Health effects of a forest environment on natural killer cells in humans: an observational pilot study

Survive, revive, and thrive: The impact of COVID-19 on global park visitation

The COVID-19 pandemic has had detrimental effects on both the physical and psychological well-being of individuals. Throughout the pandemic and in response to various policies, such as lockdowns, movement restrictions and social distancing measures, parks and greenspaces received renewed attention as people used them to help cope with the adverse effects of the pandemic. This study explored the factors influencing park and greenspace visitation at different stages of the pandemic in 2020, 2021, and 2022, from both global and regional perspectives. Data were collected primarily from Our World in Data, Google's Community Mobility Reports and the Oxford Coronavirus Government Response Tracker, and a total of 125,422 park visits were processed. Stay-at-home mandates, vaccination availability, and school closures were the most influential factors globally affecting park and greenspace visitation in 2020, 2021, and 2022, respectively. Post-2021, vaccination-related policies began to play a significantly positive role in the increase in park and greenspace visits. Following a global analysis, countries were categorized into five clusters based on social, economic, and cultural indices. The analysis revealed varying patterns of factors influencing park visitation across these clusters. Notably, income support policies were positively correlated with higher park visitation, particularly in low-income countries. Recognizing the significance of parks and green spaces as essential green infrastructure, this study suggests how the use of parks might have better coped with the COVID-19 pandemic and how future health crises might be addressed. At the same time, it considers different social, economic, and cultural contexts. Additionally, this work provides insights and suggestions as to how parks and greenspaces might be used to reduce the social inequalities exacerbated during the pandemic, especially in low-income developing countries.

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.

Biodiversity and human health: A scoping review and examples of underrepresented linkages

Mounting evidence supports the connections between exposure to environmental typologies(such as green and blue spaces)and human health. However, the mechanistic links that connect biodiversity (the variety of life) and human health, and the extent of supporting evidence remain less clear. Here, we undertook a scoping review to map the links between biodiversity and human health and summarise the levels of associated evidence using an established weight of evidence framework. Distinct from other reviews, we provide additional context regarding the environment-microbiome-health axis, evaluate the environmental buffering pathway (e.g., biodiversity impacts on air pollution), and provide examples of three under- or minimally-represented linkages. The examples are (1) biodiversity and Indigenous Peoples' health, (2) biodiversity and urban social equity, and (3) biodiversity and COVID-19. We observed a moderate level of evidence to support the environmental microbiota-human health pathway and a moderate-high level of evidence to support broader nature pathways (e.g., greenspace) to various health outcomes, from stress reduction to enhanced wellbeing and improved social cohesion. However, studies of broader nature pathways did not typically include specific biodiversity metrics, indicating clear research gaps. Further research is required to understand the connections and causative pathways between biodiversity (e.g., using metrics such as taxonomy, diversity/richness, structure, and function) and health outcomes. There are well-established frameworks to assess the effects of broad classifications of nature on human health. These can assist future research in linking biodiversity metrics to human health outcomes. Our examples of underrepresented linkages highlight the roles of biodiversity and its loss on urban lived experiences, infectious diseases, and Indigenous Peoples' sovereignty and livelihoods. More research and awareness of these socioecological interconnections are needed.

Effects of an urban forest healing program on cancer-related fatigue in cancer survivors

PURPOSE

This study aimed to examine the effects of an eight-session structured urban forest healing program for cancer survivors with fatigue.

BACKGROUND

Cancer-related fatigue (CRF) is a complex and multifactorial common symptom among cancer survivors that limits quality of life (QoL). Although health benefits of forest healing on physiological, physical, and psychological aspect as well as on the immune system have been reported in many studies, there is limited evidence on the efficacy of specialized forest program for cancer survivors.

METHOD

A single-blinded, pre-test and post-test control group clinical trial was conducted with -75 cancer survivors assigned to either the forest healing group or the control group. The intervention was an eight-session structured urban forest program provided at two urban forests with easy accessibility. Each session consists of three or four major activities based on six forest healing elements such as landscape, phytoncides, anions, sounds, sunlight, and oxygen. Complete data of the treatment-adherent sample (≥ 6 sessions) was used to examine whether sociodemographic, clinical, physiological (respiratory function, muscle strength, balance, 6-min walking test) and psychological (distress, mood state, sleep quality, QoL) characteristics at baseline moderated the intervention effect on fatigue severity at 9 weeks.

RESULTS

Significant time-group interactions were observed muscle strength, balance, 6-min walking test, distress, fatigue, moods, and QoL. The mean difference in fatigue between pre- and post-forest healing program was 9.1 (95% CI 6.2 to 11.9), 11.9 (95% CI 7.6 to 16.1) in moods, and -93.9 (95% CI -123.9 to -64.0) in QoL, showing significant improvements in forest healing group, but no significant improvements in the control group.

CONCLUSION

This study suggests that a forest healing program positively impacts the lives of cancer survivors, by addressing both physical and psychological challenges associated with CRF.

TRIAL REGISTRATION NUMBER

KCT0008447 (Date of registration: May 19, 2023).

Effects of Plant-Emitted Monoterpenes on Anxiety Symptoms: A Propensity-Matched Observational Cohort Study

Immersive experiences in green areas, particularly in forests, have long been known to produce beneficial effects for human health. However, the exact determinants and mechanisms leading to healthy outcomes remain to be elucidated. The purpose of this observational cohort study was to investigate whether inhaling plant-emitted biogenic volatile compounds, namely monoterpenes (MTs), can produce specific effects on anxiety symptoms. Data from 505 subjects participating in 39 structured forest therapy sessions at different Italian sites were collected. The air concentration of monoterpenes was measured at each site. STAI state questionnaires were administered before and after the sessions as a measure of anxiety. A propensity score matching analysis was then performed, considering an above-average exposure to inhalable air MTs as the treatment. The estimated effect was -1.28 STAI-S points (95% C.I. -2.51 to -0.06, p = 0.04), indicating that the average effect of exposure to high MT air concentrations during forest therapy sessions was to decrease anxiety symptoms.

The Relationship Between Nature and Immigrants' Integration, Wellbeing and Physical Activity: A Scoping Review

Exposure to nature has been suggested to promote immigrants' health and facilitate adaptation. This review summarizes previous research focusing on the relationship between nature and immigrants' integration, wellbeing and physical activity. A search strategy was developed and adapted to seven databases. After removing duplicates, 4861 records were screened, 81 met inclusion criteria. Community gardens and urban parks were the most studied environments. In these settings, embodied experiences (the interactive processes of sensing and cognition) can foster new memories that facilitate adaptation and attachment to new natural environments. Social interaction and reconnecting with pre-migration experiences through specific use patterns can promote cultural continuation, sense of belonging and wellbeing. Other health benefits such as physical activity, disease management and improved nutrition were less frequently studied. Barriers to participation and recommendations for research and practice were also identified. Use of stronger study designs and greater inclusion of immigrant groups in research, design and evaluation of nature-based initiatives is needed.

Population-weighted exposure to green spaces tied to lower COVID-19 mortality rates: A nationwide dose-response study in the USA

The COVID-19 pandemic has caused a huge loss of human life globally. However, few studies investigated the link between exposure to green space and risk of COVID-19 mortality rate, while also distinguishing the effects of various types of green space, considering the spatial distribution of human population and green space, and identifying the optimal buffer distances of nearby green space. It is critical and pressing to fill these significant knowledge gaps to protect and promote billions of people's health and life across the world. This study adopted a negative binomial generalized linear mixed-effects model to examine the association between the ratios of various types of green space, population-weighted exposure to those various types of green space, and COVID-19 mortality rates across 3025 counties in the USA, adjusted for sociodemographic, pre-existing chronic disease, policy and regulation, behavioral, and environmental factors. The findings show that greater exposure to forest was associated with lower COVID-19 mortality rates, while developed open space had mixed associations with COVID-19 mortality rates. Forest outside park had the largest effect size across all buffer distances, followed by forest inside park. The optimal exposure buffer distance was 1 km for forest outside park, with per one-unit of increase in exposure associated with a 9.9 % decrease in COVID-19 mortality rates (95 % confidence interval (CI): 6.9 %-12.8 %). The optimal exposure buffer distance of forest inside park was 400 m, with per one-unit of increase in exposure associated with a 4.7 % decrease in mortality rates (95 % CI: 2.4 %-6.9 %). The results suggest that greater exposure to green spaces, especially to nearby forests, may mitigate the risk of COVID-19 mortality. Although findings of an ecological study cannot be directly used to guide medical interventions, this study may pave a critical new way for future research and practice across multiple disciplines.

The Feasibility and Impact of Practising Online Forest Bathing to Improve Anxiety, Rumination, Social Connection and Long-COVID Symptoms: A Pilot Study

BACKGROUND

Long-COVID affects over 144 million people globally. In the absence of treatments, there is a need to establish the efficacy of therapies that improve patient outcomes. Forest bathing has been demonstrated to improve physical and mental outcomes but there is no evidence in Long-COVID patients. Accordingly, this pilot study sought to determine the feasibility and effectiveness of online forest bathing in adults with Long-COVID.

METHODS

Feasibility was assessed by monitoring retention rates and participant feedback. In a waitlist controlled, repeated measures design, 22 Long-COVID patients completed weekly online surveys during a four-week waitlist control period, before engaging in four weekly online forest bathing sessions, completing post-intervention surveys following each session.

RESULTS

In terms of retention, 27% did not provide post-intervention data, reasons for non-adherence were: feeling too ill, having medical appointments, or having career responsibilities. Compared with the waitlist control period, there were statistically significant improvements in Anxiety (49% decrease), Rumination (48% decrease), Social Connection (78% increase), and Long-COVID symptoms (22% decrease). Written qualitative comments indicated that participants experienced feelings of calm and joy, felt more connected socially and with nature, and experienced a break from the pain and rumination surrounding their illness.

CONCLUSIONS

Online Forest bathing resulted in significant improvements in well-being and symptom severity and could be considered an accessible and inexpensive adjunct therapy for Long-COVID patients. Where people have limited access to in-person nature, virtual nature may offer an alternative to improve health and well-being outcomes.

Recreational Visit to Suburban Forests during the COVID-19 Pandemic: A Case Study of Taiwan

COVID-19 global pandemic has caused massive disruption of travel behaviors along with other aspects of human life, such as social distancing, staying at home, and avoiding crowds. People substituted outdoor activities for indoor activities, and the forest environment has become a popular alternative. Taiwan has a high population density, but it had few COVID-19 confirmed cases in 2020 during the first wave of the COVID-19 pandemic. No forest areas have been closed due to the COVID-19 outbreak. In light of this generally increased demand for suburban forests for recreational uses, the current COVID-19 pandemic situation poses specific challenges regarding forest use, management, and policy. This study integrates visitation numbers of the popular forest recreation area and selects the unblocking index and social distancing index as the COVID-19 index to capture the impacts of forest recreation area on the COVID-19 outbreak in Taiwan. The results show both COVID-19 indices have high explanatory power for suburban forest visitation and both have a significant impact on the number of visitors. Although the number of visitors to suburban forests decreased during the COVID-19 pandemic alert, it bounced when the COVID-19 outbreak was under control. This study provides a brief overview of management implications for recreational visits during COVID-19. We posed an early warning to forest managers for greater revenge traveling post-COVID-19.

Simulated Forest Immersion Therapy: Methods Development

Shinrin-yoku, forest bathing, may provide relief from chronic and breakthrough pain in patients with axial spondyloarthritis and improve immune function through increasing NK cell numbers and activity and their downstream effectors, perforin and granulysin, after chemo- or radiation therapy in breast and prostate cancer patients. The aim of this paper is to describe the study protocol for a simulated forest immersion therapy using virtual reality and atomized phytoncides, volatile organic compounds found in forested areas designed to effect positive change for these two patient populations. The setting, including the room set up and samples with inclusion/exclusion specific to this type of intervention, is outlined. Measures and calibration procedures pertinent to determining the feasibility of simulated forest immersion therapy are presented and include: ambient and surface room temperatures and relative humidity in real time, ambient ultrafine particulate matter, ambient droplet measurement that coincides with volatile organic compounds, specific phytoncides, and virtual reality and atomization of phytoncide set up. Particular lessons learned while training and setting up the equipment are presented. Simulated forest immersion therapy is possible with attention to detail during this early phase when development of methods, equipment testing, and feasibility in deploying the intervention become operational. The expected outcome of the development of the methods for this study is the creation of a standardized approach to simulating forest therapy in a controlled laboratory space.

Forest Bathing Is Better than Walking in Urban Park: Comparison of Cardiac and Vascular Function between Urban and Forest Parks

Forest bathing is beneficial for human health. To investigate whether walking in forest or urban parks affects cardiovascular functions (CVFs), the present study was conducted in five forest trails in the Xitou Experimental Forest and in five urban parks in Taipei city. We recruited 25 adult volunteers for an observational pilot study in forest parks (n = 14) and urban parks (n = 11). CVFs were assessed by measuring the arterial pressure waveform using an oscillometric blood pressure (BP) device. The baseline and paired differences of systolic BP (SBP), central end SBP, heart rate, left ventricle (LV) dP/dt max and cardiac output in participants were lower before and after walking in a forest park than those in an urban park. In addition, the systemic vascular compliance and brachial artery compliance of those who walked in a forest park were significantly higher compared with those in an urban park. Linear mixed models demonstrated lower levels of SBP by 5.22 mmHg, heart rate by 2.46 beats/min, and cardiac output by 0.52 L/min, and LV dP/dt max by 146.91 mmHg/s among those who walked in forest compared to those in an urban park after controlling covariates. This study provides evidence of the potential beneficial effects of walking exercise in forest parks on CVFs.

A tranquil virtual reality experience to reduce subjective stress among COVID-19 frontline healthcare workers

OBJECTIVE

The novel coronavirus-19 (COVID-19) has taken an immense physical, social, and emotional toll on frontline healthcare workers. Research has documented higher levels of anxiety, depression, and burnout among healthcare workers during the pandemic. Thus, creative interventions are needed now more than ever to provide brief, accessible support to frontline workers. Virtual reality is a rapidly growing technology with potential psychological applications. In this study, we piloted a three-minute Tranquil Cinematic-VR simulation of a nature scene to lower subjective stress among frontline healthcare workers in COVID-19 treatment units. We chose to film a nature scene because of the extensive empirical literature documenting the benefits of nature exposure and health.

METHODS

A convenience sample of frontline healthcare workers, including direct care providers, indirect care providers, and support or administrative services, were recruited from three COVID-19 units located in the United States. Inclusion criteria for participation included adults aged 18 years and older who could read and speak in English and were currently employed by the healthcare system. Participants viewed a 360-degree video capture of a lush, green nature preserve in an Oculus Go or Pico G2 4K head-mounted display. Prior to viewing the simulation, participants completed a brief demographic questionnaire and the visual analogue scale to rate their subjective stress on a 10-point scale, with 1 = 'Not at all stressed' to 10 = 'Extremely stressed.' We conducted paired t-tests to examine pre- and post-simulation changes in subjective stress as well as Kruskal-Wallis tests and Mann-Whitney U tests to examine differences by demographic variables. All analyses were conducted in SPSS statistical software version 28.0. We defined statistical significance as a p-value less than .05.

RESULTS

A total of 102 individuals consented to participate in the study. Eighty-four (82.4%) participants reported providing direct patient care, 73 (71.6%) identified as women, 49 (48.0%) were between the ages of 25-34 years old, and 35 (34.3%) had prior experience with VR. The pre-simulation mean stress score was 5.5±2.2, with a range of 1 to 10. Thirty-three (32.4%) participants met the 6.8 cutoff for high stress pre-simulation. Pre-simulation stress scores did not differ by any demographic variables. Post-simulation, we observed a significant reduction in subjective stress scores from pre- to post-simulation (mean change = -2.2±1.7, t = 12.749, p < .001), with a Cohen's d of 1.08, indicating a very large effect. Further, only four (3.9%) participants met the cutoff for high stress after the simulation. Post-simulations scores did not differ by provider type, age range, gender, or prior experience with virtual reality.

CONCLUSIONS

Findings from this pilot study suggest that the application of this Tranquil Cinematic-VR simulation was effective in reducing subjective stress among frontline healthcare workers in the short-term. More research is needed to compare the Tranquil Cinematic-VR simulation to a control condition and assess subjective and objective measures of stress over time.

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 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.

Short-Term Effects of Forest Therapy on Mood States: A Pilot Study

Immersion in forest environments was shown to produce beneficial effects to human health, in particular psychophysical relaxation, leading to its growing recognition as a form of integrative medicine. However, limited evidence exists about the statistical significance of the effects and their association with external and environmental variables and personal characteristics. This experimental study aimed to substantiate the very concept of forest therapy by means of the analysis of the significance of its effects on the mood states of anxiety, depression, anger and confusion. Seven forest therapy sessions were performed in remote areas and a control one in an urban park, with participants allowed to attend only one session, resulting in 162 psychological self-assessment questionnaires administered before and after each session. Meteorological comfort, the concentration of volatile organic compounds in the forest atmosphere and environmental coherence were identified as likely important external and environmental variables. Under certain conditions, forest therapy sessions performed in remote sites were shown to outperform the control session, at least for anxiety, anger and confusion. A quantitative analysis of the association of the outcomes with personal sociodemographic characteristics revealed that only sporting habits and age were significantly associated with the outcomes for certain psychological domains.

A Scoping Review of the Health Benefits of Nature-Based Physical Activity

The health benefits of physical activity and spending time in nature are well established. However, youths and adults in the United States are not participating in sufficient levels of physical activity and are not spending much time outdoors. Recently, the need for equitable access to nature for all populations has been receiving more public health attention, though a specific focus on nature-based physical activity has been limited. The purpose of this scoping review is to operationalize the health benefits of nature-based physical activity in order to provide guidance for collaborations to program administrators, advocates, and researchers. Peer-reviewed literature is found in PubMed, Medline, Web of Science, and Google Scholar as well as in published reviews of the literature. The literature is divided into three categories of: 1) amount and location of nature-based components and physical activity; 2) added health benefits of exposure to nature-based components and physical activity; and 3) nature-based components and physical activity effect on non-white, marginalized, and vulnerable populations. This review supports and encourages multiple strategies to increase nature-based physical activity as this provides even greater benefit to health and wellness than exposure to nature or physical activity alone. Although many of the physical and mental health benefits of nature and physical activity are well established, additional research is needed to better understand the relationship between exposure to nature and nature-based physical activity, which will require greater investment and support from funding agencies.

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.

The Effects of Forest Therapy on Immune Function

We conducted a systematic review of the effects of a forest therapy program on adults’ immune function. We used PICO-SD (participants, interventions, comparisons, outcomes, study design) to identify key items. The participants were adults over the age of 18 and the intervention was forest therapy. Our comparisons included studies that comparatively analyzed urban groups or groups that did not participate in forest therapy intervention. Cases without control groups were also included. Immunological outcome measures were included in measuring intervention outcomes. All experimental studies, such as randomized controlled trials (RCTs), non-equivalent control group designs (non-RCTs), and one-group pretest-posttest design were included in the study design. A total of 13 studies were included for comparison. Forest therapy programs were divided into lodging-type and session-type programs. The representative measures for evaluating the effects of immune function were the number of NK cells, the cytotoxic activity of NK cells, and cytotoxic effector molecules. Most studies reported improvement in these measures when comparing values after intervention with values before the forest therapy intervention. Therefore, forest therapy has been found to be effective in improving immune function. More RCT studies on the effects of forest therapy on immune function are necessary.

Green-Blue Spaces and Population Density versus COVID-19 Cases and Deaths in Poland

In the last year, in connection with the COVID-19 pandemic caused by the SARS-CoV-2 coronavirus, scientific papers have appeared in which the authors are trying to identify factors (including environmental) favoring the spread of this disease. This paper presents the spatial differentiation in the total number of COVID-19 cases and deaths during the full year (March 2020-March 2021) of the SARS-CoV-2 pandemic in Poland versus green-blue spaces (green-i.a. forests, orchards, meadows and pastures, recreational and rest areas, biologically active arable land; blue-lakes and artificial water reservoirs, rivers, ecological areas and internal waters) and population density. The analysis covers 380 counties, including 66 cities. This study used daily reports on the progress of the pandemic in Poland published by the Ministry of Health of the Republic of Poland and unique, detailed data on 24 types of land use available in the Statistics Poland database. Statistical relationships were determined between the above-mentioned environmental variables and the variables characterizing COVID-19 (cases and deaths). Various basic types of regression models were analysed. The optimal model was selected, and the determination coefficient, significance level and the values of the parameters of these relationships, together with the estimation error, were calculated. The obtained results indicated that the higher the number of green-blue spaces in individual counties, the lower the total number of COVID-19 infections and deaths. These relationships were described by logarithmic and homographic models. In turn, an increase in the population density caused an increase in COVID-19 cases and deaths, according to the power model. These results can be used in the current analysis of the spread of the pandemic, including the location of potential outbreaks. In turn, the developed models can be used as a tool in forecasting the development of the pandemic and making decisions about the implementation of preventive measures.

Lipopolysaccharide-Enhanced Responses against Aryl Hydrocarbon Receptor in FcgRIIb-Deficient Macrophages, a Profound Impact of an Environmental Toxin on a Lupus-Like Mouse Model

Fc gamma receptor IIb (FcgRIIb) is the only inhibitory-FcgR in the FcgR family, and FcgRIIb-deficient (FcgRIIb^−/−) mice develop a lupus-like condition with hyper-responsiveness against several stimulations. The activation of aryl hydrocarbon receptor (Ahr), a cellular environmental sensor, might aggravate activity of the lupus-like condition. As such, 1,4-chrysenequinone (1,4-CQ), an Ahr-activator, alone did not induce supernatant cytokines from macrophages, while the 24 h pre-treatment by lipopolysaccharide (LPS), a representative inflammatory activator, prior to 1,4-CQ activation (LPS/1,4-CQ) predominantly induced macrophage pro-inflammatory responses. Additionally, the responses from FcgRIIb^−/− macrophages were more prominent than wild-type (WT) cells as determined by (i) supernatant cytokines (TNF-α, IL-6, and IL-10), (ii) expression of the inflammation associated genes (NF-κB, aryl hydrocarbon receptor, iNOS, IL-1β and activating-FcgRIV) and cell-surface CD-86 (a biomarker of M1 macrophage polarization), and (iii) cell apoptosis (Annexin V), with the lower inhibitory-FcgRIIb expression. Moreover, 8-week-administration of 1,4-CQ in 8 week old FcgRIIb^−/− mice, a genetic-prone lupus-like model, enhanced lupus characteristics as indicated by anti-dsDNA, serum creatinine, proteinuria, endotoxemia, gut-leakage (FITC-dextran), and glomerular immunoglobulin deposition. In conclusion, an Ahr activation worsened the disease severity in FcgRIIb^−/− mice possibly through the enhanced inflammatory responses. The deficiency of inhibitory-FcgRIIb in these mice, at least in part, prominently enhanced the pro-inflammatory responses. Our data suggest that patients with lupus might be more vulnerable to environmental pollutants.

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.

To stress or not to stress: Brain-behavior-immune interaction may weaken or promote the immune response to SARS-CoV-2

The COVID-19 pandemic continues to strongly affect people with health disadvantages, creating a heavy burden on medical systems and societies worldwide. Research is growing rapidly and recently revealed that stress-related factors such as socio-economic status, may also play a pivotal role. However, stress research investigating the underlying psychoneuroimmune interactions is missing. Here we address the question whether stress-associated neuroendocrine-immune mechanisms can possibly contribute to an increase in SARS-CoV-2 infections and influence the course of COVID-19 disease. Additionally, we discuss that not all forms of stress (e.g. acute versus chronic) are detrimental and that some types of stress could attenuate infection-risk and -progression. The overall aim of this review is to motivate future research efforts to clarify whether psychosocial interventions have the potential to optimize neuroendocrine-immune responses against respiratory viral infections during and beyond the COVID-19 pandemic. The current state of research on different types of stress is summarized in a comprehensive narrative review to promote a psychoneuroimmune understanding of how stress and its mediators cortisol, (nor)adrenaline, neuropeptides and neurotrophins can shape the immune defense against viral diseases. Based on this understanding, we describe how people with high psychosocial stress can be identified, which behaviors and psychosocial interventions may contribute to optimal stress management, and how psychoneuroimmune knowledge can be used to improve adequate care for COVID-19 and other patients with viral infections.

Impacts of COVID-19 pandemic on urban park visitation: a global analysis

The COVID-19 pandemic has resulted in over 33 million confirmed cases and over 1 million deaths globally, as of 1 October 2020. During the lockdown and restrictions placed on public activities and gatherings, green spaces have become one of the only sources of resilience amidst the coronavirus pandemic, in part because of their positive effects on psychological, physical and social cohesion and spiritual wellness. This study analyzes the impacts of COVID-19 and government response policies to the pandemic on park visitation at global, regional and national levels and assesses the importance of parks during this global pandemic. The data we collected primarily from Google's Community Mobility Reports and the Oxford Coronavirus Government Response Tracker. The results for most countries included in the analysis show that park visitation has increased since February 16th, 2020 compared to visitor numbers prior to the COVID-19 pandemic. Restrictions on social gathering, movement, and the closure of workplace and indoor recreational places, are correlated with more visits to parks. Stay-at-home restrictions and government stringency index are negatively associated with park visits at a global scale. Demand from residents for parks and outdoor green spaces has increased since the outbreak began, and highlights the important role and benefits provided by parks, especially urban and community parks, under the COVID-19 pandemic. We provide recommendations for park managers and other decision-makers in terms of park management and planning during health crises, as well as for park design and development. In particular, parks could be utilized during pandemics to increase the physical and mental health and social well-being of individuals.

Health Disparities in COVID-19: Addressing the Role of Social Determinants of Health in Immune System Dysfunction to Turn the Tide

It is evident that health disparities exist during the COVID-19 pandemic, a pandemic caused by the novel coronavirus SARS-CoV-2. Underlying reasons for COVID-19 health disparities are multi-factorial. However, social determinants, including those regarding socioeconomic status, social inequalities, health behaviors, and stress, may have implications on these disparities. Exposure to one or more of these social determinants is associated with heightened inflammatory responses, particularly increases in the cytokine interleukin-6 (IL-6), as well as immune system dysfunction. Thus, an amplified effect during COVID-19 could occur, potentially resulting in vulnerable patients experiencing an intensified cytokine storm due to a hyperactive and dysfunctional immune response. Further understanding how social determinants play a mechanistic role in COVID-19 disparities could potentially help reduce health disparities overall and in future pandemics.

Effects of forest bathing on pre-hypertensive and hypertensive adults: a review of the literature

The aim in this literature review was (1) to explore the physiologically and psychologically therapeutic benefits of forest bathing on adults suffering from pre-hypertension or hypertension, and (2) to identify the type, duration, and frequency of an effective forest bathing intervention in the management of pre-hypertension and hypertension, so as to provide directions for future interventions or research. The electronic databases PubMed, Cochrane Library, CINAHL, PsyINFO, and the China Academic Journals (CAJ) offered through the Full-text Database (CNKI) were searched for relevant studies published from the inception of the databases to April 2019. Of the 364 articles that were identified, 14 met the criteria for inclusion in this review. The synthesis of the findings in the included studies revealed that forest bathing interventions were effective at reducing blood pressure, lowering pulse rate, increasing the power of heart rate variability (HRV), improving cardiac-pulmonary parameters, and metabolic function, inducing a positive mood, reducing anxiety levels, and improving the quality of life of pre-hypertensive or hypertensive participants. Forest walking and forest therapy programs were the two most effective forest bathing interventions. Studies reported that practicing a single forest walking or forest therapy program can produce short-term physiological and psychological benefits. It is concluded that forest bathing, particularly forest walking and therapy, has physiologically and psychologically relaxing effects on middle-aged and elderly people with pre-hypertension and hypertension.

Measures to Promote Rural Healthcare Tourism with a Scientific Evidence-Based Approach

The present study aimed to evaluate the effects of physical activities on human health in forests in countryside and rural areas. The test experiment was conducted in a countryside forest, whereas the controlled experiment was conducted in an urban area where the study participants resided. A total of 22 participants (aged 20.9 ± 1.3 years) were evaluated in this study. Heart rate variability and salivary cortisol level were used as indices of physiological conditions, and semantic differential method, profile of mood states (POMS), and state-trait anxiety inventory (STAI) were used to evaluate the participants’ emotional states. The participants were asked to walk around forest and urban areas for 15 min. The results were as follows. As compared to the urban area, in the forest area, (1) the power of the high-frequency (HF) component of the heart rate variability (HRV) was significantly higher; (2) low-frequency (LF)/(LF + HF) was significantly lower; (3) salivary cortisol level was significantly lower; (4) the participants felt more comfortable, natural, relaxed, and less anxious and showed higher levels of positive emotions and lower levels of negative emotions. Consequently, walking in the forest area induces relaxing short-term physiological and psychological effects on young people living in urban areas.

Current Development Status of Forest Therapy in China

As a result of rapid urbanization and urban sprawl, natural ecosystems are shrinking or are fragmented, affecting people’s health and quality of life. Modern people prefer to live in large cities rather than rural areas because of greater convenience and more comfortable living conditions. As a consequence, people are suffering from many psycho-physiological health problems and have a longing for natural environments to escape the concrete jungle. Forest therapy has emerged as a preventive and alternative therapy to cope with stress and enhance people’s health and wellbeing as a result of spending time in a green and healthy environment. Here, we review the activities related to forest therapy in China and discuss the commonalities and differences between the forest therapy types. Furthermore, we summarize the current achievements of forest therapy in basic research and the development of the forest therapy industry. We also describe the challenges that forest therapy has been facing. Finally, we provide suggestions for further development in research and industry.

How Should Forests Be Characterized in Regard to Human Health? Evidence from Existing Literature

The potential of forests as a source of health has been addressed by the scientific community and is now being considered in national forest strategies, management plans and policies. Studies identifying the mechanisms by which forest characteristics may induce these effects on human health are nevertheless scarce. This systematic review of literature on forests and human health with real-life human exposure was conducted to assess the extent to which forests have been studied and described in detail and the extent to which relationships between forest variables and health effects have been reported. The analysis underlines the lack of forest descriptions in 19.35% of the 62 studies selected for review as well as the high heterogeneity of forest variables’ description. Patterns among the articles could not be identified correlating the broader forest variable (forest type) and the most studied health variables identified (blood pressure, pulse rate or/and cortisol levels). These findings, together with previous ex situ researches, suggest the need to ameliorate and incorporate more accurate descriptions of forest variables within human health studies to provide data for forest management and the potential use of these habitats for preventive medicine and clinical practice guidelines.

Residential neighbourhood greenspace is associated with reduced risk of cardiovascular disease: A prospective cohort study

Background

Living in a greener neighbourhood may reduce the risk of developing incident cardiovascular disease, but evidence is limited by reliance on cross-sectional comparisons. We use data from a longitudinal study with a time-independent measure of risk to explore the association between exposure to greenspace and cardiovascular disease.

Methods

Data was from the European Prospective Investigation of Cancer Norfolk UK cohort, baseline 1993–1997 (n = 24,420). Neighbourhoods were defined as 800m radius zones around participants’ home, according to their home postcode (zip code) in the year 2000. Greenspace exposure was identified using classified satellite imagery. Adjusted Cox proportional hazards regression examined associations between greenspace and incident cardiovascular disease. Mediation analysis assessed if physical activity mediated associations, whilst modification by rurality, socio-economic status and age was explored.

Results

The mean age of participants was 59.2 years at baseline, 54.7% were female, and mean follow-up time was 14.5 years. Individuals living in the greenest neighbourhood quartile had a 7% lower relative hazard of developing cardiovascular disease than other neighbourhoods (HR 0.93; 95% CI 0.88, 0.97; p = 0.003) after adjusting for age, sex, BMI, prevalent diabetes and socio-economic status (SES). Physical activity did not mediate the relationship (greenest compared to the least green quartile HR 0.99; 95% CI 0.97, 1.01; p = 0.416). Models predicted incidence of cardiovascular disease in the least green neighbourhoods (19.4% greenspace on average) would fall by 4.8% (95% CI 1.6%, 8.2% p = 0.003) if they were as green as the average neighbourhood (59.0% greenspace). Occupation moderated the relationship, whereby exposure to greenspace was not associated with incident CVD for participants engaged in manual occupations.

Conclusions

Greener home neighbourhoods may protect against risk of cardiovascular disease even after accounting for SES, whilst the mechanism does not appear to be strongly associated with physical activity. Putative causal mechanisms require investigation.

Medical empirical research on forest bathing (Shinrin-yoku): a systematic review

Aims

This study focused on the newest evidence of the relationship between forest environmental exposure and human health and assessed the health efficacy of forest bathing on the human body as well as the methodological quality of a single study, aiming to provide scientific guidance for interdisciplinary integration of forestry and medicine.

Method

Through PubMed, Embase, and Cochrane Library, 210 papers from January 1, 2015, to April 1, 2019, were retrieved, and the final 28 papers meeting the inclusion criteria were included in the study.

Result

The methodological quality of papers included in the study was assessed quantitatively with the Downs and Black checklist. The methodological quality of papers using randomized controlled trials is significantly higher than that of papers using non-randomized controlled trials (p < 0.05). Papers included in the study were analyzed qualitatively. The results demonstrated that forest bathing activities might have the following merits: remarkably improving cardiovascular function, hemodynamic indexes, neuroendocrine indexes, metabolic indexes, immunity and inflammatory indexes, antioxidant indexes, and electrophysiological indexes; significantly enhancing people’s emotional state, attitude, and feelings towards things, physical and psychological recovery, and adaptive behaviors; and obvious alleviation of anxiety and depression.

Conclusion

Forest bathing activities may significantly improve people’s physical and psychological health. In the future, medical empirical studies of forest bathing should reinforce basic studies and interdisciplinary exchange to enhance the methodological quality of papers while decreasing the risk of bias, thereby raising the grade of paper evidence.