Autonomic Nervous System Responses to Viewing Green and Built Settings: Differentiating Between Sympathetic and Parasympathetic Activity

Assessing response to stressful emotions: a controlled crossover study using pupillometry

Background

Fear and horror induce autonomic protective responses, acting as "survival intelligence." Pupillometry is an innovative method that captures real-time autonomic nervous system reactions to stress.

Objective

To evaluate the feasibility of pupillometry to assess the acute response to a passive real-life stressor-viewing a truthful war scene.

Methods

Thirteen medical students (10 women) with an average age of 20.4 years were enrolled in a nonrandomized controlled crossover trial. Selected clips from two different audiovisual stimuli (M1: Saving Private Ryan as a fear and horror inducer and M2: Life Is Beautiful as a control) were watched for 15 minutes, separated by a washout period of 48-72 hours. The differences in pupillometry parameters between the exposure movie and the assessment time (T0 and T1 for M1 and T0 and T1 for M2) were evaluated using a Wilcoxon test. The Wilcoxon test was also used to assess the difference between M1 and M2 within each assessment time point (T0 and T1).

Results

A significant difference in response to acute fear and horror-induced stress was observed in pupillometry parameters {baseline [6.90 (5.95; 7.40) vs. 6.60 (5.55; 7.10), P = 0.030] and final pupil diameter [4.50 (3.90; 5.20) vs. 4.10 (3.50; 4.60), P = 0.012]} between M1 and M2 in T1, suggesting the acute increase in sympathetic parameters. Although not significant, there was also a difference in pupillometry parameters (final pupil diameter [P = 0.060], average constriction velocity [P = 0.059]) after watching M1 compared with T0.

Conclusion

Our proof-of-concept study suggests that pupillometry may be used to evaluate changes in the activity of the autonomic nervous system induced by an acute passive stress stimulus.

Color and brightness at work: Shedding some light on mind wandering

INTRODUCTION

Occupational hazards are partly caused by the physical factors of the work environment, among which are ambient color and brightness, which can interfere with cognitive performance. Especially in modern work environments, performance relies heavily on cognitive functions such as attention, and an important factor in disrupting sustained attention is mind wandering (MW). This study aimed to investigate the effects of white and blue colors with two brightness levels on sustained attention and brain electrophysiology.

METHODS

A total of 20 participants were exposed to 4 different conditions (white and blue as color and 300 and 800 lx as the brightness level) in separate blocks in a virtual reality environment in which a continuous performance test (CPT) was performed.

RESULTS

The high brightness blue condition induced significant changes in sustained attention. MW network analysis showed a significant decrease in delta frequency band in the blue color condition with high brightness and beta decrease in the blue color condition with low brightness, whereas the activity of MW network increased when exposed to the white color condition.

CONCLUSION

High-brightness blue light resulted in better sustained attention and decreased activity of MW-related neural regions. It is thus recommended that these results be taken into consideration in the interior design of educational settings and cars among other environments that require a high level and maintenance of cognitive functions, especially sustained attention.

Residential quality, physical activity, and restorative perceptions: A seasonal longitudinal study

While the restorative benefits of residential environments are known, the influence of residents' physical activity on their perceptions of restorativeness in different settlements is unclear. This study aimed to investigate the mediating and moderating roles of residents' physical activities and seasons on restorative perceptions using survey data from three settlements in Harbin, China, involving a baseline survey conducted in June 2023 and questionnaires administered at 30-day intervals from July to December 2023 (534 interviews). Residents' restorative perceptions and physical activity levels were highest in autumn, with settlement quality having a seasonal moderating effect and physical activity having a mediating effect.

Temporal dynamics of autonomic nervous system responses under cognitive-emotional workload in obsessive-compulsive disorder

Dysregulation of the autonomic nervous system (ANS) is commonly observed in various mental disorders, particularly when individuals engage in prolonged cognitive-emotional tasks that require ANS adjustment to workload. Although the understanding of the temporal dynamics of sympathetic and parasympathetic tones in obsessive-compulsive disorder (OCD) is limited, analyzing ANS reactions to cognitive-emotional workload could provide valuable insights into one of the underlying causes of OCD. This study investigated the temporal dynamics of heart rate (HR) and pupil area (PA) while participants with OCD and healthy volunteers solved antisaccade tasks, with affective pictures serving as central fixation stimuli. The data of 31 individuals with OCD and 30 healthy volunteers were included in the study, comprising three separate blocks, each lasting approximately 8 min. The results revealed an increase in sympathetic tone in the OCD group, with the most noticeable rise occurring during the middle part of each block, particularly during the presentation of negative stimuli. Healthy volunteers demonstrated adaptive temporal dynamics of HR and PA from the first block to the last block of tasks, whereas individuals with OCD exhibited fewer changes over time, suggesting a reduced adaptation of the ANS sympathetic tone to cognitive-emotional workload in OCD.

Impact of green space exposure on blood pressure in Guangzhou, China: mediation by air pollution, mental health, physical activity, and weight status1

Green space exposure has been inversely associated with blood pressure (BP) levels and hypertension risk. However, empirical evidence on the underlying mechanisms are lacking. This study examined the association of green space exposure with BP and hypertension, and assessed the mediating effects by air pollution, mental health, physical activity, and weight status. Survey data from 719 adults, who lived in Guangzhou (China) in 2016, were used. Three area-level green space indicators, including network distance to the nearest park, percentage of green space and Normalized Difference Vegetation Index within a 1km Euclidean buffer around residence and workplace, were calculated and linked to individual-level BP measurements. Structural equation models were applied to estimate the direct and indirect associations of the various green space indicators on systolic BP (SBP), diastolic BP (DBP), and hypertension, respectively. After adjusting for multiple covariates, longer network distance to green space was directly associated with higher SBP. Compared to the reference group (0-500m), the differences were 0.11 mmHg (95% CI=0.03 to 0.19, P=0.006) for 500-1000m, 0.03 mmHg (95% CI=-0.05 to 0.12, P=0.45) for 1000-1500m, and 0.16 mmHg (95% CI=0.09 to 0.23, P<0.001) for >1500m, respectively. The overall and direct associations were significant for all three indicators (distance or density) with or without considering workplace exposure. The association between network distance to green and SBP was partially (18.4%, 95% CI=0 to 42.1%) mediated by mental health. There was no statistical evidence that air pollution, physical activity, or weight status mediate the association. Secondary analyses for other indicators and other outcomes showed similar results. Both distance to green space and more green space around residence and workplace were associated with lower BP and lower risk of hypertension in adults living in a Chinese metropolitan. Mental health partly mediated the association.

Promoting stress and anxiety recovery in older adults: assessing the therapeutic influence of biophilic green walls and outdoor view

Previous research has already provided evidence regarding the favorable impact of green walls and outdoor views on stress reduction and anxiety alleviation. However, there has been limited exploration into the combined effects of green walls and outdoor views on older adults. In this study, a between-subjects experiment was conducted using virtual reality (VR) technology with 23 participants. Following exposure to stressors, each participant underwent four randomized sessions, each lasting 5 min, in various virtual reality (VR) environments, encompassing non-biophilic and biophilic environments (including green walls, outdoor views, and their combination). Throughout the process, we measured physiological indicators of stress responses, including heart rate, heart rate variability, skin conductance levels, and blood pressure, using biometric sensors. Psychological changes in participants, including anxiety levels, were evaluated through the State-Trait Anxiety Inventory, recovery scales, and self-reported emotional assessments. In conclusion, in comparison to non-biophilic environments, older adults consistently exhibited lower stress levels, experienced superior anxiety relief, and demonstrated improved recovery in nature connectedness environments, with a notably faster recovery rate. These findings suggest that the incorporation of nature connectedness principles into the indoor environments of public activity spaces within older adults care facilities can significantly contribute to stress reduction and anxiety alleviation among older adults. Furthermore, these effects appear to be contingent on the specific types of nature connectedness environments. These results can provide substantial evidence to support the design of indoor common activity spaces within older adults care facilities.

Design guidelines for limiting and eliminating virtual reality-induced symptoms and effects at work: a comprehensive, factor-oriented review

Virtual reality (VR) can induce side effects known as virtual reality-induced symptoms and effects (VRISE). To address this concern, we identify a literature-based listing of these factors thought to influence VRISE with a focus on office work use. Using those, we recommend guidelines for VRISE amelioration intended for virtual environment creators and users. We identify five VRISE risks, focusing on short-term symptoms with their short-term effects. Three overall factor categories are considered: individual, hardware, and software. Over 90 factors may influence VRISE frequency and severity. We identify guidelines for each factor to help reduce VR side effects. To better reflect our confidence in those guidelines, we graded each with a level of evidence rating. Common factors occasionally influence different forms of VRISE. This can lead to confusion in the literature. General guidelines for using VR at work involve worker adaptation, such as limiting immersion times to between 20 and 30 min. These regimens involve taking regular breaks. Extra care is required for workers with special needs, neurodiversity, and gerontechnological concerns. In addition to following our guidelines, stakeholders should be aware that current head-mounted displays and virtual environments can continue to induce VRISE. While no single existing method fully alleviates VRISE, workers' health and safety must be monitored and safeguarded when VR is used at work.

Brief repeated virtual nature contact for three weeks boosts university students' nature connectedness and psychological and physiological health during the COVID-19 pandemic: A pilot study

The COVID-19 pandemic and its associated uncertainties and restrictions have adverse impacts on university students' mental wellbeing. Evidence shows that virtual nature contact has mental health benefits. However, little is known about the potential beneficial health impacts of virtual nature contact during times of social distancing, when access to the natural environment is restricted. This pilot study aimed to examine the effectiveness of a 3-week virtual nature contact in improving nature connectedness and reducing psychophysiological stress. A sample of 56 university students in Hong Kong was randomly assigned to control and nature interventions using 2-D video played for 15 min three times a week for 3 weeks. Nature connectedness, perceived restorativeness and psycho-physiological wellbeing were measured. Our findings show significant changes in psychological stress levels after nature interventions compared with the baseline, including increased happiness and stronger emotions of comfort and relaxation. When compared with the control group, the results show the nature intervention group has significantly higher levels of nature connectedness, happiness, and positive affect, but no significant effects on other psychological and physiological variables (e.g., cardiovascular responses). Our preliminary findings highlight the potential use of virtual nature contacts in bolstering university students' wellbeing at times of pandemic or when in-person visit to the natural environment is not feasible.

Effects of immersion in a simulated natural environment on stress reduction and emotional arousal: A systematic review and meta-analysis

Background

Although the mental health benefits of exposure to simulated natural environments are well established by researchers from environmental psychology, landscape architecture, and public health, it is unclear whether and to what extent technological immersion affects these benefits.

Methods

Systematical literature searches were conducted in May 2022 from six databases. The risk of bias was evaluated using the Cochrane's Risk of Bias tool 2.0 and the Risk of Bias in Non-randomized Studies of Interventions tool. We performed a random-effects meta-regression to investigate the heterogeneity. The immersion levels of included studies were classified by projection devices and motion capture, and then subgroup analysis was conducted.

Results

Twenty-six publications were included. Exposure to simulated nature was confirmed to be associated with increased positive affect 0.40 [95% confidence interval (CI): 0.22, 0.58], vigor 0.58 (95% CI: 0.30, 0.86), calmness 0.54 (95% CI: 0.17, 0.92) and decreased perceived stress -0.38 (95% CI: -0.71, -0.06), total mood disturbance -0.87 (95% CI: -1.17, -0.57), tension -0.70 (95% CI: -0.99, -0.41), fatigue -0.60 (95% CI: -0.91, -0.28), anxiety -0.72 (95% CI: -1.43, -0.02), depression -0.33 (95% CI: -0.52, -0.14), confusion -0.79 (95% CI: -1.19, -0.40), and anger -0.54 (95% CI: -0.76, -0.31). Gender, health status, study design, mean age, and single exposure duration were not significant when entered in a meta-regression. For positive affect, medium immersion was observed to produce a larger effect than low and high immersion. All included studies had a moderate to high risk of bias.

Conclusion

Audio-visual exposure to simulated nature contributes to stress relief and emotional arousal. The immersion level explains the heterogeneity of positive affect triggered by simulated nature. Focusing on the technical features will open up new possibilities for combining actual and simulated nature's mental health benefits.

Understanding how virtual reality forest experience promote physiological and psychological health for patients undergoing hemodialysis

Growing research has found that exposing patients to forest landscapes through technology improves their health. However, studies on the effects of nature therapy sessions on particularly vulnerable groups that require frequent regular treatment such as patients of chronic kidney disease (CKD) is lacking. This study aims to understand the effects of watching panoramic videos of forest walks through virtual reality (VR) headsets on patients. We also examine the effects of the frequency of virtual exposure to forests on the physiological and psychological parameters of patients undergoing dialysis. Twenty-four dialysis patients with a mean age of 65.11 year underwent a virtual nature intervention over the course of 3 weeks. The intervention consists of 3 numbers of 6-min 360-degree nature videos delivered using VR headsets. We measured heart rate variability (HRV) and heart rate (HR) using continuous electrocardiographic (ECG) monitoring and assessed their emotional states using a questionnaire survey and in-depth interviews. The results showed that the initial 6 min of watching of the panoramic videos through VR headsets resulted in significantly reduced HR and sympathetic nerve activity and increased positive emotional responses. However, repeated VR exposure did not further improve the physiological health of the respondents. Considering these results, the use of VR headsets to watch 6-min nature videos indoors can be used to enhance the positive psychological responses among dialysis and bed-ridden patients. As this study is preliminary, future random controlled trials are needed to compare and determine the best dose, content, and delivery methods of such an intervention.

Indoor nature integration for stress recovery and healthy eating: A picture experiment with plants versus green color

AIM

Urbanized environments may stimulate unhealthy food choices and stress. Several theories explain that exposure to green nature can counter these stress effects. Since we spend most time indoors, integrating nature in the interior could be a promising health promotion tool. Hence, we tested whether the beneficial effect of nature for stress recovery is also present in indoor settings via the use of plants or green colors, and whether it is applicable on eating behavior as a new outcome.

METHODS

The 92 participants (18-30y, 16% men) were divided into four groups. Each viewed a 6-min slideshow with room pictures containing either green plants, green objects, greyscale plants or greyscale objects to allow distinction between color- and plant-effects. Group differences were tested for the perceived restorativeness scale, psychological recovery and eating behavior. To allow psychological recovery testing, participants were exposed to a stressor before the picture slideshow via the Trier Social Stress Test. The change of self-reports (stress, positive and negative affect) and psychophysiology (heart rate and vagal-induced heart rate variability RMSSD) post-slideshow versus pre-slideshow was checked. Eating behavior outcomes included change in hunger, craving, and food choice (for fruits, vegetables and snacks).

RESULTS

From the four picture sets, the green plants pictures were reported as most mentally restorative and appeared most beneficial for post-stressor recovery of positive affect, but not for negative affect or stress recovery. The green plants group also had higher preference for vegetables and lower preference or craving for (unhealthy) snacks. Those significant group differences were mainly due to the presence of plants and only occasionally due to the green color.

CONCLUSION

Indoor green plant pictures were associated with higher mental restorativeness and healthier food choices. Integrating plants in the interior seems to be a relevant health promotion approach, while applying green colors seems less relevant.

Examining the Benefits of Greenness on Reducing Suicide Mortality Rate: A Global Ecological Study

Objective

This study applied an ecological-based analysis aimed to evaluate on a global scale the association between greenness exposure and suicide mortality.

Methods

Suicide mortality data provided by the Institute for Health Metrics and Evaluation and the Normalized Difference Vegetation Index (NDVI) were employed. The generalized additive mixed model was applied to evaluate with an adjustment of covariates the association between greenness and suicide mortality. Sensitivity tests and positive-negative controls also were used to examine less overt insights. Subgroup analyses were then conducted to investigate the effects of greenness on suicide mortality among various conditions.

Results

The main finding of this study indicates a negative association between greenness exposure and suicide mortality, as greenness significantly decreases the risk of suicide mortality per interquartile unit increment of NDVI (relative risk = 0.69, 95%CI: 0.59–0.81). Further, sensitivity analyses confirmed the robustness of the findings. Subgroup analyses also showed a significant negative association between greenness and suicide mortality for various stratified factors, such as sex, various income levels, urbanization levels, etc.

Conclusions

Greenness exposure may contribute to a reduction in suicide mortality. It is recommended that policymakers and communities increase environmental greenness in order to mitigate the global health burden of suicide.

Nature-Based Relaxation Videos and Their Effect on Heart Rate Variability

Growing evidence suggests that natural environments – whether in outdoor or indoor settings – foster psychological health and physiological relaxation, indicated by increased wellbeing, reduced stress levels, and increased parasympathetic activity. Greater insight into differential psychological aspects modulating psychophysiological responses to nature-based relaxation videos could help understand modes of action and develop personalized relaxation interventions. We investigated heart rate variability (HRV) as an indicator of autonomic regulation, specifically parasympathetic activity, in response to a 10-min video intervention in two consecutive studies as well as heart rate (HR). We hypothesized that a nature-based relaxation video elicits HRV increase and HR decrease, with response magnitude being affected by aspects of early life adversity (conceptualized as low parental care and high overprotection/constraint) and trait mindfulness. In Study 1, N = 60 participants (52% female, age_mean = 23.92 ± 3.13 years, age_range = 18–34 years) watched a relaxation video intervention depicting different natural scenery. We analyzed changes in HR and respiratory sinus arrhythmia (RSA) as a standard HRV measure, both based on 3-min segments from the experimental session, in multiple growth curve models. We found a decrease in HR and increase of RSA during the video intervention. Higher paternal care and lower trait mindfulness observing skills (assessed via questionnaires) were associated with higher RSA values before but not during video exposure. In Study 2, N = 90 participants (50% female, age_mean = 22.63 ± 4.57 years, age_range = 18–49 years) were assigned to three video conditions: natural scenery from Study 1, meditation video, or short clip from “The Lord of the Rings.” Again, HR decreased, and RSA increased during video segments, yet without expected group differences across different video types. We found higher parental care and lower parental overprotection to predict higher RSA at different times during the experiment. Interestingly, lower paternal overprotection predicted overall higher RSA. These results suggest a generic relaxation effect of video interventions on autonomic regulation that we discuss in light of different theories mapping restorative effects of natural environments. Further, psychological characteristics like aspects of early life adversity and trait mindfulness could contribute to individual differences in autonomic regulation. This study contributes to a better understanding of autonomic and psychological responses to relaxation videos.

Can parkland mitigate mental health burden imposed by the COVID-19? A national study in China

The worldwide coronavirus disease 2019 (COVID-19) pandemic has seriously affected not only physical health but also mental wellbeing (i.e mental stress and suicide intention) of numerous urban inhabitants across the globe. While many studies have elucidated urban parkland enhances and mental wellbeing of urban residents, the potential for parkland to mitigate mental health burden imposed by the COVID-19 has received no attention. This nationwide study systematically explored the association between parkland, the COVID-19 pandemic situation and mental wellbeing from 296 cities in China. The study innovatively used big data from Baidu Search Engine to assess city-level mental wellbeing, thereby enabling comparisons among cities. The results show that the provision of parkland is positively associated with mental wellbeing during the COVID-19 epidemic. For COVID-19-related indicators, the geographical distance to Wuhan city, work resumption rate, and travel intensity within the city are also positively associated with mental wellbeing, while the number of COVID-19 infections and the proportion of migrants from Hubei Province for each city are negatively associated with mental wellbeing. Last, the most important finding is that parkland reduces the negative effect of COVID-19 on mental wellbeing during the COVID-19 epidemic. To achieve the goal of promoting mental wellbeing through urban planning and design during the future pandemics, policymakers and planners are advised to provide more well-maintained and accessible parkland and encourage residents to use them with proper precautions.

The role of campus greenspace and meditation on college students' mood disturbance

Objective To determine whether students who engage in a sedentary task in an urban park-like setting experience improved mood and whether this effect is moderated by mindfulness meditation. Participants: 234 (133 females) undergraduate students, who either engaged in outdoor recreation frequently or infrequently. Methods: Participants engaged in 20 minutes of mindfulness meditation or a control task, either in a campus park-like setting or in a quiet room indoors. Before and after the activity, total mood disturbance (TMD) was assessed with the Profile of Mood States Questionnaire. Results: Being outside or meditating reduced TMD for those who frequently recreated outside. Those who infrequently recreated outside experienced decreased TMD if they meditated inside and increased TMD if they did not. When outside, TMD decreased regardless of activity. Conclusions: Spending time outside and practicing meditation may be effective approaches for improving college students' mental health, particularly for students who infrequently go outside.

See or Be? Contact with nature and well-being during COVID-19 lockdown

This study investigated how contact with nature benefitted well-being during a strict lockdown. The study took place in Israel during the last week of the first COVID-19 lockdown, when citizens were restricted to remain within 100 m of home. A survey company distributed questionnaires among 776 individuals. The questionnaires included demographic variables (gender, ethnic and cultural groups, age, income loss due to the pandemic), contact with nature variables (Nature near home, Nature viewed from home windows, and being in nature on the preceding day), and well-being measures (positive affect, negative affect, vitality, happiness, and stress). Before completing the well-being questionnaire, participants took part in an experiment that tested the effect of viewing nature images or urban images on well-being measures. The results showed that nature near home and nature viewed from the windows contributed to higher levels of well-being, and that being in nature on the preceding day was associated with higher levels of positive affect. These benefits emerged even among those who had been economically harmed by the pandemic. Viewing nature images was also associated with level of well-being, mainly to reduced level of stress and negative affect. The current findings extend the understanding of the benefits of access to nature during stressful times, particularly during emergencies when accessing remote nature is impossible. Furthermore, the findings highlight the dual effect of contact with nature on well-being: enhancement of positive affect together with reduction of negative affect and stress. The findings indicate that exposure to nature is much more valuable for women than for men. These findings are highly important in view of gender differences in pandemic's impact on people's well-being.

Nature versus urban hiking for Veterans with post-traumatic stress disorder: a pilot randomised trial conducted in the Pacific Northwest USA

OBJECTIVES

To evaluate feasibility and acceptability of a group-based nature recreation intervention (nature hiking) and control condition (urban hiking) for military Veterans with post-traumatic stress disorder (PTSD).

DESIGN AND SETTING

A pilot randomised controlled trial conducted in the US Pacific Northwest.

PARTICIPANTS

Veterans with PTSD due to any cause.

INTERVENTIONS

Twenty-six participants were randomised to a 12-week intervention involving either six nature hikes (n=13) or six urban hikes (n=13).

PRIMARY AND SECONDARY OUTCOME MEASURES

Feasibility was assessed based on recruitment, retention and attendance. Questionnaires and postintervention qualitative interviews were conducted to explore intervention acceptability. Questionnaires assessing acceptability and outcomes planned for the future trial (eg, PTSD symptoms) were collected at baseline, 6 weeks, 12 weeks (immediately after the final hike) and 24 weeks follow-up.

RESULTS

Of 415 people assessed for eligibility/interest, 97 were interested and passed preliminary eligibility screening, and 26 were randomised. Mean completion of all questionnaires was 91% among those in the nature hiking group and 68% in those in the urban hiking group. Over the course of the intervention, participants in the nature and urban groups attended an average of 56% and 58%, respectively, of scheduled hikes. Acceptability of both urban and nature hikes was high; over 70% reported a positive rating (ie, good/excellent) for the study communication, as well as hike locations, distance and pace. Median PTSD symptom scores (PTSD Checklist-5) improved more at 12 weeks and 24 weeks among those in the nature versus urban hiking group.

CONCLUSIONS

This pilot study largely confirmed the feasibility and acceptability of nature hiking as a potential treatment for Veterans with PTSD. Adaptations will be needed to improve recruitment and increase hike attendance for a future randomised controlled trial to effectively test and isolate the ways in which nature contact, physical activity and social support conferred by the group impact outcomes.

TRIAL REGISTRATION NUMBER

NCT03997344.

The Contribution to Stress Recovery and Attention Restoration Potential of Exposure to Urban Green Spaces in Low-Density Residential Areas

This study assessed the contributions of urban green spaces on mental health with joint consideration of people's physiological and psychological responses. The psychological and physiological responses of participants aged between 22 and 28, who visited green spaces in a low-density area of Fuzhou, Fujian Province, China, were measured using Perceived Restorativeness Scale (PRS) methods and biometric wearable sensing devices, respectively. Results showed that exposure to green space led to significant changes in PRS, electrodermal activity (EDA), facial electromyography (EMG), respiration sensor (RESP), and photoplethysmography (PPG), while there is no significant impact on skin temperature (SKT). Additionally, psychological and physiological responses were highly consistent and correlated (R < 0.8). The results also indicated that green spaces with high plant species richness, a water landscape, bumpy ground, cultural landscape, and without roadways presented a high performance on stress recovery and attention restoration. At the same time, the influence of openness was negligible in the low-density area. The study provides planners and landscape designers with specific guidance for implementing urban green spaces to improve mental health in low-density residential areas.

Implicit Associations With Nature and Urban Environments: Effects of Lower-Level Processed Image Properties

Nature experiences usually lead to restorative effects, such as positive affective states and reduced stress. Even watching nature compared to urban images, which are known to differ in several image properties that are processed at early stages, can lead to such effects. One potential pathway explaining how the visual input alone evokes restoration is that image properties processed at early stages in the visual system evoke positive associations. To study these automatic bottom-up processes and the role of lower-level visual processing involved in the restoring effects of nature, we conducted two studies. First, we analyzed nature and urban stimuli for a comprehensive set of image properties. Second, we investigated implicit associations in a dichotomous set of nature and urban images in three domains, namely, valence, mood, and stress restoration. To examine the role of lower-level processing in these associations, we also used stimuli that lacked the spatial information but retained certain image properties of the original photographs (i.e., phase-scrambled images). While original nature images were associated with “good,” “positive mood,” and “restoration,” urban images were associated with “bad” and “stress.” The results also showed that image properties differ between our nature and urban images and that they contribute to the implicit associations with valence, although spatial information and therefore recognition of the environment remained necessary for positive associations. Moreover, lower-level processed image properties seem to play no or only minor roles for associations with mood and stress restoration.

Improving Stress Management and Sleep Hygiene in Intelligent Homes

High stress levels and sleep deprivation may cause several mental or physical health issues, such as depression, impaired memory, decreased motivation, obesity, etc. The COVID-19 pandemic has produced unprecedented changes in our lives, generating significant stress, and worries about health, social isolation, employment, and finances. To this end, nowadays more than ever, it is crucial to deliver solutions that can help people to manage and control their stress, as well as to reduce sleep disturbances, so as to improve their health and overall quality of life. Technology, and in particular Ambient Intelligence Environments, can help towards that direction, when considering that they are able to understand the needs of their users, identify their behavior, learn their preferences, and act and react in their interest. This work presents two systems that have been designed and developed in the context of an Intelligent Home, namely CaLmi and HypnOS, which aim to assist users that struggle with stress and poor sleep quality, respectively. Both of the systems rely on real-time data collected by wearable devices, as well as contextual information retrieved from the ambient facilities of the Intelligent Home, so as to offer appropriate pervasive relaxation programs (CaLmi) or provide personalized insights regarding sleep hygiene (HypnOS) to the residents. This article will describe the design process that was followed, the functionality of both systems, the results of the user studies that were conducted for the evaluation of their end-user applications, and a discussion about future plans.

Do the metrics matter? An experimental investigation of Instagram influencer effects on mood and body dissatisfaction

Instagram is saturated with content from 'influencers', users who create high-quality idealised content, attain celebrity-level following, and often leverage their popularity to earn money through brand partnership/promotion. Although existing literature generally indicates the negative impact of idealised Instagram imagery on female psychological wellbeing, influencer imagery has yet to receive thorough attention. We investigated the impact of high versus low popularity influencer images on mood and body dissatisfaction. Adult women (N = 111, aged 17-40) were randomly allocated to one of three groups: either (1) the influencer-high group (idealised imagery alongside high 'like'/follow metrics); (2) the influencer-low group (the same idealised imagery adjusted for low popularity metrics); or (3) a nature control group with matched low-popularity metrics. Results revealed significantly higher negative mood and body dissatisfaction within the two influencer imagery groups compared with the control group. Interestingly, comparisons revealed no significant differences between the influencer-high and influencer-low groups on mood and body dissatisfaction. The findings suggest that users should be aware of the potentially negative impacts of viewing idealised influencer imagery, regardless of whether the content is high or low in popularity.

Restore or Get Restored: The Effect of Control on Stress Reduction and Restoration in Virtual Nature Settings

Virtual nature experiences can improve physiological and psychological well-being. Although there is ample research on the positive effects of nature, both in virtual and physical settings, we know little about potential moderators of restoration effects in virtual reality settings. According to theories of needs and control beliefs, it is plausible to assume that control over one’s actions affects how people respond to nature experiences. In this virtual reality (VR) experiment, 64 participants either actively navigated through a VR landscape or they were navigated by the experimenter. We measured their perceived stress, mood, and vitality before and after the VR experience as well as the subjective restoration outcome and the perceived restorativeness of the landscape afterwards. Results revealed that participants’ positive affective states increased after the VR experience, regardless of control. There was a main effect such that participants reported lower stress after the VR experience; however, this was qualified by an interaction showing that this result was only the case in the no control condition. These results unexpectedly suggest that active VR experiences may be more stressful than passive ones, opening pathways for future research on how handling of and navigating in VR can attenuate the effects of virtual nature.

Green nature effect on stress response and stress eating in the lab: Color versus environmental content

INTRODUCTION

It is still unclear which green nature aspects can counteract psychosocial stress: the green color or rather the environmental content (=nature). Since stress is often stimulating excess/unhealthy food intake, we hypothesize that green nature also buffers stress-induced eating. This study analyzed the effects of green/nature pictures on restorativeness, stress reactivity/response and stress eating in the lab.

METHODS

Before (5min) and after (8min) the Trier Social Stress Test, 81 participants (82% women, 19-30y) saw one of the four slideshows with nature or urban environments in green or black-white shades. Group differences were tested on Perceived Restorativeness Scale, five repeated measures of heart rate variability (HRV), salivary cortisol and mood, food wanting and snack buffet consumption.

RESULTS

The four groups did not differ in background and baseline values. Reported restorative power was higher in the nature pictures than urban pictures with an even better attentional/happiness restoration capacity for green versus black-white nature, while green urban pictures might induce more stress feelings than black-white urban pictures. The stress time patterns confirmed successful stress induction. Most consistent during stress induction was a higher happiness recovery in the green nature group. Nature overall was somewhat beneficial compared to urban pictures by lower HRV and negative emotions reactivity, although this might be due to unfavorable effects of green urban pictures. In food intake or wanting, no differences existed.

CONCLUSION

Nature pictures were estimated higher in restorative power and green nature pictures had a positive effect on happiness recovery. Thus for prevention, the environmental content (=nature) as such seems important while just a green color seemed not enough. Future research should examine the effect of green nature in realistic indoor settings and consider influence on fruit/vegetable intake instead of solely snacks.

Virtual Reality Relaxation for Patients With a Psychiatric Disorder: Crossover Randomized Controlled Trial

Background

Virtual reality (VR) relaxation is a promising mental health intervention that may be an effective tool for stress reduction but has hardly been tested in clinical trials with psychiatric patients. We developed an easy-to-use VR self-management relaxation tool (VRelax) with immersive 360° nature videos and interactive animated elements.

Objective

To investigate the immediate effects of VR relaxation on negative and positive affective states and short-term effects on perceived stress and symptoms in patients with a psychiatric disorder, compared to standard relaxation exercises.

Methods

A randomized crossover trial was conducted in 50 patients receiving ambulatory treatment for anxiety, psychotic, depressive, or bipolar disorder. Participants were randomly assigned to start with VRelax or standard relaxation and used both interventions for 10 days at home. They completed 8 visual analog scales of momentary negative and positive affective states before and after each session. Global perceived stress and psychiatric symptoms were measured before and after both intervention periods. Treatment effects were analyzed with multilevel mixed model regression analyses and 2-way analysis of variance.

Results

Both VRelax and standard relaxation exercises led to a statistically significant immediate improvement of all negative and positive affective states. Compared to standard relaxation, VRelax resulted in a significantly greater reduction of total negative affective state (change 16.2% versus 21.2%; t₁₆₈₄=−2.02, 95% CI −18.70 to −0.28; P=.04). Specifically, VRelax had a stronger beneficial effect on momentary anxiety (t₁₆₈₄=−3.24, 95% CI −6.86 to −1.69), sadness (t₁₆₈₄=−2.32, 95% CI −6.51 to −0.55), and cheerfulness (t₁₆₈₄=2.35, 95% CI 0.51 to 5.75). There were no significant differences between short-term effects of the two treatments on global perceived stress and symptoms.

Conclusions

If the results of this trial are replicated and extended, VRelax may provide a much-needed, effective, easy-to-use self-management relaxation intervention to enhance psychiatric treatments.

Trial Registration

Netherlands Trial Register NTR7294; https://www.trialregister.nl/trial/7096

Brief Relaxation Practice Induces Significantly More Prefrontal Cortex Activation during Arithmetic Tasks Comparing to Viewing Greenery Images as Revealed by Functional Near-Infrared Spectroscopy (fNIRS)

Background: There is little understanding on how brief relaxation practice and viewing greenery images would affect brain responses during cognitive tasks. In the present study, we examined the variation in brain activation of the prefrontal cortex during arithmetic tasks before and after viewing greenery images, brief relaxation practice, and control task using functional near-infrared spectroscopy (fNIRS). Method: This randomized controlled study examined the activation patterns of the prefrontal cortex (PFC) in three groups of research participants who were exposed to viewing greenery images (n = 10), brief relaxation practice (n = 10), and control task (n = 11). The activation pattern of the PFC was measured pre- and post-intervention using a portable fNIRS device and reported as mean total oxygenated hemoglobin (HbO μm). Primary outcome of the study is the difference in HbO μm between post- and pre-intervention readings during a cognitive task that required the research participants to perform arithmetic calculation. Results: In terms of intervention-related differences, there was significant difference in average HbO μm when performing arithmetic tasks before and after brief relaxation practice (p < 0.05). There were significant increases in average HbO μm in the right frontopolar cortex (p = 0.029), the left frontopolar cortex (p = 0.01), and the left orbitofrontal cortex (p = 0.033) during arithmetic tasks after brief relaxation practice. In contrast, there were no significant differences in average HbO μm when performing arithmetic tasks before and after viewing greenery images (p > 0.05) and the control task (p > 0.05). Conclusion: Our preliminary findings show that brief relaxation practice but not viewing greenery images led to significant frontal lobe activation during arithmetic tasks. The present study demonstrated, for the first time, that there was an increase in activation in neuroanatomical areas including the combined effort of allocation of attentional resources, exploration, and memory performance after the brief relaxation practice. Our findings suggest the possibility that the right frontopolar cortex, the left frontopolar cortex, and the left orbitofrontal cortex may be specifically associated with the benefits of brief relaxation on the brain.

Effect of nature exposure on perceived and physiologic stress: A systematic review

OBJECTIVE

The purpose of this systematic review is to evaluate the effect nature exposure has on stress as measured by physiologic markers and self-report.

DESIGN

Researchers searched PubMed and JSTOR. Randomized control trials and cross-sectional studies were included if they met the following criteria: 1) included a clinical cohort and controls, and the intervention was nature exposure, either real or simulated; (2) utilized measurements of sympathetic activity or perceived stress; (3) study population consisted of greater than thirty male and female volunteers. Twelve studies were included for data extraction and review.

SETTING

Researchers conducted this review at University of South Florida Morsani College of Medicine.

MAIN OUTCOME MEASURES

Researchers measured perceived stress through the Perceived Stress Scale (PSS) and Depression, Anxiety, and Stress Scale (DASS). Physiologic stress was measured by salivary cortisol, blood pressure (BP), subgenual prefrontal cortex (sgPFC) activation on functional magnetic resonance imaging (fMRI), skin conductance level (SCL), heart rate variability (HRV), muscle tension, heart period, pulse transit time, amygdala and pregenual anterior cingulate cortex (pACC) activation on fMRI, respiratory sinus arrhythmia (RSA), and pre-ejection period (PEP).

RESULTS

This review found an inverse relationship between nature exposure and various physiologic markers of stress in all 7 studies measuring physiologic stress. Perceived stress was also affected by higher exposure to nature as indicated by lower self-reports on the PSS and DASS in 5 out of 6 studies measuring perceived stress.

CONCLUSIONS

Nature exposure has been widely shown to have a positive effect in reducing stress, both perceived and physiologic.

[Improving parasympathetic functioning to contain the inflammatory response of COVID-19 infection]

COVID-19 infection results in an unrestrained inflammatory reaction in serious cases. The autonomic nervous system (ANS), in particular the parasympathetic branch, helps to regulate the inflammatory response. A dysfunction of this branch, frequent in people at risk of developing COVID-19, favours a pro-inflammatory effect. Reinforcing and stimulating the parasympathetic ANS is possible and accessible to paramedical and medical professionals.

Associations Between Child Maltreatment, Autonomic Regulation, and Adverse Cardiovascular Outcome in an Urban Population: The HELIUS Study

INTRODUCTION

A mounting body of literature emphasizes the potential negative effects of adverse childhood experiences (ACEs) on both mental and physical health throughout life, including an increased risk for developing cardiovascular disease (CVD). Since CVD is one of the leading causes of mortality and morbidity worldwide, it is of great importance to advance our understanding of the effects of on CVD. This holds both for the actual incidence and for intermediate biological pathways that may convey CVD risk, such as imbalance in autonomic nervous system regulation, resulting in a chronically heightened sympathetic activity and lowered reactivity. In a large urban, multi-ethnic population-based cohort study we investigated whether there is an association between child maltreatment, CVD incidence and autonomic regulation.

METHODS

Within the Health in an Urban Setting (HELIUS) study, a large, multi-ethnic population cohort study including n = 22,165 Amsterdam residents, we used logistic regression analyses to investigate the association between the number of self-reported types of child maltreatment (range 0-4), and self-reported adverse cardiovascular outcome (aCVO). Self-reported child maltreatment included emotional neglect, emotional abuse, physical abuse, and sexual abuse. Furthermore, in a subsample (n = 10,260), mean age 44.3, we investigated associations between child maltreatment, autonomic regulation, and aCVO using linear regression analyses. Both baroreflex sensitivity (BRS) and heart rate variability (HRV) were assessed as non-invasive indices of autonomic regulation.

RESULTS

The number of endorsed child maltreatment types was significantly associated with a higher aCVO risk. The association remained significant after adjustment for demographic, socioeconomic, health-behavioral, and psychological covariates (p = 0.011, odds ratio: 1.078, confidence interval: 1.018-1.142). The cumulative exposure to child maltreatment was negatively associated with BRS and HRV, but the association was no longer significant after correction for socioeconomic and demographic covariates.

CONCLUSION

In a large, multi-ethnic urban-population cohort study we observed a positive association between number of endorsed child maltreatment types and self-reported aCVO but not autonomic regulation, over and above the effect of relevant demographic, health, and psychological factors. Future studies should examine the potential role of the dynamics of autonomic dysregulation as potential underlying biological pathways in the association between ACEs and CVD, as this could eventually facilitate the development of preventive and therapeutic strategies for CVD.

Effects of biophilic indoor environment on stress and anxiety recovery: A between-subjects experiment in virtual reality

Previous research has demonstrated the positive associations between outdoor nature contact and stress reduction. However, similar effects of incorporating natural elements into indoor environment (i.e. biophilic design) have been less well studied. We hypothesize that exposure to biophilic indoor environments help people recover from stress and anxiety and those effects differ among different types of biophilic elements. To test these hypotheses, we conducted a between-subjects experiment with 100 participants using virtual reality (VR). Participants were randomly assigned to experience one of four virtual offices (i.e. one non-biophilic base office and three similar offices enhanced with different biophilic design elements) after stressor tasks. Their physiological indicators of stress reaction, including heart rate variability, heart rate, skin conductance level and blood pressure, were measured by bio-monitoring sensors. Their anxiety level was measured by using State-Trait Anxiety Inventory test (short version). We found that participants in biophilic indoor environments had consistently better recovery responses after stressor compare to those in the non-biophilic environment, in terms of reduction on stress and anxiety. Effects on physiological responses are immediate after exposure to biophilic environments with the larger impacts in the first four minutes of the 6-minute recovery process. Additionally, these restorative effects differ among three different types of indoor biophilic environments. This research provides evidence that biophilic design elements that impact stress recovery and anxiety. It also demonstrated the potential that virtual reality may be a way to bring nature and its therapeutic benefits to patients in hospitals.

Urban-level environmental factors related to pediatric asthma

During the 20th century, urbanization has increasing and represented a major demographic and environmental change in developed countries. This ever-changing urban environment has an impact on disease patterns and prevalence, namely on noncommunicable diseases, such as asthma and allergy, and poses many challenges to understand the relationship between the changing urban environment and the children health. The complex interaction between human beings and urbanization is dependent not only on individual determinants such as sex, age, social or economic resources, and lifestyles and behaviors, but also on environment, including air pollution, indoors and outdoors, land use, biodiversity, and handiness of green areas. Therefore, the assessment and identification of the impact of urban environment on children's health have become a priority and many recent studies have been conducted with the goal of better understanding the impacts related to urbanization, characterizing indoor air exposure, identifying types of neighborhoods, or characteristics of neighborhoods that promote health benefits. Thus, this review focuses on the role of urban environmental factors on pediatric asthma.

Physiological Benefits of Viewing Nature: A Systematic Review of Indoor Experiments

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.

Effects of biophilic interventions in office on stress reaction and cognitive function: A randomized crossover study in virtual reality

Biophilia hypothesis suggests humans have an innate connection to nature which may affect our health and productivity. Yet we currently live in a world that is rapidly urbanizing with people spending most of their time indoors. We designed a randomized crossover study to let 30 participants experience three versions of biophilic design in simulated open and enclosed office spaces in virtual reality (VR). Throughout the VR session, we measured blood pressure, heart rate, heart rate variability, and skin conductance level and administered cognitive tests to measure their reaction time and creativity. Compared to the base case, participants in three spaces with biophilic elements had consistently lower level of physiological stress indicators and higher creativity scores. In addition, we captured the variation in the intensity of virtual exposure to biophilic elements by using eye-tracking technology. These results suggest that biophilic interventions could help reduce stress and improve creativity. Moreover, those effects are related to both the types of biophilic elements and may be different based on the workspace type (open vs enclosed). This research demonstrates that VR-simulated office spaces are useful in differentiating responses to two configurations and among biophilic elements.

Is urban living good for mental health?

PURPOSE OF REVIEW

The questions of urban living, mental health and well-being are complex issues correlated to many interacting factors. The purpose of this review is to provide data on mental health challenges of urban life and perspectives to address these challenges.

RECENT FINDINGS

Urbanization may cause mental health problems, such as psychotic experiences, depression and stress-related disorders, particularly in vulnerable individuals. Challenges of urban living are even greater in developing countries, because of other urgent problems these countries are facing. New findings identified distinct neural mechanisms for an established environmental risk factor, linking the urban environment to social stress processing. Nature-based solutions may be helpful in preventing mental disorders and in alleviating psychological symptoms.

SUMMARY

The data of impact of urban living on mental health are still controversial and mechanism of association is unclear. Urban living may be related to biological or social/environmental factors or both. Most probably, urbanicity has a synergistic effect with genetic vulnerability. Interdisciplinary and intersectoral actions are needed to meet urban living challenges, such as providing access to green space and mental health services, decrease of poverty, homelessness and emerging problems of immigration to cities.

Growing Resilience through Interaction with Nature: Can Group Walks in Nature Buffer the Effects of Stressful Life Events on Mental Health?

Nature-based activities have been used as therapeutic interventions for those experiencing stress and mental ill health. This study investigates whether group walks could be a nature-based intervention to foster resilience, by buffering the effects of recent stressful life events on mental health. An observational research design with propensity score-matched samples compared the mental health of individuals who did (Nature Group Walkers, n = 1081) or did not (Non-Group Walkers, n = 435) attend nature group walks. A sub-sample of Frequent Nature Group Walkers (at least once per week, n = 631) was also investigated. Data were analyzed using multiple regression with an interaction term. All analyses were controlled for age, gender, and recent physical activity. Results showed that neither nature group walking, nor doing this frequently, moderated the effects of stressful life events on mental health. Using a main effects model, the positive associations of group walks in nature were at a greater magnitude than the negative associations of stressful life events on depression, positive affect, and mental well-being, suggesting an 'undoing' effect of nature group walks. Group walking schemes in natural environments may be an important public health promotion intervention for mental health.

Neuroscience and Sustainability: An Online Module on "Environmental Neuroscience"

Neuroscience has extensive and vital applications to environmental sustainability that have yet to be fully integrated into undergraduate education: The neurotoxicity of common chemicals and the health dangers of anthropogenic sensory noise are well known. Research on the neural bases for value-based decision making has implications for pro-environmental efforts. Neural and sensory responses to nature exposure show health benefits of such 'green' experiences. Despite these implications, the term "environmental neuroscience", in sharp contrast to "environmental psychology", is virtually unheard of in undergraduate education. Here we present a model for explicitly integrating environmentally-relevant neuroscience content into an undergraduate class without sacrificing its standard range of materials. Students completed a stand-alone online "Environmental Neuroscience Module" by reading and reflectively writing about popular science articles on environmentally-applied neuroscience issues. Results show that students saw the module as enhancing their understanding of class material and their application of neuroscience to sustainability and their lives. Students showed better performance on a knowledge test of environmental neuroscience relative to a control group. They also showed higher self-ratings of connectedness to nature, a robust predictor of eco-friendly behaviors. The module might thus serve as an efficient model for enriching neuroscience education through environmental applications while also fostering its contribution to sustainability efforts. Our approach might also point to novel ways of integrating neuroscience with disciplines like environmental studies and of reaching a diverse student body by teaching neuroscience in the context of important societal issues.

A comparison of the effects of selected mono-ethnic urban environments on the autonomic functions of Muslim and Jewish women in Israel

Few previous studies evaluated ethnic differences in the effects of urban environments on the autonomic balance in intra-ethnic environments and the mediation effects of environmental exposures (air pollution, noise, and thermal load). In a field experimental study, we exposed 48 Muslim and 24 Jewish women to park, town center, and residential street in Israeli mono-ethnic small towns. Heart rate variability (HRV), noise, thermal load, and carbon monoxide (CO) were measured by portable devices while visiting the environments and were analyzed using mixed models. The results highlight the restorative effect of parks on both ethnic groups with stronger effect for Jewish women compared to Muslim women (β coefficient (95% confidence interval (CI)): - 6.45(- 6.70, - 6.20); - 4.99 (- 5.15, - 4.83), respectively). However, significant differences were recorded in Muslim and Jewish coping with the environments and the environmental exposures as measured by HRV.

The influence of various distractions prior to upper gastrointestinal endoscopy: a prospective randomized controlled study

BACKGROUND

Although many patients still have anxiety about upper gastrointestinal (GI) endoscopy, there have been few reports on the influence of distractions for a person who is going to undergo upper GI endoscopy soon. This study was a prospective randomized controlled study investigating the influence of distractions, such as auditive and visual distractions using subjective and objective assessments including autonomic nervous function prior to upper GI endoscopy.

METHODS

206 subjects who underwent upper GI endoscopy as regular health check-ups were divided randomly into 4 groups prior to upper GI endoscopy; group 1 (control group), group 2 (auditive group), group 3 (visual group), and group 4 (combination group). We measured vital signs, autonomic nervous function, profile of mood state (POMS), and the impression for upper GI endoscopy pre- and post-distraction in the 4 groups.

RESULTS

There was no significant difference in vital signs between 5 and 15 min after sitting in group 1, however, several vital signs in all distraction groups improved significantly after distraction (Pulse rate (P): p <  0.001 in group 4; blood pressure: p <  0.05 in group 2, 3, 4) and the rate of decrease in P and diastolic blood pressure was highest in group 4 (p <  0.001). Several scores of POMS and the impression for upper GI endoscopy post-distraction improved significantly compared to pre-distraction between distraction groups and the satisfaction for distraction was highest in group 4 (p <  0.01). Regarding autonomic nerve function, the low- frequency power/ high- frequency power ratio post-distraction was significantly lower than that pre-distraction in all distraction groups (p <  0.001).

CONCLUSIONS

Although auditive distraction alone and visual distraction alone were effective, a combination distraction was more effective than any other distraction by subjective and objective assessments. These distractions, which were simple and safe, may play an assistive role in the stability of physical and psychological conditions prior to upper GI endoscopy.

TRIAL REGISTRATION

This trial was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000022801 . Registered on 10 July 2016.

Forest-based Therapy: Research Letter of a Novel Regime for Improved Respiratory Health

Nature-based therapies are well documented. However, forest-based therapy for respiratory health is still an innovative treatment. Our subject reports respiratory problems and forest walking, suggesting that improved respiratory health may be another positive outcome of forest-based therapies, when associated with activities that increase parasympathetic activity.