As his new book is published, neuroscientist Shane O’Mara tells Katie Law how just 5,000 steps a day is not only good for fitness but also our brains
Neuroscientist Shane O'Mara believes GPs ought to prescribe walking instead of pills. "Patients should be told to go out and do 5,000 steps a day," he says.
Walking isn't just good for our hearts, lungs, gut and general fitness, he claims. It's essential for healthy brain function too.
His new book, In Praise of Walking, is the result of his extensive research, which demonstrates that regular walking - by which he means every day - benefits cognition, mood, memory and problem-solving, and may also provide relief for ailments such as depression and anxiety.
While the Duchess of Cambridge has taken up shinrin-yoku - the ancient Japanese practice of contemplative walking in woodland - regular walking is now being dispensed by GPs in the Shetland Islands.
Ecotherapy, as it is dubbed, is simple, free, can be done anywhere and puts us in touch with our evolutionary past.
O'Mara, a professor of experimental brain research at Trinity College Dublin, loves walking, especially in London, and admits to feeling guilty if he notches up fewer than 12,000 steps a day.
"You don't need to be somewhere wild and green to walk and London is one of the best cities for walking in the world," he says.
People think they have to invest in hiking gear or expensive boots, he continues, but that's nonsense. A comfortable pair of shoes and the will to do it is all you need.
If distances are too great, or time too short to walk all the way to or from work, get on or off the bus a couple of stops earlier than usual, he advises. Use your smartphone's GPS system to navigate and avoid polluted main arteries.
"Pedestrianisation is a very good thing and there should be more of it. One of the problems with walking in London is that urban planners give precedence to traffic flow when they should be thinking of cities from the point of view of people on two feet," he explains.
Office workers who are sedentary all day, take note. "Immobility over long periods slows brain activity down, but the minute we stand up we become cognitively mobile," says O'Mara.
Our brain rhythms spring into life, bloodflow through the body and brain increases, our breathing changes and we immediately become more alert. Walking also reduces cortisol production and increases creativity.
In one experiment, O'Mara compared the creativity of a group of outdoor walkers to a group of indoor sitters by asking them all to come up with as many uses as possible for a set of reading glasses.
The results showed the first group to be consistently more imaginative.
People often say they get their best ideas while walking - and O'Mara never walks without his Dictaphone.
Neuroscientifically speaking, walking is a complex task. "We are only just beginning to understand what happens to the brain in motion," he says.
The act of standing, of monitoring our musculature, stabilising our spines, making our feet move, being able to spatially map our surroundings and recognise perimeters without bumping into them, all this we do without thinking about it.
Layer onto that the unique human ability to talk, think and eat while walking and you begin to understand what he means.
"In the past we had to know where places of safety were, how to forage for food on the move and to find shelter without having to think about any of it."
While walking is often thought of as a solitary activity, it is also fundamentally social - and even bonding.
Tests show that when we walk in pairs, our brain rhythms synchronise, which manifests in falling into step with each other. If we walk in larger groups, we naturally split into smaller ones. Then there are the wider social implications of walking, such as going on protest marches.
"After all, we walked out of Africa, not alone but in groups," says O'Mara, "because we evolved to walk together."
He adds: "But you don't come into the world ready to walk. Learning to do it correctly is a significant milestone in individual autonomy. It is also a significant milestone in brain development."
How babies make the transition from crawling to pulling themselves up to walking position remains a mystery, but ultimately it boils down to them "taking thousands of steps and having dozens of falls every day", until practice eventually makes perfect.
So there you have it. Forget apples. A walk a day really will keep the doctor away.
In Praise of Walking: The New Science of How We Walk and Why It's Good For Us by Shane O'Mara is published by Bodley Head, price £16.99