Positive Healthy Physiological Effects of Shinrin-yoku in Human / 日本温泉気候物理医学会雑誌

ABSTRACT

  The positive healthy physiological effects of shinrin-yoku in elderly persons were studied. Shinrin-yoku or forest bathing is considered to promote physical relaxation and to have physical and mental health benefits. In this experiment the subjects were elderly 24 male (65.5±2.5years) and 24female (65.0±3.0years) persons who participated in three measurements of shinrin-yoku effects from 2008 to 2010. All the subjects were healthy and volunteered for the experiment. The subjects participated in the shinrin-yoku measurements three times of two hours each on Wednesday in the third week of August in each year. The weather at the time of the three measurements was clear, with temperature of 30°C-32°C, humidity of 58%-60% and wind velocities of 0m/sec-2m/sec. Non-shinrin-yoku measurements were also performed on a different day in an indoor resting environment with the same subjects under the same conditions. For both the shinrin-yoku and non-shinrin-yoku measurements, the subjects were divided into three groups of 8 male and 8 female subjects equally. One was for the visual isolation group in which subjects wore eye masks, another was for the smell isolation group in which subjects wore masks, and the other was the control group in which subjects wore non-isolation material. The concentration of phytoncides in the air was measured using gas chromatography mass spectroscopy. Heart rate (HRs), blood pressure (BP), fasting levels of plasma catecholamine (adrenaline, noradrenalin and dopamine), plasma cortisol and circulating natural killer (NK) cell activity were measured before and after shinrin-yoku. Three kinds of phytoncides derived from trees were detected at the forest-bathing measurement spot in this study. The mean HRs for male subjects under shinrin-yoku and non-shinrin-yoku were 89bpm and 85bpm respectively. The mean HRs for female subjects under shinrin-yoku and non-shinrin-yoku were 86bpm and 85bpm respectively. In the smell isolation group and the control group, systric blood pressure for male and female subjects decreased significantly after shinrin-yoku. In the smell isolation group and the control group, diastolic blood pressure for male subjects decreased significantly after shinrin-yoku. In the smell isolation group and the control group, adrenaline levels for male and female subjects decreased significantly after shinrin-yoku. Among the male under the control and the female under the smell isolation and the control, noradrenaline levels decreased significantly after shinrin-yoku. Similarly, under the smell isolation, and the control, the male and female subjects showed significant decreases in the cortisol level. The NK cell activity of male and female subjects and had no significant change after shinrin-yoku. The BP, catecholamine level, cortisol level, and NK cell activity of male and female subjects showed no significant change after non-shinrin-yoku. The authors believe that this issue, and the general topic of shinrin-yoku and other environments with natural health benefits merit further study. It has been pointed out that the phytoncides and green forest environment in shinrin-yoku have a relaxing effect on the human body. As physical effects of shinrin-yoku, this study of male and female elderly subjects suggested the possibility of physiological effects in which appear within a short time and consist of multiple elements related to the human five senses, including the effects of phytoncides.   Future issues include accumulation of study results on the linkage between physiological/psychological responses and quantitative/qualitative data on odor and the visual sense.