Physiological Effects of Shinrin-yoku (Taking in the Atmosphere of the Forest) in an Old-Growth Broadleaf Forest in Yamagata Prefecture, Japan

Abstract

The physiological effects of "Shinrin-yoku" (taking in the atmosphere of the forest) were examined by investigating blood pressure, pulse rate, heart rate variability (HRV), salivary cortisol concentration, and immunoglobulin A concentration in saliva. Subjective feelings of being "comfortable", "calm", and "refreshed" were also assessed by questionnaire. The subjects were 12 male university students aged from 21 to 23 (meanϮSD: 22.0Ϯ1.0). The physiological measurements were conducted six times, i.e., in the morning and evening before meals at the place of accommodation, before and after the subjects walked a predetermined course in the forest and city areas for 15 minutes, and before and after they sat still on a chair watching the scenery in the respective areas for 15 minutes. The findings were as follows. In the forest area compared to the city area, 1) blood pressure and pulse rate were significantly lower, and 2) the power of the HF component of the HRV tended to be higher and LF/(LFϩHF) tended to be lower. Also, 3) salivary cortisol concentration was significantly lower in the forest area. These physiological responses suggest that sympathetic nervous activity was suppressed and parasympathetic nervous activity was enhanced in the forest area, and that "Shinrin-yoku" reduced stress levels. In the subjective evaluation, 4) "comfortable", "calm", and "refreshed" feelings were significantly higher in the forest area. The present study has, by conducting physiological investigations with subjective evaluations as supporting evidence, demonstrated the relaxing and stress-relieving effects of "Shinrin-yoku".

Relaxation Effect of a 2-Hour Walk in Kumano-Kodo Forest

“…Similar results are obtained even after only about 15 to 20 minutes of walking in the forest [8][9][10][11][12]. This highlights the importance of green spaces in the city [14] and garden walking [15].…”

“…These studies measured cortisol in saliva, sympathetic and parasympathetic functions, blood pressure, and heart rate variability as indices of stress. Some studies have included walking in addition to spending time in forests, but with walking times as short as 15 minutes [8][9][10][11][12].…”

Trends in research related to “Shinrin-yoku” (taking in the forest atmosphere or forest bathing) in Japan

“…''Shinrin-yoku'' in an old-growth broadleaf forest in Yamagata Prefecture [42] Oguni Town in Yamagata Prefecture is situated on the border between Yamagata and Niigata, with forests Environ Health Prev Med (2010) 15:27-37 33 covering 95% of the local area. This study was conducted in a deciduous broadleaf forest that mainly consisted of old-growth beech, with an area around Niigata Station used for comparison.…”

“…n = Forest area City area Fig. 2 Changes in salivary cortisol concentration at six measurement times in subjects a forest area and in a city area [42]. n = 9 at ''before walking'' and ''after walking'', n = 11 at the other times.…”

Looking for the role of nature experiences in planning and decision making: a perspective from the Helsinki Metropolitan Area

“…Enjoyable and accessible nature environments, for instance, encourage people to spend their time outdoors and, according to surveys and physiological studies, these activities reduce stress and promote physical and mental well-being (Ulrich et al 1991;Hartig et al 2003;Tsunetsugu et al 2007;Tyrväinen et al 2007b). The strong link between natural environments and quality of life (Stubbs, 2008) has negative aspects as well-for instance, dark forests and poorly managed parks cause fear (Lyytimäki et al 2008;Skår, 2010).…”