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Charting a Path to Health for All at Net-Zero Emissions
Climate change is the defining health challenge of the 21st century, with record-breaking temperatures and extreme weather events already exacting an unprecedented toll on human health and wellbeing. Scientific consensus is clear: rapid and deep reductions in greenhouse gas (GHG) emissions by 2050 are needed not only to reduce the risks of exceeding climate tipping points beyond which irreversible damage occurs to natural systems, but also to safeguard human health, wellbeing, and equity. Despite growing awareness of the climate–health nexus, climate interventions often fail to consider opportunities to maximise co-benefits.
Read moreForest Terpenes and Stress: Examining the Associations of Filtered vs. Non-filtered Air in a Real-Life Natural Environment
Human health may benefit from exposure to a class of biogenic volatile organic compounds (BVOCs) consisting of isoprene units, known as terpenes. In this double-blind, randomized crossover trial, participants sat in a forest for two 60-min sessions, one in which terpenes were filtered out of the ambient air they breathed, and another in which they were not, separated by a minimum of an eight-day washout period. The primary outcome was the high frequency (HF) component of heart rate variability (HRV; measured continuously). Secondary outcomes included skin conductance levels (SCL) (measured continuously), self-reported stress and affect (measured every 20 min), blood pressure, heart rate, cortisol and inflammatory cytokines (measured before and after sessions). Serum concentrations of terpenes (measured before and after sessions) were also assessed to investigate the association of absorbed dose with these outcomes. We did not observe a significant association of filter condition with most outcomes; although the trends for affect, systolic blood pressure, cortisol, TNF-α, and CRP were all in the hypothesized direction. We did observe a significant association with interleukin-6, which was −0.19 pg/mL lower in the terpenes-on vs. terpenes-off condition, adjusted for baseline (95 % CI: −0.35, −0.03); and SCL over the session as a whole. A sensitivity analysis of the subset of data from participants who completed both conditions supports these findings and revealed additional significant associations with SCL (95 % CI: −1.87, −0.05); and TNF-α (95 % CI: −2.63, −0.10). To our knowledge, this is the first RCT to filter terpenes from ambient air during forest contact. Highlights Powered Air Purifying Respirator (PAPR) helmets filtered terpenes from forest air. Psychophysiological and immunological correlates of stress were assessed. IL-6 serum levels lower after sessions with terpenes-on vs. terpenes-off filter. Skin conductance levels (SCL) lower across time with terpenes-on vs. terpenes-off. All other outcomes not significant, but many trended in the hypothesized directions. Keywords Terpenes; Forest; Nature; Health; Stress
Read moreNature Contact and Health Risk Behaviours: Results From an 18 Country Study
Emerging evidence suggests that residential greenspace is associated with a lower prevalence of health risk behaviours, but it remains unclear whether these effects are generalizable across countries or different types of nature contact. Using representative cross-sectional samples from 18 countries/regions, we examined the associations between two types of nature contact (greenspace, nature visits), current smoking and everyday drinking. After controlling for a range of covariates, greenspace was inversely associated with current smoking and everyday drinking. Visiting natural spaces at least once a week was linked to a lower prevalence of current smoking, but unrelated to everyday drinking. Increasing residential greenspace could be a promising strategy for reducing multiple health risk behaviours, whilst visit-based interventions may be a more appropriate target for smoking cessation. Highlights Examined the links between nature and health-risk behaviours in 18 countries. Greenspace predicted lower current smoking and exceeding alcohol guidelines. Weekly nature visits were associated with a lower prevalence of current smoking. Greenspace-behaviour associations were largely consistent between countries.
Read moreThe Psychological Benefits of Open-Water (Wild) Swimming: Exploring a Self-Determination Approach Using a 19-Country Sample
A growing body of qualitative and quantitative research has explored the potential benefits to mental health and well-being of open-water or “wild” swimming. To date, most studies have used small samples in specific locations, limiting generalisability, and have not distinguished open-water swimming from other forms of outdoor swimming, such as in open-air pools, raising questions about any additional benefits of wild swimming over and above swimming outside per se. Using survey data from n =1,200 recently recalled outdoor swimming visits across 19 different countries, we compared self-reported well-being outcomes for swims in either open-water (wild) locations or open-air pools. Additionally, we explored the degree to which satisfaction of the motivations identified by self-determination theory (i.e. autonomy, relatedness, and competence) may explain any differences. Swimming visits in both locations were associated with high levels of positive, and low levels of negative, well-being, as well as high levels of autonomy, relatedness and competence. Open-water swimming was, nonetheless, associated with significantly higher positive well-being than open-air pool swims, with mediation analysis indicating that feelings of greater autonomy and competence (but not relatedness) primarily accounted for the difference. Results for anxiety were more nuanced, perhaps because more competent swimmers were more likely to swim in less safe, more anxiety inducing, places. Results re-iterate, help explain, and support the generalisation of previous research reporting potential benefits of open-water swimming for mental health and well-being, and highlight the need to support further safe access to high quality open-water locations.
Read moreWill Biodiversity Actions Yield Healthy Places? A Systematic Review of Human Health Outcomes Associated With Biodiversity-Focused Urban Greening
Figure 1. Seven biodiversity-supporting elements in urban landscapes and definitions for each. Biodiversity-supporting elements are adapted from Spotswood et al. (2019). There is growing interest in using urban greening projects to support biodiversity. While there are many potential co-benefits, the health outcomes resulting from biodiversity-supporting activities have yet to be synthesized. We conducted a systematic review of health outcomes associated with seven biodiversity-supporting elements, including patch size, connections, matrix quality, habitat diversity, native plants, special resources and vegetation management. We identified 1550 studies linking elements with human health. Results show that many types of biodiversity-supporting elements are associated with a wide range of positive health outcomes. These outcomes included improved physical and mental health, increased physical activity, improved childhood development, social outcomes, and reduced exposure to harms such as sun, heat, and pollution (including light, air and noise). Other biodiversity-supporting elements such as reducing pesticide use, native plants, and habitat diversity were associated with a smaller and more specific range of health outcomes. While most findings showed positive associations between biodiversity-supporting elements and health, many also yielded mixed, neutral, or negative findings. Further, most identified study designs were observational, limiting our ability to uncover causality. We found that studies using a natural experimental design yielded a greater fraction of mixed, neutral, and negative findings compared to observational designs (the majority of studies) and experimental studies (largely short term in nature). These results confirm concerns about the strength of research findings built largely on correlational research designs. We also identify areas of trade-off between biodiversity-supporting elements and human health. These include actions that positively affect health yet negatively impact biodiversity, such as the maintenance of sports fields and trails in parks that can negatively impact habitat and disrupt wildlife behaviour. Biodiversity-supporting elements can also negatively impact some dimensions of human health, including by increasing human–wildlife conflict, disease vectors, allergenic pollen, biogenic volatile organic compounds (BVOCs), through and green gentrification. Our review reveals a large potential for co-benefits for human health to come from biodiversity-focused actions in cities. Careful attention to minimizing tensions and trade-offs could help to reduce the potential for conflict between biodiversity and human health objectives.
Read more“We don’t separate out these things. Everything is related”: Partnerships with Indigenous Communities to Design, Implement, and Evaluate Multilevel Interventions to Reduce Health Disparities
Figure 1. An overview of the partnerships in MLIs by building on the Indigenous Holistic Health and Wellness Multilevel Framework Multilevel interventions (MLIs) are appropriate to reduce health disparities among Indigenous peoples because of their ability to address these communities’ diverse histories, dynamics, cultures, politics, and environments. Intervention science has highlighted the importance of context-sensitive MLIs in Indigenous communities that can prioritize Indigenous and local knowledge systems and emphasize the collective versus the individual. This paradigm shift away from individual-level focus interventions to community-level focus interventions underscores the need for community engagement and diverse partnerships in MLI design, implementation, and evaluation. In this paper, we discuss three case studies addressing how Indigenous partners collaborated with researchers in each stage of the design, implementation, and evaluation of MLIs to reduce health disparities impacting their communities. We highlight the following: Collaborations with multiple, diverse tribal partners to carry out MLIs which require iterative, consistent conversations over time; Inclusion of qualitative and Indigenous research methods in MLIs as a way to honor Indigenous and local knowledge systems as well as a way to understand a health disparity phenomenon in a community; and Relationship building, maintenance, and mutual respect among MLI partners to reconcile past research abuses, prevent extractive research practices, decolonize research processes, and generate co-created knowledge between Indigenous and academic communities.
Read moreAssociations of Nature Contact with Emotional Ill-Being and Well-Being: The Role of Emotion Regulation
Figure 1. Bayesian structural equation model results with frequency of nature contact, emotion regulation, and emotional ill-being and well-being. Nature contact has associations with emotional ill-being and well-being. However, the mechanisms underlying these associations are not fully understood. We hypothesised that increased adaptive and decreased maladaptive emotion regulation strategies would be a pathway linking nature contact to ill-being and well-being. Using data from a survey of 600 U.S.-based adults administered online in 2022, we conducted structural equation modelling to test our hypotheses. We found that: Frequency of nature contact was significantly associated with lesser emotional ill-being and greater emotional well-being, Effective emotion regulation was significantly associated with lesser emotional ill-being and greater emotional well-being, and The associations of higher frequency of nature contact with these benefits were partly explained via emotion regulation. Moreover, we found a nonlinear relationship for the associations of duration of nature contact with some outcomes, with a rise in benefits up to certain amounts of time, and a levelling off after these points. These findings support and extend previous work that demonstrates that the associations of nature contact with emotional ill-being and well-being may be partly explained by changes in emotion regulation.
Read moreHealth Professionals and the Climate Crisis
Health professionals from every corner of the health sector—from allergy to vascular surgery, from epidemiology to environmental health, from nursing to hospital administration—have recognized the magnitude and urgency of the climate crisis. A growing literature provides guidance on how to conceptualize and meet the vast challenges we face and on how to keep our spirits up as we do so.
Read moreNature and Human Well-Being: The Olfactory Pathway
Figure 1. Conceptual framework of the pathway from exposure to natural olfactory environments to human well-being. The olfactory environment is characterized by the concentrations and ratios of airborne chemicals. Dimensions of olfactory function (i.e., sensitivity, discrimination, and identification) are influenced by a variety of individual and environmental factors, which together moderate olfactory perception. Subjective experience is a mediator through which olfactory perceptions lead to well-being outcomes. Relevant determinants of this experience include individual preference, culture, association, prior experience, and multisensory context. Other pathways to well-being include those that occur below the threshold of perception (i.e., subthreshold) and those that occur via initial affective responses that are suprathreshold but independent of top-down processes related to subjective experience. These components lead to a variety of well-being outcomes, from broader dimensions such as quality of and satisfaction with life, to emotional responses and emotion regulation, cognitive function, influences on behavior (social interactions and dietary choices), stress, depressive symptoms, (anti-)inflammatory processes, and effects from exposures to pathogens. Together, these outcomes are the result of subthreshold biochemical processes, initial affective responses, and subjective appraisals of odors from nature. A variety of other pathways mediate the relationship between olfactory environments and human well-being, although they are not illustrated here. Credit: University of Washington The world is undergoing massive atmospheric and ecological change, driving unprecedented challenges to human well-being. Olfaction is a key sensory system through which these impacts occur. The sense of smell influences quality of and satisfaction with life, emotion, emotion regulation, cognitive function, social interactions, dietary choices, stress, and depressive symptoms. Exposures via the olfactory pathway can also lead to (anti-)inflammatory outcomes. Increased understanding is needed regarding the ways in which odorants generated by nature (i.e., natural olfactory environments) affect human well-being. With perspectives from a range of health, social, and natural sciences, we provide an overview of this unique sensory system, four consensus statements regarding olfaction and the environment, and a conceptual framework that integrates the olfactory pathway into an understanding of the effects of natural environments on human well-being. We then discuss how this framework can contribute to better accounting of the impacts of policy and land-use decision-making on natural olfactory environments and, in turn, on planetary health. Related Media How the smells of nature can affect human well-being (May 29, 2024) How do the smells of nature affect well-being? A call for more research. (May 23, 2024) Nature’s scents linked to improved health and well-being (May 16, 2024)
Read moreQuantifying Nature: Introducing NatureScoreTM and NatureDoseTM as Health Analysis and Promotion Tools
The Value of Nature Exposure in the 21st Century Figure 1. New tools to quantify nature at any location in the United States (NatureScoreTM, left panel) and an individual’s daily or weekly exposure to nature (NatureDoseTM, right panel). The app provides NatureScoreTM values to users within a 1-km buffer, although values can be calculated at smaller distances or averaged across spatial units (i.e., census tracts). Humanity is undergoing a monumental shift. People have rapidly moved from a largely natural, outdoor existence to life in built, urban settings. Most places where people live and work differ dramatically from the ones we occupied for 99.9% of human history, and our current surroundings often physically separate us from the natural world. Most people—over half globally and approximately 4 in 5 in the United States—now live in urban areas,1 where nearby nature exposure tends to be limited2 and unequally distributed across socioeconomic and racial/ethnic subgroups.3-6 Adults in higher-income countries spend 80%-90% of their lives sedentary and indoors,7-9 with 6 to 8 hours or more spent each day looking at screens.10-12 The same is increasingly true for our developing youth,10,13,14 who may experience poorer health across their life span as a result.15 Over the last 30 years, physicians, scientists, and journalists have come to suspect that we are experiencing a “nature deficit disorder,” or “extinction of experience”.16-22 With the loss of direct exposure to nature has also come diminished knowledge of where food comes from, an inability to recognize plants and animals, fewer opportunities to experience awe (being in the presence of something vast that transcends current understandings of the world), and a failure to develop positive emotions and empathy toward other people and the non-human world.23-25 In response to growing concerns about this radical shift, scientists worldwide have studied how nature exposure is associated with human health.26-31 The links between declining nature exposure and increasing depression, anxiety, heart disease, and premature mortality are increasingly clear.26,32 A large and growing body of scientific literature demonstrates that exposure to nature, broadly encompassing green spaces, trees, parks, water bodies, deserts, wilderness areas, wildlife, and more,30,33 is associated with measurable and meaningful benefits to dozens of facets of psychological and physical health.31,33-35 These benefits can follow from nature exposure in a variety of forms, from passively viewing nature from a park bench to walking along a tree-lined street or practicing shinrin-yoku (“forest bathing”)36 in an urban forest. At a population level, the presence of nature has also been linked to important societal benefits, such as higher property values,37 lower healthcare expenses,38,39 lower levels of air pollution, noise, and heat,40-43 as well as lower crime rates,44,45 enhanced social mobility,46 more cohesive communities,47-50 and resilience to public health crises, such as the COVID-19 pandemic.50,51 These beneficial associations are believed to result from natural areas mitigating environmental hazards, restoring cognitive capacity, reducing stress reactivity, facilitating interactions with commensurate microbiota, and promoting healthy behaviors, such as physical activity and social interaction.30,34,52,53 Like exercise, sleep, and a healthy diet,54 nature exposure may well be a necessary health behavior to promote longevity, prevent disease, and enhance wellbeing.55-57 “Nature prescribing” by healthcare providers, a growing movement, can serve as a tool for health promotion with minimal cost, side effects, equipment needs, or training requirements. Few medications or existing interventions can match these qualities. For instance, the American Heart Association’s “Life’s Essential 8” asserts that the following can help achieve an “ideal” cardiovascular health: a healthy diet, ≥150 minutes of moderate exercise or ≥75 minutes of vigorous exercise per week, not smoking or vaping, sleeping 7 to 9 hours each night, maintaining a healthy body mass index, and regularly checking and maintaining cholesterol, fasting blood sugar, and blood pressure levels.54 Nature exposure might be comparable to several of these recommendations in terms of potential health benefits and come with fewer barriers to starting and maintaining a regular practice.
Read moreStreet Trees Provide an Opportunity to Mitigate Urban Heat and Reduce Risk of High Heat Exposure
Figure 1. Study area for this work, which is part of the Greening Research in Tacoma (GRIT) project, is located in South Tacoma, Washington, USA, shown by the black square on global map, where solar radiation shields (photographed) containing temperature loggers were installed on utility poles. Here we report on temperature data from loggers at 46 locations throughout the neighborhood (blue dots) during summer 2022. Climate change is exacerbating the need for urban greening and the associated environmental and human well-being benefits. Trees can help mitigate urban heat, but more detailed understanding of cooling effects of green infrastructure are needed to guide management decisions and deploy trees as effective and equitable climate adaptation infrastructure. We investigated how urban trees affect summer air temperature along sidewalks within a neighborhood of Tacoma, Washington, USA, and to what extent urban trees reduce risks of high summer temperatures (i.e., the levels regulated by state outdoor heat exposure rules intended to reduce heat-related illnesses). Air temperature varied by 2.57 °C, on average, across our study area, and the probability of daytime temperatures exceeding regulated high temperature thresholds was up to five times greater in locations with no canopy cover within 10 m compared to those with 100% cover. Air temperatures decreased linearly with increasing cover within 10 m, suggesting that every unit of added tree cover can help cool the air. Our findings highlight the value of trees in mitigating urban heat, especially given expected warming with climate change. Protecting existing urban trees and increasing tree cover (e.g., by planting street trees), are important actions to enhance climate change resilience of urban areas.
Read moreWhat Types of Nature Exposure Are Associated With Hedonic, Eudaimonic and Evaluative Wellbeing? An 18-Country Study
Figure 2. Summary of fully adjusted models of all dimensions of SWB and residential availability and visits to green space, coastal blue space and freshwater blue space. Although spending time in nature can improve subjective wellbeing (SWB), little is known about how different types of nature exposure are associated with different dimensions of SWB or the consistency of associations across national/cultural contexts. Using data from 18 countries, associations between green, coastal and freshwater blue space exposures (including residential availability, visits ‘yesterday’ and visits in the previous four weeks) and hedonic, eudaimonic, and evaluative wellbeing were estimated. Overall, residential nature availability showed little association with any wellbeing outcome, whereas visiting green and coastal locations ‘yesterday’ was associated with better hedonic wellbeing. Although frequently visiting green, coastal and freshwater spaces were all associated with greater evaluative wellbeing, greater eudaimonic wellbeing was only associated with frequent visits to green and freshwater spaces. Variations existed across countries. Results suggest that different types of nature exposure vary in their association with different dimensions of SWB. Understanding these differences may help us maximise the potential of natural environments as SWB-promoting resources.
Read moreAll Systems are Interrelated: Multilevel Interventions with Indigenous Communities
Figure 1. Indigenous Holistic Health and Wellness Multilevel Framework. Colonial historical trauma and ongoing structural racism have impacted Indigenous peoples for generations and explain the ongoing health disparities. However, Indigenous peoples have been engaging in multilevel, clinical trial interventions with Indigenous and allied research scientists resulting in promising success. In this paper, National Institutes of Health funded scientists in the field of Indigenous health have sought to describe the utility and need for multilevel interventions across Indigenous communities (Jernigan et al., 2020). We posit limitations to the existing socioecological, multilevel frameworks and propose a dynamic, interrelated heuristic framework, which focuses on the inter-relationships of the collective within the environment and de-centers the individual. We conclude with identified calls for action within multilevel clinical trial research.
Read moreChildren’s Interactions with Relatively Wild Nature Associated with More Relational Behavior: A Model of Child-Nature Interaction in a Forest Preschool
Figure 1. Annotated maps of the Magnolia and Trillium outdoor nature classroom sites at Fiddleheads Forest Preschool in Seattle, WA. Interaction with nature is vital for children’s physical and psychological development. Nature preschools provide the means for such interaction, but little is known about the significance of child-nature interactions in these settings. Using a randomized time-sampling methodology, we conducted an observational study of 49 children in a forest preschool. Video data was collected over 35 weeks. Based on second-by-second coding, and drawing on Interaction Pattern theory, we developed a model of child-nature interaction in this setting. We then tested our hypothesis that relatively wild areas of this environment would be positively associated with child-nature behaviors that were more relational – that is, behaviors demonstrating a bond with nature or respect, including the ability to cohabitate with other lifeforms, and to promote the well-being of nature. Results confirmed this hypothesis. Discussion focuses on the phylogenetic and ontogenetic significance of the 26 modeled child-nature interactions, and the importance of more wild natural environments for human development and flourishing.
Read moreForest Therapy as a Trauma-Informed Approach to Disaster Recovery: Insights from a Wildfire-Affected Community
Figure 1. The Association of Nature and Forest Therapy standard sequence of events used to guide a forest therapy experience. Clifford and Page, 2020. A trauma-informed approach to disaster recovery recognizes the potential impacts of trauma, promotes resilience to protect against retraumatization, and can support catering the needs of disaster survivors in affected communities. A growing body of evidence demonstrates that interaction with nature is associated with a number of physical and mental health benefits, though literature surrounding nature-based therapy and disaster survivors is limited. Through key informant interviews with forest therapy guides from a program in wildfire affected Butte County, CA, this exploratory study investigates if and how “Forest Therapy ’’ can serve as a trauma-informed approach to promote wellbeing in the face of climate change and associated disasters. We find that community-based forest therapy programs offer a promising, flexible approach to community-based trauma-informed mental health services in disaster-affected communities. Findings also identify opportunities to tailor implementation of future programs to better reach populations most impacted by disasters, including through targeted outreach and diverse guide recruitment. Future research should investigate the impacts of forest therapy on the mental health and wellbeing of participants, as well as the scalability of forest therapy programs in disaster-affected communities.
Read moreHealthy by Nature: Policy Practices Aimed at Maximizing the Human Behavioral Health Benefits of Nature Contact
Research suggests that spending time in nature is associated with numerous human behavioral health benefits, including improved executive functioning abilities, enhanced recovery from stressful situations, better mental health, and better educational outcomes. Greener neighborhoods also tend to have positive population-level health outcomes. Although promising, much of this research has focused primarily on selective populations and fails to account for cultural differences in how “nature” is conceptualized. Therefore, challenges may arise as policymakers aim to implement nature-based policies in their communities, given the immense cultural diversity of the United States alone. Given this ever-present challenge in behavioral sciences, policy recommendations aim both to maximize benefits of nature contact and to employ a flexible equity lens that allow for differences according to community need.
Read moreLand as a Process of Reconciliation: Transforming Health Narratives Among Land-Based Healing Camp Facilitators
Colonialism has resulted in isolation, lack of services, and health disparities experienced by Indigenous peoples (IPs)1 which increased risk for COVID-19. Despite this, IPs have found ways to thrive. For example, they have implemented land-based healing (LBH) interventions2, 3, 4. Increasing cultural continuity through reconnecting to the land has broad implications for the health and wellbeing of IPs. As such, CIEDAR (CoVaRR-Net’s Indigenous Engagement, Development, and Research Pillar 7) partnered with Taché Waters Healing Society (TWHS) to achieve the following objectives. To co-develop a LBH camp grounded in culture to facilitate healing from the ongoing impacts of settler-colonialism, exacerbated by the pandemic. To evaluate the LBH camp pilot by asking the following question: How does being guided upon the land influence facilitators perspectives of health and wellbeing?
Read moreLeveraging Neuroscience for Climate Change Research
Figure 1: Reciprocal relationships between the brain and a changing environment. Anthropogenic climate change poses a substantial threat to societal living conditions. Here, we argue that neuroscience can substantially contribute to the fight against climate change and provide a framework and a roadmap to organize and prioritize neuroscience research in this domain. We outline how neuroscience can be used to: (1) investigate the negative impact of climate change on the human brain; (2) identify ways to adapt; (3) understand the neural substrates of decisions with pro-environmental and harmful outcomes; and (4) create neuroscience-based insights into communication and intervention strategies that aim to promote climate action. The paper is also a call to action for neuroscientists to join broader scientific efforts to tackle the existential environmental threats Earth is currently facing. Related Media Call for Action: The Power of Neuroscience to fight against Climate Change (November 13, 2023)
Read moreNature Contact and General Health: Testing Multiple Serial Mediation Pathways with Data from Adults in 18 Countries
Figure 1. A diagram of the proposed modelling approach. Direct effects from neighbourhood nature and nature visit frequency variables to general health are not shown for clarity. Solid lines represent direct, indirect, or potential confounding effects. Dotted lines represent residual covariances. The role of neighbourhood nature in promoting good health is increasingly recognised in policy and practice, but consistent evidence for the underlying mechanisms is lacking. Heterogeneity in exposure methods, outcome measures, and population characteristics, little exploration of recreational use or the role of different types of green or blue space, and multiple separate mediation models in previous studies have limited our ability to synthesise findings and draw clear conclusions. We examined multiple pathways linking different types of neighbourhood nature with general health using a harmonised international sample of adults. Using cross-sectional survey data from 18 countries (n = 15,917), we developed a multigroup path model to test theorised pathways, controlling for sociodemographic variables. We tested the possibility that neighbourhood nature (e.g. greenspace, inland bluespace, and coastal bluespace) would be associated with general health through lower air pollution exposure, greater physical activity attainment, more social contact, and higher subjective well-being. However, our central prediction was that associations between different types of neighbourhood nature and general health would largely be serially mediated by recent visit frequency to corresponding environment types, and, subsequently, physical activity, social contact, and subjective well-being associated with these frequencies. Several subsidiary analyses assessed the robustness of the results to alternative model specifications as well as effect modification by sociodemographics. Consistent with this prediction, there was statistical support for eight of nine potential serial mediation pathways via visit frequency which held for a range of alternative model specifications. Effect modification by financial strain, sex, age, and urbanicity altered some associations but did not necessarily support the idea that nature reduced health inequalities. The results demonstrate that across countries, theorised nature-health linkages operate primarily through recreational contact with natural environments. This provides arguments for greater efforts to support use of local green/blue spaces for health promotion and disease prevention.
Read moreNature-Based Solutions and Mental Health
Nature-Based Solutions for Cities This chapter demonstrates the mental health benefits of nature-based solutions in cities. First, factors that determine urban mental health and adverse health effects of environmental stressors in cities are explained. Second, it is demonstrated that green spaces as nature-based solutions for many societal challenges provide co-benefits for mental health by reducing these stressors. It is further discussed how nature-based solutions may target supporting mental health by providing resources for human–nature interaction, enhancing social interaction and strengthening mental resilience. Nature-based interventions that are originally intended to support persons with psychiatric illness are introduced as models for the design of mentally supportive cities. And third, two case studies illustrate the mental health benefits of urban parks with the example of Leipzig, Germany and of street trees by the example of Hyderabad, India. The two case studies were used as application cases for a recent conceptual framework as a guide for putting science into practice.
Read morePhysical Activity and Social Interaction Assessments in Schoolyard Settings Using the System for Observing Outdoor Play Environments in Neighborhood Schools (SOOPEN)
Figure 1. (a) Schoolyard 1, (b) schoolyard 2, and (c) schoolyard 3 target areas for SOOPEN observations. Black outlines indicate the boundaries of each target area and white dots indicate the location where observers stood to conduct scans. For example, at School 3 (panel C), zone 1 is a paved surface, zone 2 is a covered basketball court (paved surface), zone 3 is a paved surface, zone 4 is a set of swings, zone 5 is a play structure, and zone 6 is a grass field bordered by a paved walking path Background The schoolyard environment provides key opportunities to promote physical activity and socioemotional development for children. Schoolyards can also serve as a community park resource outside of school hours. We aimed to: (i) implement and evaluate reliability of the System for Observing Outdoor Play Environments in Neighborhood Schools (SOOPEN), (ii) assess schoolyard use by children during recess and community members of all ages outside of school hours, and (iii) investigate relationships of schoolyard and children´s group characteristics with physical activity levels and prosocial interactions. Methods In this cross-sectional study, we observed student and community visitor behavior using SOOPEN at three urban elementary schoolyards in Tacoma, Washington, USA, prior to renovations intended to expand each facility’s use as a community park in neighborhoods with poor park access. We assessed interrater reliability using intraclass correlation coefficients and described current levels of schoolyard use (at the group level), physical activity, and prosocial behavior. Physical activity was assessed on a five-point scale and dichotomized to indicate moderate-to-vigorous physical activity (MVPA). Social interactions were coded as prosocial, antisocial, or neutral. We examined associations of selected schoolyard features and group characteristics with group MVPA and prosocial behavior during recess using modified Poisson regression to estimate prevalence ratios (PR) and 95% confidence intervals (CI). Results We observed a total of 981 activity-defined, informal groups in the schoolyards, and achieved good to excellent interrater reliability using SOOPEN. Community use of the schoolyards during evenings and weekends was limited (n = 56 groups). During 26, 25–50 min recess periods (n = 833 groups), 19% of groups were engaged in MVPA. Schoolyard areas with paved surfaces were associated with more MVPA (PR = 1.52, 95% CI: 1.04, 2.23) compared to field/grass areas; supervised groups were associated with less MVPA than groups not directly supervised by an adult (PR = 0.59, 95% CI: 0.36, 0.96). Schoolyard characteristics were not associated with prosocial behavior. Mixed-gender groups were associated with more MVPA and more prosocial behavior. Conclusions Our study using SOOPEN, a reliable new activity observation tool, highlights the multi-dimensional dynamics of physical activity and social interactions in schoolyards, which could be leveraged to promote healthy behaviors during and outside of school hours.
Read moreThe Health and Wellbeing Effects of Forests, Trees and Green Space
This chapter provides an overview of the empirical evidence regarding the association between green space in general, and forests and trees in particular, and health outcomes. The evidence is organised by life stage, and within the three life stages – early life (Section 3.2.), adulthood (Section 3.3.) and the elderly (Section 3.4.) – by type of health outcome. At the end of each of these three sections, the strength of the evidence for the presence (or absence) of a beneficial or detrimental association for a particular health outcome, as assessed by the authors, is summarised. Section 3.6. is devoted to modifiers of the aforementioned associations, such as gender, ethnicity and socio-economic status. In the next section (3.7.), the evidence is placed in the context of global health challenges through elaborating on the potential of green space, and forests and trees in particular, in tackling major contributors to the global burden of disease. The final section concludes that the available evidence already strongly supports a wide range of beneficial associations including neurodevelopment in children, mental health and wellbeing, spiritual wellbeing and cardiometabolic health in adults, and mental health and wellbeing, cognitive ageing and longevity in the elderly. However, this evidence is predominantly based on studies on the health and wellbeing effects of green space, and the available evidence for such effects for forests and trees is still limited for most health outcomes. Moreover, these studies have been mainly conducted in high-income countries, with their generalisability to low- and middle-income countries not being self-evident. Furthermore, the causality of the observed associations is not always clear. Nevertheless, given that many of the involved health outcomes are among the major contributors of the global burden of disease, forests, trees and green spaces have a great potential for improving health and wellbeing of humans across all life stages in our rapidly urbanising world
Read moreThe Psychological Impact of the COVID-19 Lockdown in Italy: The Moderating Role of Gender and Emotion Regulation
Figure 1. Simple slope analysis of the interaction between gender and cognitive reappraisal (outcome: Covid-19 related stress, model 1). Many researchers suggest that the COVID-19 pandemic may have more negative effects on women than men. Accordingly, we hypothesized that women would experience greater COVID-19 related distress and more psychopathological symptoms than men during the first COVID-19 lockdown in Italy. Moreover, we expected emotion regulation strategies (cognitive reappraisal and expressive suppression, as protective and risk factors respectively) to interact with gender in shaping psychological health. We administered an online questionnaire to 1519 participants during the first national COVID-19 lockdown in Italy. As predicted, women reported greater COVID-19 related distress and more psychopathological symptoms than men. Furthermore, women who made greater use of reappraisal reported lower levels of distress and fewer psychopathological symptoms. Suppression was associated with more psychopathological symptoms, but there were no interaction effects with gender. Our findings have implications for policymakers wishing to sustain women’s health during stressful situations such as the COVID-19 outbreak and beyond.
Read moreTime Spent Interacting with Nature Is Associated with Greater Well-Being for Girl Scouts Before and During the COVID-19 Pandemic
The onset of the COVID-19 pandemic rendered daily life overwhelmingly difficult for many children. Given the compelling evidence for the physical and mental health benefits of interaction with nature, might it be the case that time spent interacting with nature buffered the negative effects of the pandemic for children? To address this question, we conducted a longitudinal investigation with a cohort of 137 Girl Scouts across two time periods: right before the onset of the pandemic (December 2019–February 2020) and one year later (December 2020–February 2021). We found that during the pandemic (compared to pre-pandemic), Girl Scouts fared worse on measures of physical activity, positive emotions, negative emotions, anxiety, behavioral difficulties, and problematic media use. However, by using mixed models, we also found that, on average, Girl Scouts who spent more time interacting with nature fared less poorly (in this sense, “did better”) on measures of physical activity, positive emotions, anxiety, and behavioral difficulties, irrespective of the pandemic. Further analysis revealed that these advantageous associations were present even when accounting for the amount of nature near each child’s home (as measured by the normalized difference vegetation index, percent of natural land cover, and self-reported access to nature). To the best of our knowledge, this is the first study investigating nature interaction and children’s well-being to use data collected from the same cohort prior to and during the pandemic. In addition, we discuss the importance of opportunities to interact with nature for children’s well-being during future periods of social upheaval.
Read moreUrban Green Space and Mental Health Among People Living Alone: The Mediating Roles of Relational and Collective Restoration in an 18-Country Sample
Figure 1. Theoretical model linking exposure to green space to mental health via social restoration processes. Rates of living alone, especially in more urbanised areas, are increasing across many industrialised countries, with associated increases in feelings of loneliness and poorer mental health. Recent studies have suggested that access to nature (e.g. parks and green spaces) can reduce the stressors associated with loneliness, partly through providing opportunities to nurture personal relationships (relational restoration) and engage in normative community activities (collective restoration). Such associations might vary across different household compositions and socio-demographic or geographical characteristics, but these have not been thoroughly tested. Using data collected across 18 countries/territories in 2017–2018, we grouped urban respondents into those living alone (n = 2062) and those living with a partner (n = 6218). Using multigroup path modelling, we tested whether the associations between neighbourhood greenspace coverage (1-km-buffer from home) and mental health are sequentially mediated by: (a) visits to greenspace; and subsequently (b) relationship and/or community satisfaction, as operationalisations of relational and collective restoration, respectively. We also tested whether any indirect associations varied among subgroups of respondents living alone. Analyses showed that visiting green space was associated with greater mental well-being and marginally lower odds of using anxiety/depression medication use indirectly, mediated via both relationship and community satisfaction. These indirect associations were equally strong among respondents living alone and those living with a partner. Neighbourhood green space was, additionally, associated with more visits among respondents living with a partner, whereas among those living alone, this was sensitive to the green space metric. Within subgroups of people living alone, few overall differences were found. Some indirect pathways were, nevertheless, stronger in males, under 60-year-olds, those with no financial strain, and residents in warmer climates. In conclusion, supporting those living alone, as well as those living with a partner, to more frequently access their local greenspaces could help improve mental health via promoting relational and collective restoration.
Read moreWhere Wilderness is Found: Evidence From 70,000 Trip Reports
Figure 1. The study area, showing the boundaries of the Mt. Baker-Snoqualmie National Forest, wilderness areas within it and the trailheads for the 470 hikes in the Washington Trails Association hiking guide that we included in the sample. Map created with the R programming language using the sf, ggspatial and cowplot packages (Dunnington, 2022; Pebesma & Bivand, 2023; R Core Team, 2022; Wilke, 2019). Data from USDA Forest Service, Washington Trails Association, Washington Department of Transportation, Environmental Systems Research Institute map service and Natural Earth, facilitated by the basemaps and rnaturalearth packages for R (ESRI, 2009; Massicotte & South, 2023; Schwalb-Willmann, 2022; USDA Forest Service, 2019; WSDOT, 2023; WTA, 2023c). 1. Outdoor recreation is an essential way many people engage with nature. The provision of public spaces for recreation intersects with conservation practices motivated by intertwined social and ecological values, such as strict practices associated with the concept of ‘wilderness’. Debates persist about how such concepts and management practices influence people’s recreation experiences. 2. Many US public land management agencies facilitate opportunities for outdoor recreation, relying on management frameworks and tools intended to foster specific experiential qualities. But these frameworks and tools assume simplistic relationships between settings and people’s experiences, and managers rarely assess these relationships. 3. This study uses a data set of nearly 70,000 crowdsourced trip reports from a hiking website to understand the qualities of visitors’ experiences on trails. We study the geographic distribution of experiential qualities commonly associated with US wilderness areas: aesthetics, awe, challenge, pristineness, quietness, solitude and timelessness. Using analytical methods that rely on machine learning and natural language processing, we identify these experiential qualities in trip reports from hundreds of routes, and use generalized linear models to analyse relationships between the frequency of each experiential quality and the route’s administrative, built, biophysical, geographic and social settings. 4. We find that four of the seven experiential qualities (aesthetics, awe, challenge and solitude) are commonly described in trip reports, each appearing in 15%–55% of manually coded reports. The extent to which setting characteristics explained variability in experiences differed, ranging from 34% of the variability in the proportion of trip reports describing aesthetics to 55% for awe. The setting characteristics associated with each experiential quality also differed, with characteristics such as trail mileage and summit destinations having stronger influences on experiential qualities than characteristics such as wilderness designation. 5. Synthesis and applications. Our findings suggest the need to consider more diverse variables in experience–setting relationships, develop more robust models to characterize those relationships and create new data sources to represent understudied variables. These advances would help empirically inform and improve frameworks and tools used for recreation and wilderness planning and monitoring, and potentially promote more responsive management to evolving social– ecological values.
Read moreDevelopment and Validation of an Attitudes Towards Spending Time in Nature Scale
Figure 1. Pictorial representation of methodology steps Time spent in nature (TSN) is related to improved health and well-being; however, many adults spend little time in nature. Interventions based on health behavior theories may be effective at increasing TSN. Attitudes toward a behavior have been shown to be a strong predictor of both intention and behaviors, but valid and reliable measures regarding these attitudes are lacking. The study aim was to develop a valid and reliable attitude toward TSN scale. This scale was developed using a sequential procedure: domain identification and item generation, content validity, question pretesting, survey administration, item reduction, factors extraction, dimensionality, reliability, and validity. The investigative team generated 49 unique items. Content validity and pretesting reduced the item set to 21. A countrywide sample of 2109 adults (50.3% male, median age = 58.1; 38.8% non-White) completed an online survey. Using split-half measures, principal components analysis indicated a three-factor solution: positive attitudes, negative attitudes, and concerns about being in nature. The factor structure was upheld in confirmatory factor analyses with strong internal consistency (α = 0.92 positive attitudes; 0.84 negative attitudes; 0.84 concerns). The scales were strongly related to intentions and TSN with large effect sizes. The study resulted in a reliable and valid three-factor attitudes toward spending time in nature scale that could be used to develop interventions to increase TSN.
Read moreNature and Health: Perspectives and Pathways
As many scholars have noted, research and publications on the benefits of nature experience have grown substantially over recent years. Progress has been made on empirical fronts based on perspectives from psychology, epidemiology, sociology, exposure science, urban design, and other disciplines. Studies have revealed ways in which health outcomes differ by population characteristics (e.g., socioeconomic status), individual differences (e.g., states of baseline mental health), and interactions with different types of nature (e.g., street trees vs. large parks vs. deserts) (Barnes et al., 2019; Mitchell & Popham, 2008; Mitchell, Richardson, & Shortt, 2015; Olvera-Alvarez, Browning, Neophytou, & Bratman, 2021; Tester-Jones et al., 2020; Wheeler et al., 2015; Yin, Bratman, Browning, Spengler, & Olvera-Alvarez, 2022). Together, the evidence also illustrates the importance of accounting for different ways of “operationalizing nature” (e.g., Normalized Difference Vegetation Index [NDVI]), and methods of measuring exposure (e.g., subjective vs. objective), as well as the granularity in assessments of frequency and duration (Ekkel & de Vries, 2017; Shanahan et al., 2016).
Read moreThe Relationship Between Natural Environments and Subjective Well-Being as Measured by Sentiment Expressed on Twitter
Fig. 1. (A) The spatial distribution of tweets in the sample. (B) Land cover in Seattle. (C) Tree canopy coverage in Seattle. (D) Parks in Seattle. Land-cover and tree-canopy data were taken from the 2016 National Land Cover Database (NLCD) (Dewitz, 2019). Polygons representing urban parks within Seattle were downloaded from Seattle GeoData portal (Seattle Parks, 2012). There is growing evidence that time spent in nature can affect well-being. Nonetheless, assessing this relationship can be difficult. We used 1,971,045 geolocated tweets sent by 81,140 users from Seattle, Washington, USA to advance our understanding of the relationship between subjective well-being and natural environments. Specifically, we quantified the relationships between sentiment (negative/neutral/positive) expressed in geolocated tweets and their surrounding environments, focusing on three environmental indicators: land-cover type, tree-canopy density, and urban parks. We allowed the relationships to vary according to the broader type of environment (i.e., land-use zoning). We estimated three random-intercept partial proportional odds models corresponding to the three environmental indicators while controlling for multiple covariates. Our results suggested that for a given land-use type, tweets sent from some natural land-cover types were less likely to be negative compared to tweets sent from the urban built land-cover type. For tweets sent in industrial zones, an increase in tree-canopy cover was associated with a lower probability of having negative sentiments and with a higher probability of having positive sentiments; but for tweets sent in commercial/mixed zones, the association was reversed. Also, urban parks were generally associated with a lower probability of having negative sentiments, but tweets sent from large natural parks in residential zones were less likely to be positive. Our results suggest that the relationship between subjective well-being and natural environments depends on where people are situated in the built environment and may be more complex than previously thought. The more nuanced understanding provided by analyzing geolocated social media has potential to inform urban planning and land management.
Read moreWhat Can We Do When the Smoke Rolls In? An Exploratory Qualitative Analysis of the Impacts of Rural Wildfire Smoke on Mental Health and Well-Being, and Opportunities for Adaptation
Figure 1. Suggested content, distribution location, medium, and messenger for a wildfire smoke and wellbeing toolkit Background Extreme, prolonged wildfire smoke (WFS) events are becoming increasingly frequent phenomena across the Western United States. Rural communities, dependent on contributions of nature to people’s quality of life, are particularly hard hit. While prior research has explored the physical health impacts of WFS exposure, little work has been done to assess WFS impacts on mental health and wellbeing, or potential adaptation solutions. Methods Using qualitative methods, we explore the mental health and wellbeing impacts experienced by community members in a rural Washington State community that has been particularly hard hit by WFS in recent years, as well as individual, family, and community adaptation solutions. We conducted focus groups with residents and key informant interviews with local health and social service providers. Results Participants identified a variety of negative mental health and wellbeing impacts of WFS events, including heightened anxiety, depression, isolation, and a lack of motivation, as well as physical health impacts (e.g., respiratory issues and lack of exercise). Both positive and negative economic and social impacts, as well as temporary or permanent relocation impacts, were also described. The impacts were not equitably distributed; differential experiences based on income level, outdoor occupations, age (child or elderly), preexisting health conditions, housing status, and social isolation were described as making some residents more vulnerable to WFS-induced physical and mental health and wellbeing challenges than others. Proposed solutions included stress reduction (e.g., meditation and relaxation lessons), increased distribution of air filters, development of community clean air spaces, enhancing community response capacity, hosting social gatherings, increasing education, expanding and coordination risk communications, and identifying opportunities for volunteering. Findings were incorporated into a pamphlet for community distribution. We present a template version herein for adaptation and use in other communities. Conclusions Wildfire smoke events present significant mental health and wellbeing impacts for rural communities. Community-led solutions that promote stress reduction, physical protection, and community cohesion have the opportunity to bolster resilience amid this growing public health crisis.
Read moreAffective Benefits of Nature Contact
Figure 1. Nature contact and the process model of emotion regulation. We describe the ways in which these five family of strategies may be influenced by natural environmental factors, which in turn leads to affective benefits. Figure icon made by eucalyp from www.flaticon.com Mounting evidence demonstrates that nature exposure can have affective benefits. These include behavioral and psychophysiological responses consistent with (a) decreases in stress and negative affect; and (b) increases in subjective well-being and positive affect. What is less clear, however, is what mechanisms are responsible for these effects. In this article, we examine the evidence for affective impacts of nature exposure, consider underlying mechanisms (with a focus on affect regulation), and discuss what might moderate these effects at the individual and population level. We end by pointing to future research directions and practical applications. This includes investigations into the range of effects and duration of their impact, harnessing knowledge about temporal dynamics for insights into causal mechanisms, broadening the discussions around moderators and effect modifications to include diverse perspectives on the relationship between nature exposure and psychological well-being, and integrating findings into existing frameworks from public health.
Read moreAffective Benefits of Nature Contact: The Role of Rumination
Figure 1. Structural equation mediation model of the relationships between time in nature, rumination and positive and negative affect. Ovals denote latent variables (i.e., all but “Weekly time in nature”). Standardized coefficients are presented. *indicates path with significant relationship (α = 0.05). †Indicates path with marginally significant relationship (α = 0.10). For the “ab” paths, significance was tested with bootstrapped 95% confidence intervals. The “ab” paths indicate the indirect effect of time in nature on affect. The “c” paths indicate the total effect of time in nature on affect. The “c”’ paths indicate the direct effect of time in nature on affect. Mounting evidence shows that nature contact is associated with affective benefits. However, the psychological mechanisms responsible for these effects are not well understood. In this study, we examined whether more time spent in nature was associated with higher levels of positive affect in general, and lower levels of negative affect and rumination in general. We also conducted a cross-sectional mediation analysis to examine whether rumination mediated the association of nature contact with affect. Participants (N = 617) reported their average time spent in nature each week, as well as their general levels of positive and negative affect, and the degree to which they typically engaged in rumination in daily life. We then used structural equation modeling to test our hypotheses. Our results support the hypothesis that nature contact is associated with general levels of affect, and that rumination mediates this association for negative affect, and marginally mediates this association for positive affect.
Read moreAn Ecosystem Service Perspective on Urban Nature, Physical Activity, and Health
Figure 1. Conceptual model of the relationships among urban nature (as part of the urban system), PA (quantity and quality), and health, alignedwith an ecosystem service approach. Numbers correspond with The Current State of Knowledge points 1 and 2. Nature underpins human well-being in critical ways, especially in health. Nature provides pollination of nutritious crops, purification of drinking water, protection from floods, and climate security, among other well-studied health benefits. A crucial, yet challenging, research frontier is clarifying how nature promotes physical activity for its many mental and physical health benefits, particularly in densely populated cities with scarce and dwindling access to nature. Here we frame this frontier by conceptually developing a spatial decision-support tool that shows where, how, and for whom urban nature promotes physical activity, to inform urban greening efforts and broader health assessments. We synthesize what is known, present a model framework, and detail the model steps and data needs that can yield generalizable spatial models and an effective tool for assessing the urban nature–physical activity relationship. Current knowledge supports an initial model that can distinguish broad trends and enrich urban planning, spatial policy, and public health decisions. New, iterative research and application will reveal the importance of different types of urban nature, the different subpopulations who will benefit from it, and nature’s potential contribution to creating more equitable, green, livable cities with active inhabitants.
Read moreAssociations Between Green/Blue Spaces and Mental Health Across 18 Countries
Figure 1. Relationships between: (1) Green space visits in last 4 weeks, (2) Inland-blue space visits in last 4 weeks, (3) Coastal-blue space visits in last 4 weeks, and (4) nature connectedness (1–7); and positive well-being (0–100; a,e,l,m), risk of mental distress (0–1; b,f,j,n), use of depression medication (0–1; c,g,k,o), and use of anxiety medication (0–1; d,h,l,p), averaged across 18 countries (n = 16,302). Living near, recreating in, and feeling psychologically connected to, the natural world are all associated with better mental health, but many exposure-related questions remain. Using data from an 18-country survey (n = 16,307) we explored associations between multiple measures of mental health (positive well-being, mental distress, depression/anxiety medication use) and: (a) exposures (residential/recreational visits) to different natural settings (green/inland-blue/coastal-blue spaces); and (b) nature connectedness, across season and country. People who lived in greener/coastal neighbourhoods reported higher positive well-being, but this association largely disappeared when recreational visits were controlled for. Frequency of recreational visits to green, inland-blue, and coastal-blue spaces in the last 4 weeks were all positively associated with positive well-being and negatively associated with mental distress. Associations with green space visits were relatively consistent across seasons and countries but associations with blue space visits showed greater heterogeneity. Nature connectedness was also positively associated with positive well-being and negatively associated with mental distress and was, along with green space visits, associated with a lower likelihood of using medication for depression. By contrast inland-blue space visits were associated with a greater likelihood of using anxiety medication. Results highlight the benefits of multi-exposure, multi-response, multi-country studies in exploring complexity in nature-health associations.
Read moreAssociations of Residential Brownness and Greenness with Fasting Glucose in Young Healthy Adults Living in the Desert
Figure 1. Aerial image showing examples of brownness, greenness, and grayness in a residential area of El Paso, Texas, in June, 2019. Image source: GoogleEarth®, © 2020 Google; © 2020 INEGI. Evolutionary psychology theories propose that contact with green, natural environments may benefit physical health, but little comparable evidence exists for brown, natural environments, such as the desert. In this study, we examined the association between “brownness” and “greenness” with fasting glucose among young residents of El Paso, Texas. We defined brownness as the surface not covered by vegetation or impervious land within Euclidian buffers around participants’ homes. Fasting glucose along with demographic and behavioral data were obtained from the Nurse Engagement and Wellness Study (n = 517). We found that residential proximity to brownness was not associated with fasting glucose when modeled independently. In contrast, we found that residential greenness was associated with decreased levels of fasting glucose, despite the relatively low levels of greenness within the predominantly desert environment of El Paso. A difference between the top and bottom greenness exposure quartiles within a 250 m buffer was associated with a 3.5 mg/dL decrease in fasting glucose levels (95% confidence interval: −6.2, −0.8). Our results suggest that within the understudied context of the desert, green vegetation may be health promoting to a degree that is similar to other, non-desert locations in the world that have higher baselines levels of green.
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