Forest Air Boosts Immune System for a Month

A study conducted by an immunologist in Japan revealed that exposure to forest environments can significantly enhance the human immune system. Twelve men who spent three days walking in a forest showed a notable increase in natural killer cells, which are crucial for fighting cancer and virus-infected cells. Remarkably, this immune boost persisted for a full month after their return. In contrast, a control group walking in a city showed no such changes. The researcher suggests that phytoncides, compounds released by trees like pine, cedar, and cypress to protect themselves, are responsible for activating these immune cells when inhaled. The findings imply that regular forest walks could offer a simple, natural way to maintain a strong immune system.