How Walking in Nature Prevents Depression
A study finds that wild environments boost well-being by reducing obsessive, negative thoughts.
The Atlantic | 30 June 2015
“When we walk, we naturally go to the
fields and woods: What would become of us, if we walked only in a
garden or a mall?” wrote Henry David Thoreau in The Atlantic in 1862.
Thoreau
extolled (and extolled and extolled—the piece was more than 12,000
words long) the virtues of walking in untamed environments. In the
decades since, psychologists have proved him right. Exposure to nature
has been shown repeatedly to reduce stress and boost well-being.
But
scientists haven’t been sure why. Does it have to do with the air? The
sunshine? Some sort of evolutionary proclivity toward green-ness?
A group of researchers from Stanford University thought
the nature effect might have something to do with reducing rumination,
or as they describe it, “a maladaptive pattern of self-referential
thought that is associated with heightened risk for depression and other
mental illnesses.” Rumination is what happens when you get really sad,
and you can’t stop thinking about your glumness and what’s causing it:
the breakup, the layoff, that biting remark. Rumination shows up as
increased activity in a brain region called the subgenual prefrontal
cortex, a narrow band in the lower part of the brain that regulates
negative emotions. If rumination continues for too long unabated,
depression can set it.
For a study published this week in the Proceedings of the National Academy of Sciences,
the Stanford scientists examined whether a nature walk could reduce
rumination in 38 mentally healthy people. They picked city dwellers
because, the researchers predicted, they would have “a somewhat elevated
level of rumination resulting from the ongoing and chronic stressors
associated with the urban experience.” As in, “Christ almighty, is this the Metro escalator or the ice road to Stalingrad? Move along, people!”
After
some preliminary tests, half the participants walked for 90 minutes
through a grassland dotted with oak trees and shrubs (“views include
neighboring, scenic hills, and distant views of the San Francisco Bay”).
The other half took a jaunt along El Camino Real, a four-lane,
traffic-logged street in Palo Alto. The nature walkers showed decreases
in rumination and in activity in their subgenual prefrontal cortices.
The urban walkers showed no such improvements.
In
general, decreases in rumination are linked to so-called “positive
distractions,” like taking part in a hobby or enjoying a long chat with a
friend. You’d think that walking in uninterrupted nature wouldn’t
provide many diversions from a whorl of dark thoughts. Surprisingly, the
opposite seemed to be true: Natural environments are more restorative,
the authors write, and thus confer greater psychological benefits.
This
effect should work with many types of natural landscapes, particularly
those that engender “soft fascination,” the “sense of belonging,” and
the “sense of being away,” the researchers note. So while your back yard
might do, those little sidewalk parks that have sprouted up at
Manhattan intersections might not.
In part because of studies like
this, architects and designers are increasingly taking green space into
account in their blueprints and plans. But that might become harder to
accomplish: More than half the world’s population lives in cities
currently, and by 2050, about 70 percent will.
That’s yet another thing Thoreau warned us about:
“Nowadays
almost all man's improvements, so called, as the building of houses and
the cutting down of the forest and of all large trees, simply deform
the landscape, and make it more and more tame and cheap.”