Effects of visual stimulation using wooden-wall images with different amounts of knots on psychological and physiological responses

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

Physiological effects of visual stimulation with full-scale wall images composed of vertically and horizontally arranged wooden elements

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

Physiological adjustment effect of visual stimulation by fresh rose flowers on sympathetic nervous activity

IntroductionAs modern societies are often stressful due to urbanization and artificialization, the physiological relaxing effects of natural environments or nature-derived stimuli on humans have attracted attention and scientific data are being accumulated. It is known that there is inter-individual variation in these effects. The study aim was to apply the law of initial values to investigate the physiological adjustment effect of viewing fresh roses on sympathetic nervous activity.MethodsIn this crossover study, a total of 214 high school students, office workers, healthcare workers, and elderly people were analyzed. The participants viewed fresh roses in a vase for 4 min. In the control condition, participants did not view any fresh roses during the period. To offset any order effect, participants received visual stimuli in the order of fresh roses then the control (no fresh roses) or the control and then fresh roses. ln (LF/HF) of heart rate variability (HRV) obtained from a-a interval measurements using an acceleration plethysmograph and used as an index of sympathetic nervous activity. The initial value was ln (LF/HF) of HRV during the control viewing (no fresh roses), and the change value was ln(LF/HF) of HRV during visual stimulation by fresh roses minus the control viewing.Results and DiscussionThe correlation between the two was assessed by determining Pearson’s correlation coefficient r, which was significantly negative. A physiological adjustment effect was observed such that participants with high initial sympathetic nervous activity showed a decrease in activity after visual stimulation with fresh roses, whereas participants with low initial activity showed an increase

Influence of Forest Therapy on Cardiovascular Relaxation in Young Adults

Background. Despite increasing attention toward forest therapy as an alternative medicine, very little evidence continues to be available on its therapeutic effects. Therefore, this study was focused on elucidating the health benefits of forest walking on cardiovascular reactivity. Methods. Within-group comparisons were used to examine the cardiovascular responses to walking in forest and urban environments. Forty-eight young adult males participated in the two-day field research. Changes in heart rate variability, heart rate, and blood pressure were measured to understand cardiovascular reactivity. Four different questionnaires were used to investigate the changes in psychological states after walking activities. Results. Forest walking significantly increased the values of ln(HF) and significantly decreased the values of ln(LF/HF) compared with the urban walking. Heart rate during forest walking was significantly lower than that in the control. Questionnaire results showed that negative mood states and anxiety levels decreased significantly by forest walking compared with urban walking. Conclusion. Walking in the forest environment may promote cardiovascular relaxation by facilitating the parasympathetic nervous system and by suppressing the sympathetic nervous system. In addition, forest therapy may be effective for reducing negative psychological symptoms

Physiological and Psychological Benefits of Viewing an Autumn Foliage Mountain Landscape Image among Young Women

Empirically, viewing nature landscapes, including mountains, can promote relaxation. This study aimed to examine the physiological and psychological effects of visual stimulation using an autumn foliage mountain landscape image on autonomic nervous and brain activities. We included 27 female university students who viewed mountain and city (control) landscape images displayed on a large, high-resolution display for 90 seconds. As an indicator of autonomic nervous activity, heart rate variability (high frequency [HF], reflecting parasympathetic nervous activity, and low frequency/high frequency [LF/HF], reflecting sympathetic nervous activity) and heart rate were recorded. Simultaneously, as an indicator of brain activity, oxyhemoglobin concentrations in the prefrontal cortex were assessed using near-infrared time-resolved spectroscopy. Viewing the mountain landscape image significantly increased HF, indicating increased parasympathetic nervous activity. Furthermore, the visual stimulation using the mountain image induced comfortable, relaxed, and natural feelings, as well as improved mood states. In conclusion, viewing an autumn foliage mountain landscape image via large display induced physiological and psychological relaxation in women in their 20s

Physiological Effects of Visual Stimulation with Forest Imagery

This study was aimed to clarify the physiological effects of visual stimulation using forest imagery on activity of the brain and autonomic nervous system. Seventeen female university students (mean age, 21.1 ± 1.0 years) participated in the study. As an indicator of brain activity, oxyhemoglobin (oxy-Hb) concentrations were measured in the left and 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 ratio of low-frequency (LF) and high-frequency components (LF/HF), which reflected sympathetic nervous activity, were measured. Forest and city (control) images were used as visual stimuli using a large plasma display window. After sitting at rest viewing a gray background for 60 s, participants viewed two images for 90 s. During rest and visual stimulation, HRV and oxy-Hb concentration in the prefrontal cortex were continuously measured. Immediately thereafter, subjective evaluation of feelings was performed using a modified semantic differential (SD) method. The results showed that visual stimulation with forest imagery induced (1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex and (2) a significant increase in perceptions of feeling “comfortable,” “relaxed,” and “natural.

Physiological Effects of Touching the Wood of Hinoki Cypress (Chamaecyparis obtusa) with the Soles of the Feet

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 ± 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’ feet were touched to a 600 × 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 “comfortable,” “relaxed,” “natural,” “warm,” “uneven,” “dry,” and “soft” after touching Hinoki. Thus, our cumulative findings indicate that touching Hinoki with the soles of the feet induces physiological relaxation

Elucidation of a Physiological Adjustment Effect in a Forest Environment: A Pilot Study

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

Physiological Effects of Touching Wood

This study aimed to clarify the physiological effects of touching wood with the palm, in comparison with touching other materials on brain activity and autonomic nervous activity. Eighteen female university students (mean age, 21.7  ±  1.6 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. Plates of uncoated white oak, marble, tile, and stainless steel were used as tactile stimuli. After sitting at rest with their eyes closed, participants touched the materials for 90 s. As a result, tactile stimulation with white oak significantly (1) decreased the oxy-Hb concentration in the left/right prefrontal cortex relative to marble, tile, and stainless steel and (2) increased ln(HF)-reflected parasympathetic nervous activity relative to marble and stainless steel. In conclusion, our study revealed that touching wood with the palm calms prefrontal cortex activity and induces parasympathetic nervous activity more than other materials, thereby inducing physiological relaxation

Physiological Effects of Nature Therapy: A Review of the Research in Japan

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