and flow in healthy people who are standing, walking and running, were shelved indefinitely because of the outbreak of COVID-19.

Intriguingly, though, he has found a sweet spot where the rhythm of our footsteps synchronises with our heart rate. In Greene’s experiments the biggest boost in blood flow happened when the heart rate and step rate synchronised at around 120 beats and steps per minute. Walking in sync with the heart rate seems to provide a steady and predictable increase in blood flow to the brain, which, Greene speculates, might contribute to the feel-good factor that comes from a good, brisk walk.

Perhaps unsurprisingly, an even bigger blood flow boost comes from running, when the feet are hammered with 4–5G of force with each step as you pound the ground. But, as Greene told me on a mid-hike video call from the mountains of Idaho, cushioned shoes probably take some of that benefit away. Running barefoot, or wearing minimal shoes, might well mean that you get a better boost, although this has yet to be confirmed in a scientific study.

All of this got me idly daydreaming about inventing a rhythmic foot massager that could boost blood flow to the brain and net me my first million. But other scientists make a good case for why actually standing up and moving are part of the deal.

In a word: gravity. Or, more specifically, the physiological changes that happen when we put weight on our bones, and what that, in turn, does to our minds.

We tend to think of bones as dry white sticks that hold up our insides, but in reality bone is a living tissue that is constantly being built up and broken down to adjust to the stresses that are – or are not – put upon it. We know this because, without the constant need to fight gravity to stay upright and move, astronauts and people who are bedridden for long periods quickly lose bone mass: the cells that break down excess bone work harder than those that build and repair. What’s less well known is that the brain is also affected by a lack of bone-building. Studies have linked the loss of bone mass seen in osteoporosis to an increased risk of cognitive decline.4 Astronauts also seem to suffer short-term cognitive problems after a stint in space, as do people who have experienced prolonged bed rest.

It is now emerging that these two things are very much connected by one strange and surprising fact: our bones are in constant conversation with our brains. What they talk about depends very much on how much we ask our bones to move while also resisting the pull of gravity.

To find out more I arranged to meet a bona fide legend of neuroscience, Eric Kandel, who won the Nobel Prize in Physiology or Medicine in 2000 for his part in the discovery of the molecular basis of how our brains store memories.

When we meet, on a bright October day in New York in 2019, he is a week away from his ninetieth birthday. He’s still interested in memory but, perhaps unsurprisingly given his advanced age, has turned his focus towards maintaining memory well into later life. From what I can see, this seems to be going pretty well for him. He still works five days a week at Columbia University’s shiny new Jerome L. Greene Science Center in West Harlem, and most days he walks the two and a half miles from home to his lab. His enthusiasm for science is as bright as ever, and he can’t wait to tell me about his latest work on the link between movement and memory.

‘I like to do a lot of walking,’ he tells me. ‘And reading about that, I came across the fact that bone is an endocrine gland and it releases a hormone called osteocalcin. I did some experiments where I put osteocalcin into experimental animals, and [found that] it enhances memory, and strengthens various intellectual functions. I said, gee, this is pretty nifty. I’m not wasting my time.’

The work he was reading about came from another Columbia University scientist, who is based a couple of miles north in the Department of Genetics and Development. Gerard Karsenty had been working on the genetics of bone since the 1990s, trying to work out why bones accumulate calcium and harden while other organs don’t. The main candidate at the time was the gene for osteocalcin, a protein released only from osteoblasts – the cells that are responsible for building new bone. Since osteocalcin is released during the bone-building process, it seemed likely that it played a role in making bones physically strong.

In fact, as Karsenty told me when I went to his office to find out more, it was doing nothing of the sort. ‘I was thinking that I would unravel the secret of bone mineralisation,’ Karsenty recalls, looking both wistful and amused by his youthful ambition. ‘And lo and behold, the bone couldn’t care less whether there is osteocalcin or not.’

Even under an electron microscope the skeletons of mice that had been genetically engineered to lack osteocalcin looked entirely healthy. But it soon became clear that all was not well with the mice. For a start, they were unusually docile: they didn’t try to run away from being handled or try to bite when they were picked up; they just sat there and let the world pass them by. Yet despite looking for all the world as if they were chilling out, they also showed more anxious behaviours than normal mice, being more likely to hide in a darkened corner than to explore somewhere new.

They also flunked a gold-standard test of mouse memory, the Morris water maze. In this test scientists first train mice to find a submerged platform in a deep and steep-sided pool. Once they have learned to find it reliably, the test is repeated but with murky water, to see if they can remember their way to safety. Healthy mice find this pretty easy, but the osteocalcin-deficient mice were clueless, swimming around aimlessly trial after trial. But when Karsenty injected osteocalcin into their blood, all of these problems went away, and they became as bright as the average mouse.

Twenty years of research in Karsenty’s lab has since shown that osteocalcin is released during bone-building, not to strengthen us physically but to travel via the blood carrying messages to the brain. It does so via specialised receptors in the hippocampus, the brain region responsible for memory in general and spatial memory in particular. Without osteocalcin that communication doesn’t happen, and in mice at least, the hippocampus and other brain regions end up smaller and less connected than normal.

Mice are not humans, obviously, but Karsenty is confident that these results apply to humans too. ‘Bone is one of the latest organs to appear during evolution, and there are no genes that are expressed in bone in the mouse that have not been conserved in the human. So, it’s unlikely that what we’ve seen in the mouse is misleading,’ he says.

Only a few studies have so far been done in humans, but those that have been done suggest that there is a link between low osteocalcin levels in the blood and poor performance on cognitive tests from middle age onwards. One recent study found particularly low levels of osteocalcin in people with Alzheimer’s disease. Both Kandel and Karsenty are independently doing further human studies, Karsenty into osteocalcin levels in neurodegenerative disease and Kandel into the link between memory and variations in levels of osteocalcin circulating in the blood.

Depressingly for those of us of a certain age, the amount of osteocalcin in the blood peaks in early adulthood and starts to drop from around the age of thirty in women and forty-five in men. Kandel takes this as a sign that putting weight on our bones is essential at all ages, but particularly from middle age onwards. ‘Movement is essential. And the older one gets, the more important it becomes,’ he says.

One unknown factor is how much exercise is necessary to seriously up your osteocalcin levels. For his part, Karsenty isn’t convinced that most of us are up to the challenge. ‘Ideally, if you exercise every day since you are thirty years old, you would have more osteocalcin, but it’s unlikely that anybody would do it,’ he says. Plus, he says, osteocalcin only peaks for a couple of hours, before returning to an age-appropriate baseline. He suggests that an osteocalcin pill might be a better way to maintain memory, particularly in people who are less able to move.

But there’s more than just memory at stake. Osteocalcin also talks to the muscles, telling them to release more fuel for exercise. In fact, it’s starting to look like a multi-purpose hormone that tells the body it’s time to think and move at the same time – more evidence that human beings are cognitively engaged athletes by nature. ‘Movement is a survival function that requires muscle in running, but also knowing where to go, which is cognition. These functions are connected,’ says Karsenty.

As for the question of why our bones evolved to specialise in memory and movement as well as scaffolding, Karsenty thinks that it’s all part of an ingenious mind–body strategy that evolved to help us escape danger. In a recent series of experiments in mice, Karsenty’s team showed that osteocalcin release from bone is a key part of the fight-or-flight response. When the brain signals danger, they found, osteocalcin is released from bone into the bloodstream, where it can circulate, turning off the ‘rest and digest’ part of the nervous system while revving up the body for escape.5

The memory boost that we get from osteocalcin is all about survival too. It helps us to remember the lessons of each emergency for next time. The bonus is that we can bypass the fear part of the process and choose to stress our bones instead: the mental benefits still appear.

As an aside, there may be yet another way to get your osteocalcin boost – no exercise or fear necessary. It has been known for some time now that blood from young mice has the power to boost both the health and brainpower of older mice. Off the back of this research, in 2016 a Silicon Valley start-up company called Ambrosia started selling blood transfusions from sixteen- to twenty-five-year-olds to people over the age of thirty, at $8,000 a pop.6

Between 2016 and 2018 the company ran an in-house clinical trial, which it claimed showed a decrease in blood markers for cancer, Alzheimer’s disease and inflammation in thirty-somethings who received young blood. These claims have not been published in any scientific journal, and the methods used in the trial – participants paid $8,000 to participate, and there was no placebo group – attracted widespread criticism. In February 2019 the US Food and Drug Administration published a warning against plasma transfusions from private companies, stating that ‘there have not been any well-controlled studies that show the clinical benefit of the administration of plasma from young donors, and there are associated safety risks’.7 Ambrosia paused operations shortly afterwards before quietly returning in late 2019, offering transfusions from blood bank stock rather than direct from young donors.8 With blood bank stock there’s no guarantee that the blood comes from younger donors, however. According to the American Association of Blood Banks, the average blood donor in the US is between thirty and fifty years old and 16 per cent of donations are from over-sixty-fives.9

Back in the world of science, the head-scratching continues about what the secret ingredient in young blood might be, if indeed it does have the same effect in humans. Karsenty speculates that – in mice, at least – osteocalcin could be the answer. If you give old mice young blood without osteocalcin, the elixir of youth doesn’t work its magic.

Does putting weight on your bones have the power to preserve memory and mood well into old age? And if some weight is good, would adding more, by adding ankle weights or carrying kettle bells, be even better? We don’t know for certain. But, all things considered, it makes sense to not give into gravity but to fight it like your chance of a happy, healthy old age depends on it. Because there is a growing body of evidence that it might.


Leaving physiology aside for a moment, another reason why walking – and running – improves mental well-being is that it temporarily changes your window on the world. Whether walking, running or moving under your own steam by other means, there is no escaping the fact that you are, literally, getting somewhere. And this can tip over into a figurative sense of progress too.

Marcus Scotney stumbled on this principle about twenty-five years ago and, it’s fair to say, took it to extremes. Having struggled with depression throughout his teens, he found that the only thing that made him feel better was running for the hills. And then over them. And then back down the other side. He turned out to be pretty good at it too – now, in his mid-forties, he is a professional ultra-marathon runner and coach who in 2017 won the Dragon’s Back – a five-day, 188-mile race across the Welsh mountains that is known for breaking even the toughest of athletes. He did it in under forty hours, setting a new course record.

We arrange to meet in a car park deep in the UK’s Peak District on a roasting hot day in August. It’s a reunion of sorts – Marcus and I went to school together from the age of five until we were eighteen. We were never especially close friends, but there’s solidarity among those who were too uncool for school (me too short and frizzy, him too skinny and ginger) that never quite leaves you, and we greet each other with a big hug.

I’ve made all the excuses I can think of to not do any running today but he’s not having it. ‘I need to interview you, Marcus,’ I say. ‘I can’t run and talk at the same time.’

‘If you’re running so fast that you can’t talk, then you’re running too fast,’ he replies.

‘I’m not sure our stride lengths are compatible.’

‘Actually, my stride length is quite short,’ he says.

Luckily for me, on the day we meet he’s tapering his training to prepare for the Ultra Trail du Mont Blanc, another of the toughest mountain marathons in the world, this time 106 miles, across the Alps. So instead of running we hike.

In the twenty-odd years since we last saw each other, he’s been on quite a journey. After we left school he spent several years battling multiple addictions, including a dalliance with Class-A drugs and some dealing on the side. That ended when he was beaten bloody by a rival gang of dealers and, mortified by having to reel off a list of all the drugs he’d taken to the hospital doctors, he moved back in with his parents and sorted himself out. Incredibly, through all of this, he kept running. The day after he took that beating he ran his first two-day mountain marathon with a broken jaw, his teeth wired together and under doctor’s orders not to exert himself.

Over the next few years he settled into the relative calm of marriage, kids and a working life, first as an outdoor instructor and then as a church pastor. He continued running and represented both England and Great Britain in fifty- and hundred-mile races. Then, when he was at the top of his running game and close to being ordained as a priest, a series of personal set-backs led to a mental breakdown.

Even in the retelling his first decade of adulthood sounds exhausting. According to Marcus, though, his backstory isn’t unusual for someone in this sport. ‘It’s almost a cliché in ultra-running, because so many people come into it with mental health issues,’ he says. ‘We all want to get away from something.’ He’s laughing when he says this, but I don’t think he’s joking. ‘If you run for long enough you feel like you’ve come far enough away from stuff,’ he adds.

The psychology of moving forwards through space backs this up. Experiments suggest that literally moving forwards translates into a figurative sense of progress too, and this can have a huge effect on how we feel about ourselves and our lives.

According to two of the fathers of embodied cognition, George Lakoff and Mark Johnson, our understanding of the world and the language we use to describe it are inextricably linked to the geometry of our bodies and the way we move. Successful people are ‘on the up’, for example, while on a bad day you feel ‘down’. When you ‘get over’ a problem in life, you ‘move on’.10

In keeping with this, psychologists have found that a person’s direction of movement influences what they think about. Moving forwards inspires thoughts about the future, while moving backwards brings back memories of the past.11

It doesn’t even have to be actual, physical, movement – in lab-based experiments where volunteers watched a starscape that appeared to move either forwards or backwards, and even when they were asked to close their eyes and imagine moving in one direction or the other, the mere suggestion of motion was enough to direct the content of their thoughts.

Research also suggests that moving forwards distorts the way we perceive time. Most people (at least in Western culture – it differs in some parts of the world) move along an imaginary timeline where the past is behind our back and the future directly in front of our chests. But experiments suggest that, when we move, this timeline gets stretched and distorted so that the past feels further away. In one impressively low-tech experiment, volunteers were asked to walk from a starting position (a gaffer-tape line on the floor) to another (a black bucket a few metres ahead), and were then probed on how distant past or future events seemed to be.12

That the past feels more distant as we physically move forwards is important, because a major risk factor for depression is the tendency to ruminate, getting stuck in a loop of over-analysing things you’ve said, done or experienced in the past while getting steadily more despondent. Physically moving forwards can help prevent this by making the bad stuff seem further behind you.

This is definitely true for Marcus. ‘When you struggle with depression, there’s this assumption that when that person says “I can’t be bothered to move”, that staying put is what they want. But, actually, when you’re depressed it’s like you’re tied to the chair and you want to get away,’ he says. ‘Running gives you that sense of: I’m here, and I can end up there. Moving forward gives you the strength to know that you can move forward.’

Of course, one of the problems with depression is that, when tied to the chair, it can be incredibly difficult to find the motivation to untie yourself and move at all, let alone run. So, for some people at least, medication can provide the impetus to get going in the first place. In a recent study an increase in voluntary movement was found to be a good indicator that an antidepressant was kicking in.13

There’s also evidence that depressed people walk differently to non-depressed people: more slowly, hardly moving their arms and assuming a slumped posture, with their eyes to the floor.14 It seems likely that the depression causes the walk rather than the other way around – and yet a change in walking style has been shown to change the contents of thoughts. In experiments when people walked with a high-energy, bouncing gait they were able to remember more happy words from a list of emotionally charged words, while those who were asked to walk slowly and with little bounce remembered more of the negative ones, even when they weren’t aware that they were doing a ‘depressed’- or ‘happy’-style gait.15

Interestingly, trail runners don’t slog along the ground like a roadrunner, but instead take smaller steps and bounce off the landscape like a rubber ball. Which might explain the big grin on Marcus’s face when he finally persuades me to run, downhill, and back to the car park. ‘Imagine that the ground is made of hot coals and you don’t want to spend too much time on it,’ he says. So, I should spring? I ask. ‘Yes!’ he says, bounding away down the hill in front of me. ‘At the end of a hundred miles,’ he calls over his shoulder, ‘maybe not quite so springy …’


It’s a little-known fact that Charles Darwin struggled with both his physical and his mental health throughout his adult life, which his daily constitutionals presumably helped with. According to the written testimony of his son Francis, though, Darwin wasn’t exactly bounding along, trail-runner style or synching his footsteps with his heart rate at 120 beats per minute. Instead he would amble around his thinking path, stroking his beard and seemingly in a world of his own:

As he paced […] he struck his heavy iron-shod walking-stick against the ground, and its rhythmical click became a familiar sound that spoke of his presence near us.16

That doesn’t sound much like a man who was springing off hot coals. Even so, the Darwin-style shuffle has some specific, and important, mind-related benefits of its own, which may have helped him to explain life on Earth in a way that no one else ever had. There is now a growing pile of evidence that if we make like Darwin and get musing on the move, it could help all of us to come up with more creative and original ideas.

Creative thinking is one of those skills that our species likes to claim as uniquely ours, but the sad fact is that very few people find that it comes naturally – at least in adulthood, which is when we could probably make the most use of it.

The root of the problem can be found in the brain and the way that, while hosting its body-wide chatroom, it adds its own ten-pence worth in the form of predictions based on previous experience about what is likely to happen next. This process helps speed up decision-making and reduce the likelihood of surprises, while constantly updating its prediction based on what the rest of the body is saying. It’s a role that falls largely to the prefrontal cortex – the logical, thinking and impulse-controlling parts of the brain that are housed behind the forehead.

When you get the urge to do a cartwheel in the supermarket, say something inappropriate in a meeting or jump a red light, this is the part of the brain that jumps in and reminds you not to be so stupid. It’s a useful feature in all kinds of situations and saves us a lot of time and potential embarrassment, but the downside is that it does the same job for ideas, shutting down thoughts that are a bit out there but which might just work.

These brain regions don’t get fully wired into the rest of the brain until early adulthood, which helps to explain both the unbridled creativity of children and the less than stellar impulse control of the average teen. Once it’s fully integrated, though, it works as the proverbial ‘box’, and thinking outside of it becomes much more difficult.

Difficult, but not impossible. Lots of things can temporarily reduce activity in the prefrontal cortex (a state called hypofrontality) – and many of them involve moving.

One thing that works in our favour here is that, whenever you’re moving under your own steam at a pace that feels easy, the activity in the prefrontal cortex gets temporarily turned down, perhaps because the brain reallocates blood flow to the circuits involved in moving and navigation and away from ‘thinking’. Since the job of the prefrontal cortex is to narrow down the number of thoughts and memories to the most sensible and obvious, turning ‘the box’ down a little allows the mind to wander without restriction and, potentially, to make new connections without the chatroom facilitator jumping in to veto them before they’ve fully formed. Reducing this filter allows access to a broader set of options – ideas that you might not otherwise consider.

Another job of the prefrontal cortex is to direct our attention towards a particular goal and hold our attention on that goal while we think about a solution. According to the work of the Dutch social psychologist Ap Dijksterhuis, for certain kinds of problems this kind of goal-directed, conscious, straight-line thinking is actually the worst way to go about making a decision.17 Conscious thinking makes use of working memory, a kind of mental notepad where we place information while we work with it to come to a conclusion. This is a skill that relies heavily on the prefrontal cortex, and comes with a catch: working memory is limited to around five pieces of information, plus or minus two. Any more than that and we start to lose our thread.

Dijksterhuis argues that when problems have more moving parts than our working memory can handle – like those that Darwin was wrestling with – we will actually do better if we take conscious thinking out of the equation altogether. In this, his ‘unconscious thought theory’, being distracted from thinking about a problem allows unconscious processes to get stuck into the problem instead. And since this kind of thinking isn’t restricted by the number of mental slots in working memory, it can take far more into consideration at any one time. Then, when a solution presents itself, the answer bursts through into consciousness as a moment of insight, or an ‘aha’ moment.

In experiments, Dijksterhuis asked volunteers to study the details of several different apartments, all with many pros and cons. One group of people were distracted for three minutes before making a final decision, while another group was asked to choose straight away. The people who were distracted for three minutes made better choices than those who had thought directly about the problem.18

Not everyone is convinced that unconscious thought is any better than direct thinking, or even that it exists at all – the problem with unconscious thoughts is that the person having them is unaware of their existence, which makes them tricky to measure. But whatever the cause, there is good evidence that a short spell of hypofrontality not only provides some respite from depressive rumination but also boosts creativity by favouring blue-sky thinking over run-of-the-mill solutions. We know this because experiments at Kansas University showed that when activity in the prefrontal cortex was temporarily knocked out using a type of brain stimulation called tDCS, volunteers were able to come up with twice the number of creative suggestions when asked to think of new uses for everyday objects. They also came up with ideas significantly faster when their idea-narrowing prefrontal ‘box’ was taken out of the equation.19

On a visit to Kansas in 2016 I was able to have a go at this experiment for myself. Once Evangelia Chrysikou, the lead researcher, plugged my brain into the tDCS machine, which was, in turn, connected to a 9-volt battery, I felt my attention drift off to the middle distance. Then, when shown a variety of everyday objects, I had no problem coming up with new ideas on how to use them. Obviously, a dartboard could be used to wipe your feet, the metal bits sticking up would be great for scraping the mud off your shoes. And surely everyone would agree that blowing your nose into a velvet drawstring bag would be far more hygienic than a tissue.20

But you don’t need to be wired up to a 9-volt battery to get this kind of a creative boost. A recent study by researchers at Stanford University confirmed what Darwin stumbled on over a hundred years ago: that walking has a very similar effect.21 In a series of experiments the researchers also asked people to come up with unusual uses for a variety of familiar objects. Sometimes the volunteers were sitting while doing this; at other times they were walking. In addition, sometimes they were asked to sit and walk indoors and other times outside. The results showed that, compared with sitting, walking increased people’s ability to come up with creative uses for ordinary objects by up to 60 per cent. If they walked first and then sat down, the effect of walking spilled over so that they were more creative for a short time afterwards, too. ‘Taking a walk before brainstorming should help improve performance,’ the researchers concluded.

In this particular study it didn’t matter where people did their walking. Walking on a treadmill while looking at a bare wall was just as effective as strolling outdoors. However, there is some evidence to suggest the opposite – that spending time in green space provides an extra boost.22 Other research suggests that time in nature works as a kind of reset button on our ability to pay attention. Wherever you do your walking, though, getting into the right state of mind is the most important thing, and ambling along at a comfortable pace seems to be the most user-friendly, and effective, way to get there.

All things considered, then, it’s troubling that the world’s big thinkers spend more time bent over a desk than wandering the hills and valleys pondering new ways to solve our woes. And even among the common or garden average-size thinker, few people these days go walking just for its own sake (17 per cent of people according to a recent survey, and that includes dog walkers, who arguably don’t have much of a choice).23 Meanwhile a group of economists have sounded the alarm that creative ideas seem to be getting thinner on the ground as the years go by. Coincidence? Perhaps. But it does seem to be a problem worth looking at. In a paper for the US-based non-profit organisation the National Bureau of Economic Research they pointed out that, despite the fact that research effort has been increasing year-on-year for decades, the output from that same research is diminishing.24

Even children, who are the most naturally creative beings on the planet, partly because of their small and not yet perfectly formed prefrontal cortex, seem to be losing their edge. In 2011 the psychologist Kyung Hee Kim, from the College of William & Mary, in Williamsburg, Virginia, compared scores on a standardised test of creativity from the 1990s to the 2000s. Shockingly, she found that the scores had significantly decreased in that period, particularly among younger children. A more recent update of that research suggests that the trend has been getting worse since then. Kim largely blames this on the modern educational obsession with testing. Even so, given the findings that movement can enhance a creative state of mind, and given that it’s easier to change individual behaviour than educational policy, she recognises that modern lifestyles also play a part.

‘The rise in sedentary lifestyles is a factor in the decline of creative thinking,’ she told me in an email, pointing out that the rise of passive play, such as watching TV and other screen-based games at the expense of active play, is a serious problem both at home and at school.

In her view it doesn’t necessarily matter what kind of activity you do, whether it’s walking, running or physically acting out stories: moving around can help bring ideas forward in a way that sitting around never will. ‘Creative thinking is stimulated by physical activity, whether walking, running or active playing,’ she says.

One way to help stop the rot, then, is for anyone who is able to do so to get on their feet whenever possible and move forwards at whatever speed feels easy to them. If physically walking isn’t possible, or if cycling or canoeing is more your thing, then moving forwards in other ways will have at least some of the benefits as long as you do it at a level that is easy enough for you to be able to forget that you are moving and let your mind wander. Ideally this would be done alone somewhere familiar, so that your thinking mind can switch off, drift away and come back with a shiny new idea. It really is that simple.

Well, sort of. The catch is that the quality of the ideas that come out during a period of hypofrontal musing very much depends on what’s in there in the first place, which in turn depends on the experience and memories of the person doing the musing. Memories are stored in widely distributed networks across the brain (and, some claim, the body), which is why one thought can instantly bring to mind something else, like a domino effect. Each person’s network is different, because of their completely different life experience. The upside of this, say the Stanford researchers, is that, so long as they can temporarily switch off their filter, each person can tap into their unique network of knowledge and memories for inspiration. And when the ‘aha’ moment comes, things that may seem totally disconnected suddenly fit together in ways that are so blindingly obvious you can’t believe no one else has thought of them. And they may not have done, because they’re not you.

There’s no shortage of problems in the world needing creative solutions: climate change, famine, war, global pandemics, ageing, population bottlenecks, dwindling resources, you name it. There’s plenty for humanity to get its teeth into.

The point here is that the next generation of Darwins will struggle to plumb the depths of their own minds if they spend most of their time sitting around, staring at the nearest screen. Add that to the mood-boosting effects of synching your steps to your heart rate, the memory-protecting power of bone-derived hormones and the mental benefits of physically moving forwards through space, and suddenly sitting still seems like the worst possible way to go about the business of thinking.

How to move: on two feet

•Time it right: Walking at the fairly brisk pace of 120 steps per minute (two steps per second) synchronises your footsteps with the heartbeat, adding a small but significant boost of blood to the brain that might contribute to the feel-good factor of exercise.

•Go somewhere: Mentally moving forwards through space has been shown in psychological studies to direct thoughts to the future and away from depressive rumination, while making the past feel more distant. Whether on two feet, two wheels or some other means, get out and move.

•Wander to think: Walking, or running, at a pace that feels easy turns the ‘thinking’ brain down and lets the mind wander in a way that boosts creativity and problem-solving. Do it before a meeting for a mental boost.

•Defy gravity: Putting weight on your bones stimulates the release of osteocalcin, which improves memory and may future-proof the brain for old age. Maybe add a backpack for extra weight (and snacks).


Fighting Fit

Physical strength is an expression of the total functioning of the organism.

Jean Barrett Holloway

Terry Kvasnik had been training for this moment his entire life. Starting with gymnastics at the age of three and then moving on to breakdancing, martial arts and parkour, he spent his twenties and thirties living the dream, working first as an acrobat in a London West End show and later for Cirque du Soleil. When a car pulled in front of his moped as he was riding along at 40 mph, it could all have been over in a flash. Thankfully, he knew exactly what to do. Or at least his body did.

‘It was like my body said, “I’ve got this, step out of the way, Terry”,’ he says. ‘I just knew … “I’m going to flip”.’ And so, he did. Using the moped as a launch pad he dived up and over the car, rolled over on his back and popped back up onto his feet, 10 metres from the wreck of his moped. It was only then that his mind caught up. ‘I turned around and sat down again, like, holy shit, what just happened?’

He walked away from the accident with mild concussion, a torn cartilage in his chest and a banged-up knee, but it’s a miracle he survived it at all. Ironically, he had only moved to Los Angeles, where the accident happened, to try and find work as a stuntman. ‘I often think it was my subconscious trying to get itself a stunt fix,’ he laughs.

Kvasnik is, it is fair to say, a fairly expert mover. But whether you’re a car-leaping acrobat or ordinary mortal, there is a lot to be said for having life-saving strength and agility in your back pocket for when you need it. Evidence from psychology studies has been accumulating for some time that having the physical skills to get out of sticky situations makes a big difference to how mentally capable and emotionally resilient we feel as we battle our way through life. Becoming a master of your body, in other words, might help you become a master of your mind.

As far back as 1988, a study of teenage girls showed that weight-training that boosted their physical strength by 40 per cent over twelve weeks increased the girls’ feelings of confidence about their ‘general effectiveness in life’. It also improved their ability to resolve social conflicts that had nothing to do with physical confrontation. The study’s lead author, weightlifting enthusiast Jean Barrett Holloway, lamented ‘a population of women who exhibit strength levels below their own potential’ and were missing out on the mental and emotional side-benefits as a result.1

In the thirty or so years since then, women have actually begun to catch men up in the strength stakes, but this piece of good news is tainted by the fact that men are getting progressively weaker. A study from 2016 compared the grip strength of twenty- to thirty-five-year-old students in 1985 with a similar number of modern men. The men of the 1980s could exert 117 lb. of force, compared to millennial man’s measly 98 lb.2

The next generation are seemingly even worse. A recent assessment of British schoolchildren found that ten-year-olds are significantly weaker than they used to be – showing a 20 per cent decrease in muscle strength and a 30 per cent decrease in muscle endurance since 1998.3 Worse, their weakness is accelerating with every year that passes, and the trend has been speeding up since 2008. Unsurprisingly, the main culprit is too much sitting and not nearly enough weight-bearing exercise. There are similar trends across Europe and the US.

This is a worry because strength is good for all kinds of reasons. For a start, it has been linked to a longer, healthier life. Studies that followed people over decades found that muscle weakness is linked to a greater chance of dying from any cause, regardless of whether you are carrying too much fat and independent of the amount of cardio you may do.

There is also a link between bodily strength and a healthy brain. A ten-year study of twins showed that greater strength in middle age is linked not only to more grey matter but also to a better functioning memory and a quicker brain a decade later, while grip strength (an overall indicator of muscle power) is associated with a healthier hippocampus.

More important, perhaps, is how physical strength makes you feel. Since Barrett Holloway’s initial studies, strength training has been shown pretty conclusively to make life feel significantly more manageable, boosting self-esteem and helping people feel capable of meeting physical and emotional challenges.4

A brief dip back into the philosophy of consciousness suggests a possible explanation. According to the neuro-scientist and philosopher Antonio Damasio, our sense of self – the feeling that there is one ‘me’ living this life in this body in this moment – is built firmly on our body’s implicit assessment of what it can handle.

This is because, as we’ve already seen, the tissues of our bodies never, ever shut up. They constantly prattle on, like children in the back of a car, back and forth to each other and to and from the brain, commenting on how things are going on the inside. Part of the power of movement is that it allows us to change this commentary in the moment, which has an immediate impact on how we think and feel. But its effects can run even deeper than that. Any movement that strengthens muscles and bones can change the content of the commentary for the long haul. Moving in a way that makes us stronger can dramatically change our sense of who we are and what we can achieve in life.

This assessment comes from the moment-to-moment tweaking of countless physiological dials that keep our biology within a safe, liveable range. This system, homeostasis, comes in three basic flavours: hormones released in the bloodstream; nerve signals to and from our organs; and physical feedback from our muscles, bones and other tissues.

Part of this system is what Damasio calls the body’s ‘musculoskeletal division’, which has the job of updating the brain about the state of the muscles, bones and other parts of the body that are involved in movement. ‘Even when no active movement is being performed, the brain is also being informed of the state of its musculoskeletal apparatus,’ writes Damasio.5

If our eyes are our window on the world, in other words, then our flesh and bones are the vehicle that allows us to act on that information in ways that tip the odds of survival in our favour. At the risk of getting my metaphors in a twist, this is not a passive vehicle, driven by an all-knowing mind, but a chatty one, like KITT, the talking car in the classic 1980s TV show (and soon-to-be film) Knight Rider, who constantly witters on about the odds of mission success. It’s not surprising, then, that the way we feel has a lot to do with whether our particular vehicle is creaking and rusty or primed and ready to turbo-boost over the next road-block.

If we let our bodies become weak, the message coming from the musculoskeletal division of the self will read: stiff, feeble, could definitely do better. And if, as psychologist Louise Barrett puts it, this read-out feeds directly into our perception of ‘what that body can achieve in the world’, then it’s hardly surprising that sedentary lifestyles have been linked to anxiety and low self-esteem.6

The good news is that we can upgrade our vehicle at any time. Adding capacity to the muscles, bones and other weight-bearing tissues of the body is not only expressed internally as a tangible feeling of being capable in all walks of life: it also shows on the outside, giving off clear messages of confidence in posture and behaviour. As if to prove that the mind–body loop never ends, this change in posture then feeds back into our mental state.

Micah Allen, a neuroscientist at Aarhus University in Denmark who studies interoception – how the messages coming from the body feed into our inner lives – says that, in his own experience, increasing his strength through climbing had unexpected side-effects that spilled over into life and work. ‘Climbing is something where you start off and you literally don’t know if you’re going to have the strength to make it to the top of the route and back down,’ he says. But as he progressed, he started to notice a creeping sense that he was more capable in other walks of life too. ‘Before, if I had a meeting with someone, I could be more easily intimidated or more nervous,’ he says. ‘But something about that implicit sense of confidence of knowing what my body was doing, purely anecdotally to me, it definitely did have an effect.’

There is some evidence to suggest that his hunch is correct. Research confirms that people who do more physical activity tend to score higher on a scale of ‘global self-efficacy’ – which measures their sense of how much control they have over their lives. The effect is seen in healthy adults, children and adolescents alike, and according to studies comparing different forms of exercise, strength training has faster and more powerful effects on self-esteem than improvements in cardiovascular fitness and other kinds of exercise that focus on balance or flexibility.

Feeling capable and in control is, of course, the polar opposite of feeling anxious. It’s a common misconception that anxiety is about living in a state of abject terror. Often (and I am speaking from experience here) it is more of a rumbling undercurrent of uncertainty about life and whether you can cope with the challenges it holds. Studies using weight-bearing exercise as a treatment for anxiety have found that getting stronger seems to make at least some of that angst go away, boosting self-worth while reducing symptoms of anxiety and improving sleep.

Similarly in depression, the overriding emotion isn’t necessarily sadness, but more a pervasive, visceral feeling of ‘I. Just. Can’t’. Studies consistently show that weight training seems, literally, to lighten the load. Perhaps strength training helps to change the internal feedback from ‘nope’ to ‘let’s give it a shot …’, providing a sense of confidence that the body can deal with the trials of life, allowing the ‘thinking’ mind to take a break.

This raises the important question of whether there is a link between rising levels of anxiety and depression in our society and an increasing proportion of people who are physically weak. Scientifically, no one has looked at this question in detail, so it’s difficult to be sure. However, given the evidence that sedentary lifestyles lead to anxiety and that strength training improves both self-esteem and symptoms of mental illness, it seems both likely and ripe for investigation. It’s entirely possible that we, in Western society, have spent the past few decades turning ourselves into cosseted caged animals who no longer have implicit faith that our bodies are up to life’s challenges. In short, poor mental health might be part of the price we pay for a cushy life of sofas and supermarkets.

The easy life may also be making large numbers of people feel down in ways that are less dramatic than depression but which can still colour life in shades of grey. According to Damasio, the unconscious messages coming from the body provide not only the basis for the self but also a kind of undercurrent to our consciousness that sets the mood for everything else that happens.7 These ‘background feelings’, as he calls them, act a bit like the soundtrack of a film: they have the power to make us feel happy, sad, hopeful or on edge, for reasons that we can’t quite put our finger on.

It stands to reason, then, that if we can change the tune on our background feelings we can also change the way we feel. Perhaps if we can make our bodies physically stronger we can change that background music, from the sinister discords of a psychological thriller to the rousing harmonies of a superhero theme.

Get strong for what?

I’m not sure what music is playing in the background of Jerome Rattoni’s life, but I’d be willing to bet that it’s both powerful and upbeat.

I’m in a tiny gym, tucked under the railway arches in Hackney, east London, with twenty or so fitness instructors, all of whom are looking at Rattoni in open-mouthed admiration. He has just hopped up and grabbed a bar that’s more than a foot above his head and then, with no visible effort, pulled up his entire body weight until the bar is by his waist. Finally, he hops up onto the bar and crouches on top, elbows rested casually on his knees as he grins down at us.

‘What is the point of a pull-up?’ he asks. The instructors and I start to mumble about upper body strength.

‘No,’ he says, dropping back to join us on the floor. ‘The point of a pull-up is to get up on top of something. Otherwise why would I bother? I go up, I come down again. I could have just stayed down.’

His deadpan delivery and French accent, combined with a Gallic shrug and a twinkle in his eye, not only make an excellent point about the futility of what most people do in the gym but also hint at a way that we might make strength training more effective, both physically and mentally, and a whole lot more fun.

Rattoni is a master instructor for MovNat, a system of fitness training that emphasises natural human ways of moving. Devised in 2008 by another Frenchman, Erwan Le Corre, MovNat is like a lovechild of forest bathing and parkour, which focuses on getting strong in the natural environment by climbing, jumping, balancing, swimming, running, lifting and carrying the way our ancestors presumably did. In this brave new world, true fitness is not about lifting weights to get big muscles or running to score a personal best: it is about having a body that is strong and agile enough to move like the animals that we often forget we are. Once we have these skills, the theory goes, we will be free to stride confidently through the world, sweeping aside danger, leaping over obstacles and laughing in the face of stress.

It sounds good. And there’s no doubt about it: if a tiger were to appear in Hackney Park, where, to the amusement of the local dogs, Rattoni has brought us to practise our crawling skills, he would be the only one getting out of here alive. O