- Physical activity improves cognitive function during the activity and in the period shortly after exercise.
- Where you walk and how fast you walk impact the effect of the exercise on your cognitive function.
- The health benefits of walking may begin before you reach 10,000 steps.
When I was diagnosed with bone cancer in my left femur 15 years ago this summer, I thought, “I’ll never be able to walk the streets of Paris with my daughters.”
Well, I was in Paris last week, and at least some of the time, I was walking – or, more accurately, limping – along the streets with my girls. At least the garbage strike had lifted, and those streets were relatively clean!
One morning we took a Hemingway walking tour, which took us through the streets of the Left Bank, visiting sites associated with the Lost Generation – Hemingway, Fitzgerald, Joyce; Gertrude Stein, Alice B. Toklas, Sylvia Beach, and others. Along the way, our guide read us this quote from Hemingway’s posthumously published memoir, A Movable Feast:
I would walk along the quais when I had finished work or when I was trying to think something out. It was easier to think if I was walking and doing something or seeing people doing something that they understood.
That quotation is one of the more famous descriptions of an idea that goes back to the ancient world (“It is solved by walking,” the 4th-century philosopher Diogenes said) and continues until today (Aaron Sorkin added a scene into the new version of Camelot that opens on Broadway tonight in which Guinevere encourages King Arthur to walk around the castle, a move that produces the idea of the Round Table).
In effect, this reverence for ambulation has taken on near scriptural status in recent years: walking is good for the body! good for the mind! good for the soul! and good for the imagination! Like leaches and whisky in their time, walks have become the go-to tonic of modern times.
Worried about finding the funds to pay your taxes? Take a walk!
The idea that walking could have abundant side effects on mental health, creativity, and well-being goes back decades, with a series of tests on rodents. Studies showed that active animals showed greater neurological activity than sedentary ones. With the addition of several tests, largely of undergraduates, this new consensus about the power of walking began to take over popular media.
More recently, academics began pushing back – hard.
Just this February, Luis Ciria of the University of Granada and six colleagues published a major study in Nature using a metareview of existing research claiming that most studies on the benefits of walking were overstated and based on flimsy data.
Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary randomized controlled trials, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions.
Moreover, those benefits were reduced even further when other moderating factors were considered.
These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.
As it happens, within days, more reliable evidence appeared.
A massive new study released two weeks ago by Boris Cheval from the University of Geneva and eight colleagues used a new technique of sampling the DNA of 350,000 people. They provided the best evidence yet that “higher levels of moderate and vigorous physical activity lead to increased cognitive functioning.” As one of the lead researchers summarized the finding: “Absolutely, exercise is one of the best things you can do” for your brain.
So what’s a layperson to think about this debate? Well, another new study by New Zealand’s Travis Gibbons and colleagues, released last year, provides what turns out to be the most salient answer: not all walks are equal.
Here, based on the most up-to-date findings, are three ways to think about the impact of walking on the mind:
1. Where you walk matters.
Simply put, walking in nature is more impactful than walking on city streets. A study released in January confirmed that exercise increases cognitive function but that the environment in which that exercise is performed may be just as important as the exercise itself.
Katherine Boere of the University of Victoria in Canada and two colleagues asked subjects to perform cognitive tasks after taking indoor and outdoor walks. Their study, also in Nature, called “Exercising Is Good for the Brain but Exercising Outside Is Potentially Better,” reported that all forms of exercise were effective but outdoor exercise “had an additional impact on cognitive attentional scores,” “lower reaction times,” and “higher accuracy” on tests.
When it’s time to strap on your boots for walking, green exercise is better than gray.
2. How fast you walk matters.
That 2022 study by Travis Gibbons on the connection between the type of exercise and the impact on brain function homed in on a subtle point: brisk exercise has greater benefits than moderate exercise. While Gibbons focused on cycling, the lessons can apply to walking, too.
The researchers compared results for 90 minutes of light cycling with six minutes of high-intensity intervals. During the easier tasks, positive outcomes rose slightly as early as 30 minutes; but during the high-intensity intervals, the benefits soared as early as six minutes. As Gibbons told The Washington Post last week: “Exercise is good for your brain and that exercising longer, or particularly, harder, may maximize the benefits.”
3. How many steps you take matters–but not as much as you think.
Finally, even within the cult of walking, there’s an even more cultish number: 10,000 steps. Like 10,000 hours, another myth, 10,000 steps is a lie that sounds good. (The number came from a decades-old marketing campaign for a Japanese pedometer.)
Amanda Paluch of the University of Massachusetts Amherst did a meta-analysis of 15 studies covering 50,000 participants and found that the popular number is unnecessary for increased benefits. Instead, getting between 6,000 and 8,000 daily steps is sufficient for most people.
“The major takeaway is there’s a lot of evidence suggesting that moving even a little more is beneficial, particularly for those who are doing very little activity,” Paluch said last year. “More steps per day are better for your health. And the benefit in terms of mortality risk levels off around 6,000 to 8,000 for older adults and 8,000 to 10,000 for younger adults.”
One more note before I send you out for a stroll. Another secret to successful walking is a really long walk, from hiking the Appalachian Trail to completing the Camino de Santiago.
Martin Mau of the University of Southern Denmark did one of the few studies of prolonged walking—from hikes to walkabouts to pilgrimages. In his study, which carries the charming title, “Becoming a Person: How Long-Distance Walking Can Lead To Personal Growth,” he wrote that in such journeys, “the destination is so far away, that the walker is not preoccupied with ‘getting there,’ instead, the walker has free time that is not allocated for some specific purpose.”
Freed from focusing on reaching a certain milestone, we are liberated instead to focus on the world around us. By letting our bodies wander, we let our minds wander. It’s precisely that act of wandering that may be the most important secret to being more creative. As Hemingway once said, the goal of being a better person is using the know-how we gain as adults “to acquire the courage to do what children did when they knew nothing.”
This piece is adapted from my newsletter, The Nonlinear Life.