We just have to admit that the term “recharging” isn’t accurate. Worse, it’s misleading. People don’t have anything like batteries for storing energy, so when we use that expression we’re actually making unreasonable demands of ourselves. The energizing, healthful effect we get from walking out in nature doesn’t last very long, and it cannot be stored in the form of a sort of dividend that can be paid out later. But are there positive effects to be gained from taking regular walks in nature—and, specifically, the forest?
I’ve been in the business of improving workplaces and homes for thirty years; time and again, I’ve seen that we need to “top up” our supply of nature every day, 24/7, in order to give our best, and, most of all, to feel healthy. And there is scientific research to prove this, as you will see. Scientists and researchers have documented a score of specific and measurable physical and mental health benefits from being out in nature. Walking along forest paths, breathing in forest air, and seeing the dappled play of light among the leaves definitely does a body good. However, the problem—which led me to develop the Forest Air method—is that this restorative energy cannot be stored and used later.
Because our bodies don’t act like a battery, we tend to be like the miser, scurrying in and out of our homes and workplaces hoping to capture some life-giving rays.
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A DEEP DIVE INTO FOREST BATHING
For years, Japan’s national health service has been encouraging people to indulge in shinrin-yoku, “forest bathing.” I love how the word evokes humans diving into the bushes and splashing about among the leaves, but shinrin-yoku simply means going for a walk in the woods (just as many Norwegians do!). The purpose of shinrin-yoku is not to lose weight or to get a stamp in your passport or to rack up steps on your Fitbit. (Although all of these, of course, can be part of a bath in the forest.) Instead, the walk should be short and leisurely; exercise is not the main aim. The ancient Romans instinctively turned to nature to feel better. The Norwegians have made a national pastime out of walking in nature. Immersing oneself in the atmosphere of the forest has become an integral part of preventive care and healing in Japanese medicine. What is it the Japanese know that the rest of the world doesn’t?
The unmistakable fragrance of a stand of evergreen trees is representative of the fact that all plants exude fleeting organic compounds called phytoncides, which are used not only as a defense against enemies, but also as a way to communicate with other plants of the same species. These compounds, such as the pinenes and limonenes of evergreens, form an aromatic cocktail that is regarded by the Japanese as highly beneficial for health. Immersing oneself in a forest doesn’t just feel calming and restorative; since 2004, researchers in Japan have investigated the effect plants have on health and well-being. Lower blood pressure and anxiety, less irritation and anger, and a strengthening of the immune system were found to be, literally, a walk in the park.1
Even in the sterile environment of a research lab, far from a forest, health benefits were noted. Experiments showed that just a photograph of a restful nature scene conveying shinrin-yoku was enough to cause a drop in blood pressure. Just the scent of certain ethereal oils from forest plants caused a greater drop in blood pressure than other smells. And just touching a natural material like an oak plank had the same effect—an effect that was not demonstrated when this same material was coated with a layer of paint.
Experiments were also conducted in the open air. In Chiba, Japan, a control group took a bracing stroll around the city’s railway station, while another group walked for twenty minutes in an oak forest in one of the city’s parks. The physiological and mental responses of both groups were then tested. The forest group not only showed clear signs of heightened cerebral activity but exhibited improved concentration. The forest group also had a lower count of cortisol compared to the control group. Cortisol is known as the “stress hormone” for good reason, as a high level of cortisol is one of the signatures of elevated stress. A short walk among the trees was all that was required to lower the concentration of this hormone—to de-stress.
Another of these experiments, carried out in 2010, tested the nervous systems of participants who were split into two groups, one walking in the forest and one walking through a built-up urban environment. The forest group had lower levels of cortisol, lower pulse rates, reduced blood pressure, an increase in the activity of the parasympathetic nervous system, and a reduction in the activity of the sympathetic nervous system. These last two results were particularly exciting for me to see.
Remember learning about the nervous system in biology class? The sympathetic nervous system is the part of the autonomic nervous system that enables us to react swiftly to dangerous situations (the “fight or flight” response), while the parasympathetic nervous system is what calms us down when the danger has passed. So elevated levels of activity in the sympathetic nervous system means that you are prepared and ready for conflict. Our ancestors had to deal with fierce predators, while today our bodies seem to get keyed up to fight (or flee) at the drop of a hat. (Just think of the tension and anxiety you feel in a traffic-snarled commute.) Researchers were able to document a very important connection:
Shinrin-yoku soothes your unease and helps calm you down after agitation.
Later studies have also shown that green surroundings have a favorable impact on chronic stress.
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And for those who suffer from debilitating anxiety or illnesses, later studies have also shown that green surroundings have a favorable impact on chronic stress. An experiment carried out in the 1990s at Hokkaido University showed that shinrin-yoku led to a significant lowering of the levels of blood sugar in people suffering from type 2 diabetes, on average a change from 179 mg/dL (before a walk in the woods) to 108 mg/dL (after). Does the length of a walk matter? In this experiment, apparently not: Subjects walked between two miles and four miles, but the length of the walk had no impact on the results.2 Good news for those of us who just don’t have the time to walk for hours every day, as much as we would like to!
BUT YOU CAN’T TAKE IT WITH YOU
Around the world, researchers back up the claim that a simple walk in the woods works wonders. As much of the world’s population now lives and works in cities, the question for researchers then became how different urban environments might effect one’s sense of well-being. Finnish researchers in Helsinki, in a study published in 2014, investigated just that. In three groups, participants traversed busy city streets, a green space in the middle of the city, or a wooded area. Would they feel restored? Filled with vitality? More creative? Hands down the wooded area made people feel the most restored, vital, and creative, but the city park also had a marked positive effect on the participants’ well-being. Another striking observation? Stress levels not only went down, they went down quickly.3
People feel better after taking a walk in a park, but can these feelings be measured? In the United States, researchers at Stanford University studied the psychological effects of experiences of nature on both thoughts and feelings. Subjects were divided into two groups, each of which was to take a fifty-minute walk in the Stanford area in either a high-traffic urban setting or in a park. A series of psychological tests was conducted before and after the walk. Those who had walked in nature reported lower levels of anxiety, fewer depressive thoughts, and fewer negative feelings. Higher scores in memory tests showed that their intellectual capacity had also increased. Another study made by the same group of researchers investigated the effects of walking in the woods on common urban ailments such as depression and negative thinking. This study too showed measurable physical effects on the activity of the brain: lower levels of activity in the subgenual prefrontal cortex (sgPFC), the part associated with self-centeredness and chronic worrying.4 Walking in nature isn’t just a feel-good exercise.
A walk through the woods also helps those suffering from chronic physical pain. In a South Korean study, patients