Natural experiences can calm us even as they help reinvigorate our immune system.
Forest bathing, also known as shinrin-yoku, is the ancient practice of visiting a forest and breathing in its air. A Japanese nature therapy practice used as a natural remedy for stress relief and mental fatigue, forest bathing has received much scientific attention in recent years, with many studies exploring the physiological and psychological benefits of spending time in nature.
Urbanization is a growing global trend, and 68 percent of the world’s population is projected to live in urban areas by the year 2050. Urban living environments are associated with increased anxiety and mental health concerns, and urbanicity also has numerous negative impacts on physical health, including increased weight gain, poor food quality, and increased risk of cardiovascular problems when compared to those living in rural areas.
For these reasons and others, researchers have begun tracking and comparing the effects of nature excursions such as forest bathing on human health. In addition to psychological benefits, there is now evidence that forest bathing may improve immunological function.
Immunological Benefits of Forest Bathing
A study conducted in Japan explored the effects of forest bathing on immune function. Healthy male participants between the ages of 35 and 55 years were selected to participate in a three-day nature trip that involved hiking in the woods.
Natural killer (NK) cell levels were measured in the men before and after the trip, and nearly all participants experienced an increase in natural killer cell activity after the trip. Natural killer cells are key to the innate immune system and help our bodies reject cancer cells and viral infections. Researchers also measured perforin, granzymes, and granulysin-expression in peripheral blood lymphocytes and found that the trip dramatically increased the production of these anti-cancer proteins, signifying that forest bathing may indeed increase immunological function.
This wasn’t the first study to find shinrin-yoku beneficial for stimulating immune function, however. A study of healthy young females found similar results in natural killer cell production and anti-cancer proteins after a three-day nature excursion, and found that the results lasted at least seven days after the trip had ended.
Researchers believe that phytoncides, a type of aromatic compound released from trees and plants, may be responsible for the decrease in hormone stress levels and increase in NK production. Other studies have backed these results and found that NK production levels were still increased even 30 days after such trips, suggesting forest bathing once a month may drastically improve immunological function.
Researched Benefits of Forest Bathing
In addition to its benefits on the immune system, forest bathing has been studied for its positive effects on a variety of ailments including: