By: Maya Honda-Granirer
Photo credits of: Maya Honda-Granirer
For years, the Japanese have understood the life-changing benefits of the forest. The concept was formally given a name by the Japanese government in 1982 – “shinrin-yoku,” which translates to “forest-bathing”. Finally, science has caught up with traditional knowledge and we’re starting to understand the scientific powers of mother nature. We all know that walking in nature is good for us. Here’s the science behind it.
Pine, fir, cedar and cypress trees are complex organisms that store phytoncides (substances that are generally produced by plants which have some antimicrobial function), such as alpha-pinene and beta-pinene. A study in 2010 supports traditional knowledge by demonstrating that these essential oils, which manifest in scents, reduce the cortisol stress hormone. Another study in 2015 has shown that walking in a forest decreases brooding, while increasing positive emotions. Brooding, as defined by dictionary.com, is to be “preoccupied with depressing, morbid or painful memories or thoughts”. In this randomized study, Ph.D. student, Gregory Bratman and his colleagues assigned 60 people to a 50-minute walk in a natural or urban environment. Those who walked in the natural setting showed less anxiety, stress and brooding. In a similar study conducted by Bratman, results showed that those who walked in a natural setting (rather than an urban setting) had increased neural activity in the subgenual prefrontal cortex, the inactivity of which is linked to depression and anxiety.
A study conducted on older city-dwellers showed that those who lived and walked in forests had greater activity in the amygdala, “a roughly almond-shaped mass of gray matter inside each cerebral hemisphere, involved with the experiencing of emotions” (Google Dictionary). This means that they were able to cope with stress and experienced less aggressiveness, fear and anxiety.
According to the New York Department of Environmental Conservation and numerous studies, being in a forest contributes to a boost in the immune system, increased the ability to focus (even among children with ADHD), accelerated recovery from illness or surgery and improved sleep.
We know that walking in forests makes us happier, but it also makes us smarter. A rising phenomenon called Directed Attention Fatigue occurs when we focus on specific activities for long periods of time. This drains our mental energy, alters our emotions and negatively impacts our emotions. When in a forest, our attention wanders from the old tree to the colourful bird to the dynamic shadows creating patterns on the ground. This gives the “focus” part of our brain a rest and restores our patience and ability to concentrate, which leads to increased cognitive ability.
Neuroscience shows that when walking, the hippocampus – the part of the brain primarily associated with memory – is activated. The hippocampus is stimulated to produce more hippocampal cells, which leads to improved memory. Walking in the forest regularly can decrease your risk of Alzheimer’s Disease by up to 50% and slow the progression of it for those who are already diagnosed.
The impact of forest walking on a restless mind is best explained by Shakespeare, rather than science. He wrote in The Tempest, “A turn or two I’ll walk, To still my beating mind.” In our current world, restlessness and loneliness are frequently intertwined. Despite (or perhaps because of) the ever-growing influence of social media on our lives, people are reporting more loneliness. Walking in the forest alleviates the loneliness we often carry in our bustling lives. Whether it’s walking with a friend, exchanging hellos with a passerby or lingering in your own thoughts, being in a forest clears your mind and gives you a deeper connection with the world.
Many of us wish that the world would turn into a kinder place. Well, immersing yourself in forests can lead us one step closer to that goal. An experiment carried out by Juyoung Lee and Dacher Keltner at the University of California consisted of exposing participants to beautiful scenes of nature. Then, these participants were asked to play two games, the Dictator Game and the Trust Game, which measure generosity and trust. Those who saw the nature scenes displayed more generosity and trust than those who were shown less beautiful, non-natural scenes (as decided subjectively). The conclusion drawn from this experiment was that nature makes human beings kinder.
Not only does walking in a forest increase one’s mental state, but it may increase your lifespan. Immersing yourself in a forest can keep your heart healthy by lowering your blood pressure. A study in Japan showed that participants who walked in a forest came back with lower blood pressure (both systolic – blood pressure when the heart beats – and diastolic – blood pressure between heartbeats) while those who walked in an urban setting experienced no change in blood pressure.
Although in need of further support, some studies have also suggested that forest walks may be helpful to fighting cancer. One agent in our bodies that fights cancer is the Natural Killer cell (NK cells). Dr. Li of the Nippon School in Tokyo and his colleagues wanted to see if spending time in forests impacted the body’s production of NK cells. Indeed, his hypothesis triumphed. The phytoncides released by trees (which were mentioned earlier) have antifungal and antibacterial properties. After the inhalation of these phytoncides, participants’ (who were exposed to these phytoncides for 3 days) bodies responded by increasing their production of… you guessed it! Natural Killer Cells. The increased NK activity lasted for more than seven days after the initial study. The control group, which did not inhale these phytoncides, showed no increased activity. Next time you go for a walk in the forest, enjoy every breath. Those inhalations might just fend off cancer.
All these physical and mental health benefits from walking in forests are shown to increase one’s lifespan. According to health experts, 25-minute daily walks can add up to seven years to your life.
I only scratched the surface with this short article; there are so many more benefits of forest walking that science hasn’t discovered yet. Nonetheless, if I were to summarize all of the scientific evidence for the benefits of walking in the forest, this article wouldn’t be anything short of a book series! Science explicitly shows that walking in the forest makes us healthier, smarter, calmer and kinder people. However, forests are quickly disappearing from our environment. Therefore, it’s so important to protect and propagate what’s left of our beautiful green spaces. To tweak the famous 1860s proverb: A walk in the forest a day will keep the doctor away.
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