I met Eileen at a garden I managed for developmentally disabled adults. She was a client at that facility, prone to loud involuntary screams and groans as is sometimes the case with this population — unless she was in the garden. There, she sat quietly, face to the sun and hands in her lap, the surrounding greenery and flowers lulling her into complete silence.
This seemed a miracle to me. Why did her behavior change so dramatically outdoors? How could her surroundings have such a profound effect? Was it a fluke? A coincidence?
Turns out there’s a mountain of research that explains Eileen’s transformation — and the tremendous physical and mental benefits we all experience in the garden or deeper in the great outdoors. As those of us who like playing in the dirt can attest, tending a garden is the perfect antidote to the whirring and digitizing of everyday life. Getting in tune with the seasons, tending a plot, hiking in the woods on a sunny day; these activities feel good not just because they’re diversions. Rather, they ignite measurable physiological changes that occur in our brains and bodies.
A Stanford University study showed that those who took a 90-minute walk in nature showed reduced activity in an area of the brain linked to risk of mental illness. A study in the Netherlands confirmed that gardening reduced the stress hormone cortisol. In Norway, a study of people suffering from depression or bipolar disorder confirmed that half the participants who spent six hours a week gardening had measurable improvement in their depression symptoms — and continued to feel better three months after the study ended.
Even the simple act of touching dirt reduces stress and improves mood. That’s because a bacterium present in soil called mycobacterium vaccae stimulates areas of the brain that produce serotonin, the feel-good hormone. Researchers have found that eating trace amounts of soil on garden vegetables actually helps us manage stress and enhance brain function. In fact, the results are so compelling that new studies are underway to determine if soil bacteria could help treat post-traumatic stress disorder.
This, of course, should come as no surprise. As humans, we’ve co-evolved with M. vaccae and a zillion other bugs. But we’ve turned our backs on many of these microscopic friends in favor of indoor activities and a penchant for hyper-cleanliness. This can throw our immune systems off kilter and result in numerous health issues.
Is it any wonder, then, that some leading-edge doctors are writing “park prescriptions?” For instance, UCSF pediatrician Nooshin Razani helps her patients connect with nature to prevent and treat chronic illness, depression, anxiety, and isolation.
“Nature prescriptions” are becoming the norm elsewhere as well. Doctors in parts of Scotland can now prescribe a walk outdoors to treat hypertension and anxiety. In Japan and South Korea, “shinrin-yoku,” or “forest bathing” provides hard evidence that walking among trees lowers blood pressure, pulse rate and cortisol levels.
These studies confirm the sentiment of the late Oliver Sacks, who wrote, “I cannot say exactly how nature exerts its calming and organizing effects on our brains, but I have seen in my patients the restorative and healing powers of nature and gardens, even for those who are deeply disabled neurologically. In many cases, gardens and nature are more powerful than any medication.”Sacks and all the researchers confirm what we know intuitively: being in nature feels good. In the end, isn’t that enough to keep at it? And could there be a more inviting place than Marin to give in to a dose of eco-therapy?
In essence, the studies measure what feels immeasurable — the earthy crumble of dirt under fingernails, the satisfaction of a bucket of weeds freshly plucked, a bountiful harvest, winter melting into spring, a long walk on a cool day, Eileen’s silence outdoors.