Article
The Effects of a Short Forest Recreation Program on
Physiological and Psychological Relaxation in Young
Polish Adults
Ernest Bielinis 1,* , Lidia Bielinis 2, Sylwia Krupin´ ska-Szeluga 2, Adrian Łukowski 3,4 and
Norimasa Takayama 5
1 Department of Forestry and Forest Ecology, Faculty of Environmental Management and Agriculture,
University of Warmia and Mazury, Pl. Łódzki 2, 10-727 Olsztyn, Poland
2 Department of General Pedagogy, Faculty of Social Science, ul. Z˙ ołnierska 14, 10-561 Olsztyn, Poland;
lidia.bielinis@uwm.edu.pl (L.B.); krupinska_sylwia91@wp.pl (S.K.-S.)
3 Institute of Dendrology Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland;
adrian.lukowski@gmail.com
4 Faculty of Forestry, Poznan´ University of Life Sciences, Wojska Polskiego 71c, 60-625 Poznan´ , Poland
5 Environmental Planning Laboratory, Department of Forest Management, Forestry and Forest Products
Research Institute in Japan, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan; hanri@ffpri.affrc.go.jp
* Correspondence: ernest.bielinis@uwm.edu.pl; Tel.: +48-603-809-211
Received: 14 October 2018; Accepted: 5 January 2019; Published: 7 January 2019
Abstract: Forest recreation is an activity that could be successfully used to alleviate negative
symptoms of stress in individuals. Multiple positive psychological and physiological effects have
been described in the literature, especially regarding works describing research from Asian countries
such as Japan, Korea, and Taiwan. In East-Central Europe, however, the effectuality of forest
recreation has not been addressed in scientific research. Thus, a special recreation program was
developed, and its usability was examined with the involvement of 21 young Polish adults. A pre-
and post-test design was used, wherein four psychological questionnaires were applied (Profile of
Mood States, Positive and Negative Affect Schedule, Restorative Outcomes Scale, Subjective Vitality
Scale), and physiological measures were assessed (pulse rate, blood pressure) before and after the
program. A field study was also conducted at the nature reserve Redykajny, near the suburban
forest of the city of Olsztyn. The recreational program had a significant impact on psychological
and physiological parameters. After recreation, the negative mood markers of the negative affect
decreased and the positive affect, including restoration and vitality, increased. Furthermore, pulse
rates, systolic blood pressures, and mean arterial pressures of the participants were significantly
lower after the program. These results reveal that the short forest recreation program may be effective
in reducing negative symptoms of stress.
Keywords: emotional affect; blood pressure; forest bathing; forest therapy; mood; nature reserve;
pulse rate; restoration; Shinrin-Yoku; stress reduction
1. Introduction
Recreation is a wholesome activity undertaken for pleasure, as well as any action that refreshes
the mental attitude of an individual [1]. Forest recreation aimed at improving physical and mental
health, as well as reducing stress, is called “forest therapy” (also “forest bathing”, from Japanese
Shinrin-Yoku) [2,3]. This type of forest recreation is well known in Japan and in some other Asian
countries, where it is practiced as a remedy for problems induced by stress [4]. The importance of forest
therapy in these countries is high, as shown by the multiplicity of organizations involving individuals
Forests 2019, 10, 34; doi:10.3390/f10010034
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and professionals interested in this topic (e.g., the Forest Therapy Society, the International Society of
Nature, and Forest Medicine).
To achieve a broad range of effects on health improvements in practice, researchers have developed
different “forest recreation programs”. The effects of these programs on humans have been tested for
short-term, middle-term, and long-term scenarios. One short recreation program (a few minutes) had
a positive influence on mood states and on the cardiovascular relaxation of Japanese participants [5].
Similarly, a one-day forest therapy study conducted in Japan significantly influenced mood states and
decreased pulse rate [6]. Another short-term program conducted in a young conifer forest in Japan
demonstrated that viewing and walking in the forest affected the psychology of participants, increasing
their comfort and making them feel refreshed and calm. Physiological indices were also affected, as this
program resulted in lowered diastolic blood pressure and pulse rate in the participants [7]. A two-day
forest therapy program conducted in urban parks in China had an antianxiety effect [8], and another
two-day forest therapy program conducted in a recreational forest in Taiwan had a significant positive
influence on the mood states of women involved in the study, causing a decrease in both anxiety
levels and systolic blood pressure [9]. A five-day forest therapy program conducted in Japan also
had a positive influence on the mood states of the participants [10]. Forest recreation has also been
reported to be effective in increasing human natural killer cell activity and expression of anticancer
proteins [11–13], and to affect human immune function [14], as well as cardiovascular and metabolic
parameters [15]. These forest recreation programs appear to have a broad spectrum of beneficial effects on
the physiological and psychological parameters measured in Asian participants. Little is known, however,
regarding the effectiveness of forest recreation programs on individuals living in East-Central Europe.
One study has tested the effects of 15 minutes of viewing the forest on psychological relaxation [16],
but there have been no reports of experiments investigating the effects of longer exposure to the forest
environment or testing the effects of forest recreation programs conducted in this region.
Estimating the effects of forest recreation on human health is possibly of high importance to
East-Central Europe citizens. Expectations regarding the functions of forests have recently changed in
this region, whereas the status of “other than wood production activity in the forest” has increased
as well [17]. The growing importance of the social function of a forest, especially its usefulness for
recreation, is more frequently expected by society, which has been reflected in an increasing number of
scientific reports addressing this topic. The importance of forest recreation is also growing in Poland,
where forests cover 29.5% of the land area and the population’s awareness of the positive influence of
this environment on health is increasing.
Polish forests are of medium age, with most trees being 41–80 years of age. Forest management
in Poland is conducted in a close to natural, sustainable way. Thus, there are not many deforested
areas, and forest stands are suitable for forest recreational activities. Various kinds of activities are
popular in Polish forests, with forest walks and mushroom picking being the most popular. In addition,
individuals appreciate forest areas and perceive them as useful for forest recreation. Forest therapy
roads are not designed, however, and the effectuality of forest therapy programs is not tested, while
the severity of stress increases in workers, and their mental health declines. One of the main aims of
the present study was therefore to verify the hypothesis that a short-term forest recreation program can
influence the physiological and psychological relaxation of participants. The second hypothesis tested the
usefulness of a forest near Olsztyn, on the nature reserve Redykajny, for forest recreation. The positive
influence of this environment on the tested parameters was identified as a needed, desired effect, which
could indicate that the nature reserve Redykajny is a proper area for conducting forest recreation
programs. To verify these two hypotheses, the influence of a short-term (few hours) forest recreation
program conducted at the reserve was estimated for young and working or learning Polish citizens.
In summary, the purposes of conducting and presenting this study were: (i) To fill in the gaps in
knowledge regarding how effective a forest recreation program might be on the psychological and
physiological relaxation of adults in East-Central Europe, and (ii) to assess the usefulness of the tested
area for conducting forest recreation programs affecting the psychological and physiological relaxation
of participants.
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2. Materials and Methods
2.1. Participants
Twenty-one participants living in the city of Olsztyn were recruited for this study. Persons
recruited for the study were former friends of researchers and their acquaintances who agreed
to participate in the study. Twelve students from the University of Warmia and Mazury were
selected (not from the forestry course). To avoid having only student sample, an additional nine
working, non-student persons were recruited. Only young adults between the ages of 21 and 29 years
participated in this study (demographics of the participants are presented in Table 1). Non-healthy
adults, with mental or physical diseases or metabolic syndromes, were excluded from the study.
Because it is less likely for young people to be taking medications, and because they appear to be
more stable in terms of their physical condition, we assumed that individual differences among them
would be smaller than in the case of older people. This group was therefore considered homogenous.
An optimal sample size was used to balance the need for quick testing and the need to obtain
reliable results. Additionally, the results of other researchers have indicated that a sample size of
12–16 participants in forest therapy experiments is enough to draw significant conclusions [10,18].
Thus, our group of 21 individuals was large enough to obtain valuable information.
Before the experiment, the participants were informed that they would be asked to contribute to a
research study on “forest recreation”, and informed consent was obtained. The participants were also
informed of the research plan on the first and second days of research. All procedures performed in
this study were in accordance with the ethical standards of the Polish Committee of Ethics in Science
and with the 1964 Helsinki Declaration and its later amendments.
Table 1. Demographic information of study participants.
Parameter
Value (Mean ± SD)
Total sample number
Sex
Activities
Age (years)
Weight (kg)
Height (cm)
BMI (kg/m2)
21
Female = 9, male = 12
Students = 12, workers = 9
23.86 ± 2.67
76.09 ± 13.95
172.81 ± 7.12
25.38 ± 3.78
Note: BMI: Body Mass Index; SD: Standard Deviation.
2.2. Study Sites
The indoor pre-test experiment was conducted in an apartment in the city of Olsztyn. The field
post-test experiment was conducted in the forested area of the nature reserve Redykajny, which covers
14 ha in the northwest part of the suburban forest of Olsztyn. Meteorological data on the pre-test
day and post-test day were collected from the meteorological station in Olsztyn-Mazury (location:
53◦28 50” N, 20◦56 10” E). The mean annual temperature in Olsztyn is 7.9 ◦C, the mean annual
precipitation is 635 mm, and the altitude is 139 m. On the pre-test day, the average temperature was
20 ◦C, atmospheric pressure was 1018 hPa, the speed of the southeast wind was 14 km/h, and humidity
was 50%. Cloudiness was absent, and no precipitation was observed. On the post-test day, the average
temperature was 25 ◦C, atmospheric pressure was 1014 hPa, humidity was 46%, the speed of the east
wind was 22 km/h, and humidity was 46%. Cloudiness was low, and no precipitation was observed.
Sound levels and illuminance were measured on both experimental days with a Huawei P9
Lite smartphone (Huawei, China) using the “Sound Meter” and “Light Meter” applications, both of
which have been shown to be excellent applications comparable to a professional laboratory sound
analyzing instrument [19,20], and using a professional illuminance analyzing instrument. The mean
sound level (±SD) measured with the “Sound Meter” application in the indoor environment was
47.86 ± 10.24 dB, whereas the mean sound level in the forest environment was 38.08 ± 5.19 dB.
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The mean illuminance in the indoor environment measured with the “Light Meter” was 710 ± 493.79 lx,
whereas the mean illuminance in the forest environment was 37,755.24 ± 45,561.35 lx. Physical and
meteorological parameters concerning this study are presented in Table 2. Sound levels and illuminance
were measured 15 times in a random part of each environment (in one room of the apartment and in
each forest area) at random times during the experimental procedure.
Table 2. Physical and meteorological parameters during the forest therapy experiment.
Parameter
Sound level (dB)
Illuminance (lx)
Forest tree density (n/ha)
Parameter
Temperature (◦C)
Humidity (%)
Cloudiness
Wind speed (km/h)
Room Environment
(Mean ± SD, n = 15)
47.86 ± 10.24
710 ± 493.79
-
The Day before
Forest Recreation
20
50
Absent
14
Forest Environment (Mean ± SD, n = 15)
Area 1
Area 2
Area 3
37.33 ± 4.85
23,657.67 ± 24,959.55
600
39.4 ± 4.81
88,515.27 ± 38,563.678
200
37.53 ± 5.94
1092.8 ± 467.83
1200
The Day of Forest Recreation
25
46
Small
22
The forest areas used in this study, numbered from 1 to 3 (Figure 1), were parts of the nature
reserve Redykajny. The whole area of the reserve is covered mainly by 85- to 130-year-old Picea abies
(L.) H. Karst. and 80- to 180-year-old Pinus sylvestris. L. Area 1 is covered by 105-year-old P. abies
(40%), 180-year-old P. sylvestris (40%), 85-year-old P. abies (20%), and a mixture of additional species
(Quercus robur L., Fagus sylvatica L.: 20%). Species composition in Area 2 is the same, but a less-dense
part of the stand was selected—an area previously prepared by foresters for regeneration, leaving
200 residual trees/ha. Area 3 is covered by 60-year-old, 90-year-old, and 120-year-old P. abies (10%, 50%,
and 20%, respectively), along with Alnus glutinosa (L.) Gaertn., Betula pendula Roth and 80-year-old
P. abies (10% each). The ground in the part of the reserve intended for the forest recreation program is
covered with moss and herbaceous vegetation. All views in this selected place were of the forest alone,
undisturbed by buildings or other objects.
Figure 1. The walking route at the nature reserve Redykajny during the forest recreation program.
Colored points indicate places intended for recreational activities. Points of stay are numbered from
the start (Area 1) to the end (Area 3) of the walk. Map provided by F. Ordon.
–
recreation program was applied. The participants’ psychological and physiological responses were
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2.3. Procedure
In this study, a pre-test–post-test design with a short, one-day intervention of the forest recreation
program was applied. The participants’ psychological and physiological responses were measured
indoors on the day before forest recreation, and then under field conditions on the next day, directly
after the forest recreation. On the pre-test day, before the pre-test, the subjects simply participated
in their ordinary, everyday activities. These activities did not consist of performing tasks identical
to those planned for the “forest recreation”. The same time of each day (15:45–16:15) was chosen for
psychological and physiological measurements to achieve comparable results. Measuring at different
times during the day may cause biased results, due to the effect of the circadian rhythm on humans [21],
and thus we chose the same time of measurement for each day. As the intervention was planned for
several hours, the pre-test was carried out in the same hour as the post-test, at the same time of the day,
but the day before (to avoid performing measurements during different hours of the biological clock).
The participants took part in a single exit to the forest (in a single intervention) which is a common
practice in forest therapy research. Their relaxation at individual stages of the intervention took place
in privacy, and each participant chose a separate place a few meters away from other participants
to be able to relax and follow the instructions of the researcher leading the therapy. The conducted
forest recreation program engaged participants’ senses: Auditory (e.g., listening to the sounds of the
forest in a sitting position with closed eyes), visual (viewing the forest), and tactile (touching forest
items, cuddling up to trees). The sense of smell was engaged during all activities, which is illustrated
in Figure 2. The activities were repeated three times, once in each of the selected forest areas, which
participants moved among on foot. The walking route and place of stay for forest recreation are
shown in Figure 1. The time spent standing in the forest throughout the forest recreation program was
approximately 5 h. In addition, participants could relax throughout the intervention, which made
the intervention not an effort. The schedules of indoor and field experiments are shown in Table 3.
The purpose of choosing three different activities in three different parts of the forest was to replicate a
previous study, where different activities were repeated in different forest areas [6], and this scheme
was applied to obtain an effect of forest therapy in this study comparable to that observed in the
previous study. The three different localities intended for forest recreation provided the participants
with a variety of views and experiences that could be useful in recreation and could increase the
recreational effect.
Table 3. Schedule of the indoor (first day) and field (second day) experiments.
Date
12 May 2018 (Saturday)
13 May 2018 (Sunday)
Time
15:45~16:15
11:30~12:00
12:00~12:15
12:15~12:30
12:30~12:45
12:45~13:00
13:00~13:05
13:05~13:20
13:35~13:50
13:50~14:05
14:05~14:20
14:20~14:30
14:30~14:45
15:00~15:15
15:15~15:30
15:30~15:45
15:45~16:15
Activity
Psychological and physiological response pretest
Orientation, traveling to Area 1
Listening to the sounds of the forest
Viewing at the forest
Touching forest items
Cuddling up to a tree
Traveling to Area 2
Listening to the sounds of the forest
Viewing at the forest
Touching forest items
Cuddling up to a tree
Traveling to Area 3
Listening to the sounds of the forest
Viewing at the forest
Touching forest items
Cuddling up to a tree
Psychological and physiological response post-test
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(a)
(b)
(c)
(d)
Figure 2. Activities undertaken during a forest recreation intervention: (a) Listening to the sounds
of the forest; (b) viewing the forest; (c) touching forest items; (d) cuddling up to a tree. All photos
provided by F. Ordon.
2.4. Measurements
Four psychological questionnaires were used to measure the psychological effect of forest therapy
on the participants. In the Polish language, a 65-item version of the Profile of Mood States (POMS)
questionnaire was chosen [22] to assess the program’s effect on the emotional states of participants.
POMS is a reliable and valid measure of psychological distress [23], and has previously been used to
estimate the influence of the forest environment on mood states [16,24,25]. This tool measures six mood
states: Confusion, fatigue, anger or hostility, tension or anxiety, depression or dejection, and vigor.
A five-point Likert scale was used for each item to evaluate participants’ mood states, with each item
assessed from 0 (strongly agree) to 4 (strongly disagree).
The Positive and Negative Affect Schedule (PANAS) was used to measure the emotional affect of
each participant. PANAS questionnaires contain 20 items, with 10 items addressing negative affect
and 10 addressing positive affect. The reliability and validity of the PANAS is high [26], and its use
for forest recreation assessments has been previously described [16,25]. A Polish adaptation of this
schedule was used in the current study [27]. Each item was assessed using a five-point Likert scale
(1—strongly disagree, 5—strongly agree). The PANAS scale was used for this study because it is often
used in research on forest therapy.
The Restorative Outcome Scale (ROS) is a reliable and valid tool developed based on previous
research concerning restorative phenomena [28,29]. Originally, this scale was used to assess humans’
restoration in the forest environment [16,25]. It contains six to nine items, with each item assessed by
participants on a seven-point Likert scale (1—not at all, 7—completely). In this study, we used a scale
modified for forest experiments by Takayama et al. [26]. The scale with modifications was adapted
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into Polish [16]. In this study, “Restorative Outcome” was measured (i.e., a general restorative effect
that was obtained as a result of the intervention).
The Subjective Vitality Scale (SVS) [30] was used for vitality assessment. A version with four
items, adapted to research in the forest environment, [25] was used in this study. The four items
were assessed by participants using a seven-point Likert scale (1—not at all, 7—completely), with one
inversely scored item. A Polish version was applied in this research [16]. Four common items were
chosen: “I feel alive and vital”, “I don’t feel very energetic”, “I have energy and spirit”, and “I look
forward to each new day”.
Different time frames may be used in the POMS, PANAS, ROS, and SVS questionnaires, but in
this study, the time frame “at the present moment” was applied. The raw data from each questionnaire
were used for statistical purposes.
The physiological indices measured in this study were parameters connected to blood circulation
in the body. All were measured with portable devices on the day before the forest recreation program
and directly after the forest recreation program. Participants’ pulse rates (in bpm), systolic blood
pressures (SBPs), and diastolic blood pressures ((DBPs), both in mmHg) were measured with a blood
pressure monitor (Tech-Med, TMA 10-PRO, Beijing, China). Measurements were conducted in a sitting
position, in the same arrangement pre-test and post-test. The relative value of mean arterial pressure
(MAP) was calculated after measurements as ((2 × DBP) + SBP)/3 [31].
2.5. Data Analysis
Raw data from psychological questionnaires and raw data from physiological measures were
used for statistical analyses. MAP was calculated in Excel (Microsoft, Redmond, WA, USA), as were
all mean values and SD values. A paired sample t-test was applied to compare pre-test and post-test
measurements. Statistical analyses were conducted using SPSS Statistics Version 24 (IBM, Armonk,
NY, USA). Cohen’s d was used to estimate the effect size, with a Cohen’s d close to 0.2 described as a
weak effect, close to 0.5 as a medium effect, and close to 0.8 as a strong effect.
3. Results
Results of the paired sample t-test examining the psychological differences before (pre-test) and
after (post-test) the forest recreation program are presented in Table 4. There was a significant decrease
in four negative mood states of the POMS scale after the program, including confusion (t = 2.392,
p < 0.05), anger or hostility (t = 2.838, p < 0.05), tension or anxiety (t = 3.185, p < 0.01), and depression or
dejection (t = 2.823, p < 0.05). Regarding emotional affect, the level of negative aspects in participants
decreased significantly after the forest recreation program (PANAS negative: t = 2.905, p < 0.01).
In turn, the effect of participant restoration increased significantly post-test (ROS: t = −5.225, p < 0.001).
Furthermore, there was a significant increase in participants’ vitality levels post-test (SVS: t = −3.759,
p < 0.01), in comparison to those levels before the test.
Results of the paired sample t-test regarding physiological differences pre- and post-test are
presented in Table 5. There was a significant decline in three physiological indices after the forest
recreation program: Pulse rate (t = 3.581, p < 0.01), SBP (t = 3.366, p < 0.01), and MAP (t = 2.537, p < 0.05).
There were no significant differences in participants’ DBPs pre- and post-test.
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Table 4. Effects of the forest recreation program on emotional state, emotional affect, restoration,
and vitality.
Pre-Test
Post-Test
Psychological Indices
t
Mean ± SD Mean ± SD
p
Rate of
Change (%)
ES
Mood State (POMS)
Confusion
1.10 ± 0.63 0.71 ± 0.53 2.392 0.027 *
−35.8
1.07
Fatigue
1.22 ± 0.76 0.81 ± 0.79 1.817
0.084
−33.52
0.81
Anger or hostility
1.02 ± 0.73 0.58 ± 0.39 2.838 0.010 *
−42.58
1.27
Tension or anxiety
0.90 ± 0.64 0.40 ± 0.44 3.185 0.005 **
−55.56
1.42
Depression or dejection
0.72 ± 0.64 0.33 ± 0.35 2.823
0.011 *
−54.39
1.26
Vigor
2.39 ± 0.62 2.51 ± 0.92 −0.754 0.459
5.24
0.34
Emotional Affect (PANAS)
Negative
Positive
1.65 ± 0.58 1.27 ± 0.37 2.905 0.009 **
−23.31
1.30
2.94 ± 0.61 3.14 ± 0.93 −1.099 0.285
6.8
0.49
Restorativeness (ROS)
4.30 ± 0.99 5.63 ± 1.02 −5.225 0.000 ***
30.81
2.34
Vitality (SVS)
4.40 ± 10 5.42 ± 1.03 −3.759 0.001 **
22.97
1.68
Note: POMS: Profile of Mood States; PANAS: Positive and Negative Affect Schedule; ROS: Restorative Outcomes
Scale; SVS: Subjective Vitality Scale; ES: Effect size; * p < 0.05; ** p < 0.01; *** p < 0.001; n = 21.
Table 5. Effects of the forest recreation program on physiological stress indices.
Physiological Indices
Pre-Test
Post-Test
t
Mean ± SD Mean ± SD
p
Rate of
Change (%)
ES
Pulse rate (bpm)
86.05 ± 9.50 81.19 ± 9.63 3.581 0.002 **
−5.65
1.60
Systolic blood pressure (mmHg) 135.1 ± 11.39 127.33 ± 9.47 3.366 0.003 **
−5.75
1.51
Diastolic blood pressure (mmHg) 83.62 ± 8.56 80.38 ± 9.67 1.400 0.177
−3.87
0.63
MAP (mmHg)
100.78 ± 7.85 96.03 ± 9.00 2.537 0.020 *
−4.71
1.13
Note: MAP: Mean arterial pressure; ES: Effect size; * p < 0.05; ** p < 0.01; n = 21.
4. Discussion
4.1. Psychological Effects
This study confirmed that a short program of forest recreation has a positive influence on the
psychological indices of young learning and working adults. Negative emotions (confusion, anger
or hostility, tension or anxiety, depression or dejection) of the participants were alleviated after this
program, consistent with the results of previous studies [16,25,32]. The emotional state of vigor,
however, did not increase significantly after the recreation program. The negative aspect of emotional
affect, based on the PANAS, diminished after the recreation program, which had also been observed
earlier [16], but was not always confirmed [25]. Positive emotional affect did not increase significantly
post-test, which has not been confirmed by previous studies. Both aspects of PANAS have also been
used as good indicators of the psychological response of participants in measuring the effect of the
thinning in the forest [33]. The restoration and vitality reported by participants increased after the
program, as has been observed in other forest therapy research [34]. These findings indicate that, in
comparison to a short stay in the forest [16,25], longer stays within the elaborated forest recreation
program also have a significant positive psychological effect on participants.
The observed positive influence of a forest recreation program on psychological indices suggests
that this kind of intervention might be used in a therapeutic process. Forest recreation is a remedy for
problems such as increased stress levels in the population and decreased levels of mental health [35]
and, as shown in our study, it also works in East-Central Europe. Further research concerning mental
health (e.g., with patients in mental hospitals) may also help establish if forest recreation programs are
effective for the treatment of the mentally ill, which was not tested in this study.
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The natural reserve Redykajny is a good place for the citizens of Olsztyn to be mentally refreshed,
as a five-hour visit to this place had a significant positive effect on many psychological indices.
In the future, the possibility of building special infrastructure, which could be designed for forest
recreation, should be considered at the local governance level. In addition, a mental hospital is
located in the city of Olsztyn, and its buildings are near the suburban forest of Olsztyn, which affords
the possibility of using forest therapy roads for the treatment of patients. The observed positive
effects on the psychological indices observed in this study will be a good argument in stimulating
the establishment of infrastructure for therapeutic purposes and the development of strategies for
therapeutic-friendly cities.
4.2. Physiological Effects
4.2.1. Pulse Rate
A lowered pulse rate has frequently been observed in previous studies in the field of forest
recreation [6,36–39]. In this study, the pulse rate of participants was also lower after the forest
recreation program, indicating that this form of activity may be useful in alleviating the negative
effects of leading a highly stressful lifestyle [40]. Stressful work can increase the pulse rate level, which
may have negative implications for human health and well-being [41]. Even a short forest recreation
program, such as the one proposed in the present study, might be a useful tool in lowering the pulse
rates of subjects, which is especially easy in areas located near cities, as is the case with Redykajny.
The causes of the relaxing effects on pulse rate induced by forest recreation have yet to be identified:
However, several theories may be useful in explaining this effect. One is the “psycho-evolutionary
theory” [42,43], which states that humans have lived for a very long time in the natural environment,
and during this time some adaptations to unthreatening environmental conditions evolved, which may
be observed as a relaxing response to this environment. Another theory, formulated by Kaplan [44],
suggests that the forest environment has acquired some special requirements that are essential for
restoration, and one of them is to be an idyllic place for “being away”, which allows resting one’s
directed attention. In contrast, a theory proposed by Miyazaki et al. [45] suggests that humankind has
spent more than 99.99% of its evolutionary history living in untransformed, natural environments,
and thus their physiological processes function best in the forest, which could be observed as, for
example, a lowering effect on their pulse rate. These three theories also prove useful in explaining the
positive response of blood pressure.
4.2.2. Blood Pressure
As demonstrated in previous studies [5–7,10,24,37], our findings confirmed that a short forest
recreation program influences participants’ blood pressures. SBP decreased significantly after the
intervention, whereas DBP did not change after the program. Such tendencies have also been observed
by other authors [10]. MAP, defined as the average pressure in a person’s arteries during one cardiac
cycle, is likely a better indicator of perfusion to vital organs than SBP [46]. Thus, the significant
decrease in MAP after the forest recreation program indicates that this activity might be useful in
the prevention of many health issues, such as cardiac events. This is important for public health,
because cardiac events are one of the most important causes of death worldwide [47], and doing any
activity that can lower indices positively linked with cardiac events could be extremely important
for the health of each individual. The lowering of SBP indicates the influence of the forest recreation
intervention on autonomic nerve system activity [5,48], and thus it may be concluded that the tested
intervention did have an influence on this system. Higher SBP is linked with cardiovascular disease
and mortality, making every method that effectively lowers SBP valuable to overall human health [49].
Future experiments should focus on searching for areas that are best predisposed to forest recreation
purposes, with the highest potential to decrease the blood pressures of participants.
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Investigations addressing the effects of staying in the forest for five hours are not sparse, as two
other forest recreation programs involving approximately five-hour stays in the forest conducted in
Japan demonstrated similar effects on blood pressure reduction [6,50]. Forest recreation may prove
useful in preventing the progression of hypertension [50]. Physiological stress was reduced in the
current study in a manner similar to that reported by other short-staying studies dealing with forest
recreation. In other words, participants were physiologically relaxed, but the superiority or inferiority
of programs (differing lengths of interventions) should be examined in future studies.
5. Conclusions
In this study, we estimated the effects of a short forest recreation program on physiological
and psychological relaxation in young adults. Measurements were performed on the day before the
intervention and directly after the intervention. The results showed that participants’ levels of negative
mood (confusion, anger or hostility, tension or anxiety, depression or dejection) and negative affect
significantly decreased after the program, whereas components of their positive affect—restoration
and vitality—increased. Physiological parameters such as pulse rate, systolic blood pressure, and mean
arterial pressure lowered after the program. These findings indicate that short forest recreation
programs may positively influence the psychological and physiological characteristics of participants,
which provides evidence for the hypothesis that forest therapy in East-Central Europe could be
successful. Our short forest recreation program was conducted with success at the nature reserve
Redykajny, confirming its usability for this type of recreation.
6. Experimental Limitations
In this study, a pre-test–post-test design was applied to one group. This design is frequently used
to assess the effectuality of forest recreation programs [6,8–10]. The current study did not have a control
group, however, which might violate its internal validity. Furthermore, in forest recreation research,
a randomized, controlled trial should be used to reduce bias. Other factors possibly influencing the
results should be controlled for during this kind of study. The effectuality of the regular use of this
kind of intervention and the effectuality of this potential therapy on the overall quality of life of
participants should be tested in future studies. Although many kinds of forest therapy programs have
been developed, which of them is the most effective in improving respondents’ bodies and minds
remains unknown, and should also be addressed in future studies. Unfortunately, there is a lack of
research that has investigated the lasting effects of this intervention. Therefore, such research should
be carried out in the future to check whether the effects of forest recreation can have some prolonged
effects on study participants.
Sympathetic or parasympathetic nervous system activity and stress hormone levels of participants,
which are usually estimated in this kind of research [10,48], were not assessed this time. Only non-costly,
quick-to-collect parameters were measured before and after the program, including physiological
ones (pulse and blood pressure) and psychological ones (responses to four selected, previously-tested
research questionnaires [16]). Using measures that were not time-consuming ensured accomplishing
the aims of this research study in a relatively short time and without the potential bias caused by
measuring at different times of the day.
Author Contributions: E.B. conceived and designed the experiment, conducted data analysis, and prepared the
first version of the manuscript. L.B., S.K.-S and A.Ł. consulted on experimental design, as well as reviewing and
editing the manuscript. N.T. contributed to publication by reviewing and editing the manuscript.
Acknowledgments: We thank Filip Ordon for technical support and sharing photos. We would also like to thank
the Faculty of Forestry at the University of Life Sciences in Poznan´ and the Chair of Department of Forestry
and Forest Ecology at the University of Warmia and Mazury in Olsztyn for organizing financial support for the
manuscript’s publication.
Conflicts of Interest: The authors declare no conflict of interest.
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