Forest Bathing Benefits: Tokyo Study

Forest bathing is an ancient Japanese practice rebranded as ‘Shinrin-yoku’ in the early 1980s. It’s become famous recently. Japan invented it and Forest bathing isn't merely a pleasant walk in the woods. It’s a therapeutic practice with measurable effects.

The Forest as a Healer

Six million Americans suffer from high blood pressure. Many take drugs to manage it. This study raises a different kind of intervention. Dr. Ching Li, a Japanese scientist based in Tokyo, sent 12 men aged 37 to 55 to a forest for three days and took their blood before and after the trip. Natural killer (NK) cell activity, an immune function, increased in 11 of the 12 men by around 50%, simply by standing under trees. The practice started in Japan, where it was used as a way to address a range of health issues. The practice works by exposing the body to certain compounds released by trees, known as phytonsides. These compounds are aromatic and have been shown to have a positive effect on the body’s immune response. Trees did not evolve this for humans, but it’s a happy accident that humans can stand in it and get the benefits.

The Science of Shinrin-Yoku

A key activity of forest bathing is walking around. The researcher then repeated the experiment in an urban setting, in a city. The results were the same. The environment did not matter. The property of the woods is not the forest, it's the air. In 2009, they took forest bathing to an extreme. The subjects were placed in an urban hotel room. They had the same three days of exposure to the elements. It worked. It also showed that NK cell activity and stress hormones decreased. They followed the subjects for a time and found the results still lingered. After a month, the effects were still measurable. Forest bathing isn't about a calming effect. The mood doesn't matter. It's about getting outside and putting the body in contact with nature. Some cells in the blood stream are known as natural killer cells or 'NK' cells. NK cells are a type of cytotoxic lymphocyte critical to the innate immune system. The activity of NK cells is often used as a measure of immune function, and it has been shown to be boosted through forest bathing. But it doesn't work through the classic mode of exercises or rest. The process involves being in proximity to certain trees.

The Phytonsides

The mechanism behind the health benefits of forest bathing lies in the phytonsides released by trees. These are aromatic compounds found in the air of forests. By inhaling these compounds, the body’s immune response is enhanced. Nature has created a natural way to boost the immune system.

A Study in the City

The 2009 study demonstrated the efficacy of forest bathing in an urban setting. Twelve men, the same age as before, were placed in a hotel room in a city. They inhaled hinoki cypress oil released from a humidifier. There was a significant increase in natural killer cell activity and a decrease in stress hormones. This study reinforced the idea that the benefits of forest bathing are not tied to the physical location but to the exposure to the compounds in the air.

What's the protocol?

Dr. Li found that the protocol was simple. For health benefits, it suggested a couple of hours under trees once a month. No retreat, no detox, just the air. The calm was real. It's just not the interesting part.

The Quiet Way

Use Japanese forest bathing regularly without even knowing it. But for the best experience, shed the noise. You walk in the forest. No agenda, no expectations. No rush.

• Forego electronics, leave the phone in your car.
• Wear comfortable shoes, dress for the weather, and plan to walk at a relaxed pace.
• If you wander off the path, wear a whistle.
• Choose a forest in which you feel comfortable and safe.
• Leave the phone in the car.
• Take a deep breath. Notice the smell.