Shinrin-yoku (taking in the atmosphere of the forest)

OBJECTIVE: To investigate the effects of short-term forest bathing on human health.

METHODS: Twenty healthy male university students participated as subjects and were randomly divided into two groups of 10. One group was sent on a two-night trip to a broad-leaved evergreen forest, and the other was sent to a city area. Serum cytokine levels reflecting inflammatory and stress response, indicators reflecting oxidative stress, the distribution of leukocyte subsets, and plasma endothelin-1 (ET-1) concentrations were measured before and after the experiment to evaluate the positive health effects of forest environments. A profile of mood states (POMS) evaluation was used to assess changes in mood states.

RESULTS: No significant differences in the baseline values of the indicators were observed between the two groups before the experiment. Subjects exposed to the forest environment showed reduced oxidative stress and pro-inflammatory level, as evidenced by decreased malondialdehyde, interleukin-6, and tumor necrosis factor a levels compared with the urban group. Serum cortisol levels were also lower than in the urban group. Notably, the concentration of plasma ET-1 was much lower in subjects exposed to the forest environment. The POMS evaluation showed that after exposure to the forest environment, subjects had lower scores in the negative subscales, and the score for vigor was increased.

CONCLUSION: Forest bathing is beneficial to human health, perhaps through preventive effects related to several pathological factors.