Therapeutic effect of forest bathing on human hypertension in the elderly

Nature-based interventions for physical health conditions: A systematic review and meta-analysis

Nature-based interventions (NBIs) are activities, strategies, or programs taking place in natural settings, such as exercising in greenspaces, to improve the health and well-being of people by integrating the benefits of nature exposure with healthy behaviours. Current reviews on NBIs do not report the effects on different groups of physical health conditions. The purpose of this systematic review and meta-analysis was to identify and synthesize the evidence of the effect of NBIs on physical health outcomes and biomarkers of physical health conditions. Overall, 20,201 studies were identified through searching MEDLINE, Embase, CINAHL, SPORTDiscus, and CENTRAL databases up to June 7, 2024. Inclusion criteria were: 1) randomized controlled intervention studies; 2) population with a physical health condition; 3) NBIs vs. different intervention or no intervention; and 4) measuring physical health outcomes and/or biomarkers. Twenty-six studies were included in the review, 15 of which contributed to the meta-analysis. Compared to control groups, NBIs groups showed significant improvements in: diastolic blood pressure (MD -3.73 mmHg [-7.46 to -0.00], I2 = 62%) and heart rate (MD -7.44 bpm [-14.81 to -0.06], I2 = 0%) for cardiovascular conditions, fatigue (SMD -0.50 [-0.82 to -0.18], I2 = 16%) for central nervous system conditions, and body fat percentage (MD -3.61% [-5.05 to -2.17], I2 = 0%) for endocrine conditions. High effect heterogeneity was found in several analyses and the included studies had moderate-to-high risk of bias (RoB). The non-significant outcomes showed a direction of effect in favour of NBI groups for cardiovascular, central nervous system, endocrine, musculoskeletal, and respiratory conditions. This review found some beneficial effects in favour of NBIs for health outcomes in at least three condition groups though RoB and inconsistent effects limited some interpretations. NBIs are promising therapies that healthcare professionals can consider integrating into clinical practice.

The effect of forest-based health and wellness on the stress-relieve of middle-aged people

In order to explore the impact of experience in forest-based health and wellness (FHW) on the stress of middle-aged people, 12 participants aged 35-39 were selected to conduct a 3-day/2-night study on FHW experience in Wencheng, Wenzhou. Huawei bracelets were used to monitor participants' movement, pulse and blood pressure and their mood state was measured before and after the health care experience using the Profile of Mood States (POMS) scale. After the FHW experience, the lowest value of bracelet stress appeared on the second day of the experience for men and women. The total mood disturbance (TMD) decreased by 38.8 points on average, which significantly improved the positive mood and relieved the stress. The decompression effect of the FHW experience showed some variability among individuals. Furthermore, there were gender differences in alleviation of fatigue and puzzlement, which was greater for females than males.

Greenspaces And Cardiovascular Health

Accumulating evidence suggests that living in areas of high surrounding greenness or even brief exposures to areas of high greenery is conducive to cardiovascular health, which may be related to the environmental, social, psychological, and physiological benefits of greenspaces. Recent data from multiple cross-sectional, longitudinal, and cohort studies suggest that living in areas of high surrounding greenness is associated with a lower risk of all-cause and cardiovascular mortality. High levels of neighborhood greenery have been linked also to a decrease in the burden of cardiovascular disease risk factors as reflected by lower rates of hypertension, dyslipidemia, and diabetes. Those who live in greener environments report better mental health and more frequent social interactions, which can benefit cardiovascular health as well. In this narrative review, we discuss evidence linking greenspaces to cardiovascular health as well as the potential mechanisms underlying the beneficial effects of greenspaces, including the impact of vegetation on air, noise and light pollution, ambient temperature, physical activity, mental health, and biodiversity. We review literature on the beneficial effects of acute and chronic exposure to nature on cardiovascular disease risk factors, inflammation and immune function, and we highlight the potential cardiovascular effects of biogenic volatile organic compounds that are emitted by trees and shrubs. We identify current knowledge gaps in this area and underscore the need for additional population studies to understand more clearly and precisely the link between greenness and health. Such understanding is urgently needed to fully redeem the promise of greenspaces in preventing adverse environmental exposures, mitigating the effects of climate change, and creating healthier living environments.

Effects of forest walking on physical and mental health in elderly populations: a systematic review

There is a growing awareness that spending time in nature is associated with improvement of well-being; nevertheless, the prescription of forest bathing is still limited. The aim of this systematic review was to explore the physiological and psychological benefits of different forest therapies on healthy and pathological elderly populations (>60 years) to identify the most-effective type, duration, and frequency of these interventions. A search for literature was carried out in December 2021 using PubMed, EMBASE, ResearchGate, Google Scholar and Web of Science. Grey literature was searched as well. After removal of the duplicates, within the 214 articles identified, ten met the inclusion criteria. The methodological quality of the selected studies was rated. Forest walking, alone and in combination with other activities is the most effective intervention. The selected studies reported a positive impact on physical components, including reduction in blood pressure and heart rate and improvements in cardiopulmonary and neurochemical parameters. Favorable modifications have also been noted in the psychological field, with improvements in depression, stress levels and in quality of life perception. In conclusion, forest walking may play an important role in promoting physical and mental health in healthy and pathological elderly populations. However, the lack of high-quality studies limits the strength of the results, calling for more trials.

Exposure to green spaces, cardiovascular risk biomarkers and incident cardiovascular disease in older adults: The Seniors-Enrica II cohort

INTRODUCTION

The impact of residential green spaces on cardiovascular health in older adults remains uncertain.

METHODS

Cohort study involving 2114 adults aged ≥ 65 years without cardiovascular disease (CVD), residing in five dense municipalities (Prince et al., 2015) of the Madrid region and with detailed characterization of their socioeconomic background, health behaviors, CVD biological risk factors, and mental, physical, and cognitive health. Greenness exposure was measured using the Normalized Difference Vegetation Index (NDVI) at varying distances from participants' homes. Traffic exposure, neighborhood environment, neighborhood walkability, and socioeconomic deprivation at the census level were also assessed. Serum N-terminal pro-B-type natriuretic peptide (NT-ProBNP), high-sensitivity troponin T (hs-TnT), interleukin 6 (IL-6), and Growth Differentiation Factor 15 (GDF-15) were measured at baseline, and incident CVD events identified through electronic medical records (International Classification of Primary Care-2 codes K74, K75, K77, K90, and K92).

RESULTS

After adjusting for sex, age, educational attainment, financial hardship and socioeconomic deprivation at the census level, an interquartile range (IQR) increase in NDVI at 250, 500, 750, and 1000 m around participants' homes was associated with mean differences in ProBNP of -5.56 % (95 %CI: -9.77; -1.35), -5.05 % (-9.58; -0.53), -4.24 % (-8.19, -0.19), and -4.16 % (-7.59; -0.74), respectively; and mean differences in hs-TnT among diabetic participants of -8.03 % (95 %CI: -13.30; -2.77), -9.52 % (-16.08; -2.96), -8.05 % (-13.94, -2.16) and -5.56 % (-10.75; -0.54), respectively. Of similar magnitude, although only statistically significant at 250 and 500 m, were the observed lower IL-6 levels with increasing greenness. GDF-15 levels were independent of NDVI. In prospective analyses (median follow-up 6.29 years), an IQR increase in residential greenness at 500, 750, and 1000 m was associated with a lower risk of incident CVD. The variables that contributed most to the apparent beneficial effects of greenness on CVD were lower exposure to traffic, improved cardiovascular risk factors, and enhanced physical performance. Additionally, neighborhood walkability and increased physical activity were notable contributors among individuals with diabetes.

CONCLUSION

Increased exposure to residential green space was associated with a moderate reduction in CVD risk in older adults residing in densely populated areas.

Green space and stroke: A scoping review of the evidence

BACKGROUND

Global industrialisation and urbanisation has led to an increased interest in the link between the environment and health. Stroke is a major cause of morbidity and mortality, and there is increased evidence that environmental factors may affect both the incidence and severity of stroke. This review summarises the evidence for relationship between green space exposure and stroke incidence and outcomes.

METHODS

We conducted a literature search in Medline and Scopus until 1 August 2023, and screened references of relevant articles. Selected articles were appraised for their relevance, and critically reviewed. The findings were thematically categorised.

RESULTS

Of the 1342 papers identified, 27 were included. These involved a mix of study designs (cohort, cross-sectional, quasi-experimental, time stratified case crossover and ecological). There was consistent evidence indicating a protective association between green space exposure and disability and stroke-related death with mortality hazard ratios between 0.66 and 0.95. Most studies also showed that green space was inversely associated with stroke risk, with risk estimates from studies showing a protective effect ranging between 0.4 and 0.98; however, results were more mixed and some did not reach statistical significance. The moderating effects of green spaces on ambient temperatures, noise and air pollution, and psychosocial health plus greater enjoyment and opportunity for exercise and enrichment of the human microbiome may underly these associations.

CONCLUSION

There is likely some protective effect of green space on stroke, with the benefits most convincingly shown for post-stroke outcomes. More research is recommended to confirm the protective association between green space exposure and reduced stroke risk.

Effects of Nature-Based Multisensory Stimulation on Pain Mechanisms in Women with Fibromyalgia Syndrome: A Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND

The term "nature-based sensory stimuli" refers to the sensory information produced by biotic and abiotic agents from natural environments. The literature has reported the beneficial effects of these agents on various pain dimensions in non-clinical populations.

AIMS

To evaluate the potential analgesic effects of nature-based multisensory stimulation in women with fibromyalgia syndrome.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group trial with a 1:1 allocation ratio was conducted. Forty-two women with fibromyalgia syndrome interacted with either different plant species with flowers, stones, and soil organic matter or their synthetic imitations for 30 minutes. Outcome measurements were performed before and after the intervention, including clinical pain intensity using the Numeric Rating Scale, cold pain thresholds using the Cold Pressor Test, mechanical hyperalgesia and wind-up using a monofilament, and pressure pain thresholds using a pressure algometer.

RESULTS

Analyses revealed group × time interactions for clinical pain intensity (F = 7.915, p = .008), cold-water immersion time (F = 7.271, p = .010), mechanical hyperalgesia (F = 4.701, p = .036), and pressure pain threshold (p ≤ .017). Between-group differences were found in clinical pain intensity (p = .012), cold pain thresholds (p = .002), and pressure pain thresholds (p < .05). The experimental group exhibited reduced clinical pain intensity (p = .001) and increased pressure pain thresholds (p ≤ .034).

CONCLUSIONS

Women with fibromyalgia syndrome may benefit from multisensory stimulation using biotic and abiotic agents from natural environments for 30 minutes. Interacting with flowering plants and soil components appears to induce analgesic effects.

Nature-Based Interventions Targeting Elderly People's Health and Well-Being: An Evidence Map

BACKGROUND

Healthy aging encompasses more than the absence of disease, emphasizing the preservation of functional abilities for enhanced well-being and quality of life. Nature-based interventions are scientifically proven contributors to healthy aging.

OBJECTIVE

To develop an evidence map showcasing nature-based interventions targeting older individuals' health and well-being.

METHODS

The evidence map was developed through critical analysis of systematic reviews and clinical trials utilizing the tools AMSTAR2 and CONSORT. A systematic search spanning the past decade was conducted across databases: Cochrane, SCOPUS, PubMed, Web of Science, Embase, and LILACS.

RESULTS

Twelve articles met the eligibility criteria. Nature-based interventions such as forest bathing, hiking, therapeutic gardens, virtual reality, and forest sounds were identified. Outcomes were categorized into physical aspects (cardiovascular and pulmonary; neuro-immuno-endocrinological) and mental/behavioral aspects. The final map integrated interventions, outcomes, and quality assessments.

CONCLUSIONS

The survey highlights the positive impact of nature-based interventions on the health of the elderly. This study provides insights across various domains, fostering the development of programs and policies in management to promote healthy aging. Regarding healthcare, it encourages discourse among professionals regarding the integration of nature-based practices for equitable care in both individual and group settings. Furthermore, it underscores the need for research in the Southern Hemisphere, particularly in Brazil, where the study was conducted.

Explore the effects of forest travel activities on university students' stress affection

This study aims to explore the effects of forest travel activities on university students' stress affection. Forty volunteer university students participated in this study. All participants were asked to complete physiological (Heart Rate Variability) and psychological (Brief Profile of Mood State and State-Trait Anxiety Inventory) tests before and after the travel activities. The results reported that students' heart rates were significantly lower after the forest travel activities than before. All domains of negative mood and anxiety decreased from the pre-test to the post-test. This study found that university students could feel less stressed if they went on forest travel activities.

Adaptive outdoor physical activities for adults with mobility disability: a scoping review

Introduction

Outdoor physical activity (PA) contributes to the physical and mental health and well-being of individuals with a mobility impairment. However, individuals are commonly excluded from outdoor PA because of accessibility challenges. No reviews summarizing evidence on factors that facilitate/hinder participation and inclusion of individuals with mobility disabilities in adaptive outdoor PA were identified.. This makes it challenging to establish the key components for implementing inclusive outdoor PA interventions. A scoping review was conducted to identify barriers and facilitators to participation in adaptive outdoor PA and identify suggestions for adaptive outdoor PA design.

Methods

A scoping review of qualitative and quantitative studies was conducted based on the methodological framework of Arksey and O'Malley with modifications by Levac. Barriers and facilitators were categorized into four levels based on a Social Ecological Model (SEM). Suggestions for interventions designed to overcome accessibility issues of outdoor PA were classified based on Universal Design (UD).

Results

Thirty-seven factors regarding barriers and facilitators of outdoor adaptive PA were extracted from 19 studies published between 2002 and 2023. Barriers and facilitators were identified primarily in four levels of the SEM, including intrapersonal, social-environmental, physical-environmental, and policy-related. Eleven design suggestions were identified and categorized according to the seven principles of UD. This study identified gaps in the presented barriers and facilitators and the design suggestions of the included studies, mainly at the social and environmental level, such as a lack of innovation in program delivery and logistics.

Conclusion

This study identified gaps in knowledge about facilitators and barriers to outdoor adaptive PA and in the design of interventions addressing them. Future research should focus on the strategies addressing these gaps by involving individuals with mobility disability in designing interventions to gain a better insight into their needs.

Forest Bathing Increases Adolescents' Mental Well-Being: A Mixed-Methods Study

Previous research has demonstrated that practicing forest bathing has significant positive effects on adult psychological well-being. Considering the ongoing adolescents' mental health crisis of increasing anxiety and depression, determining whether forest bathing has similar effects on adolescents is an important expansion of forest bathing research. This study investigated the possibility that forest bathing could improve adolescents' mental well-being and sought to determine participants' experiences of forest bathing. It used a convergent, parallel, mixed-methods design that was partially co-created with 24 participants aged 16-18 as part of a youth participatory action research (YPAR) project in which participants practiced forest bathing three times over 3 weeks. As measured using the Warwick-Edinburgh Mental Well-Being Survey, the mean participant mental well-being increased significantly after forest bathing, with moderate to large effect sizes. Participants described reduced stress and increased feelings of relaxation, peace, and happiness. These findings correlate with previous forest bathing research involving adult participants. It is recommended that educators and others who work with adolescents consider forest bathing as a simple, low-cost way to improve adolescents' mental well-being.

Effects of Linpan nature therapy on health benefits in older women with and without hypertension

Background

Nature therapy can significantly benefit the physiology and psychology of middle-aged and older people, but previous studies have focused on forest environments. The restoration potential of rural environments in urban fringe areas, which are more accessible to older people on a daily basis, has not been fully studied. This study assessed the effects of nature therapy on the physical and mental health of older women in a rural setting (locally known as Linpan) in the urban fringe area of Chengdu, China.

Methods

We recruited a total of 60 older women (65.3 ± 5.5 years old) living in cities for 3 days of nature therapy in the winter (30 subjects) and spring (30 subjects), including 20 hypertensive patients.

Results

The results showed that the overall blood pressure, pulse and sleep dysfunction rating scores of the participants were significantly lower than the pretest levels, and the finger blood oxygen saturation, mid-day salivary alpha-amylase and cortisol were increased post-treatment. Increases in these biomarker indicates and increase in stress. There were significant differences in the changes in systolic blood pressure between the hypertension group (HTN) and the normal group (normal) (HTN decreased by 8.8%, normal decreased by 5.4%), salivary alpha-amylase content (HTN decreased by 0.3%, normal increased by 16.9%), and sleep dysfunction rating scores (HTN decreased by 59.6%, normal decreased by 54%). The decreases in systolic blood pressure and pulse in the winter group were higher than those in the spring group by 1.8 and 4.4%, respectively, while the increases in salivary alpha-amylase content and salivary cortisol content were lower than those in the spring group by 11.7 and 11.2%, respectively, and the decrease in sleep dysfunction rating scores was lower than that in the spring group by 7.1%.

Conclusion

Our study concluded that nature therapy based on various health activities in the Linpan has significant health effects on older women. It can regulate blood pressure and pulse in older women, relieve cardiovascular disease, improve sleep quality. Meanwhile, older women with high blood pressure experienced a more significant effect than the healthy group.

Health effects of green prescription: A systematic review of randomized controlled trials

An increasing number of studies have examined the effects of green prescription on various health outcomes. The aim of this study was to systematically review published randomized controlled trial studies on the health benefits of green prescriptions. We searched PubMed, Scopus, and Web of Science for the relevant original articles published in English until June 30, 2023. Our search initially retrieved 26176 articles, of which 31 studies were included in our review after removing the duplicates and excluding ineligible articles based on their titles, abstracts, and full-text review. Consistent positive health benefits of green prescription were reported for psychological health and wellbeing (16 out of 24 studies), cardiometabolic health (five out of nine studies), physical activity (eight out of nine studies), and inflammation (two out of two studies). The reviewed studies did not report any significant benefits in orthopedic conditions, pain, and recovery from exhaustion disorder due to their implemented green prescriptions; however, the number of studies was too small to generalize the effect of green prescriptions on these outcomes. The quality of these studies was generally acceptable, with 28 studies having some concerns regarding their overall risk of bias and only three studies with a high risk of bias. All in all, this systematic review suggests that green prescriptions can be effective in improving various health outcomes, but further studies with larger sample sizes and objective measures are needed.

Impact of Environmental Factors on Hypertension and Associated Cardiovascular Disease

Hypertension is the primary cause of cardiovascular diseases and is responsible for nearly 9 million deaths worldwide annually. Increasing evidence indicates that in addition to pathophysiologic processes, numerous environmental factors, such as geographic location, lifestyle choices, socioeconomic status, and cultural practices, influence the risk, progression, and severity of hypertension, even in the absence of genetic risk factors. In this review, we discuss the impact of some environmental determinants on hypertension. We focus on clinical data from large population studies and discuss some potential molecular and cellular mechanisms. We highlight how these environmental determinants are interconnected, as small changes in one factor might affect others, and further affect cardiovascular health. In addition, we discuss the crucial impact of socioeconomic factors and how these determinants influence diverse communities with economic disparities. Finally, we address opportunities and challenges for new research to address gaps in knowledge on understanding molecular mechanisms whereby environmental factors influence development of hypertension and associated cardiovascular disease.

Bibliometric Analysis of Nature-Based Therapy Research

Unrestrained urbanisation and natural space loss are reducing contact with nature in today's society, producing negative consequences for people's mental and physical health and wellbeing. Nature-based therapies, such as physical activity in natural settings, forest bathing, therapeutic hiking, or experiential learning, reduce anxiety and depressive symptoms and improve the quality of life in both general and specific populations. A bibliometric analysis of research on nature-based therapies was performed by applying the traditional laws of bibliometrics (exponential growth law, Bradford's concentration law, Lotka's law, Zipf's law, etc.) to documents published in journals indexed in the Core Collection of the Web of Science (WoS). Graphical visualisation was performed using the VOSviewer software. Annual publications between 2006 and 2021 presented an exponential growth trend (R² = 91%). The International Journal of Environmental Research and Public Health (MDPI) and Urban Forestry & Urban Greening (Elsevier) were the most productive and cited journals. Ikei, Miyazaki, and Song are the most cited prolific authors. The USA and South Korea were the countries with the highest scientific production. In recent years, there has been a growing interest in adventure, nature, and forest therapies among researchers. Nature-based therapies have experienced a growing interest in recent years. Positive effects on mental, physical, and emotional health have been found in different populations and research lines, although more studies with different designs and populations are needed.

Effect of nature prescriptions on cardiometabolic and mental health, and physical activity: a systematic review

Nature prescriptions are gaining popularity as a form of social prescribing in support of sustainable health care. This systematic review and meta-analysis aims to synthesise evidence on the effectiveness of nature prescriptions and determine the factors important for their success. We searched five databases from inception up to July 25, 2021. Randomised and non-randomised controlled studies featuring a nature prescription (ie, a referral or an organised programme, by a health or social professional, to encourage spending time in nature) were included. Two reviewers independently conducted all steps of study selection; one reviewer collected summary data from published reports and conducted the risk of bias assessment. Random-effect DerSimonian-Laird meta-analyses were conducted for five key outcomes. We identified 92 unique studies (122 reports), of which 28 studies contributed data to meta-analyses. Compared with control conditions, nature prescription programmes resulted in a greater reduction in systolic blood pressure (mean difference -4·82 mm Hg [-8·92 to -0·72]) and diastolic blood pressure (mean difference -3·82 mm Hg [-6·47 to -1·16). Nature prescriptions also had a moderate to large effect on depression scores (post-intervention standardised mean difference -0·50 [-0·84 to -0·16]; change from baseline standardised mean difference -0·42 [-0·82 to -0·03]) and anxiety scores (post-intervention standardised mean difference -0·57 [-1·12 to -0·03]; change from baseline standardised mean difference -1·27 [-2·20 to -0·33]). Nature prescriptions resulted in a greater increase in daily step counts than control conditions (mean difference 900 steps [790 to 1010]) but did not improve weekly time of moderate physical activity (mean difference 25·90 min [-10·26 to 62·06]). A subgroup analysis restricted to studies featuring a referring institution showed stronger effects on depression scores, daily step counts, and weekly time of moderate physical activity than the general analysis. Beneficial effects on anxiety and depression scores were mainly provided by interventions involving social professionals whereas beneficial effects on blood pressures and daily step counts were provided mainly by interventions involving health professionals. Most studies have a moderate to high risk of bias. Nature prescription programmes showed evidence of cardiometabolic and mental health benefits and increases in walking. Effective nature prescription programmes can involve a range of natural settings and activities and can be implemented via social and community channels, in addition to health professionals.

The effects of forest bathing on psychological well-being: A systematic review and meta-analysis

Globally, around half (55%) of the population live in fast-paced urban settings where many people find it challenging to manage their stress and respond to crises with a positive mindset. This resulted in prolonged distress where anxiety and fatigue caused physical and mental health concerns. Nature walks involving immersive exposure in the forest, and green spaces have been posited to offer physiological and psychological benefits. Therefore, in this systematic review, we evaluated the effects of forest bathing on psychological and physiological outcomes. We searched four English and five non-English databases (Chinese and Korean) for peer-reviewed studies published between January 2000 and March 2021. This review adhered to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analysis Statement 2020. The primary outcomes explored in this review were mainly psychological, including anxiety, depression, mood and quality of life. The secondary outcomes were physiological outcomes such as blood pressure and heart rate. We conducted a meta-analysis on each outcome using the random-effects model. Heterogeneity was assessed by the I² statistic. Thirty-six articles (21 in English, 3 in Chinese and 12 in Korean) with 3554 participants were included in this review. Our meta-analysis suggested that forest bathing can significantly reduce symptoms of depression and anxiety. However, we did not observe as many benefits in physiological outcomes. Against the background of the negative effects of urbanization on mental well-being, this review highlighted the potential therapeutic role of forests in the contemporary world, lending further evidence-based support for forest conservation.

How Does the Experience of Forest Recreation Spaces in Different Seasons Affect the Physical and Mental Recovery of Users?

BACKGROUND

In recent years, increasing attention has been given to the recovery effect of the forest environment on physical and mental health. Therefore, providing users with a high-quality forest landscape space is a very important research topic for forest landscape designers and forest resource managers.

MAIN PURPOSE

From the perspective of different seasons, this study explores the differences in landscape perceptions and physical and mental recovery of users when they experience different forest recreation spaces and the interactions between them.

METHODS

First, this study used virtual reality video experience and questionnaires for participants. Then, the paired-samples t test, one-way ANOVA and the independent-samples t test were used for statistical analysis. Finally, we also used structural equation models to analyze the relationship between landscape perception and recovery.

MAIN RESULTS

(1) The restoration effect and perception of forest recreation spaces on people are influenced by space types and seasonal factors. (2) People's restoration from forest environments is a gradual process from spatial cognition to emotional response. (3) The perception of the natural attributes and form of the recreation space plays a key role in the restorative effect of the environment to people, while the natural form is more important in spring than autumn. Based on the above conclusions, we suggest that the characteristic factors of the landscape environment and their different restoration effects for users in different dimensions should be considered when planning forest recreation space.

The Effects of Forest Therapy on the Blood Pressure and Salivary Cortisol Levels of Urban Residents: A Meta-Analysis

Urban residents have a higher risk of hypertension and psychological stress than rural residents. Aside from medical interventions, understanding how to control hypertension and alleviate the stress of urban populations has become a public concern. As an alternative medical measure, forest therapy has shown the effects of normalizing blood pressure (BP) and reducing stress increasingly in recent literature, but this is still inconclusive. In order to systematically verify forest therapy’s effects on the BP and mental stress of urban residents, we conducted meta-analyses to assess the changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and salivary cortisol concentration (SCC; a stress biomarker) between the forest therapy group and urban control group. We searched 4 online databases, and 21 studies on BP involving 2270 participants and 13 studies on SCC involving 1786 participants were included. Through the meta-analysis, the mean difference and confidence interval (CI) estimates indicated that forest therapy significantly reduced participants’ SBP −3.44 (95% CI −5.74, −1.14), DBP −3.07 (95% CI −5.59, −0.54), and SCC −0.07 (95% CI −0.10, −0.04), as compared with urban control. Yet, there was substantial heterogeneity (I2 = 72.87−88.59%) among these studies. We also found that each prediction interval (PI) for SBP (95% PI −13.30, 6.42), DBP (95% PI −15.54, 9.41), and SCC (95% PI −0.18, 0.05) were all much wider than the CIs and contained values above 0. This means that forest therapy may reduce SBP, DBP, and SCC on average, but may not exclude adverse results. Meta-regression analyses showed that participants’ age and baseline SBP levels determined the heterogeneity among SBP studies. After forest therapy, older participants and those with higher baseline SBP levels had greater SBP-lowering effects. Among DBP studies, the primary source of heterogeneity was participants’ baseline DBP levels; participants with higher baseline DBP levels had greater DBP reduction. In subgroup analyses, we discovered that longer-term forest therapy programs (≥20 min) resulted in a greater reduction in BP and SCC than shorter-term forest therapy programs (<20 min). Additionally, seated viewing, walking, or multi-session programs in forests were observed to have similar effects on reducing BP and SCC. Despite extensive analyses, the study did not identify any sources of heterogeneity among forest therapy programs for lowering SCC levels. Overall, we conclude that forest therapy programs have beneficial therapeutic effects on urban residents’ physio-psychological health through lowering BP and relieving stress (reducing SCC). This finding provides solid evidence of the contribution of forest therapy to urban residents’ health and wellbeing.

Chemical Composition of Atmospheric Air in Nemoral Scots Pine Forests and Submountainous Beech Forests: The Potential Region for the Introduction of Forest Therapy

Studies show that forests are one of the main recreational destinations. This can be explained by their beneficial effects on the health of their visitors, which can be attributed to compounds from the terpene group. The aim of this research was to determine the chemical composition of air in the interiors of Nemoral Scots pine forests and submountainous beech forests, with the determination of compounds of the terpene group. Samples of organic compounds present in the air were collected with the use of Tenax TA sorbent tubes. The process of separation, identification, and determination of the extracted organic compounds was carried out with the use of the gas chromatography technique integrated with a flame ionization detector. Additional identification of the extracted compounds was carried out with the use of GC coupled with mass spectrometry. The most abundant group of compounds was the aliphatic hydrocarbons, both saturated (linear and branched) and unsaturated (terpenes). Carbonyl compounds were also found in the collected samples, but they constituted no more than 10% of all compounds present on the chromatograms. The concentrations of terpenes and terpenoids in the forest atmosphere varied from 10 to 74 µg·m^-3, representing on average 33% of the total volatile organic compounds.

Is altitude a determinant of the health benefits of nature exposure? A systematic review and meta-analysis

Introduction

Nature exposure is a widely accepted option for promoting public health owing to the recent surge of scientific evidence. However, the actual settings to facilitate this initiative is yet to be extensively reviewed. In this systematic review, we have aimed to provide an up-to-date summary of interventional studies investigating the psycho-physiological effects of forests and urban forests, including details on their physical settings, and investigate an effect-modifying role of altitude and summarize data on the magnitude and shape of the association.

Methods

A keyword search using five electronic academic databases (PubMed, Embase, PsycINFO, Web of Science, and Scopus) was conducted to identify relevant articles published in English from the inception year to the end of February 2022. The methodological quality was evaluated using the ROBINS-I or ROB2 tool, depending on the study design. Meta-regression and random effects model were jointly used to examine the relationship between altitude and health outcomes.

Results

We included 27 eligible studies and 31 cases extracted from 19 studies were used for the meta-analysis. In the meta-regression, we observed a non-linear association between altitude and psycho-physiological effects. Altitude had a positive quadratic association with anxiety (p < 0.000, adjusted R ² = 96.79%), depression (p < 0.000, adjusted R ² = 98.78%), and fatigue (p < 0.000, adjusted R ² = 64.74%) alleviating effects. Conversely, altitude demonstrated a negative non-linear association with the blood pressure-lowering effect (p = 0.009, adjusted R ² = 32.83%). Additionally, the thermal index (THI) and illuminance (lx) levels were significantly associated with effect sizes of psychological restoration.

Discussion

This review provides moderate-certainty evidence for an effect-modifying role of altitude. The meta-regression results suggested the optimal and minimal altitude ranges for psychological restoration and physiological relaxation, respectively. Despite some limitations, the study findings provide a significant basis for utilizing altitude, which is easily accessible and simple, to promote the health benefits of nature-based initiatives.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022310894, identifier: CRD42022310894.

The impact of greenspace or nature-based interventions on cardiovascular health or cancer-related outcomes: A systematic review of experimental studies

SIGNIFICANCE

Globally, cardiovascular disease (CVD) and cancer are leading causes of morbidity and mortality. While having different etiologies, CVD and cancer are linked by multiple shared risk factors, the presence of which exacerbate adverse outcomes for individuals with either disease. For both pathologies, factors such as poverty, lack of physical activity (PA), poor dietary intake, and climate change increase risk of adverse outcomes. Prior research has shown that greenspaces and other nature-based interventions (NBIs) contribute to improved health outcomes and climate change resilience.

OBJECTIVE

To summarize evidence on the impact of greenspaces or NBIs on cardiovascular health and/or cancer-related outcomes and identify knowledge gaps to inform future research.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 and Peer Review of Electronic Search Strategies (PRESS) guidelines, we searched five databases: Web of Science, Scopus, Medline, PsycINFO and GreenFile. Two blinded reviewers used Rayyan AI and a predefined criteria for article inclusion and exclusion. The risk of bias was assessed using a modified version of the Newcastle-Ottawa Scale (NOS). This review is registered with PROSPERO, ID # CRD42021231619.

RESULTS & DISCUSSION

Of 2565 articles retrieved, 31 articles met the inclusion criteria, and overall had a low risk of bias. 26 articles studied cardiovascular related outcomes and 5 studied cancer-related outcomes. Interventions were coded into 4 categories: forest bathing, green exercise, gardening, and nature viewing. Outcomes included blood pressure (BP), cancer-related quality of life (QoL) and (more infrequently) biomarkers of CVD risk. Descriptions of findings are presented as well as visual presentations of trends across the findings using RAW graphs. Overall studies included have a low risk of bias; and alluvial chart trends indicated that NBIs may have beneficial effects on CVD and cancer-related outcomes.

CONCLUSIONS & IMPLICATIONS

(1) Clinical implication: Healthcare providers should consider the promotion of nature-based programs to improve health outcomes. (2) Policy implication: There is a need for investment in equitable greenspaces to improve health outcomes and build climate resilient neighborhoods. (3) Research or academic implication: Research partnerships with community-based organizations for a comprehensive study of benefits associated with NBIs should be encouraged to reduce health disparities and ensure intergenerational health equity. There is a need for investigation of the mechanisms by which NBIs impact CVD and exploration of the role of CVD biological markers of inflammation among cancer survivors.

Spending Time in the Forest or the Field: Investigations on Stress Perception and Psychological Well-Being-A Randomized Cross-Over Trial in Highly Sensitive Persons

Research suggests that stays in a forest promote relaxation and reduce stress compared to spending time in a city. The aim of this study was to compare stays in a forest with another natural environment, a cultivated field. Healthy, highly sensitive persons (HSP, SV12 score > 18) aged between 18 and 70 years spent one hour in the forest and in the field at intervals of one week. The primary outcome was measured using the Change in Subjective Self-Perception (CSP-14) questionnaire. Secondary outcomes were measured using the Profile Of Mood States (POMS) questionnaire and by analyzing salivary cortisol. We randomized 43 participants. Thirty-nine were allocated and included in the intention-to-treat analysis (90% female, mean age 45 years). CSP-14 in part showed significant differences-total score (p = 0.054, Cohen's d = 0.319), item "integration" (p = 0.028, Cohen's d = 0.365)-favoring the effects of the forest. These effects were more pronounced in summer (August). In October, during rainfall, we detected no relevant differences. POMS only showed a significant difference in the subcategory "depression/anxiety" in favor of the field. The amount of cortisol in saliva was not different between the groups. A short-term stay in a forest in summer caused a greater improvement in mood and well-being in HSP than in a field. This effect was not detectable during bad weather in the fall.

A Forest Bathing Intervention in Adults with Intellectual Disabilities: A Feasibility Study Protocol

Forest bathing practices benefit individuals' physical and mental health. A growing number of published studies provide evidence of such effects in diverse populations and contexts. However, no literature has been found that evaluates the effects of forest bathing on people with intellectual disabilities. In this paper, we present a quasi-experimental pre-post protocol for assessing the preliminary efficacy and feasibility of a forest bathing intervention in a group of adults with intellectual disability. An 11-weekly session program will be applied in the forests of the Ollo Valley, Navarre (Spain). The preliminary efficacy outcomes will be blood pressure, psycho-physiological coherence parameters and quality of life. The feasibility of the intervention will be assessed through data on barriers and facilitators of the implementation process and indicators of environmental comfort (physiological equivalent temperature and thermic perception). This study offers an opportunity for people with intellectual disabilities to benefit from a forest bathing intervention and explore its effects not only on their quality of life, but also on the improvement in their physiological and psychological state. This feasibility study is an essential step to explore crucial aspects for a future full-scale trial.

Does Forest Therapy Have Physio-Psychological Benefits? A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Forest therapy involves visiting forests or conducting forest-based treatment activities to improve one's health. Studies have investigated the health benefits of forests, but consensus has not been reached. This study comprised a systematic review and meta-analysis to determine how forest therapy affects the physiological and psychological health of adults. The Cumulative Index to Nursing and Allied Health Literature, Embase, and Medline databases were searched on 31 August 2021. Systematic review and meta-analysis, risk evaluation, GRADE evaluation, and advertisement effect evaluation were performed for each article. The effect size was calculated by dividing blood pressure as a physiological indicator and depression as a psychological indicator. Of the 16,980 retrieved studies, 17 were selected based on the inclusion criteria. Of these, eight studies were included in the meta-analysis. The effect size of forest therapy on improving systolic and diastolic blood pressure was not significant; however, it significantly reduced depression. While the results have limited generalizability due to the inclusion of few studies, the effects of forest therapy on reducing depression have been confirmed. Since the application of forest therapy was heterogeneous in these studies, a moderator effect analysis or subgroup analysis in meta-analysis should be performed in the future.

Effects of forest bathing (shinrin-yoku) on individual well-being: an umbrella review

The aim of this review was to outline the most relevant benefits of forest bathing for well-being promotion. This study was designed as an umbrella literature review. Medline (via PubMed), EMBASE, Web of Science, Cochrane Library, Google Scholar, Scopus, PsycINFO, CINAHL and the DOAJ were systematically searched for relevant reviews up to February 2021. After article selection, 16 systematic reviews met inclusion criteria. Overall, the best available evidence supports the use of forest bathing as a complementary practice for the promotion of psychophysical well-being, whereas evidence for its use as a therapeutic practice for the improvement of organic diseases needs to grow before clear and specific clinical indications can be formulated. The positive impact of forest bathing on individual quality of life, along with its favorable cost-effectiveness profile, may justify its possible adoption for public health strategies of well-being promotion. Further investigations on the topic are advised.

Mapping of Research in the Field of Forest Therapy-Related Issues: A Bibliometric Analysis for 2007-2021

Exposure to forest environments promotes human health. The number of relevant studies in this area has increased rapidly. However, an overall review of relevant analyses from the perspectives of bibliometrics and visualization is lacking. A scientometric analysis of 2,545 publications from 2007 to 2021 via the Web of Science database was conducted to identify the knowledge structure and frontiers objectively. The publications were subsequently analyzed in terms of the distribution of journals and countries, citation bursts, major subject areas, and evolutionary stages. The findings showed that the knowledge foundation of forest therapy was multidisciplinary with most published in the fields of environmental sciences and ecology but lacking input from social disciplines. The research hotspots evolved from the early focus on individual benefits obtained from nature to increasing attention on human well-being at the social-ecological scale. More rigorous experiments with strict randomized controlled trials and blinding are needed to accommodate the trend of forest therapy toward non-pharmacological treatments. According to Shneider's four-stage theory, forest therapy research is in the third stage of the scientific research process. More future studies utilizing novel technologies and decision-making frameworks to solve practical issues are needed for introducing health into policies and promoting human well-being.

Essential Oils, Phytoncides, Aromachology, and Aromatherapy—A Review

Chemical compounds from plants have been used as a medicinal source for various diseases. Aromachology is a unique field that studies the olfactory effects after inhaling aromatic compounds. Aromatherapy is a complementary treatment methodology involving the use of essential oils containing phytoncides and other volatile organic compounds for various physical and mental illnesses. Phytoncides possess an inherent medicinal property. Their health benefits range from treating stress, immunosuppression, blood pressure, respiratory diseases, anxiety, and pain to anti-microbial, anti-larvicidal, anti-septic, anti-cancer effects, etc. Recent advancements in aromatherapy include forest bathing or forest therapy. The inhalation of phytoncide-rich forest air has been proven to reduce stress-induced immunosuppression, normalize immune function and neuroendocrine hormone levels, and, thus, restore physiological and psychological health. The intricate mechanisms related to how aroma converts into olfactory signals and how the olfactory signals relieve physical and mental illness still pose enormous questions and are the subject of ongoing research. Aromatherapy using the aroma of essential oils/phytoncides could be more innovative and attractive to patients. Moreover, with fewer side effects, this field might be recognized as a new field of complementary medicine in alleviating some forms of physical and mental distress. Essential oils are important assets in aromatherapy, cosmetics, and food preservatives. The use of essential oils as an aromatherapeutic agent is widespread. Detailed reports on the effects of EOs in aromatherapy and their pharmacological effects are required to uncover its complete biological mechanism. This review is about the evolution of research related to phytoncides containing EOs in treating various ailments and provides comprehensive details from complementary medicine.

Mountain Hiking vs. Forest Therapy: A Study Protocol of Novel Types of Nature-Based Intervention

Introduction: The global rise of urbanization has much triggered scientific interest in how nature impacts on human health. Natural environments, such as alpine landscapes, forests, or urban green spaces, are potential high-impact health resources. While there is a growing body of evidence to reveal a positive influence of these natural environments on human health and well-being, further investigations guided by rigorous evidence-based medical research are very much needed. Objective: The present study protocol aims at testing research methodologies in the context of a prospective clinical trial on nature-based interventions. This shall improve the standards of medical research in human–nature interactions. Methods: The ANKER Study investigates the influence of two novel types of nature-based therapy—mountain hiking and forest therapy—on physiological, psychological, and immunological parameters of couples with a sedentary lifestyle. Two intervention groups were formed and spent a seven-day holiday in Algund, Italy. The “forest therapy group” participated in daily guided low-power nature connection activities. The “hiking group”, by contrast, joined in a daily moderate hiking program. Health-related quality of life and relationship quality are defined as primary outcomes. Secondary outcomes include nature connection, balance, cardio-respiratory fitness, fractional exhaled nitric oxide, body composition and skin hydration. Furthermore, a new approach to measure health-related quality of life is validated. The so-called “intercultural quality of life” comic assesses the health-related quality of life with a digitally animated comic-based tool.

Nature-Based Interventions for Psychological Wellbeing in Long-Term Conditions: A Systematic Review

Background: With the global burden of disease increasing, particularly in relation to often preventable chronic diseases, researchers and clinicians are keen to identify interventions that can mitigate ill health and enhance the psychological wellbeing of people living with long-term conditions (LTCs). It is long established that engagement with nature can support human health and wellbeing, and in recent years, nature-based interventions (NBIs) have been advanced as of potential benefit. This review thus sought to systematically appraise published evidence of the application of NBIs to address psychological wellbeing for those living with LTCs. Methods: A systematic search of three databases, PsycINFO, MEDLINE and SCOPUS, was undertaken, and the BestBETs quality assessment checklist was used to appraise methodological quality of elicited studies. Results: Of 913 studies identified, 13 studies (12 using quantitative methods, one qualitative) were used. Included papers reported use of a variety of psychological outcomes alongside more circumscribed physiological outcomes. Quality appraisal showed modest robustness, some methodological weaknesses and a dominance of application in developed countries, yet synthesis of studies suggested that reported psychological and physiological outcomes present a strong argument for NBIs having a promising and positive impact on psychological wellbeing. Conclusions: NBIs have positive psychological and physiological impacts on people with LTCs, suggesting they may be a suitable addition to current maintenance treatment. Future research should focus on minimising study bias and increasing the potential for cross-cultural applications.

What Activities in Forests Are Beneficial for Human Health? A Systematic Review

Over the past decade, clinical trials of forest-based interventions have increased, leading to their recognition as preventive medicine. However, little is known about the differences in health effects according to the activity characteristics of interventions. This study aimed to understand the types of activities and their associated health effects to identify differences in health effects between activities. PubMed, PsycINFO, Web of Science, and Scopus databases were searched, and methodological quality was assessed using Cochrane ROB2. A total of 32 randomized controlled trials (RCTs) met the eligibility criteria. Health outcomes were collected from 6264 participants aged 6–98 years, and the sample size was 12–585. The Interventions were walking (n = 21), staying (n = 7), exercise (n = 4), indirect exposure (n = 4), and the activity time was between 10 and 240 min. Overall, walking showed consistent positive health effects, and there were differences in effects on anxiety and depression, cognitive function, stress hormone, and inflammation according to the activity. However, most of the included studies had a high risk of bias, and interventions were limited to specific activities, durations, and frequencies. Although a few limitations remain, the findings in this study are of great significance in providing the basis for the design of forest-based interventions.

Greenspace, Inflammation, Cardiovascular Health, and Cancer: A Review and Conceptual Framework for Greenspace in Cardio-Oncology Research

Cardiovascular disease (CVD) is a leading cause of global morbidity and mortality. Cancer survivors have significantly elevated risk of poor cardiovascular (CV) health outcomes due to close co-morbid linkages and shared risk factors between CVD and cancer, as well as adverse effects of cancer treatment-related cardiotoxicity. CVD and cancer-related outcomes are exacerbated by increased risk of inflammation. Results from different pharmacological interventions aimed at reducing inflammation and risk of major adverse cardiovascular events (MACEs) have been largely mixed to date. Greenspaces have been shown to reduce inflammation and have been associated with CV health benefits, including reduced CVD behavioral risk factors and overall improvement in CV outcomes. Greenspace may, thus, serve to alleviate the CVD burden among cancer survivors. To understand pathways through which greenspace can prevent or reduce adverse CV outcomes among cancer survivors, we review the state of knowledge on associations among inflammation, CVD, cancer, and existing pharmacological interventions. We then discuss greenspace benefits for CV health from ecological to multilevel studies and a few existing experimental studies. Furthermore, we review the relationship between greenspace and inflammation, and we highlight forest bathing in Asian-based studies while presenting existing research gaps in the US literature. Then, we use the socioecological model of health to present an expanded conceptual framework to help fill this US literature gap. Lastly, we present a way forward, including implications for translational science and a brief discussion on necessities for virtual nature and/or exposure to nature images due to the increasing human-nature disconnect; we also offer guidance for greenspace research in cardio-oncology to improve CV health outcomes among cancer survivors.

Assessing the Effects of Nature on Physiological States Using Wearable Technologies

Nature therapy and forest bathing (FB) have been shown to have quantifiable positive effects on human health, but the physiological effects of a guided interactive nature activity remain unexplored. Autonomic nervous system responses to a guided nature walk (Nature Break) were assessed through the continuous measurement of the electrodermal activity (EDA), fingertip temperature, and heart rate (HR) of n = 48 participants, using a wearable sensor. Psychological distress was assessed before and after the activity using the Profile of Mood States (POMS) for n = 38 (24 females, 14 males, mean age = 43.55 ± 11.61 years) participants. The negative dimensions of POMS decreased and the positive (vigor) dimensions increased following a Nature Break. Significant differences were found across all of the physiological features, with some differences occurring between the morning and afternoon groups and between different days. The participants’ mean HR decreased throughout the Nature Break. Our results suggest that interactive nature activities have positive psychological benefits and demonstrate the feasibility of using wearable sensors to monitor physiological responses in a naturalistic forest bathing activity.

Effects of Plant Communities on Human Physiological Recovery and Emotional Reactions: A Comparative Onsite Survey and Photo Elicitation Study

We investigated the effects on humans, in terms of skin conductance levels (SCLs) and positive and negative affect schedule (PANAS) scores, of plant communities that differed in their vegetation structure (single-layer woodland, tree-shrub-grass composite woodland, tree-grass composite woodland, and single-layer grassland) through two perceptual methods: onsite surveying and photo elicitation. The results showed that (1) the choice of perception method significantly impacted the PANAS scores of the participants but had no influence on the SCL and (2) viewing a single-layer grassland reduced the SCL (representing the physiological stress level) and improved the positive affect score. The recovery effects for the four vegetation communities were ranked in the order of single-layer grassland > tree-shrub-grass composite woodland > single-layer woodland > tree-grass composite woodland. (3) Gender and professional background significantly impacted the plant community perception methods and landscape experience, and negative affect scores were lower for male participants than for female participants. Participants without backgrounds in landscape design exhibited higher positive affect scores under photo elicitation. Based on the conclusions drawn above, the onsite survey is preferable between the two perception methods. It is recommended that in future landscape designs, combinations of plant community types should be reasonably matched through onsite perception. These research results can provide a scientific basis for the future design of landscapes based on perception experience.

Analysis of Urban Forest Healing Program Expected Values, Needs, and Preferred Components in Urban Forest Visitors with Diseases: A Pilot Survey

Although the effectiveness of urban forest therapy has been studied and proven, most people are not well aware of the positive healing effects of urban forests that are easily accessible in daily life compared to the known healing effect of forests located outside urban areas. In addition, there has been a study on the analysis of urban forest healing program needs in the general population, but there is a lack of evidence on the expected values and needs of urban forest healing for people with diseases. Therefore, this pilot survey aimed to investigate the expected values, needs, and preferred components of urban forest healing programs in urban forest visitors with disease via an online user survey and see if there were any differences in the purpose of the urban forest visits and expected values of urban forest healing depending on the type of disease. The survey was conducted on 294 urban forest visitors with diseases. About 79% of respondents agreed with the healing effects of urban forest, however most respondents expected healing effects on mental health rather than on physical health ("mood change" was the highest with score of 4.43/5, followed by "reliving stress" (4.35/5) and "mental and physical stability" (4.31/5)). In addition, more than 82.0% of respondents agreed to participate in the program if a healing program for disease was developed. The results of the current pilot survey indicate that the purpose of the urban forest visits and expected values of urban forest healing were largely not different by the type of disease, and people with disease had a relatively lower awareness and lower expected values of urban forest healing effects on physical health, but high demand for the program. Urban forest therapy programs should be developed based on the specific clinical characteristics of the disease to maximize the effectiveness of the program. Additionally, policies should be implemented to promote the beneficial effects of urban forest healing not only for mental health but also for physical health.

Effects of forest environment (Shinrin-yoku/Forest bathing) on health promotion and disease prevention -the Establishment of "Forest Medicine"

Humans have enjoyed forest environments for ages because of the quiet atmosphere, beautiful scenery, mild climate, pleasant aromas, and fresh, clean air. In Japan, since 2004, serial studies have been conducted to investigate the effects of forest environments (Forest bathing/Shinrin-yoku) on human health. My research team has established a new medical science called Forest Medicine. The Forest Medicine is a new interdisciplinary science, belonging to the categories of alternative medicine, environmental medicine and preventive medicine, which studies the effects of forest environments (Forest bathing/Shinrin-yoku) on human health. It has been reported that Forest bathing/Shinrin-yoku has the following beneficial effects on human health:1 Shinrin-yoku increases human natural killer (NK) activity, the number of NK cells, and the intracellular levels of anti-cancer proteins, suggesting a preventive effect on cancers. 2 Shinrin-yoku reduces blood pressure and heart rate showing preventive effect on hypertension and heart diseases. 3 Shinrin-yoku reduces stress hormones, such as urinary adrenaline and noradrenaline and salivary/serum cortisol contributing to stress management. 4 Shinrin-yoku increases the activity of parasympathetic nerves and reduces the activity of sympathetic nerves to stabilize the balance of autonomic nervous system. 5 Shinrin-yoku improve sleep. 6 Shinrin-yoku increases the levels of serum adiponectin and dehydroepiandrosterone sulfate. 7 In the Profile of Mood States (POMS) test, Shinrin-yoku reduces the scores for anxiety, depression, anger, fatigue, and confusion, and increases the score for vigor, showing preventive effects on depression. 8 Shinrin-yoku may apply to rehabilitation medicine 9 Shinrin-yoku in city parks also has benefits on human health. 10 Shinrin-yoku may have preventive effect on COVID-19 by boosting immune function and by reducing mental stress.Taken together, these findings suggest that Shinrin-yoku may have potential preventive effects on non-communicable diseases.

Less COVID-19 deaths in southern and insular Italy explained by forest bathing, Mediterranean environment, and antiviral plant volatile organic compounds

The coronavirus disease 2019 (COVID-19) is causing major sanitary and socioeconomic issues, yet some locations are less impacted than others. While densely populated areas are likely to favor viral transmission, we hypothesize that other environmental factors could explain lower cases in some areas. We studied COVID-19 impact and population statistics in highly forested Mediterranean Italian regions versus some northern regions where the amount of trees per capita is much lower. We also evaluated the affinity of Mediterranean plant-emitted volatile organic compounds (VOCs) isoprene, α-pinene, linalool and limonene for COVID-19 protein targets by molecular docking modeling. Results show that while mean death number increased about 4 times from 2020 to 2021, the percentage of deaths per population (0.06-0.10%) was lower in the greener Mediterranean regions such as Sardinia, Calabria and Basilica versus northern regions with low forest coverage, such as Lombardy (0.33%) and Emilia Romagna (0.29%). Data also show that the pandemic severity cannot be explained solely by population density. Modeling reveals that plant organic compounds could bind and interfere with the complex formed by the receptor binding domain of the coronavirus spike protein with the human cell receptor. Overall, our findings are likely explained by sea proximity and mild climate, Mediterranean diet and the abundance of non-deciduous Mediterranean plants which emit immunomodulatory and antiviral compounds. Potential implications include 'forest bathing' as a therapeutic practice, designing nasal sprays containing plant volatile organic compounds, and preserving and increasing forest coverage.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10311-021-01309-5.

Effects of Urban Green Space on Cardiovascular and Respiratory Biomarkers in Chinese Adults: Panel Study Using Digital Tracking Devices

Background

The health benefits of urban green space have been widely reported in the literature; however, the biological mechanisms remain unexplored, and a causal relationship cannot be established between green space exposure and cardiorespiratory health.

Objective

Our aim was to conduct a panel study using personal tracking devices to continuously collect individual exposure data from healthy Chinese adults aged 50 to 64 years living in Hong Kong.

Methods

A panel of cardiorespiratory biomarkers was tested each week for a period of 5 consecutive weeks. Data on weekly exposure to green space, air pollution, and the physical activities of individual participants were collected by personal tracking devices. The effects of green space exposure measured by the normalized difference vegetation index (NDVI) at buffer zones of 100, 250, and 500 meters on a panel of cardiorespiratory biomarkers were estimated by a generalized linear mixed-effects model, with adjustment for confounding variables of sociodemographic characteristics, exposure to air pollutants and noise, exercise, and nutrient intake.

Results

A total of 39 participants (mean age 56.4 years, range 50-63 years) were recruited and followed up for 5 consecutive weeks. After adjustment for sex, income, occupation, physical activities, dietary intake, noise, and air pollution, significant negative associations with the NDVI for the 250-meter buffer zone were found in total cholesterol (–21.6% per IQR increase in NDVI, 95% CI –32.7% to –10.6%), low-density lipoprotein (–14.9%, 95% CI –23.4% to –6.4%), glucose (–11.2%, 95% CI –21.9% to –0.5%), and high-sensitivity C-reactive protein (–41.3%, 95% CI –81.7% to –0.9%). Similar effect estimates were found for the 100-meter and 250-meter buffer zones. After adjustment for multiple testing, the effect estimates of glucose and high-sensitivity C-reactive protein were no longer significant.

Conclusions

The health benefits of green space can be found in some metabolic and inflammatory biomarkers. Further studies are warranted to establish the causal relationship between green space and cardiorespiratory health.

Can Different Forest Structures Lead to Different Levels of Therapeutic Effects? A Systematic Review and Meta-Analysis

In recent decades, forests have expanded from natural resources for conservation and production to health-promoting resources. With the growing body of evidence supporting the therapeutic effects of forests, the number of investigations on the relationship between forest characteristics and therapeutic effects have increased. However, quantitative synthesis of primary studies has rarely been conducted due to a limited number of health studies including forest description and high heterogeneity of forest variables. In this study, we conducted a systematic review and meta-analysis to evaluate the relationship between the forest structure and the therapeutic effect. We systematically searched the studies examining the therapeutic effects of forests with different stand density and canopy density and synthesized the results. As a result of subgroup analysis, we found that stand density modifies the therapeutic effects. Emotional and cognitive restoration showed greatest improvement in low-density forests with a stand density of less than 500/ha and the therapeutic effects diminish as the stand density increases. The impact of canopy density was not found due to a lack of studies reporting canopy density. Although some limitations remain, the findings in this study have great significance in providing the basis for establishing management strategies of forests for therapeutic use.

Evidence-Based Status of Forest Healing Program in South Korea

Various effects of forest healing on health have been reported, but a certification system to assess the effectiveness of forest healing programs does not exist. In this study, a systematic review (SR) on the "health benefits of forests" and "meta-analysis of forest therapy" was conducted after analyzing the status and level of evidence of 75 forest healing programs that were conducted post-certification in South Korea. The SR for "health benefits of forests" distinguished between activities and time, resulting in 90.9% of walking activities for more than an hour under psychological health, and 100.0% of exercise activities for less than an hour under physiological health. However, the effect of indirect activities performed for more than an hour was unknown. Thus, we confirmed that many indoor activities in the field had low effect size or no established basis regarding the feasibility of its operation. The SR on "meta-analysis of forest therapy" to check whether the program was effective. The highest number of healing effects were obtained for blood pressure (32), followed by psychological depression (24). The findings of this can serve as baseline data to facilitate future development and dissemination of evidence-based forest healing programs.

The Role of Social Context in Physiological and Psychological Restoration in a Forest: Case Study of a Guided Forest Therapy Program in Taiwan

Existing studies have demonstrated the restorative benefits of being in forests. However, most studies have designed participants to engage individually in forest walking and viewing, which neglects the social aspect of conversation. Researchers suggested that social context should be studied in order to have a better understanding how forests foster human health. To this end, we examined the role of social context using three types of forest therapy programs: a guided program, a self-guided program, and a walk alone program. A between-subject, pretest–posttest field experimental design was employed to evaluate restorative effects by measuring the physiological responses and mood states incurred in different forest therapy programs. Our findings showed, that the walk alone group exhibited a significant systolic blood pressure decrease and a significant increase in sympathetic nervous activity; the self-guided group showed a significant increase in heart rate values and significant decreases in systolic blood pressure and diastolic blood pressure; and the guided group revealed a significant decrease in systolic blood pressure. Further, the three forest therapy programs had positive effects on improving mood states, except a nonsignificant vigor–activity increase in the walk alone group. The three programs did not exhibit significant differences in changes of restorative benefits in physiological and psychological measures except for a significant difference in changes in sympathetic nervous activity between the walk alone group and guided group. The results showed the restorative benefits of forest therapy are apparent regardless of the program type. The management team should continue promoting forest therapy for public health by providing different types of forest therapy programs and experiences.

Green Space and Health in Mainland China: A Systematic Review

Non-communicable diseases (NCDs) have become a major cause of premature mortality and disabilities in China due to factors concomitant with rapid economic growth and urbanisation over three decades. Promoting green space might be a valuable strategy to help improve population health in China, as well as a range of co-benefits (e.g., increasing resilience to climate change). No systematic review has so far determined the degree of association between green space and health outcomes in China. This review was conducted to address this gap. Five electronic databases were searched using search terms on green space, health, and China. The review of 83 publications that met eligibility criteria reports associations indicative of various health benefits from more green space, including mental health, general health, healthier weight status and anthropometry, and more favorable cardiometabolic and cerebrovascular outcomes. There was insufficient evidence to draw firm conclusions on mortality, birth outcomes, and cognitive function, and findings on respiratory and infectious outcomes were inconsistent and limited. Future work needs to examine the health benefits of particular types and qualities of green spaces, as well as to take advantage of (quasi-)experimental designs to test greening interventions within the context of China's rapid urbanization and economic growth.

Increased Use of Porch or Backyard Nature during COVID-19 Associated with Lower Stress and Better Symptom Experience among Breast Cancer Patients

Contact with nature has been used to promote both physical and mental health, and is increasingly used among cancer patients. However, the COVID-19 pandemic created new challenges in both access to nature in public spaces and in cancer care. The purpose of our study was to evaluate the change in active and passive use of nature, places of engaging with nature and associations of nature contact with respect to improvements to perceived stress and symptom experience among breast cancer patients during the pandemic. We conducted a cross-sectional survey of people diagnosed with breast cancer using ResearchMatch (n = 56) in July 2020 (the first wave of COVID-19). In this US-based, predominantly white, affluent, highly educated, female sample, we found that, on average, participants were first diagnosed with breast cancer at 54 years old and at stage 2 or 3. Eighteen percent of participants experienced disruptions in their cancer care due to the pandemic. As expected, activities in public places significantly decreased as well, including use of parks/trails and botanical gardens. In contrast, spending time near home, on the porch or in the backyard significantly increased. Also observed were significant increases in indoor activities involving passive nature contact, such as watching birds through a window, listening to birdsong, and smelling rain or plants. Decreased usage of parks/trails was significantly associated with higher stress (Coef = -2.30, p = 0.030) and increased usage of the backyard/porch was significantly associated with lower stress (Coef = -2.69, p = 0.032), lower symptom distress (Coef = -0.80, p = 0.063) and lower symptom severity (Coef = -0.52, p = 0.009). The most commonly reported alternatives to outdoor engagement with nature were watching nature through a window (84%), followed by looking at images of nature (71%), and listening to nature through a window (66%). The least commonly enjoyed alternative was virtual reality of nature scenes (25%). While outdoor contact with nature away from home decreased, participants still found ways to experience the restorative benefits of nature in and around their home. Of special interest in planning interventions was the fact that actual or real nature was preferred over that experienced through technology. This could be an artifact of our sample, or could represent a desire to be in touch with the "real world" during a health crisis. Nature contact may represent a flexible strategy to decrease stress and improve symptom experience among patients with cancer, particularly during public health crises or disruptions to cancer care.

Forest Therapy Alone or with a Guide: Is There a Difference between Self-Guided Forest Therapy and Guided Forest Therapy Programs?

There are generally two types of forest therapy. One is to walk or view the forest alone without a guide, and the other is to be accompanied by a guide. This study aimed to investigate the healing factors and health benefits of self-guided forest therapy and guided forest therapy programs and examine the differences in characteristics between interventions. Thirty-seven undergraduate students participated in a randomized experiment (19 in the self-guided forest therapy and 18 in the guided forest therapy program). Data were collected from 111 self-reported essays after each intervention (three essays per person). Results revealed that the forest healing factors contained four categories in common: auditory element, visual element, tactile element, and olfaction element. Forest therapy’s health benefits included five categories in common: change of mind and body, introspection, change of emotion, cognitive change, and social interaction. Among the typical differences, the self-guided forest therapy group mentioned more keywords related to introspection than the guided forest therapy program group. On the other hand, the guided forest therapy program group mentioned more keywords associated with the change of emotion and social interaction than the self-guided forest therapy. Our findings show that self-guided forest therapy provides an opportunity for self-reflection to focus on and think about one’s inner self. On the other hand, guided forest therapy programs provide positive emotional changes and promoting social bonds through interaction with others. Therefore, because the effects that can be obtained vary depending on the type of forest therapy, participants can utilize forest healing to suit the desired outcomes.

Using greenspace and nature exposure as an adjunctive treatment for opioid and substance use disorders: Preliminary evidence and potential mechanisms

The demand for opioid medication to effectively treat pain has contributed to the surging opioid crisis, which is a major source of morbidity and mortality in the U.S. More than 100,000 people begin opioid maintenance treatment (OMT) annually, the standard pharmacotherapy for opioid use disorder (OUD). Although OMT is the standard care for OUD, patients often experience or develop a heightened sensitivity to pain (hyperalgesia) as a result of the opioid medication, and also have high rates of stress, affective, and anxiety-related conditions. These conditions are interactive with other behavioral and environmental correlates of opioid and other substance use disorders including impulsive decision-making (e.g., harmful opioid use associated with increased delay discounting), and a lack of alternative (i.e., substance-free) and social reinforcement. Collectively these complex and multifaceted factors constitute significant predictors of lack of adherence to OMT (and other pharmacotherapies) and relapse. There is an urgent need, therefore, to develop novel adjunctive treatments that preserve the benefits of OMT and various pharmacotherapies, and simultaneously diminish continued pain and hyperalgesia, reduce stress and anxiety-related conditions, target relevant behavioral mechanism such as impulsive choice, and also serve to enhance the value of alternative and substance free activities. Here, we discuss evidence that an environmental manipulation - access to greenspace and nature - could serve as a potential adjunctive treatment to standard pharmacotherapies by targeting multiple biological and behavioral mechanisms that standard pharmacotherapies do not address.

Forest Bathing Always Makes Sense: Blood Pressure-Lowering and Immune System-Balancing Effects in Late Spring and Winter in Central Europe

Various formats of forest bathing have been receiving increasing attention owing to their perspectives in health promotion and the treatment of chronic lifestyle diseases. The majority of field studies are still being conducted in the Far Eastern region, and they often make psychological assessments mainly in the green season. In our pretest–posttest field experiment, twelve healthy, working-age volunteers participated in a 2-h leisurely forest walking program, first in the green season (May) and then in the winter season (January), in the Mecsek Hills, next to Pécs, Hungary. Systolic blood pressure decreased after the trips both in late spring and in the winter. Based on changes in the expressions of CD69, an early activation marker, NKG2D, a major recognition receptor, perforin, granzyme B, and TIM-3, an inhibitory immune checkpoint molecule, on CD8+ cytotoxic T, NK, NK^dim, NK^bright, and NKT cells, we detected the stimulation of NK^bright cells and activation of all examined immune cell subsets in the green season. In the winter, a slight activating and an interesting balancing effect regarding TIM-3 could be observed considering our finding that basal (pretest) TIM-3 expression by NK cells was significantly lower in the winter. Our work expands the knowledge on and potentials of forest medicine.

Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review

Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types.

Effects of Variations in Color and Organ of Color Expression in Urban Ornamental Bamboo Landscapes on the Physiological and Psychological Responses of College Students

Visual characteristics (e.g., the color and shape) of ornamental plants can significantly affect their beneficial influence on humans. Prior research, however, has largely focused on the effects of the color or shape of flowers and the impact of differences in the visual appearance of foliage plants and plants with ornamental stalks has not yet been fully explored. This study examined the psychophysiological effects of urban ornamental bamboos that expressed different colors on different organs. Three hundred Chinese college students participated in the experiment. They were randomly assigned to view images of five ornamental bamboo landscapes with the following different visual characteristics: green stalks (GS) non-green stalks (NGS) multicolored stalks (MS) green leaves (GL) and multicolored leaves (ML). Before and after viewing the images, their EEG, blood pressure, pulse, profile of mood states (POMS) score, and state-trait anxiety inventory (STAI) score were measured. The results showed that ornamental bamboo landscapes have extremely significant beneficial psychophysiological effects as compared to urban landscapes. After viewing landscapes in the NGS and MS groups, EEG, blood pressure, and pulse rate of subjects showed more beneficial changes. Significant gender differences were observed only in systolic blood pressure and in the vigor score. In addition, an extremely significant interaction between color and organ of color expression was observed on systolic and diastolic blood pressure. Organ of expression had significant main effects on all the physiological indicators and the fatigue, vigor, and irritability scores, while color only had a main effect on systolic blood pressure. Our study concluded that viewing urban ornamental bamboo landscapes with different visual characteristics has different effects on humans. With regards to ornamental bamboo, the organ expressing the color had a greater impact on psychophysiological responses than did the type of color itself. These study results can provide guidance for landscape construction of urban greening.