Search

Wood is an important material used in decorating human living environment. Knots are prominent features found on wood surface. Moreover, they are commonly considered as undesirable surface defects, which reduce not only the mechanical properties but also the aesthetic qualities of lumber. The effects of visual stimulation using knotty wood on psychological responses among humans have been relatively well investigated. However, only few studies have assessed physiological responses. Hence, the present study aimed to assess whether knotty wood surface can reduce not only psychological but also physiological benefits for humans. Two full-sized knotty wooden-wall images and a clear wooden-wall image were used as visual stimuli using computer graphics techniques. Twenty-eight adult Japanese female university students viewed each image for 90 s in random order. During exposure to the visual stimuli, the oxyhemoglobin concentrations in the left and right prefrontal cortex and heart rate variability were consecutively measured and utilized as indicators of central and autonomic nervous system activities, respectively. In addition, the psychological effects of knotty images were examined using the modified semantic differential method and the Profile of Mood State 2nd Edition. There was no significant difference in the effects of the three images on physiological responses. All visual stimuli more or less promoted psychological comfort and relaxation. However, compared with the clear wooden-wall image, the wooden-wall image with several knots was associated with reduced psychological benefits, and the psychological responses in viewing the wooden-wall image with few knots did not remarkably differ.

Growing interest in the relaxation effect of nature has elicited demands for scientific verification of the various natural elements. This study investigated the physiological and psychological responses of 27 females in their 20 s to viewing a waterfall and urban images (control) presented via a large, high-resolution display for 90 s. High-frequency [HF] for parasympathetic nervous activity and the ratio of low-frequency (LF)/[LF + HF] for sympathetic nervous activity by heart rate variability and heart rate were recorded. Simultaneous changes in oxyhemoglobin concentration in the prefrontal cortex were recorded by near-infrared time-resolved spectroscopy. The modified semantic differential method and Profile of Mood States Second Edition were used to assess the psychological effects on the participants after viewing each image. The results showed that viewing the waterfall image, compared with viewing the urban image, (1) increased sympathetic nervous activity; (2) provided comfortable, relaxed, and natural impressions; (3) improved mood states. In conclusion, visual contact with a waterfall image physiologically activated sympathetic nervous activity and psychologically evoked positive moods and feelings.

The aim of the current study was to assess seasonal differences in physiological responses to walking in urban parks. In total, 51 Japanese male university students participated in this research. During each season, the participants walked for 15 min in an urban park and a city area, which was used as the control site. Heart-rate variability and heart rate were used as physiological indicators. The mean values of each indicator in a comparison between walking in an urban park and a city area were compared according to each season. In addition, to show the physiological effect of walking in an urban park, differences (between walking in an urban park and walking in a city area) were calculated. Then, differences according to each season were compared. The results showed that the participants had increased parasympathetic nervous system activity in all seasons except summer. Moreover, they had decreased sympathetic nervous system activity in spring and fall and decreased heart rate in all seasons. Compared with walking in urban parks in summer, walking in urban parks in spring, fall, and winter had a greater relaxation effect on parasympathetic and sympathetic nervous system activities; hence, the physiological effects of walking in urban parks vary based on season.

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.

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.

This study aimed to clarify the physiological effects of touching hinoki cypress (hereinafter called “hinoki”) (Chamaecyparis obtusa) wood with the palm of the right hand on brain activity and autonomic nervous activity. Twenty-two female university students (mean age 21.1 ± 0.2 years) participated in the study. As an indicator of brain activity, oxyhemoglobin (oxy-Hb) concentrations were measured in the left/right prefrontal cortex using near-infrared time-resolved spectroscopy. Heart rate variability (HRV) was used as an indicator of autonomic nervous activity. The high-frequency (HF) component of HRV, which reflected parasympathetic nervous activity, and the low-frequency (LF)/HF ratio, which reflected sympathetic nervous activity, were measured. Plate (300 × 300 mm) of uncoated hinoki was used as tactile stimulation. Marble was used as a control material. After sitting at rest with their eyes closed, the participants touched the materials for 90 s with their eyes still closed. The results showed that tactile stimulation with hinoki significantly decreased oxy-Hb concentration in the left prefrontal cortex and increased ln(HF) reflected parasympathetic nervous activity compared with marble. In conclusion, our study showed that touching hinoki wood with the palm calms prefrontal cortex activity and increases parasympathetic nervous activity, thereby inducing physiological relaxation.

Objectives The present study aimed to clarify the effects of viewing fresh roses on prefrontal cortex activity, autonomic nervous activity and subjective assessments of psychological relaxation. Design A crossover design, in which each experimental group crosses over from one treatment to another, was used. Setting and interventions : A total of 15 female university students (mean age 21.7 ± 1.1 years) viewed fresh roses for 3 min; the control consisted of no experimental stimulus. Main outcome measures : Physiological effects on prefrontal cortex activity were determined by near-infrared time-resolved spectroscopy, which was assessed by measuring oxyhemoglobin (oxy-Hb) concentration in the left and right prefrontal cortex; effects on autonomic nervous activity were assessed by measuring heart rate variability (HRV) and heart rate. Modified semantic differential method and Profile of Mood States were used to determine subjective evaluations. Results Viewing roses induced: 1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex; 2) a marginally significant decrease in ln[LF/(LF + HF)] of HRV, which is associated with sympathetic nervous activity; 3) a significant increase in perceptions of feeling ‘comfortable,’ ‘relaxed,’ and ‘natural;’ and 4) a significant improvement in mood state. Conclusions These findings indicate that visual stimulation with roses induces physiological and psychological relaxation.

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.

Considering the increasing demand for rural areas to play a role in easing stress mainly experienced by urban dwellers, we investigated from a multidisciplinary collaborative approach, i.e., physiological, psychological, and rural business management perspectives, the relaxation effects of forest-therapy tourism, an emerging type of rural tourism, on a group of urban office workers. Also investigated were conditions necessary for a sustainable rural business in Chizu, western Japan. First, the results verified physiological and psychological relaxation effects, which lasted from three to five days after forest therapy. The lasting physiological and psychological effects among those with systolic blood pressure ≥120 mmHg, however, were weaker than in the entire sample. Second, due to the ageing and depopulation of the local community, increasing the number of households that provided home stay services was difficult. In summary, it is necessary to fully integrate scientific evidence to support a viable new rural tourism business.

We examined the sustained effects of a forest therapy program on the blood pressure of office workers. Twenty-six office workers (mean age ± standard deviation, 35.7 ± 11.1 years) participated in a 1-day forest therapy program. Systolic and diastolic blood pressure and pulse rate were used as measurement indices. The evaluations were performed three times before breakfast, lunch, and dinner 3 days before, during, and 3 and 5 days after the forest therapy program. Systolic and diastolic blood pressure significantly decreased during the forest therapy program relative to the value from 3 days before the program, and this decrease was maintained 3 and 5 days after the forest therapy program. There were no significant differences in pulse rate. We then specifically focused on nine participants whose systolic blood pressure was above 120 mmHg. For the measurement before dinner, the systolic blood pressure significantly decreased (from 133.8 to 116.6 mmHg) during the forest therapy program, and this decrease was maintained at 3 and 5 days after the program (126.4 and 124.0 mmHg, respectively). A significant decrease in diastolic blood pressure (from 88.6 to 77.1 mmHg) was observed during the forest therapy program. In conclusion, systolic and diastolic blood pressure decreased during the forest therapy program and these decreases were maintained for 5 days.

With increasing attention on the health benefits of a forest environment, evidence-based research is required. This study aims to provide scientific evidence concerning the physiological and psychological effects of exposure to the forest environment on middle-aged hypertensive men. Twenty participants (58.0 ± 10.6 years) were instructed to sit on chairs and view the landscapes of forest and urban (as control) environments for 10 min. Heart rate variability (HRV) and heart rate were used to quantify physiological responses. The modified semantic differential method was used to determine psychological responses. Consequently, the high-frequency component of HRV, a marker of parasympathetic nervous activity that is enhanced in relaxing situations, was significantly higher and heart rate was significantly lower in participants viewing the forest area than in those viewing the urban area. The questionnaire results indicated that viewing the forest environment increased “comfortable,” “relaxed,” and “natural” feelings than viewing the urban environment. In conclusion, viewing forest landscape produces physiological and psychological relaxation effects on middle-aged hypertensive men.

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.

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.

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 &plusmn, 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 &ldquo, comfortable,&rsquo, &rsquo, &ldquo, relaxed,&rdquo, and &ldquo, natural&rdquo, and improved mood states. The findings of this study demonstrated that forest-derived auditory stimulation induced physiological and psychological relaxation effects.

The effects of forest activities on health promotion have received increasing attention. The aim of this study was to evaluate the physiological and psychological effects of brief walks in forests on young women. The experiments were conducted in 6 forests (test) and 6 city areas (control). Overall, 12 participants in each area (60 participants in total, mean age: 21.0 &plusmn, 1.3 years) were instructed to walk in a forest and a city area for approximately 15 min, simultaneously, their heart rate variability, heart rate, blood pressure, and pulse rate were measured to quantify their physiological responses to walking. The modified semantic differential method, Profile of Mood States (POMS), and the State&ndash, Trait Anxiety Inventory (STAI) were used to determine their psychological responses. Walking in a forest was associated with significantly higher parasympathetic nervous activity and lower sympathetic nervous activity and heart rate. In addition, scores for the comfortable, relaxed, and natural parameters and vigor subscale of POMS were significantly higher, whereas scores for negative feelings, such as tension&ndash, anxiety, depression&ndash, dejection, anger&ndash, hostility, fatigue, and confusion, were significantly lower, as were the total mood disturbance of POMS and the anxiety dimension of the STAI. The subjective evaluations were generally in accordance with the physiological responses. A brief walk in a forest resulted in physiological and psychological relaxation effects in young women.

This study aimed to clarify the psychological benefits of brief walks through forest areas. In addition, we aimed to examine the associations between psychological responses and trait anxiety levels. Five-hundred-and-eighty-five participants (mean age, 21.7 &plusmn, 1.6 years) were instructed to walk predetermined courses through forest (test) and city (control) areas for 15 min. The Profile of Mood State (POMS) questionnaire and State-Trait Anxiety Inventory were used to assess participants&rsquo, psychological responses and trait anxiety levels, respectively. The results revealed that walking through forest areas decreased the negative moods of &ldquo, depression-dejection&rdquo, &ldquo, tension-anxiety&rdquo, anger-hostility&rdquo, fatigue&rdquo, and &ldquo, confusion&rdquo, and improved the participants&rsquo, positive mood of &ldquo, vigor&rdquo, compared with walking through city areas. Furthermore, a significant correlation was found between participants&rsquo, trait anxiety levels and their changes in the subscale of &ldquo, of POMS after walking through forest areas. A more effective reduction in the feeling of &ldquo, after walking through forest areas was observed for participants with high trait anxiety levels than for those with normal and low trait anxiety levels. This study showed the psychological benefits of walking through forest areas and identified a significant correlation between psychological responses to walking through forests and trait anxiety levels.

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.

Background: In recent years, the physiological relaxation effects of natural environments have been widely exploited, and although individual differences in the effects of forest therapy are known, assessment methods have not been clearly established. This study used a classification based on Type A and Type B behavior patterns to explain individual differences in physiological responses to forest environments. Methods: We performed physiological experiments in 44 forest and urban (controls) areas. In total, 485 male university students (age, 21.8 ± 1.6 years) participated in the study. The subjects were asked to visit forest or urban environments randomly and observe each landscape for 15 min. The subjects’ pulse rates and blood pressures were tested to evaluate their physiological responses. The Kwansei Gakuin daily life questionnaire was used to identify Type A and Type B behavior patterns in subjects. Results: The pulse rate was significantly lower in the Type B group after exposure to forest areas than after exposure to urban areas, whereas no significant difference was observed in the Type A group. In addition, the pulse rate was significantly lower in the low scoring subjects in the Type B group, which was consistent with changes in their diastolic blood pressure. Conclusions: These results suggest that individual differences in pulse rate and blood pressure in response to forest environments can be explained by Type A and Type B behavior patterns.

The natural environment is increasingly recognized as an effective counter to urban stress, and “Forest Therapy” has recently attracted attention as a relaxation and stress management activity with demonstrated clinical efficacy. The present study assessed the physiological and psychological effects of a forest therapy program on middle-aged females. Seventeen Japanese females (62.2 ± 9.4 years; mean ± standard deviation) participated in this experiment. Pulse rate, salivary cortisol level, and psychological indices were measured on the day before forest therapy and on the forest therapy day. Pulse rate and salivary cortisol were significantly lower than baseline following forest therapy, indicating that subjects were in a physiologically relaxed state. Subjects reported feeling significantly more “comfortable,” “relaxed,” and “natural” according to the semantic differential (SD) method. The Profile of Mood State (POMS) negative mood subscale score for “tension–anxiety” was significantly lower, while that for “vigor” was significantly higher following forest therapy. Our study revealed that forest therapy elicited a significant (1) decrease in pulse rate, (2) decrease in salivary cortisol levels, (3) increase in positive feelings, and (4) decrease in negative feelings. In conclusion, there are substantial physiological and psychological benefits of forest therapy on middle-aged females.

In recent times, attention has been focused on the role of urban green spaces in promoting human health and well-being. However, there is a lack of evidence-based research on the physiological effects of walking in urban green areas. This study aimed to clarify the physiological and psychological effects of walking in urban parks during fall. Twenty-three males (mean age 22.3 ± 1.2 years) were instructed to walk predetermined 15-min courses in an urban park and in a nearby city area (control). Heart rate and heart rate variability were measured to assess physiological responses, and the semantic differential method, Profile of Mood States, and State-Trait Anxiety Inventory were used to measure psychological responses. We observed that walking in an urban park resulted in a significantly lower heart rate, higher parasympathetic nerve activity, and lower sympathetic nerve activity than walking through the city area. In subjective evaluations, participants were more “comfortable,” “natural,” “relaxed,” and “vigorous” after a walk in the urban park. Furthermore, they exhibited significantly lower levels of negative emotions and anxiety. These findings provide scientific evidence for the physiological and psychological relaxation effects of walking in urban parks during fall.

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.

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.

We clarified the physiological effects of tactile stimulation of the soles of the feet with the wood of the Hinoki cypress (Chamaecyparis obtusa) based on measurements of prefrontal cortex and autonomic nervous activities. Nineteen female university-attending students (age: 21.2 &plusmn, 0.3 years) were included. Oxy-hemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined by using near-infrared time-resolved spectroscopy. The high frequency (HF) indicating parasympathetic nervous activity and the ratio of low frequency (LF)/HF indicating sympathetic nervous activity were measured using heart rate variability. To evaluate the psychological effects caused by contact with the materials, the modified semantic differential method was used. The soles of the participants&rsquo, feet were touched to a 600 &times, 600-mm plate made of Hinoki, which was finished in non-coating and brushing for 90 s. A marble plate served as the control. Next, subjective evaluation tests were administered to the participants. Compared with touching marble, touching Hinoki significantly (1) decreased the oxy-Hb concentrations in the left and right prefrontal cortices, which indicates decreased prefrontal cortex activity, (2) increased ln(HF), which indicates increased parasympathetic nervous activity, (3) decreased ln(LF/HF) ratio, which indicates decreased sympathetic nervous activity. Additionally, (4) according to subjective evaluations, the participants perceived themselves as being more &ldquo, comfortable,&rdquo, &ldquo, relaxed,&rdquo, natural,&rdquo, warm,&rdquo, uneven,&rdquo, dry,&rdquo, and &ldquo, soft&rdquo, after touching Hinoki. Thus, our cumulative findings indicate that touching Hinoki with the soles of the feet induces physiological relaxation.

There is a significant positive relationship between exposure to forest environments and physical and mental health. However, there are individual differences within these responses, and this phenomenon has posed questions in various fields. Here, we show that the physiological effect of a forest environment can differ depending on a subject’s initial values and that forests have a physiological adjustment effect close to an appropriate level. Subjects with high initial blood pressure and pulse rate showed a decrease in these values after walking in a forested area, whereas those with low initial values showed an increase. There was no physiological adjustment effect observed in an urban area; thus, these effects are specific to a forest environment.

The relaxation effects of gardening have attracted attention, however, very few studies have researched its physiological effects on humans. This study aimed to clarify the physiological and psychological effects on high school students of viewing real and artificial pansies. Forty high school students (male: 19, female: 21) at Chiba Prefectural Kashiwanoha Senior High School, Japan, participated in this experiment. The subjects were presented with a visual stimulation of fresh yellow pansies (Viola x wittrockiana “Nature Clear Lemon”) in a planter for 3 min. Artificial yellow pansies in a planter were used as the control. Heart rate variability was used as a physiological measurement and the modified semantic differential method was used for subjective evaluation. Compared with artificial pansies, visual stimulation with real flowers resulted in a significant decrease in the ratio of low- to high-frequency heart rate variability component, which reflects sympathetic nerve activity. In contrast, high frequency, which reflects parasympathetic nerve activity, showed no significant difference. With regard to the psychological indices, viewing real flowers resulted in “comfortable”, “relaxed”, and “natural” feelings. The findings indicate that visual stimulation with real pansies induced physiological and psychological relaxation effects in high school students.

Nature therapy has been demonstrated to induce physiological relaxation. The psychophysiological effects of nature therapy (stimulation with bonsai trees) on adult male patients with spinal cord injury (SCI) were examined. Oxyhemoglobin concentration changes in the prefrontal cortex were measured using near-infrared spectroscopy, and heart rate variability was analyzed. Psychological responses were evaluated using the modified semantic differential method and Profile of Mood States (POMS) subscale scores. Visual stimulation of adult male patients with SCI elicited significantly decreased left prefrontal cortex activity, increased parasympathetic nervous activity, decreased sympathetic nervous activity, increased positive feelings, and resulted in lower negative POMS subscale scores. Nature therapy can lead to a state of physiological and psychological relaxation in patients with SCI.

Salivary cortisol and secretory immunoglobulin A (S-IgA) are important biomarkers for environmental and public health research. The present study investigated the diurnal variations of these salivary biomarkers, with a focus on the change of distribution characteristics (i.e., skewness and kurtosis) of the concentrations. The participants in this study were 113 healthy young males. Salivary samples were collected in the morning (6:30–7:30 a.m.) and afternoon (1:00–4:00 p.m.). The skewness and kurtosis of salivary cortisol concentrations in afternoon samples (skewness = 1.06, kurtosis = 4.78) were significantly higher than those in morning samples (skewness = 0.49, kurtosis = 2.80). The differences in skewness and kurtosis of S-IgA concentrations were non-significant; however, the standard deviation and interquartile ranges for afternoon S-IgA concentrations were significantly smaller than those for morning S-IgA concentrations. Logarithmic transformation improved the distribution of afternoon cortisol values, making it an almost normal distribution, but the transformation showed no improvement in the distribution of morning cortisol or S-IgA values. The present study explored diurnal changes in the distribution characteristics of salivary cortisol and S-IgA. Consideration of a possible diurnal change in the distribution characteristics is needed when we compare the difference in these salivary biomarkers between different times of day.

Empirical evidence suggests that three-dimensional (3D) images of nature promote physiological relaxation in humans by providing more realistic effects compared with two-dimensional (2D) images. However, no studies have evaluated the physiological relaxation effects of nature-derived 3D images on prefrontal cortex and autonomic nerve activity. The present study aimed to clarify the physiological relaxation effects of visual stimulation by 3D flower images on prefrontal cortex and autonomic nerve activity. Nineteen male university students (22.2 ± 0.6 years) were presented with 3D and 2D images of the water lily for 90 s. Prefrontal cortex activity was measured using near-infrared spectroscopy, while autonomic nerve activity was measured using heart rate variability (HRV). Psychological effects were determined using a modified semantic differential method (SD). Compared with visual stimulation by 2D images, that by 3D images resulted in a significant decrease in oxyhemoglobin concentration in the right prefrontal cortex, lower sympathetic activity as calculated by the ratio of the low-frequency to high-frequency HRV component, and a significantly greater realistic feeling as evidenced by higher SD ratings. In conclusion, visual stimulation by realistic 3D floral images promotes physiological relaxation more effectively than the corresponding 2D image.

BACKGROUND AND PURPOSE Natural scenes like forests and flowers evoke neurophysiological responses that can suppress anxiety and relieve stress. We examined whether images of natural objects can elicit neural responses similar to those evoked by real objects by comparing the activation of the prefrontal cortex during presentation of real foliage plants with a projected image of the same foliage plants. METHODS Oxy-hemoglobin concentrations in the prefrontal cortex were measured using time-resolved near-infrared spectroscopy while the subjects viewed the real plants or a projected image of the same plants. RESULTS Compared with a projected image of foliage plants, viewing the actual foliage plants significantly increased oxy-hemoglobin concentrations in the prefrontal cortex. However, using the modified semantic differential method, subjective emotional response ratings (“comfortable vs. uncomfortable” and “relaxed vs. awakening”) were similar for both stimuli. CONCLUSIONS The frontal cortex responded differently to presentation of actual plants compared with images of these plants even when the subjective emotional response was similar. These results may help explain the physical and mental health benefits of urban, domestic, and workplace foliage.

Objective To provide scientific evidence of the physiological and psychological effects of forest and urban environments on 47 young male adults undergoing stay-in forest therapy. Methods Field experiments were conducted at four sites in Japan. At each site, 12 subjects participated in the experiment. The experiments were conducted in forest and urban environments, and the subjects' physiological and psychological responses to these environments were compared. On the first day, six subjects were sent to a forest area, and the other six were sent to an urban area as controls. The groups were switched the next day. Heart rate variability and heart rate were measured to assess physiological responses. The semantic differential method for assessing emotions, the reports of "refreshed" feeling, and the Profile of Mood States (POMS) were used to assess psychological responses. The physiological and psychological responses of each subject were recorded during and after walking, and the differences in indices were compared between the two environments. Results The forest environment was associated with a higher parasympathetic nervous activity, a lower sympathetic nervous activity, and a lower heart rate than the urban environment. The subjective evaluation scores were generally in accordance with the physiological reactions and were significantly higher in the forest environment than in the urban environment. POMS measurements showed that the forest environment was psychologically relaxing and enhanced psychological vigor. Conclusions This study provided clear scientific evidence of the physiological effects of forest therapy. The results will contribute to the development of forest therapy research and support the inclusion of forest therapy in preventive medicine.

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.

The benefits of various nature-derived stimuli that can be used for stress relief and relaxation has recently gained immense attention, however, there are very few studies about their influence on elderly patients. The present study aims to present the effects of viewing bonsai on autonomic nervous activity, prefrontal cortex activity, and subjective assessment findings of psychological relaxation in elderly patients undergoing rehabilitation. Fourteen participants aged 64&ndash, 91 years (mean age &plusmn, standard deviation, 78.6 &plusmn, 9.6 years) participated in this study. Miniature potted 10-year-old Japanese cypress bonsai trees were used as visual stimuli. Participants viewed the bonsai for 1 min, and the control comprised of no experimental stimulus. Physiological effects on autonomic nervous activity were assessed by measuring the heart rate variability (HRV) and pulse rate. The effects on prefrontal cortex activity were determined using near-infrared spectroscopy, which involved assessment of oxyhemoglobin concentrations in the left and right prefrontal cortices. Subjective evaluations were achieved by the modified semantic differential method. Viewing bonsai resulted in a significant increase in parasympathetic nervous activity, a significant decrease in sympathetic nervous activity, and a significant increase in the perceptions of feeling &ldquo, comfortable&rdquo, and &ldquo, relaxed.&rdquo, In conclusion, our findings indicated that viewing bonsai induces physiological and psychological relaxation.

Humans have evolved into what they are today after the passage of 6–7 million years. If we define the beginning of urbanization as the rise of the industrial revolution, less than 0.01% of our species’ history has been spent in modern surroundings. Humans have spent over 99.99% of their time living in the natural environment. The gap between the natural setting, for which our physiological functions are adapted, and the highly urbanized and artificial setting that we inhabit is a contributing cause of the “stress state” in modern people. In recent years, scientific evidence supporting the physiological effects of relaxation caused by natural stimuli has accumulated. This review aimed to objectively demonstrate the physiological effects of nature therapy. We have reviewed research in Japan related to the following: (1) the physiological effects of nature therapy, including those of forests, urban green space, plants, and wooden material and (2) the analyses of individual differences that arise therein. The search was conducted in the PubMed database using various keywords. We applied our inclusion/exclusion criteria and reviewed 52 articles. Scientific data assessing physiological indicators, such as brain activity, autonomic nervous activity, endocrine activity, and immune activity, are accumulating from field and laboratory experiments. We believe that nature therapy will play an increasingly important role in preventive medicine in the future.