Go for a walk, you’ll feel much better. Sound familiar? Now, we’ve all benefited from a good long walk, but why is it that we do feel so much better? And why is it that walking in nature makes us feel even better again?
Gregory Bratman, a graduate student at the Emmett Interdisciplinary Programme in Environment and Resources at Stanford University wanted to find out. Bratman had previously been studying the psychological effects of urban living. He’d found that he and his colleagues had felt happier and more attentive after walking briefly through lush, green sections of their university campus than volunteers who had spent the same time walking through areas surrounded by heavy traffic. He wanted to find out if these environments actually changed our brain chemistry.
In Bratman’s previous study, he’d found that urban dwellers who don’t access the outdoors have more psychological problems than those living near parks or those who often frequented city parks. Those who had recently spent time in a leafy, green environment had lower levels of stress hormones in their bloodstream. He also found that city dwellers had a higher risk of depression, anxiety and other mental illnesses than their counterparts living in areas exposed to a more natural environment.
In Bratman’s new study, he and his collaborators decided to take a close look at the effect a walk may have on a person’s propensity to ‘brood’. Now, the very term does tend to conjure up images of young, handsome men in a Bronte sister’s novel – which is kind of apt, because brooding is a mental state where we can’t stop mulling over things that concern us about ourselves or our lives. For the less literary folk, you may like to know that ‘brooding’ is known by the scientific community as ‘morbid rumination’. It’s like a broken record of fretting that’s not at all helpful or good for us. It can also be a precursor to depression and tends to be more prevalent in city-dwellers and those living in urban areas, according to several studies.
Your subgenual prefrontal cortex (the brooding bit)
When we succumb to rumination, there is an increase in activity in the area of our brain known as our subgenual prefrontal cortex. Researchers reasoned that if they could assess the activity in this part of the brain of various participants before and after they had walked through nature, they could then assess the extent to which nature alters people’s minds.
To carry out the study, Bratman and his peers recruited 38 healthy, adult city dwellers. Each subject completed a questionnaire to help determine their current levels of morbid rumination. Then, the researchers checked the brain activity of each, achieved by using scanning machines that track blood flow through the brain. (Generally speaking, greater blood flow in certain parts of the brain indicates more activity).
The researchers then commenced the study. Half of the participants were assigned to a 90-minute solo walk through a leafy, quiet, park-like portion of the Stanford University campus. The other (less fortunate) group were assigned to walk alongside a busy, hectic multi-lane highway in the city. No one in the study was allowed a companion or to listen to music while walking.
After the study, each participant’s brain activity was assessed once again. As you may have guessed, those in the latter group had a high level of activity in their subgenual prefrontal cortex. Meaning: they were just as broody as before!
Volunteers in the former group, the ones pleasantly strolling through quiet, leafy parks showed slight, but significant improvements in their brain chemistry. Participants mentioned that they were no longer dwelling on negative thoughts as they were prior to their walk. Scans confirmed this, revealing less activity in their subgenual prefrontal cortex.
Mr Bratman concluded that the results “strongly suggested that getting out into natural environments” could be an immediate and manageable way for city dwellers to improve their moods. There are still questions remaining, though, such as how long one needs to walk outdoors, how often and exactly which natural environments are the most soothing? Is it the peace and quiet; is it the smell of greenery; is it the sunshine; or is it the visual appeal of trees and grass? Do we need to be physically active in conjunction with experiencing these sensations?
Regardless of the questions still remaining, there still appears to be reasons enough for us all to go outside and take a walk along a green, leafy path, leaving our broody subgenual prefrontal cortex in peace!
Sage Institute of Fitness – it’s more than a job, it’s a rewarding career.
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