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The physiological effects of Shinrin-Yoku (taking in the forest atmosphere or forest bathing): Evidence from field experiments in 24 forests across Japan

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This paper reviews previous research on the physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing), and presents new results from field experiments conducted in 24 forests across Japan. The term Shinrin-yoku was coined by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and can be defined as making contact with and taking in the atmosphere of the forest. In order to clarify the physiological effects of Shinrin-yoku, we conducted field experiments in 24 forests across Japan. In each experiment, 12 subjects (280 total; ages 21.7 +/- 1.5 year) walked in and viewed a forest or city area. On the first day, six subjects were sent to a forest area, and the others to a city area. On the second day, each group was sent to the other area as a cross-check. Salivary cortisol, blood pressure, pulse rate, and heart rate variability were used as indices. These indices were measured in the morning at the accommodation facility before breakfast and also both before and after the walking (for 16 +/- 5 min) and viewing (for 14 +/- 2 min). The R-R interval was also measured during the walking and viewing periods. The results show that forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments. These results will contribute to the development of a research field dedicated to forest medicine, which may be used as a strategy for preventive medicine.
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SPECIAL FEATURE The Trends on the Research of Forest Bathing in Japan,
Korea and in the World
The physiological effects of Shinrin-yoku (taking in the forest
atmosphere or forest bathing): evidence from field experiments
in 24 forests across Japan
Bum Jin Park ÆYuko Tsunetsugu ÆTamami Kasetani Æ
Takahide Kagawa ÆYoshifumi Miyazaki
Received: 18 July 2008 / Accepted: 6 April 2009 / Published online: 2 May 2009
ÓThe Japanese Society for Hygiene 2009
Abstract This paper reviews previous research on the
physiological effects of Shinrin-yoku (taking in the forest
atmosphere or forest bathing), and presents new results from
field experiments conducted in 24 forests across Japan. The
term Shinrin-yoku was coined by the Japanese Ministry of
Agriculture, Forestry, and Fisheries in 1982, and can be
defined as making contact with and taking in the atmosphere
of the forest. In order to clarify the physiological effects of
Shinrin-yoku, we conducted field experiments in 24 forests
across Japan. In each experiment, 12 subjects (280 total; ages
21.7 ±1.5 year) walked in and viewed a forest or city area.
On the first day, six subjects were sent to a forest area, and the
others to a city area. On the second day, each group was sent
to the other area as a cross-check. Salivary cortisol, blood
pressure, pulse rate, and heart rate variability were used as
indices. These indices were measured in the morning at the
accommodation facility before breakfast and also both
before and after the walking (for 16 ±5 min) and viewing
(for 14 ±2 min). The R–R interval was also measured
during the walking and viewing periods. The results show
that forest environments promote lower concentrations of
cortisol, lower pulse rate, lower blood pressure, greater
parasympathetic nerve activity, and lower sympathetic nerve
activity than do city environments. These results will con-
tribute to the development of a research field dedicated to
forest medicine, which may be used as a strategy for pre-
ventive medicine.
Keywords Therapeutic effects of forest Heart rate
variability Salivary cortisol Blood pressure Pulse rate
Introduction
The growing interest in environmental stress has been
accompanied by a rapid accumulation of evidence indi-
cating that environment can elicit substantial stress in
people living in urban environments [1]. Furthermore, it is
broadly conceived that the natural environment can
enhance human health [2]. There have been several ques-
tionnaire studies on the psychological effects of forest
environments. A previous study found an enhancement
of positive emotions among subjects who were shown
pictures of natural environments [36]. Moreover, other
studies have also found that forest environments improve
the psychological wellbeing of people [712].
The term Shinrin-yoku (taking in the forest atmosphere
or forest bathing) was coined by the Japanese Ministry of
Agriculture, Forestry, and Fisheries in 1982. It can be
defined as making contact with and taking in the atmo-
sphere of the forest: a process intended to improve an
individual’s state of mental and physical relaxation [13].
Shinrin-yoku is considered to be the most widespread
activity associated with forest and human health.
Nowadays, there is considerable interest in stress control
and relaxation. Further, the field of medical science has
always favored evidence-based medicine (EBM); this
B. J. Park (&)Y. Miyazaki
Center for Environment, Health and Field Sciences,
Chiba University, Kashiwa-no-ha 6-2-1,
Kashiwa, Chiba 277-0882, Japan
e-mail: bjpark@faculty.chiba-u.jp
Y. Tsunetsugu T. Kagawa
Forestry and Forest Products Research Institute,
1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
T. Kasetani
Chiba Prefectural Agriculture and Forestry
Research Center Forestry Research Institute,
1887-1 Haniya, Sammu, Chiba 289-1223, Japan
123
Environ Health Prev Med (2010) 15:18–26
DOI 10.1007/s12199-009-0086-9
emphasizes the importance of scientific evidence in med-
ical practice. With improved measurement techniques, the
relaxation effect induced by forest settings can be clarified
in a field test by measuring the changes induced in physi-
ological parameters such as salivary cortisol, pulse rate,
blood pressure, and heart rate variability (HRV).
With this social background, the Association of Thera-
peutic Effects of Forests was established in Japan in 2004,
with the purpose of conducting a Therapeutic Effects of
Forests project in Japan. At the European level, similar
efforts were made through COST Action E39 on forest and
human health from 2004 to 2008 [14], and on the global level,
the International Union of Forest Research Organizations
(IUFRO) launched a new taskforce on forests and human
health in Finland in 2007 with the purpose of fostering cross-
disciplinary dialogue between the different researchers in
this field, especially forestry and health professionals.
As part of this effort, the Japanese Society of Forest
Medicine was established in 2007 under the Japanese
Society for Hygiene, with the purpose of promoting
research in the field of forest medicine, including the
effects of forest bathing trips and the therapeutic effects of
forests on human health. At the same time, several field
studies on the physiological effects of the natural envi-
ronment were carried out [13,1519].
In this paper, we review selected field studies performed
on the physiological effects of Shinrin-yoku and a study
dealing with the relationship between its psychological
effects and physical environmental factors. In addition, we
report new results from field experiments conducted in 24
forests across Japan.
Field methods
Subjects and study sites
We conducted physiological experiments in 24 areas from
2005 to 2006 in Japan. In each experiment, 12 normal male
university students (280 in total; ages 21.7 ±1.5 years)
participated as subjects; none reported a history of physical
or psychiatric disorders. The study was performed under
the regulations of the Institutional Ethical Committee of the
Forestry and Forest Products Research Institute in Japan.
On the day before the experiments, subjects were fully
informed of the aims and procedures of the experiment and
their informed consent was obtained.
Physiological measurements
Seven physiological parameters were analyzed in the
present study (Table 1). For the measurement of salivary
cortisol concentration, saliva was collected by holding two
pieces of absorbent cotton in the mouth for 2 min and using
a saliva collection tube (no. 51.1534, Sarstedt, Numbrecht,
Germany). On collection, the tube was sealed with tape and
immediately stored, refrigerated, and frozen; it was later
analyzed for cortisol concentration (SRL, Inc., Japan).
Heart rate variability (HRV) was analyzed for the periods
between consecutive R waves in the electrocardiogram (R–
R intervals) measured by a portable electrocardiograph
(AC-301A, GMS Corporation). The power levels of the
high-frequency (HF; 0.15–0.4 Hz) and low-frequency
components (LF; 0.04–0.15 Hz) were calculated [20] every
minute by the maximum-entropy method (Mem-Calc,
GMS Ltd. [21]). The HF power is considered to reflect
parasympathetic nervous activity [22]. Furthermore, the
power ratios HF/LF and LF/(LF ?HF) were determined to
reflect the sympathetic nervous activity [23]. Systolic blood
pressure, diastolic blood pressure, and pulse rate were
measured by a digital blood pressure monitor using oscil-
lometric methods (HEM1000, Omron, Japan) on the right
upper arm.
Psychological measurements
The Profile of Mood States (POMS) was used to gauge
the psychological response [24]. The POMS consists of
30 adjectives rated on a 0–4 scale that can be consolidated
into the following six effective dimensions: T–A (tension
and anxiety), D (depression and dejection), A–H (anger
and hostility), F (fatigue), C (confusion), and V (vigor).
Because of its responsiveness, the POMS have been widely
used in the assessment of mood changes resulting from a
variety of interventions. For the Japanese subjects, the
Japanese edition of the POMS was used.
Physical environmental factors
In the physical experiment, the temperature and relative
humidity, radiant heat, wind speed, predicted mean vote
(PMV), and predicted percentage dissatisfied (PPD) were
measured using a portable amenity meter (AM-101, Kyoto
Electronics Manufacturing Co. Ltd., Japan) at each study
site. In addition, atmospheric pressure (Kestrel 4000,
Nielsen-Kellerman, Japan) was also measured at some
locations. Relative illumination was calculated from photos
of the sky captured by a digital camera (Coolpix 4500,
Nikon, Japan) equipped with a fisheye lens (FC-E8, Nikon,
Japan).
Experimental design
After being given an orientation to the experiment on the
day before the first day of experimentation, the subjects
visited and previewed the forest and city study sites. Next,
Environ Health Prev Med (2010) 15:18–26 19
123
test measurements of all the physiological indexes and
subjective feelings were conducted at the accommodation
facility. In order to control the background environmental
conditions, identical, separate rooms were prepared as
lodgings for each subject and identical meals were served
during the experiments.
The subjects were randomly divided into two groups. On
the first day of the experiments, six subjects were sent to a
forest site, and the other six subjects to a city site. On the
second day, the subjects were sent to the other type of site as
a cross-check. The first measurement was taken in the early
morning at the accommodations before breakfast. After the
first measurement, subjects were sent to either a forest or
city site. It took almost the same amount of time to reach
both the forest and city sites from the accommodations. As
shown in Fig. 1, upon arrival at the given site, the subjects
were seated on chairs and viewed the landscape (for
14 ±2 min). They also walked around the given site (for
16 ±5 min). The second and third measurements were
taken before and after this walking. The fourth and fifth
measurements were taken before and after the viewing.
These measurements were taken for one person at a time. In
addition to these five measurements, the R–R interval was
measured continuously during the walking and viewing
exercises at the given site. The HRV was calculated once a
minute using the R–R interval data. The exercise loads
during the walking exercise in the forest and city sites were
estimated with an activity monitor (AC-301A, GMS,
Japan); there was no difference in exercise load between
walking in a forest site and walking in a city site.
The consumption of alcohol and tobacco was prohibited
and caffeine consumption was controlled.
Review of field studies performed on the physiological
effects of Shinrin-yoku in Japan
We searched the major journals on medical science,
physiological anthropology, and environmental science for
reports on field studies on the physiological effects of
Shinrin-yoku in Japan. Only articles presenting evidence of
the relaxing effects related to Shinrin-yoku have been
reviewed in this paper. Table 2presents a summary of the
reviewed papers.
An early study by Ohtsuka et al. [25] showed that blood
glucose levels in diabetic patients decrease when they walk
in a forest for 3 or 6 km, depending on their individual
physical ability. By the middle of the decade in which the
above-mentioned study was performed, research on the
physiological effects of Shinrin-yoku began in earnest,
using improved technologies for measuring physiological
indicators. These studies used a wide range of physiolog-
ical indices such as salivary cortisol, pulse rate, blood
pressure, and HRV. Moreover, the experiments were
designed with full consideration for cross-checks and
control stimuli. The studies showed that viewing forest
landscapes and walking in forest settings leads to lower
concentrations of cortisol, lower pulse rate, lower blood
pressure, enhanced HF component of the HRV, and lower
LF/HF [or LF/(LF ?HF)]. In particular, Park et al. [13]
showed that forest environments can lower the absolute
value of the total hemoglobin concentration (t-Hb), an
index of cerebral activity, in the left prefrontal area of the
brain. The absolute value of hemoglobin concentration had
never previously been measured in the field.
Table 1 Measured physiological parameters and subjective
evaluation
Autonomic nervous
activity
Pulse rate, systolic blood pressure, diastolic
blood pressure
Heart rate variability (HRV)
HF component (parasympathetic nervous
activity)
LF/HF or LF/(LF ?HF) (sympathetic
nervous activity)
Endocrine system
activity
Salivary cortisol concentration
Immune system
activity
Salivary immunoglobulin A concentration
Fig. 1 Forest viewing and
walking
20 Environ Health Prev Med (2010) 15:18–26
123
Though these studies focused on short-span exposures to
stimuli (approximately 15 min of viewing and approxi-
mately 15 min of walking), the results strongly supported
that participating in Shinrin-yoku activity could effectively
relax the human body.
Results of a physiological experiment
in 24 forests across Japan
Figure 2shows the average cortisol concentration in the
saliva. Salivary cortisol was significantly lower in the
forest area (13.4% decrease after the viewing; 15.8%
decrease after the walking). Moreover, the average pulse
rate was significantly lower (Fig. 3) in the forest area
(6.0% decrease after viewing; 3.9% decrease after walk-
ing). Figure 4shows that the average systolic blood pres-
sure was significantly lower in the forest setting (1.7%
decrease after viewing; 1.9% decrease after walking).
Figure 5shows similar results for the average diastolic
blood pressure (1.6% decrease after viewing; 2.1%
decrease after walking). The average power of the HF
components of the HRV, which is related to parasympa-
thetic nervous activity, increases when we feel relaxed.
This value was significantly enhanced in the forest settings
(56.1% enhancement after viewing; 102.0% enhancement
after walking; Fig. 6). The average LF/HF ratio of the
HRV, which is related to sympathetic nervous activity,
increases when we feel stress. This value decreased when
the subjects were walking in or viewing a forest (18.0%
Table 2 Findings from the literature review of physiological effects of Shinrin-yoku
Authors Stimuli versus control Results of Shinrin-yoku
Park et al. (2008) [17] FV versus UV Decreased PR and SC
Enhanced HF
Tsunetsugu et al. (2007) [19] FW versus UW or FV versus UV Decreased PR, SBP, DBP, SC, and LF/(LF ?HF)
Enhanced HF
Park et al. (2007) [13] FW versus UW or FV versus UV Decreased SC and TH
Furuhashi et al. (2007) [40] FW versus UW or FV versus UV Decreased PR, SBP, DBP, SC, and LF/(LF ?HF)
Enhanced HF
Tsunetsugu et al. (2006) [18] FW versus UW or FV versus UV Decreased SC and IgA
Park et al. (2006a) [15] FW versus UW or FV versus UV Decreased LF/(LF ?HF)
Enhanced HF
Park et al. (2006b) [16] FW versus UW or FV versus UV Decreased SC and IgA
Yamaguchi et al. (2006) [41] FV versus UV or FV versus UV Decreased SAA
Ohtsuka et al. (1998) [25] FW versus Non FW Decreased BG
HF, HF of HRV; LF/(LF ?HF), LF/(LF ?HF) of HRV; LF/HF, LF/HF of HRV
PR pulse rate, SBP systolic blood pressure, DBP diastolic blood pressure, SC salivary cortisol, IgA salivary immunoglobulin A concentration,
SAA salivary amylase activity, BG blood glucose, TH total hemoglobin concentration in prefrontal areas, FW forest walking group, FV forest
viewing group, UW urban walking group, UV urban viewing group
Salivary cortisol concentration (µg/dl)
0.0
0.1
0.2
0.3
0.4
0.5
0.6 Forest area
City area
**
Salivary cortisol concentration (µg/dl)
0.0
0.1
0.2
0.3
0.4
0.5
0.6 Forest area
City area
**
Walking, N=74
Viewing, N=260
Fig. 2 Change in salivary
cortisol concentration after
forest viewing and walking.
Mean ±standard deviation
(SD); ** p\0.01; p-value
by ttest
Environ Health Prev Med (2010) 15:18–26 21
123
decrease after viewing; 19.4% decrease after walking;
Fig. 7).
Overall, the results show that viewing forest landscapes
leads to lower concentrations of cortisol, lower pulse rate,
lower blood pressure, enhanced HF components of HRV,
and lower LF/HF. These results strongly support the
findings of indoor research using heart rate and blood
pressure on the effects of viewing a forest scene on
recovery from stress [1,2628]. The effect of walking in a
forest setting is the same as that of viewing a forest setting.
This result corroborates Hartig et al.’s finding [27] that
walking in a nature reserve initially fosters blood pressure
Pulse rate (beat/min.)
50
60
70
80
90 Forest area
City area
**
Pulse rate (beat/min.)
50
60
70
80
90
Forest are
a
City area
**
57=N ,
g
niklaW862=N ,
g
niweiV
Fig. 3 Change in pulse rate
after forest viewing and
walking. Mean ±SD;
** p\0.01; pvalue by ttest
Systolic blood pressure (mmHg)
80
90
100
110
120
130
140
150
160 Forest area
City area
**
Systolic blood pressure (mmHg)
80
90
100
110
120
130
140
150
160 Forest area
City area
*
57=N ,
g
niklaW862=N ,
g
niweiV
Fig. 4 Change in systolic blood
pressure after forest viewing
and walking. Mean ±SD;
** p\0.01; * p\0.05;
pvalue by ttest
Diastolic blood pressure (mmHg)
40
50
60
70
80
90 Forest area
City area
*
Diastolic blood pressure (mmHg)
40
50
60
70
80
90 Forest area
City area
*
57=N ,
g
niklaW862=N ,
g
niweiV
Fig. 5 Change in diastolic
blood pressure after forest
viewing and walking.
Mean ±SD; * p\0.05;
pvalue by ttest
22 Environ Health Prev Med (2010) 15:18–26
123
changes that indicate greater stress reduction than that
afforded by walking in city surroundings.
From the perspective of physiological anthropology,
human beings have lived in the natural environment for
most of the 5 million years of their existence. Therefore,
their physiological functions are most suited to natural
settings [29]. This is the reason why the natural environ-
ment can enhance relaxation. The results of the physio-
logical experiments conducted in this study yield
convincing answers explaining the relationship between
the natural environment and the relaxation effects in a
human being (e.g., decrease in blood pressure and pulse
rates, inhibition of sympathetic nervous activity, enhance-
ment of parasympathetic nervous activity, and decrease in
cortisol concentration levels in human beings).
The endocrine stress system comprises two broad
components with considerable central anatomic intercon-
nection, namely, the sympathetic adrenal-medullary (SAM)
axis and the hypothalamic-pituitary-adrenal (HPA) axis
[30]. The SAM axis is involved in immediate sympathetic
activation preparing an individual to deal with a stressor,
resulting in changes such as increased heart rate (HR) and
blood pressure (BP) [31]. Cortisol is released by the HPA
axis in response to stress [32]. While subjects viewed forest
landscapes or walked around forest environments, their
pulse rate, blood pressure, and cortisol concentration
decreased. This suggests that both the main components of
the endocrine stress system reacted in response to Shinrin-
yoku.
In particular, high cortisol levels can correspond to a
low value of natural killer (NK) activity [33]. Further,
cortisol concentration also holds great significance in terms
of human immunological activity. Furthermore, the study
of Li et al. [3436] reported that forest surroundings could
aid in the recovery of the human immune system, as
determined from the perspective of NK activity.
For this reason, it can be suggested that not only forest
environments but also other natural settings such as wat-
ersides or grasslands could promote relaxation in human
beings. No evidence from field experiments conducted
on other natural environments are available; however,
Laumann et al. [28] have reported that, when subjects
0
100
200
300
400
500
600
700
800 Forest area
City area
*
HF power of HRV (msec2)
0
100
200
300
400
500
600
700
800 Forest area
City area
**
HF power of HRV (msec2)
27=N ,
g
niklaW462=N ,
g
niweiV
Fig. 6 Change in HF power
of HRV upon forest viewing
and walking. Mean ±SE;
** p\0.01; * p\0.05;
pvalue by ttest
0
2
4
6
8
10
12
14
16
18 Forest are
a
City area
Forest area
City area
*
0
2
4
6
8
10
12
14
16
18
**
LF/HF of HRV
LF/HF of HRV
27=N ,
g
niklaW462=N ,
g
niweiV
Fig. 7 Change in LF/HF
of HRV upon forest viewing
and walking. Mean ±SE;
** p\0.01; * p\0.05;
pvalue by ttest
Environ Health Prev Med (2010) 15:18–26 23
123
viewed natural environment through videos, including
those of waterside scenes, they had a longer cardiac int-
erbeat interval and lower heart rate, measured as the dif-
ference from the baseline, compared with subjects who
viewed urban environment through videos.
All the indices were generally in excellent agreement
with each other, implying that the forest environment
possessed relaxing and stress-relieving effects. Our results
also corroborate widely held beliefs that forest surround-
ings aid the physical relaxation of urban dwellers. In
addition, these results suggest that physiological respon-
ses—pulse rate, blood pressure, salivary cortisol concen-
tration, and HRV—can reflect the relaxing effects of forest
environments.
Psychological effects and relationship between
psychological effects and physical environmental
factors in ten forests across Japan
The changes in the average POMS subscale scores after the
viewing are presented in Fig. 8. Significant differences are
seen between the changes resulting from viewing a forest
landscape and those from viewing a city landscape. When
subjects viewed a forest landscape, the POMS tension sub-
scale score changed by –1.1 points, which is significantly
lower than the change (3.5 points) after viewing a city
landscape. The change in the POMS depression subscale
score (–0.3 points) on viewing a forest landscape is also
significantly lower than the score (0.1 points) on viewing a
city landscape. There is a significant difference in the change
in the POMS anger subscale score between viewing forest
(–0.2 points) and city landscapes (1.0 points). The change
in the POMS fatigue subscale score (–3.1 points) on viewing
a forest landscape is significantly lower than the score
(1.8 points) on viewing a city landscape. The change in the
POMS confusion subscale score (–1.0 points) on viewing a
forest landscape is also significantly lower than that
(1.8 points) on viewing a city landscape. However, the
change in the POMS vigor subscale score (1.9 points) on
viewing a forest landscape is significantly higher than that
(–1.9 points) on viewing a city landscape.
The changes in the average POMS subscale scores after
walking are shown in Fig. 9. The results are the same
as those for viewing. When walking, the changes in the
average POMS subscales of tension (forest:–1.1 points,
city: 3.2 points), depression (forest: –0.2 points, city: 0.8
points), anger (forest: –0.2 points, city: 0.8 points), fatigue
(forest: –2.1 points, city: 1.3 points), and confusion (forest:
–1.1 points, city: 1.1 points) are significantly different in
the forest and city areas. And the change in the POMS
vigor subscale score (4.2 points) on walking in forest
settings is significantly higher than that (–0.2 points) on
walking in city settings.
The POMS measurements show that forest environ-
ments can relieve human psychological tension, depres-
sion, anger, fatigue, and confusion, and moreover, that they
can enhance human psychological vigor. Furthermore,
from the viewpoint of attention restorative theory (ART)
[37], these results strongly support that the forest is a good
restorative environment for human beings.
Kasetani et al. [38] reported that a relationship exists
between the POMS score and the physical environmental
factors (Fig. 10). The POMS anger subscale score and
relative illumination had a significant correlation coeffi-
cient (R=0.66) in the forest areas. Moreover, the POMS
fatigue subscale score and relative humidity had a signifi-
cant correlation coefficient (R=0.70). Finally, the POMS
Change of POMS score (points)
T-A D A-H FCV
** ** ** ** **
*
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
Forest area
City area
Fig. 8 Change in average POMS scores upon forest viewing.
Mean ±SD; n=116; ** p\0.01; * p\0.05; pvalue by Wilco-
xon signed-rank test. T–A tension and anxiety, Ddepression and
dejection, A–H anger and hostility, Ffatigue, Cconfusion, Vvigor
Change of POMS score (points)
T-A D A-H F C V
** ** ** ** ***
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
Forest area
City area
Fig. 9 Change in average POMS scores upon forest walking.
Mean ±SD; n=78; ** p\0.01; pvalue by Wilcoxon signed-rank
test. T–A tension and anxiety, Ddepression and dejection, A–H anger
and hostility, Ffatigue, Cconfusion, and Vvigor
24 Environ Health Prev Med (2010) 15:18–26
123
depression subscale score and atmospheric pressure had a
significant correlation coefficient (R=0.63).
When viewing a forest landscape, the low relative illu-
mination reduces anger, and the low relative humidity
lowers fatigue. Forests located at high elevations with low
atmospheric pressure can reduce depression. We hope that
these results can be used as basic guidelines in the design
of therapeutic forest environments [39].
Conclusion
The results of studies performed on the physiological
effects of Shinrin-yoku show that forest environments
could lower concentrations of cortisol, lower pulse rate,
lower blood pressure, increase parasympathetic nerve
activity, and lower sympathetic nerve activity compared
with city settings. The results of the physiological mea-
surements suggest that Shinrin-yoku can aid in effectively
relaxing the human body, and the psychological effects of
forest areas have been correlated with the various physical
environmental factors of forest. The studies of Shinrin-
yoku provide valuable insights into the relationship
between forests and human health.
These results of Shinrin-yoku studies will contribute to
support the development of a research field dedicated to
forest medicine, which may be used to develop new
strategies in preventive medicine. The results of the field
experiments also provide a platform for interested enter-
prises, universities, and local governments to promote the
effective use of forest resources in stress management,
health promotion, rehabilitation, and the prevention of
disease.
Acknowledgments This study was partly supported by a Grant-in-
Aid for Scientific Research (S: 16107007) from The Ministry of
Education, Culture, Sports, Science, and Technology (MEXT).
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-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0 10000 20000 30000
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-5
-4
-3
-2
-1
0
50 60 70 80 90
R=0.70 -1.2
-1
-0.8
-0.6
-0.4
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850 900 950 1000 1050
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Relative illumination (lux) Relative humidity (%)Atmospheric prssure (hPa)
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Fig. 10 Relationship between
POMS and physical
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area [38]
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