“Move, move, move!” My dad shouted from the door, “get your coat on, let’s go out, now”!
Of course as a teenager the only answer was “Why”?
“What’s the rush, why do we have to go for a walk”, besides which I’d seen the woods so many times before, it’s still the same as yesterday and the day before and the day before that.
Come on; use it or you’ll lose it.Your brain.
What’s he on about now?, I thought.
Daniel Levitin in his book – ‘The Changing Mind ‘ – wrote about movement and its effect on the brain.
He said that children have no memories before the age of two and very few have any memories before the age of five.
One of my earliest memories was being taken to nursery school when I was five years old. I can clearly remember the chain-link fence that enclosed the yard and the two storey wooden building. The sound of dogs barking from the house next-door. The khaki shorts I wore still haunt me to this day.
Levitin suggests that the development of the hippocampus is linked to movement. The hippocampus is the part of the brain which holds our memories. Its shape is like a sea horse and one major role that the hippocampus plays is to help us find our way from A to B. It’s like your personalised GPS.
In the first year of life there is very little movement apart from the odd bottom-shuffle and crawl. Between one and two years movement is more about wobbling and falling down. Mostly there’s a lot of pram rides, sitting in front of mobile devices, the occasional block-building and dummies (in the mouth kind).
What’s been discovered over the years is movement has effects on the brain. Movement and specifically walking, triggers the hippocampus to grow and develop.
It turns out that there are two major types of cells in the hippocampus.
Place cells are location specific cells – think kitchen, bedroom, or bathroom.
Grid cells – connect A to B. How is the kitchen related to the dining room? How do I get from the bedroom to the bathroom? That last question is a really important question at 4 AM.
Grid cells are responsible for joining the dots between places and events. However it takes up to the age of six for the hippocampus to mature. According to Levitin that’s why we don’t have many memories before then.
Generally adults and older adults don’t move as much as children; think sitting, sitting, sitting. The NHS reckons we as a nation sit for over nine hours a day, and that does not count sleep time.
Someone comes into your house and you offer them a seat. We had a friend drive four hours to see us and the first thing said was come in, sit down. If someone at work is not at their desk they get labelled as a slacker.
We look after our older adults by checking they get enough rest -sitting.
Society’s lifestyle is a sedentary one.
So what does that have to do with your brain?
As we get older the hippocampus shrinks and that is because the cells are smaller in size and number.
Scientists have found that as you age there are less place cells especially. When there is less movement there are no new places to be seen, no vistas to explore. No new dots on the brain’s landscape.
At the same time there are fewer grid cells. With no new dots to be joined up we don’t need them. The average adult brain at rest uses up to 20% of the body’s energy. That’s a huge amount of processing power. Consider a massive electricity network with wires everywhere, with substations and junction boxes that need updating and replacing. When we reduce the amount of movement that we do, we don’t need as many place and grid cells. Why waste energy growing cells you don’t use. Of course having less of these place and grid cells come at a price. Poorer memories. The answer?
Exercise is not the solution.
When you hear the word exercise what comes to mind? Usually thoughts like sweat, hard work, uncomfortable, painful, even boring. You can get images of stretchy tights, young, fit, gymaholics. And unless you’re only of that elite bunch that’s not how you see yourself.
The word that matters most is movement. Any kind of movement. You can use weights if you want, you can run if you want, you can clean the house all day if you want.
When we look at the Blue zones, places in the world that people lived the longest and had years of good mental function none of them went to gyms. We found people sweeping floors, carrying water, tending gardens.
Movement was not running, hiking or involved high mountains. It was simply moving freely.
Science has discovered that physical activity:
1) Increases new connections being formed in the synapses of adults.
2) Stimulates better memory and overall mental cognition.
3) Increases new cell formation (neurogenesis) at least in rats.
Movement stimulates the hippocampus to grow and develop in kids. In adults it can slow down memory decline and hopefully one day we can show that movement can grow your memory and cognition.
Does it matter where you move?
If you run on a treadmill or get out you will get benefit in terms of your heart and lung fitness. You will benefit from burning fat, you will reduce your blood pressure and improve how your body handles sugar.
I try get out for a slow shuffle three times a week. That might be a Parkrun or other organised activities like Run-talk-run a charity that promotes mental health as the goal, not personal bests.
On my regular circuits I have to avoid tree roots that raise the tarmac. So I can look like I’m doing the latest dance craze. Then there’s avoiding the dog mess, or worse yet there’s running around the dog walkers who’ve stopped to chat in the middle of the footpath. This manoeuvre means risking a trip to the emergency department if I slip on the muddy grass.
Of course you don’t have to deal with these things when you get on a treadmill.
But, while the evidence is that both treadmill and parks give your heart a boost. Moving in the outdoors gives you more for your money and effort. The brain gets a workout as well, at no extra cost. Same time spent, same number of calories burnt and it helps the brain.
Avoiding trip hazards and inconsiderate pavement users means that there’s some mental juggling going on. That activity has some positive effects.
More input from your eyes and feet form new connections by sending messages across more synapses in the brain. To jump over a puddle involves a lot more messaging than your feet repeatedly landing on a rubberised treadmill.
The brain’s immune system
We all now know about our immune system. The pandemic meant that every news channel talks about how to strengthen your body’s immune system. Very little is mentioned about the brain’s immune system – the microglia. These are small but very important cells that protect the brain from damage.
Microglia are the equivalent to the brain’s garbage collectors. When parts of the brain starts to go offline these little cells release neuro-chemicals that cause inflammation. In the short-term this inflammation destroys and cleans up the problem cells. Later on, the microglia release other chemicals that calm down the inflammation.
Another way to think of microglia is like builders. These guys come into your house to fix the roof; which involves creating a mess and then tidying up after themselves when they are finished.
The problem is that as we get older the microglia become bad at tidying up after they finish the job. They are still good at starting inflammation but not so good at stopping it. This chronic inflammation can damage normal cells, cause learning and memory difficulties as well as increasing the risks of dementia and Alzheimer’s disease.
In animals that move frequently, post-mortem exams show brains with lots of happy, helpful microglia. This is so even for old mice who still have the ability to learn and remember their way through new mazes.
Now whenever I avoid the cracked paving or the dog walkers I’m more likely to raise a cheer – at least internally – rather than a scowl . I think about my happy little brain cells and their functioning GPS.
Forty years later, I figured out what my Dad was trying to tell me. Science is now backing up the idea of more moving and less sitting. I’m a (very) slow learner. We have no clear definition of an older adult in terms of brain health so in terms of looking after your brain it is never too soon or too later to start.
At the end of the day the step-counter does matter, aim for an average of over eight thousand steps. But also as important is to move in outdoor spaces, where there’s loads of input to the brain. As you remember your hippocampus it remembers you.