長文読解（人文系・自然科学系の文章）- 問題6

The concept of "forest bathing," or shinrin-yoku in Japanese, has gained international recognition as a scientifically-backed method for improving mental and physical health. Developed in Japan during the 1980s, this practice involves immersing oneself mindfully in a forest environment, engaging all five senses rather than simply hiking or exercising.
Recent studies conducted by researchers at Nippon Medical School have demonstrated remarkable physiological benefits. Participants who spent just two hours in forest environments showed a 50% increase in natural killer cell activity, which plays a crucial role in fighting cancer and viral infections. Additionally, levels of the stress hormone cortisol decreased by an average of 15.8% compared to urban environments.
The therapeutic effects are attributed to phytoncides, antimicrobial compounds released by trees and plants. These airborne chemicals not only protect plants from harmful bacteria and fungi but also boost human immune function when inhaled. Cedar, pine, and oak trees are particularly rich sources of these beneficial compounds.
Today, forest bathing is prescribed by doctors in Japan and South Korea as a complementary treatment for various conditions including depression, anxiety, and hypertension. Over 60 designated forest therapy trails now exist across Japan, each scientifically evaluated for their healing properties.