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This study aimed to demonstrate the effects of forest-derived visual, auditory, and combined stimulation on brain activity, autonomic nervous system activity, and subjective spatial impressions. The participants included 20 Japanese female university students (age 22.1 ± 1.8 years). Each participant viewed a gray image for 60 s with no sound (rest period), followed by an image of a forest scene with no sound (visual stimulation), a gray image with forest sounds (auditory stimulation), an image of a forest scene with forest sounds (combined stimulation), and a gray image with no sound (control) for 90 s. As indicators, near-infrared spectroscopy, heart rate variability measurement, heart rate monitoring, and modified semantic differential method were used. Compared to the control condition, combined stimulation significantly decreased oxyhemoglobin (oxy-Hb) concentrations in both prefrontal cortices and increased parasympathetic nervous activity, reflecting a relaxed state; visual and auditory stimulation significantly decreased the oxy-Hb concentration in the right prefrontal cortex; and “comfortable,” “relaxed,” “natural,” and “realistic” feelings increased significantly for all stimulations. In conclusion, forest-derived visual, auditory, and combined stimuli induced physiologically and psychologically relaxing effects, and physiological relaxation was more pronounced under combined stimulus.
Chorong Song; Harumi Ikei; Yoshifumi Miyazaki. Effects of forest-derived visual, auditory, and combined stimuli. Urban Forestry & Urban Greening 2021, 64, 127253 .
AMA StyleChorong Song, Harumi Ikei, Yoshifumi Miyazaki. Effects of forest-derived visual, auditory, and combined stimuli. Urban Forestry & Urban Greening. 2021; 64 ():127253.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Yoshifumi Miyazaki. 2021. "Effects of forest-derived visual, auditory, and combined stimuli." Urban Forestry & Urban Greening 64, no. : 127253.
It has been recently suggested that contact with nature improves mood via reducing the activity of the prefrontal cortex. However, the specific regions within the prefrontal cortex that underlie this effect remain unclear. In this study, we aimed to identify the specific regions involved in the mood-improving effect of viewing images of nature using a 52-channel functional near-infrared spectroscopy (fNIRS). Specifically, we focused on the orbitofrontal cortex (OFC) and dorsolateral prefrontal cortex (dlPFC), two regions associated with affective processing and control. In a randomized controlled crossover experiment, we assigned thirty young adults to view images of nature and built environments for three minutes each in a counterbalanced order. During image viewing, participants wore a fNIRS probe cap and had their oxyhemoglobin (oxy-Hb) measured. Immediately following each image viewing, participants indicated their mood in terms of comfortableness, relaxation, and vigor. Results showed that viewing images of nature significantly increased comfortableness and relaxation but not vigor compared to viewing images of built environments, with a large effect size. Meanwhile, the concentration of oxy-Hb in only the right OFC and none of the other regions significantly decreased while viewing the images of nature compared to built environments, with a medium effect size. We speculate that viewing images of nature improves mood by reducing the activity of or calming the OFC. Since the OFC is hyperactive in patients with depression and anxiety at rest, contact with nature might have therapeutic effects for them.
Rikuto Yamashita; Chong Chen; Toshio Matsubara; Kosuke Hagiwara; Masato Inamura; Kohei Aga; Masako Hirotsu; Tomoe Seki; Akiyo Takao; Erika Nakagawa; Ayumi Kobayashi; Yuko Fujii; Keiko Hirata; Harumi Ikei; Yoshifumi Miyazaki; Shin Nakagawa. The Mood-Improving Effect of Viewing Images of Nature and Its Neural Substrate. International Journal of Environmental Research and Public Health 2021, 18, 5500 .
AMA StyleRikuto Yamashita, Chong Chen, Toshio Matsubara, Kosuke Hagiwara, Masato Inamura, Kohei Aga, Masako Hirotsu, Tomoe Seki, Akiyo Takao, Erika Nakagawa, Ayumi Kobayashi, Yuko Fujii, Keiko Hirata, Harumi Ikei, Yoshifumi Miyazaki, Shin Nakagawa. The Mood-Improving Effect of Viewing Images of Nature and Its Neural Substrate. International Journal of Environmental Research and Public Health. 2021; 18 (10):5500.
Chicago/Turabian StyleRikuto Yamashita; Chong Chen; Toshio Matsubara; Kosuke Hagiwara; Masato Inamura; Kohei Aga; Masako Hirotsu; Tomoe Seki; Akiyo Takao; Erika Nakagawa; Ayumi Kobayashi; Yuko Fujii; Keiko Hirata; Harumi Ikei; Yoshifumi Miyazaki; Shin Nakagawa. 2021. "The Mood-Improving Effect of Viewing Images of Nature and Its Neural Substrate." International Journal of Environmental Research and Public Health 18, no. 10: 5500.
Wood is a sustainable and natural material used in interior design for living environment. Knots are prominent features on wood surfaces, and they affect a user’s building preference and impression. Data on the effects of wood knots on human physiological responses are limited. Hence, further studies should be conducted. This study examined the effects of interior wall images comprising knotty or clear wood on physiological responses. Computer graphics were used to prepare wall images of knotty or clear lumber. A gray image was set as the control. In total, 28 adult Japanese female university students were included in this study. They observed two types of wood interior wall images for 90 s. The control was also set for 90 s. The oxyhemoglobin level in the prefrontal cortex measured by near-infrared time-resolved spectroscopy (TRS) and the activities of parasympathetic and sympathetic nerves assessed using the heart rate variability (HRV) were utilized as physiological indexes. TRS sensors, which emit and receive near-infrared light, were attached to frontal pole (Fp) 1 and Fp2, based on the international 10–20 method. R-R interval was measured using HRV sensors attached based on the three-point guidance method, and frequency data were analyzed to assess high frequency (HF), which reflects parasympathetic nervous system activity, and the ratio of high and low frequencies (LF/HF), which reflects sympathetic nervous system activity. The knotty wood sedated the right prefrontal cortex activity compared with the control and enhanced parasympathetic nerve activity compared with before stimulation. Clear wood sedated the left prefrontal cortex activity compared with the control and suppressed sympathetic nerve activity compared with before stimulation. Subjective evaluations revealed that compared with gray wall images, both knotty and clear wood images significantly promoted comfort, relaxation, and natural feeling and improved overall mood states. In addition, clear wood image had a more positive subjective effect than knotty image. Wall images comprising knotty or clear wood, when used as a visual stimulus, have a physiological relaxation effect among adult women in their 20s.
Harumi Ikei; Masashi Nakamura; Yoshifumi Miyazaki. Physiological Effects of Visual Stimulation Using Knotty and Clear Wood Images among Young Women. Sustainability 2020, 12, 9898 .
AMA StyleHarumi Ikei, Masashi Nakamura, Yoshifumi Miyazaki. Physiological Effects of Visual Stimulation Using Knotty and Clear Wood Images among Young Women. Sustainability. 2020; 12 (23):9898.
Chicago/Turabian StyleHarumi Ikei; Masashi Nakamura; Yoshifumi Miyazaki. 2020. "Physiological Effects of Visual Stimulation Using Knotty and Clear Wood Images among Young Women." Sustainability 12, no. 23: 9898.
The impact on the Profile of Mood States (POMS) of both walking in forest environments and viewing forest landscapes has already been demonstrated in previous research conducted by the authors of this paper. In both walking and viewing, decreases in tension-anxiety (T-A), depression-dejection (D), anger-hostility (A-H), fatigue (F), and confusion (C) were observed and an increase in vigor (V) was observed in forest environments when compared to urban environments. Walking and viewing exhibited similar tendencies, however the responses were quantitatively different. This study re-analyzes the POMS scores of 57 young Japanese women with specific reference to the differences between walking in and viewing forest environments. First, a comparison was made of POMS scores after walking and after viewing. F and C scores were found to be smaller after walking than after viewing, while the V score was larger after walking than after viewing. No significant differences were found in T-A, D, and A-H scores after either walking or viewing. The POMS scores in urban environment also exhibited the identical results. These results suggest that the act of walking has the psychological effect of increasing vigor and reducing some negative emotions, such as fatigue and confusion, regardless of environment. Second, to separate the walking effect from the environmental effect, the difference in forest and urban environment POMS scores was determined for each subject, and comparisons were then made between walking and viewing. The results reveal a significantly larger V score when walking than when viewing. Walking and viewing did not exhibit significant differences in other POMS scores. These results suggest that vigor is more enhanced by walking in forest environments than when viewing forest landscapes. This study, therefore, revealed the specific effects of walking in forest environments.
Hiromitsu Kobayashi; Harumi Ikei; Chorong Song; Takahide Kagawa; Yoshifumi Miyazaki. Comparing the impact of forest walking and forest viewing on psychological states. Urban Forestry & Urban Greening 2020, 57, 126920 .
AMA StyleHiromitsu Kobayashi, Harumi Ikei, Chorong Song, Takahide Kagawa, Yoshifumi Miyazaki. Comparing the impact of forest walking and forest viewing on psychological states. Urban Forestry & Urban Greening. 2020; 57 ():126920.
Chicago/Turabian StyleHiromitsu Kobayashi; Harumi Ikei; Chorong Song; Takahide Kagawa; Yoshifumi Miyazaki. 2020. "Comparing the impact of forest walking and forest viewing on psychological states." Urban Forestry & Urban Greening 57, no. : 126920.
Studies on the psychological effects of nature have been increasing, but few studies have focused on individual differences in these effects. The purpose of this study was to examine the individual differences in the psychological effects of forest sounds based on Type A and Type B behavior patterns. The Kwansei Gakuin (KG) daily life questionnaire was used as an indicator for Type A and Type B behavior patterns. This study included 29 female university students (mean age, 22.3 ± 2.1 years) who were exposed to high-resolution forest and city sounds for 60 s, and they provided subjective evaluations on a modified Semantic Differential method and the Profile of Mood States questionnaire. After exposure to the forest sounds, the Type A group (n = 12) reported higher levels of feeling comfortable, relaxed, and natural, as well as lower levels of anger–hostility, than the Type B group (n = 17). The findings demonstrated that the Type A and Type B groups experienced different psychological effects from forest-derived auditory stimulation.
Hyunju Jo; Harumi Ikei; Chorong Song; Yoshifumi Miyazaki. Individual differences in the psychological effects of forest sounds based on Type A and Type B behavior patterns. Urban Forestry & Urban Greening 2020, 55, 126855 .
AMA StyleHyunju Jo, Harumi Ikei, Chorong Song, Yoshifumi Miyazaki. Individual differences in the psychological effects of forest sounds based on Type A and Type B behavior patterns. Urban Forestry & Urban Greening. 2020; 55 ():126855.
Chicago/Turabian StyleHyunju Jo; Harumi Ikei; Chorong Song; Yoshifumi Miyazaki. 2020. "Individual differences in the psychological effects of forest sounds based on Type A and Type B behavior patterns." Urban Forestry & Urban Greening 55, no. : 126855.
Benefits related to health promotion by getting closer to forests have received increasing attention in modern stressful society; however, evidence-based research about how our brain activity changes when we stay in a forest environment is limited. Thus, the goal of this study was to evaluate the influence of viewing real forest landscapes on the activity in the prefrontal cortex area of young women’s brains. The experiment included 29 women (age: 21.0 ± 1.4 years) and was executed in five forest and five urban areas. The participants stayed in the forest and urban areas and viewed each view for 15 min. While viewing scenery, they had the oxyhemoglobin (oxy-Hb) concentrations in the left and right areas of their prefrontal cortexes measured continuously. Viewing real forest landscapes was associated with a significantly lower oxy-Hb concentration in the right area of the prefrontal cortex than when seeing urban areas. In conclusion, viewing real forest landscapes substantially diminished oxy-Hb concentrations in the right area of the prefrontal cortex, which is linked to physiological relaxation.
Chorong Song; Harumi Ikei; Takahide Kagawa; Yoshifumi Miyazaki. Effect of Viewing Real Forest Landscapes on Brain Activity. Sustainability 2020, 12, 6601 .
AMA StyleChorong Song, Harumi Ikei, Takahide Kagawa, Yoshifumi Miyazaki. Effect of Viewing Real Forest Landscapes on Brain Activity. Sustainability. 2020; 12 (16):6601.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Takahide Kagawa; Yoshifumi Miyazaki. 2020. "Effect of Viewing Real Forest Landscapes on Brain Activity." Sustainability 12, no. 16: 6601.
The aim of this study was to validate the psychological advantages of viewing forest landscapes. Moreover, the associations between trait anxiety levels and psychological responses were evaluated. A total of 650 university male students (age, 21.7 ± 1.6 years) viewed a scenery in a forested area and an urban area for 15 min. Furthermore, the Profile of Mood States questionnaire and State-Trait Anxiety Inventory were employed for the assessment of the psychological responses and the level of trait anxiety, respectively, of the participants. Results showed that compared with viewing a city area, viewing forest areas increased positive mood state, such as vigor, and decreased negative mood states. Furthermore, trait anxiety level and changes in the psychological responses such as depression–dejection, fatigue, and confusion after viewing forest landscapes were significantly correlated. The participants with high anxiety levels had greater reduction in negative mood state, including confusion, than those with low anxiety levels. In conclusion, viewing forest landscapes induced psychological relaxation, which was more evident in individuals with high anxiety levels.
Chorong Song; Harumi Ikei; Bum-Jin Park; Juyoung Lee; Takahide Kagawa; Yoshifumi Miyazaki. Association between the Psychological Effects of Viewing Forest Landscapes and Trait Anxiety Level. International Journal of Environmental Research and Public Health 2020, 17, 5479 .
AMA StyleChorong Song, Harumi Ikei, Bum-Jin Park, Juyoung Lee, Takahide Kagawa, Yoshifumi Miyazaki. Association between the Psychological Effects of Viewing Forest Landscapes and Trait Anxiety Level. International Journal of Environmental Research and Public Health. 2020; 17 (15):5479.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Bum-Jin Park; Juyoung Lee; Takahide Kagawa; Yoshifumi Miyazaki. 2020. "Association between the Psychological Effects of Viewing Forest Landscapes and Trait Anxiety Level." International Journal of Environmental Research and Public Health 17, no. 15: 5479.
The number of people addicted to gambling has increased worldwide. They often suffer from debilitating medical conditions associated with stress or depression. This study examined the physiological and psychological reactions of gambling disorder (GD) patients while listening to high-definition forest or city sounds using headphones. In total, 12 Japanese male GD patients were exposed to high-definition forest or city sound waves for 1 min via headphones. Near-infrared spectroscopy of the prefrontal cortex was used to examine oxyhemoglobin (oxy-Hb) concentrations. Heart rate and heart rate variability are indicators of autonomic nervous function. We performed subjective evaluation via the modified version of the semantic differential (SD) method with the profiles of the mood states (POMS). Experiencing forest sounds led to substantial differences as opposed to listening to city sounds: (1) oxy-Hb levels of the bilateral prefrontal cortices were lower (2) the modified SD method resulted in increased comfortable and relaxed feelings, (3) the negative POMS subscale scores were significantly lower, indicating that negative emotions diminished markedly when patients listened to forest sounds. This is the first study to show that sounds of forest relaxed individuals physiologically and psychologically to minimize GD.
Hiroko Ochiai; Chorong Song; Hyunju Jo; Masayuki Oishi; Michiko Imai; Yoshifumi Miyazaki. Relaxing Effect Induced by Forest Sound in Patients with Gambling Disorder. Sustainability 2020, 12, 5969 .
AMA StyleHiroko Ochiai, Chorong Song, Hyunju Jo, Masayuki Oishi, Michiko Imai, Yoshifumi Miyazaki. Relaxing Effect Induced by Forest Sound in Patients with Gambling Disorder. Sustainability. 2020; 12 (15):5969.
Chicago/Turabian StyleHiroko Ochiai; Chorong Song; Hyunju Jo; Masayuki Oishi; Michiko Imai; Yoshifumi Miyazaki. 2020. "Relaxing Effect Induced by Forest Sound in Patients with Gambling Disorder." Sustainability 12, no. 15: 5969.
Population growth and increased stress caused by urbanization have led to social problems that are predicted to intensify in the future. In these conditions, the recently established ”nature therapy” has revealed that an environment rich in various plant life significantly contributes to the relief of physical and mental stress. Meanwhile, from the perspective of reduction in the energy required for transportation and the retention of plant freshness, urban horticulture, in which plant life exists harmoniously with the city, has attracted considerable attention. Interactions between humans and plants in urban horticulture are considered to contribute to the good health and wellbeing of people. Therefore, we incorporate human-centered thinking based on nature therapy into horticultural produce-centered thinking based on conventional urban horticulture. By introducing a pioneering urban horticulture plant factory as an example, we propose the possibility of sustainable urban horticulture based on nature therapy.
Na Lu; Chorong Song; Takanori Kuronuma; Harumi Ikei; Yoshifumi Miyazaki; Michiko Takagaki. The Possibility of Sustainable Urban Horticulture Based on Nature Therapy. Sustainability 2020, 12, 5058 .
AMA StyleNa Lu, Chorong Song, Takanori Kuronuma, Harumi Ikei, Yoshifumi Miyazaki, Michiko Takagaki. The Possibility of Sustainable Urban Horticulture Based on Nature Therapy. Sustainability. 2020; 12 (12):5058.
Chicago/Turabian StyleNa Lu; Chorong Song; Takanori Kuronuma; Harumi Ikei; Yoshifumi Miyazaki; Michiko Takagaki. 2020. "The Possibility of Sustainable Urban Horticulture Based on Nature Therapy." Sustainability 12, no. 12: 5058.
In Japanese households, it is customary to walk barefoot on wood floors. This study sought to clarify the physiological effects produced via tactile application of sugi (Cryptomeria japonica) to the sole of the feet, using the brain and autonomic nervous activities as indicators. Twenty-seven female university students (mean age, 21.9 ± 1.9 years) participated in this study. Oxy-hemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined using near-infrared time-resolved spectroscopy. High frequency (HF), denoted parasympathetic nervous activity, and low frequency (LF)/HF indicated sympathetic nervous activity; both were measured using heart rate variability. The wooden material was unpainted sugi wood with two different finishes uzukuri brushing or sanding. A similarly sized marble plate served as a control. The sole of the feet of each participant touched each material for 90 s. The results found that the uzukuri wood significantly decreased oxy-Hb concentration in the left prefrontal cortex compared with touching the marble. Furthermore, compared to before contact, the uzukuri wood showed significantly decreased oxy-Hb concentrations in the right prefrontal cortex, increased ln(HF), and decreased the ln(LF/HF) ratio. Moreover, the contact with sanded wood significantly decreased oxy-Hb concentrations in the right prefrontal cortex compared with before contact. Thus, it is concluded that tactile application of sugi to the sole of the feet induced physiological relaxation.
Harumi Ikei; Yoshifumi Miyazaki. Positive physiological effects of touching sugi (Cryptomeria japonica) with the sole of the feet. Journal of Wood Science 2020, 66, 1 -12.
AMA StyleHarumi Ikei, Yoshifumi Miyazaki. Positive physiological effects of touching sugi (Cryptomeria japonica) with the sole of the feet. Journal of Wood Science. 2020; 66 (1):1-12.
Chicago/Turabian StyleHarumi Ikei; Yoshifumi Miyazaki. 2020. "Positive physiological effects of touching sugi (Cryptomeria japonica) with the sole of the feet." Journal of Wood Science 66, no. 1: 1-12.
The authors wish to add the following corrections to their paper published in the International Journal of Environmental Research and Public Health [1] [...].
Chorong Song; Harumi Ikei; Bum-Jin Park; Juyoung Lee; Takahide Kagawa; Yoshifumi Miyazaki. Correction: Song, C.; Ikei, H.; Park, B.J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Psychological Benefits of Walking through Forest Areas. Int. J. Environ. Res. Public Health 2018, 15, 2804. International Journal of Environmental Research and Public Health 2020, 17, 1316 .
AMA StyleChorong Song, Harumi Ikei, Bum-Jin Park, Juyoung Lee, Takahide Kagawa, Yoshifumi Miyazaki. Correction: Song, C.; Ikei, H.; Park, B.J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Psychological Benefits of Walking through Forest Areas. Int. J. Environ. Res. Public Health 2018, 15, 2804. International Journal of Environmental Research and Public Health. 2020; 17 (4):1316.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Bum-Jin Park; Juyoung Lee; Takahide Kagawa; Yoshifumi Miyazaki. 2020. "Correction: Song, C.; Ikei, H.; Park, B.J.; Lee, J.; Kagawa, T.; Miyazaki, Y. Psychological Benefits of Walking through Forest Areas. Int. J. Environ. Res. Public Health 2018, 15, 2804." International Journal of Environmental Research and Public Health 17, no. 4: 1316.
We investigated the effects of walking in a forest environment on salivary cortisol concentrations. Seventy-four young male participants walked for 15 min in forested and urban environments, and saliva was collected before and after walking. Our previous study reported salivary cortisol concentrations after walking only. This study was aimed at clarifying the combined effects of walking and environment by comparing post-walking data with pre-walking data. Walking in a forest environment decreased mean cortisol concentration from 9.70 to 8.37 nmol/L, whereas walking in an urban environment barely changed mean cortisol concentration, from 10.28 to 10.01 nmol/L. Two-way repeated analysis of variance revealed a significant interaction effect between the environment and walking (p < 0.001) in addition to the main effects of each (p < 0.001 and p = 0.001, for walking and environment, respectively). For further analysis, the proportion of participants who exhibited decreased cortisol after forest-walking was compared with the previously reported proportion of participants who exhibited decreased cortisol after viewing forest landscapes. Although the proportion of positive responders was slightly higher after walking (69%) than it was after viewing (60%), this difference was not statistically significant (p = 0.093). The present study revealed a significant combined effect of walking and the environment on cortisol concentrations.
Hiromitsu Kobayashi; Chorong Song; Harumi Ikei; Bum-Jin Park; Takahide Kagawa; Yoshifumi Miyazaki. Combined Effect of Walking and Forest Environment on Salivary Cortisol Concentration. Frontiers in Public Health 2019, 7, 376 .
AMA StyleHiromitsu Kobayashi, Chorong Song, Harumi Ikei, Bum-Jin Park, Takahide Kagawa, Yoshifumi Miyazaki. Combined Effect of Walking and Forest Environment on Salivary Cortisol Concentration. Frontiers in Public Health. 2019; 7 ():376.
Chicago/Turabian StyleHiromitsu Kobayashi; Chorong Song; Harumi Ikei; Bum-Jin Park; Takahide Kagawa; Yoshifumi Miyazaki. 2019. "Combined Effect of Walking and Forest Environment on Salivary Cortisol Concentration." Frontiers in Public Health 7, no. : 376.
The authors wish to add the following corrections to their paper published in the International Journal of Environmental Research and Public Health
Juyoung Lee; Bum-Jin Park; Tatsuro Ohira; Takahide Kagawa; Yoshifumi Miyazaki. Correction: Lee, J. et al. Acute Effects of Exposure to a Traditional Rural Environment on Urban Dwellers: A Crossover Field Study in Terraced Farmland. Int. J. Environ. Res. Public Health 2015, 12, 1874–1893. International Journal of Environmental Research and Public Health 2019, 16, 5052 .
AMA StyleJuyoung Lee, Bum-Jin Park, Tatsuro Ohira, Takahide Kagawa, Yoshifumi Miyazaki. Correction: Lee, J. et al. Acute Effects of Exposure to a Traditional Rural Environment on Urban Dwellers: A Crossover Field Study in Terraced Farmland. Int. J. Environ. Res. Public Health 2015, 12, 1874–1893. International Journal of Environmental Research and Public Health. 2019; 16 (24):5052.
Chicago/Turabian StyleJuyoung Lee; Bum-Jin Park; Tatsuro Ohira; Takahide Kagawa; Yoshifumi Miyazaki. 2019. "Correction: Lee, J. et al. Acute Effects of Exposure to a Traditional Rural Environment on Urban Dwellers: A Crossover Field Study in Terraced Farmland. Int. J. Environ. Res. Public Health 2015, 12, 1874–1893." International Journal of Environmental Research and Public Health 16, no. 24: 5052.
Contact with nature has been proposed as a solution to achieve physiological relaxation and stress recovery, and a number of scientific verification outcomes have been shown. Compared with studies of the other senses, studies investigating the visual effects of nature have been at the forefront of this research field. A variety of physiological indicators adopted for use in indoor experiments have shown the benefits of viewing nature. In this systematic review, we examined current peer-reviewed articles regarding the physiological effects of visual stimulation from elements or representations of nature in an indoor setting. The articles were analyzed for their stimulation method, physiological measures applied, groups of participants, and outcomes. Thirty-seven articles presenting evidence of the physiological effects of viewing nature were selected. The majority of the studies that used display stimuli, such as photos, 3D images, virtual reality, and videos of natural landscapes, confirmed that viewing natural scenery led to more relaxed body responses than viewing the control. Studies that used real nature stimuli reported that visual contact with flowers, green plants, and wooden materials had positive effects on cerebral and autonomic nervous activities compared with the control. Accumulation of scientific evidence of the physiological relaxation associated with viewing elements of nature would be useful for preventive medicine, specifically nature therapy.
Hyunju Jo; Chorong Song; Yoshifumi Miyazaki. Physiological Benefits of Viewing Nature: A Systematic Review of Indoor Experiments. International Journal of Environmental Research and Public Health 2019, 16, 4739 .
AMA StyleHyunju Jo, Chorong Song, Yoshifumi Miyazaki. Physiological Benefits of Viewing Nature: A Systematic Review of Indoor Experiments. International Journal of Environmental Research and Public Health. 2019; 16 (23):4739.
Chicago/Turabian StyleHyunju Jo; Chorong Song; Yoshifumi Miyazaki. 2019. "Physiological Benefits of Viewing Nature: A Systematic Review of Indoor Experiments." International Journal of Environmental Research and Public Health 16, no. 23: 4739.
Wood is a raw material that is used not only in the production of structural members for various buildings, but also in the interior finishes that are directly seen and touched by the occupants. Wood has also been recognized as a human-friendly material, but few studies have experimentally confirmed the physiological benefits it brings to humans. Therefore, the aim of the present study was to investigate the physiological effects of visual stimulation with wood. Two types of full-scale square, wooden-wall images composed of vertically or horizontally arranged lumber, were prepared using computer graphics and projected onto a large display to create the visual stimuli, and a gray image was also prepared as a control. Twenty-eight female Japanese university students participated in the study. The participants initially spent 60 s viewing the gray background (rest period) and then observed each of the wooden-wall images and the gray image separately in a random order for 90 s each. During the visual stimulation, the oxyhemoglobin (oxy-Hb) concentration as an indicator of prefrontal brain activity and heart rate variability as an indicator of autonomic nervous activity were continuously measured in each participant. Subjective evaluation of each visual stimulus was then performed using a modified semantic differential method and the Profile of Mood States 2nd Edition test. It was found that visual stimulation with either of the wooden interior wall images induced a significant decrease in oxy-Hb concentration in the left and right prefrontal cortex compared with the gray image. Furthermore, the subjective evaluation showed that the wooden-wall images provided a significantly more “comfortable,” “relaxed,” and “natural” impression than the gray image and decreased the negative mood states, with the vertically arranged wooden-wall image having a more positive effect than the horizontally arranged image.
Masashi Nakamura; Harumi Ikei; Yoshifumi Miyazaki. Physiological effects of visual stimulation with full-scale wall images composed of vertically and horizontally arranged wooden elements. Journal of Wood Science 2019, 65, 1 -11.
AMA StyleMasashi Nakamura, Harumi Ikei, Yoshifumi Miyazaki. Physiological effects of visual stimulation with full-scale wall images composed of vertically and horizontally arranged wooden elements. Journal of Wood Science. 2019; 65 (1):1-11.
Chicago/Turabian StyleMasashi Nakamura; Harumi Ikei; Yoshifumi Miyazaki. 2019. "Physiological effects of visual stimulation with full-scale wall images composed of vertically and horizontally arranged wooden elements." Journal of Wood Science 65, no. 1: 1-11.
Wood is used as an interior material in Japan, and it is empirically known that contact with wood induces relaxation in humans. However, evidential data regarding these physiological effects are lacking. In this study, we examined the physiological effects of tactile stimulation based on measurements of brain and autonomic nervous activities by using the wood of sugi (Cryptomeria japonica). Twenty-one female university students (mean age, 22.0 ± 2.0 years) participated in the study. Oxyhemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined using near-infrared time-resolved spectroscopy. High frequency (HF), denoting parasympathetic nervous activity, and the ratio of low frequency (LF)/(LF + HF), indicating sympathetic nervous activity, were measured using heart rate variability. HF (0.15–0.40 Hz) and LF (0.04–0.15 Hz) components were calculated by the maximum entropy method. The wood material surfaces were finished by: (1) brushing with a stainless steel wire brush and (2) sanding with a belt sander. A marble plate served as a comparator. The palm of each participant’s right hand touched each material for 90 s. Touching brushed or sanded sugi significantly decreased oxy-Hb concentrations in the left and right prefrontal cortices, increased ln(HF), and decreased the ln(LF/(LF + HF)) ratio compared with touching marble. Thus, our findings indicate that compared with touching marble, touching sugi with the palm induces physiological relaxation, as indicated by calmer prefrontal cortex activity, higher parasympathetic nervous activity, and lower sympathetic nervous activity.
Harumi Ikei; Chorong Song; Yoshifumi Miyazaki. Physiological effects of touching sugi (Cryptomeria japonica) with the palm of the hand. Journal of Wood Science 2019, 65, 1 -7.
AMA StyleHarumi Ikei, Chorong Song, Yoshifumi Miyazaki. Physiological effects of touching sugi (Cryptomeria japonica) with the palm of the hand. Journal of Wood Science. 2019; 65 (1):1-7.
Chicago/Turabian StyleHarumi Ikei; Chorong Song; Yoshifumi Miyazaki. 2019. "Physiological effects of touching sugi (Cryptomeria japonica) with the palm of the hand." Journal of Wood Science 65, no. 1: 1-7.
The aim of this study was to investigate the physiological effects on brain activity and autonomic nervous activity of forest-related visual, olfactory, and combined visual and olfactory stimuli. Twenty-one female Japanese university students (age, 21.1 ± 1.0 years) participated. In a soundproofed chamber with an artificial climate, each participant was presented for 90 s with the following conditions: an image of a forest landscape of Hinoki cypress trees with no odor (visual stimulus), a gray image with Hinoki cypress leaf essential oil (olfactory stimulus), an image of a forest landscape of Hinoki cypress trees with Hinoki cypress leaf essential oil (combined stimulus), and a gray image with no odor (control). As an indicator of brain activity, oxyhemoglobin concentrations were measured in the left and right prefrontal cortices using near-infrared time-resolved spectroscopy. Heart rate variability and heart rate were used as indicators of autonomic nervous activity. The high-frequency component of heart rate variability, which reflects parasympathetic nervous activity, and the low-frequency/high-frequency ratio, which reflects sympathetic nervous activity, were evaluated. The following results were obtained in comparison with the control conditions: (1) the combined stimuli resulted in significantly decreased oxyhemoglobin concentrations in the left and right prefrontal cortices; (2) the olfactory stimulus resulted in significantly decreased oxyhemoglobin concentration in the right prefrontal cortex; and (3) the visual stimulus resulted in significantly decreased sympathetic nervous activity related to arousal or situations of stress. Results of a questionnaire indicated that these forest-related stimuli significantly increased the participants’ feelings of “comfortable” and “relaxed,” with the visual and combined stimuli significantly increasing feelings related to the terms “natural” and “realistic.” In conclusion, forest-related visual, olfactory, and combined visual and olfactory stimuli induced physiological and psychological relaxation effects, and the combined visual and olfactory stimuli exhibited an additive effect.
Chorong Song; Harumi Ikei; Yoshifumi Miyazaki. Physiological effects of forest-related visual, olfactory, and combined stimuli on humans: An additive combined effect. Urban Forestry & Urban Greening 2019, 44, 126437 .
AMA StyleChorong Song, Harumi Ikei, Yoshifumi Miyazaki. Physiological effects of forest-related visual, olfactory, and combined stimuli on humans: An additive combined effect. Urban Forestry & Urban Greening. 2019; 44 ():126437.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Yoshifumi Miyazaki. 2019. "Physiological effects of forest-related visual, olfactory, and combined stimuli on humans: An additive combined effect." Urban Forestry & Urban Greening 44, no. : 126437.
Research Highlights: This study demonstrated that viewing forest landscapes induced physical and mental health benefits on young women. Background and Objectives: The health-promoting effects of spending time in forests have received increasing attention; however, there is a lack of evidence-based research investigating the effects of spending time in forests on women. This study aimed to evaluate the physiological and psychological effects of viewing forest landscapes on young women. Materials and Methods: The experiments were conducted in six forests and six city areas and included 65 women (mean age, 21.0 ± 1.3 years). Participants viewed a forest and a city area for 15 min, during which their heart rate variability and heart rate were measured continuously. Blood pressure and pulse rate were measured before and after the viewing. After the viewing, participants’ psychological responses were assessed using the modified semantic differential method, Profile of Mood States (POMS), and the State–Trait Anxiety Inventory (STAI). Results: Compared with viewing city areas, viewing forest landscapes was associated with significantly higher parasympathetic nervous activity and lower sympathetic nervous activity and heart rate. Moreover, scores of the comfortable, relaxed, and natural parameters and vigor subscales of POMS were significantly higher with forest viewing. The scores of negative feelings, such as tension–anxiety, depression–dejection, anger–hostility, fatigue, and confusion, were significantly lower, as were scores for the total mood disturbance observed using POMS and the anxiety dimension observed using STAI. Conclusions: Viewing forest landscapes resulted in physiological and psychological relaxations in young women.
Chorong Song; Harumi Ikei; Takahide Kagawa; Yoshifumi Miyazaki. Physiological and Psychological Effects of Viewing Forests on Young Women. Forests 2019, 10, 635 .
AMA StyleChorong Song, Harumi Ikei, Takahide Kagawa, Yoshifumi Miyazaki. Physiological and Psychological Effects of Viewing Forests on Young Women. Forests. 2019; 10 (8):635.
Chicago/Turabian StyleChorong Song; Harumi Ikei; Takahide Kagawa; Yoshifumi Miyazaki. 2019. "Physiological and Psychological Effects of Viewing Forests on Young Women." Forests 10, no. 8: 635.
Exposure to natural sounds is known to induce feelings of relaxation; however, only few studies have provided scientific evidence on its physiological effects. This study examined prefrontal cortex and autonomic nervous activities in response to forest sound. A total of 29 female university students (mean age 22.3 ± 2.1 years) were exposed to high-resolution sounds of a forest or city for 60 s, using headphones. Oxyhemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined by near-infrared spectroscopy. Heart rate, the high-frequency component of heart rate variability (which reflects parasympathetic nervous activity), and the ratio of low-frequency to high-frequency (LF/HF) components (which reflects sympathetic nervous activity) were measured. Subjective evaluation was performed using the modified semantic differential method and profiles of mood states. Exposure to the forest sound resulted in the following significant differences compared with exposure to city sound: decreased oxy-Hb concentrations in the right prefrontal cortex; decreased ln(LF/HF); decreased heart rate; improved feelings described as “comfortable,’’ “relaxed,” and “natural”; and improved mood states. The findings of this study demonstrated that forest-derived auditory stimulation induced physiological and psychological relaxation effects.
Hyunju Jo; Chorong Song; Harumi Ikei; Seiya Enomoto; Hiromitsu Kobayashi; Yoshifumi Miyazaki. Physiological and Psychological Effects of Forest and Urban Sounds Using High-Resolution Sound Sources. International Journal of Environmental Research and Public Health 2019, 16, 2649 .
AMA StyleHyunju Jo, Chorong Song, Harumi Ikei, Seiya Enomoto, Hiromitsu Kobayashi, Yoshifumi Miyazaki. Physiological and Psychological Effects of Forest and Urban Sounds Using High-Resolution Sound Sources. International Journal of Environmental Research and Public Health. 2019; 16 (15):2649.
Chicago/Turabian StyleHyunju Jo; Chorong Song; Harumi Ikei; Seiya Enomoto; Hiromitsu Kobayashi; Yoshifumi Miyazaki. 2019. "Physiological and Psychological Effects of Forest and Urban Sounds Using High-Resolution Sound Sources." International Journal of Environmental Research and Public Health 16, no. 15: 2649.
After the article was published, an error was found in Fig. 2. The following change should be made to the figure in the published article. The change does not affect the conclusions of the article in any way.
Harumi Ikei; Chorong Song; Juyoung Lee; Yoshifumi Miyazaki. Correction to: Comparison of the effects of olfactory stimulation by air-dried and high-temperature-dried wood chips of hinoki cypress (Chamaecyparis obtusa) on prefrontal cortex activity. Journal of Wood Science 2019, 65, 13 .
AMA StyleHarumi Ikei, Chorong Song, Juyoung Lee, Yoshifumi Miyazaki. Correction to: Comparison of the effects of olfactory stimulation by air-dried and high-temperature-dried wood chips of hinoki cypress (Chamaecyparis obtusa) on prefrontal cortex activity. Journal of Wood Science. 2019; 65 (1):13.
Chicago/Turabian StyleHarumi Ikei; Chorong Song; Juyoung Lee; Yoshifumi Miyazaki. 2019. "Correction to: Comparison of the effects of olfactory stimulation by air-dried and high-temperature-dried wood chips of hinoki cypress (Chamaecyparis obtusa) on prefrontal cortex activity." Journal of Wood Science 65, no. 1: 13.