Photo Credit: © Zurijeta/Shutterstock.com
December 23, 2013
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From your first steps into the forest, your entire body feels
changed. You feel the gentle breeze on your skin and the trail under
your feet. You breathe in and notice the clean, crisp air with the
familiar smell of the forest that is sometimes punctuated with the odors
of specific plants you pass, like a fragrant flower or a pungent sage.
After a long hike, you feel recharged, and not just because of the
exercise.
If that describes you, you’re not alone. A growing body
of science is showing that nature is good for you. That includes
spending time in nature, but it even includes looking at natural scenes
out a window.
Should this really be news? After all, human being
evolved in nature for millions of years, not even changing their
surroundings with agriculture until 10,000 years ago. In many parts of
the world, homes are still made from locally obtained materials like
wood, palm or grass thatch, mud, and even cow dung. Travel within
villages occurs on trails, not roads, and peasant farmers forage foods,
herbs and building materials from wild vegetation near their homes. At
night, the stars shine overhead without any city lights to compete with
them.
But as obvious as it may seem, it’s still helpful to study
how nature impacts our lives and our health. Modern science allows us to
hone in on exactly how and why nature is so good for us—something
intuition alone cannot provide.
Some of what we know about the impact of nature on health is incomplete.
One recent study
tested over 1,200 elderly adults. Those who had not engaged in outdoor
recreation in the past year were the most prone to major depression.
Those who spent time outside four or more times a week suffered the
least depression. This study found a correlation, but it did not
necessarily find causation. Were people depressed because they did not
go outside, or did they not go outside because they were depressed?
The basics behind the “nature is healthy” concept goes back decades. In 1984, a
classic study
found that hospital patients recovered from surgery quicker if their
room offered a view of nature compared to those who looked out on a
brick wall. Another
study, published in 2003, found that health increased with the amount of greenspace in one’s living environment.
Nowadays, scientists are using this basic understanding to fine-tune the hows and whys of nature’s impact on health.
One
study
concluded that the psychological benefits of nature increase with
biodiversity, defined by the richness of different types of habitats,
plant species, and birds.
Another line of research
has examined whether benefits of exercise on self-esteem and mood can
be increased if exercise is done in a natural environment, known as
“green exercise.”
In
one instance,
mental health patients’ self esteem improved significantly more if they
participated in green exercise than if they simply participated in a
social club. (
One study
of adults even found that exercising on a treadmill indoors while
viewing pleasant outdoor scenes achieves such an effect, although
another study failed to replicate the effect with adolescents.)
So why is Mother Earth just so darn healthy?
One reason, called Attention Restoration Theory, was
outlined by Stephen Kaplan, in the 1980s and '90s but it actually dates back to a theory proposed in 1892.
Over a century ago, psychologist William James then proposed the idea of “voluntary attention.” Kaplan
describes it
as “the kind of attention that went ‘against the grain’... It was to be
employed when something did not of itself attract attention, but when
it was important to attend nonetheless.” Studying for finals or reading a
software instruction manual fall into this category.
Kaplan, a
psychologist at University of Michigan, takes this theory further by
combining it with another 19th-century theory, namely that one can
become fatigued from expending too much of this voluntary attention,
also known as directed attention. A student who announces, “My brain is
fried” after a weekend of studying is expressing this kind of fatigue.
One
way to deal with directed attention fatigue is sleep, but sleep alone
is not enough. Aside from sleep, one requires “restorative
experiences”—and that is what nature provides. Kaplan outlines many
components to this, such as the sensation of “getting away,” an
effortless fascination with one’s surroundings, and what he calls a
sense of “extent,” a sense of being connected to a larger world.
Once
outside, you are free to effortlessly follow a butterfly with your
eyes, listen to songbirds, or observe the motion of the leaves in the
breeze. But this attention requires little energy, and it leaves your
mind free to wander onto other things even as you watch a brilliant
sunset or a hawk soaring overhead.
A pioneer of using this theory to promote health is
Bernadine Cimprich,
associate professor emerita at the University of Michigan School of
Nursing. In various experiments on breast cancer patients, she found
that
exposure to the natural environment
helped patients recover the capacity for directed attention. For a
cancer patient who must pay attention to a doctor’s instructions,
capacity for directed attention could be a matter of life and death.
These
are known as cognitive benefits, improvements in your ability to think.
That is distinct from psychological benefits such as improvements in
mood, self-esteem, or stress. It also differs from physical benefits,
like reduced disease or mortality. However, these measurements are
linked, sometimes obviously, in the case of a cancer patient who is
better able to follow a doctor’s directions, but sometimes in a less
obvious way.
Stress, while uncomfortable emotionally, is also
unhealthy physically. When stressed, your body produces stress hormones
like cortisol. While adaptive in an acute situation (i.e. running away
from an angry bear), it is harmful
if you remain stressed all the time. Among other things, cortisol suppresses your immune system.
Because
of our bodies’ physical response to stress, it’s easy to measure stress
objectively simply by testing saliva samples for stress hormones. A
2013
study did
just this, testing saliva sampled before and after study participants
sat in various settings (natural and urban) for 20 minutes. They found
evidence that spending time in a natural environment reduces stress.
The
healing power of nature has massive implications for public health.
Unlike pharmaceuticals, surgery, or even counseling, nature is free and
easily available for most people. Aside from the occasional bee sting or
poison ivy rash, nature comes without side effects. Even in sub-zero
temperatures, when it’s unpleasant to go outside, we can benefit simply
by viewing nature out our windows.
In New Hampshire,
Riverbend Community Mental Health, Inc, takes advantage of nature’s healing powers by working with patients at a local farm. Patients and staff regularly visit
Owen Farm, where they interact with animals, work in the garden and take part in other aspects of farm life.
Far
too often, Americans refer to natural spaces as “empty.” Talk to
someone driving across a vast stretch of the country without towns and
they will say they are in the “middle of nowhere.” What’s there?
“Nothing,” they might answer.
But a natural space is not “nothing”
or “empty." It’s not only wildlife habitat and a carbon sink, it’s also
a resource for improving human health. A forest might have a dollar
value if all of the trees were cut down and the wood was sold, but it
also has a value if we leave it intact and spend time in it
recreationally. What we do not know yet is the dollar value it has in
terms of surgeries, medications, deaths, and other losses prevented. And
is that even important?
If you’re looking to improve your health,
mental or physical, in the new year, one way to do so is to get
outside. And if you exercise or socialize while you’re out there, all
the better.
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