Therapeutic effect of forest bathing on human hypertension in the elderly.

OBJECTIVE: To provide scientific evidence supporting the efficacy of forest bathing as a natural therapy for human hypertension. METHODS: Twenty-four elderly patients with essential hypertension were randomly divided into two groups of 12. One group was sent to a broad-leaved evergreen forest to experience a 7-day/7-night trip, and the other was sent to a city area in Hangzhou for control. Blood pressure indicators, cardiovascular disease-related pathological factors including endothelin-1, homocysteine, renin, angiotensinogen, angiotensin II, angiotensin II type 1 receptor, angiotensin II type 2 receptor as well as inflammatory cytokines interleukin-6 and tumor necrosis factor α were detected. Meanwhile, profile of mood states (POMS) evaluation was used to assess the change of mood state of subjects. In addition, the air quality in the two experimental sites was monitored during the 7-day duration, simultaneously. RESULTS: The baselines of the indicators of the subjects were not significantly different. Little alteration in the detected indicators in the city group was observed after the experiment. While subjects exposed to the forest environment showed a significant reduction in blood pressure in comparison to that of the city group. The values for the bio-indicators in subjects exposed to the forest environment were also lower than those in the urban control group and the baseline levels of themselves. POMS evaluation showed that the scores in the negative subscales were lowered after exposure to the forest environment. Besides, the air quality in the forest environment was much better than that of the urban area evidenced by the quantitative detection of negative ions and PM10 (particulate matter < 10 µm in aerodynamic diameter). CONCLUSION: Our results provided direct evidence that forest bathing has therapeutic effects on human hypertension and induces inhibition of the renin-angiotensin system and inflammation, and thus inspiring its preventive efficacy against cardiovascular disorders.

Effects of short-term forest bathing on human health in a broad-leaved evergreen forest in Zhejiang Province, China.

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.