Lack of nature contact

A lower connection to nature is related to lower mental health benefits from nature contact

Type of study: non-rct observational study

Number of citations: 14

Year: 2024

Authors: Chia-Chen Chang, Brenda B. Lin, Xiaoqi Feng, Erik Andersson, John Gardner, T. Astell‐Burt

Journal: Scientific Reports

Journal ranking: Q1

Key takeaways: A stronger connection to nature is linked to lower stress and anxiety levels, while a weaker connection to nature is less clear, affecting the psychological benefits from nature contact.

Nature and mental health: An ecosystem service perspective

Type of study:

Number of citations: 1214

Year: 2019

Authors: Gregory N. Bratman, C. Anderson, M. Berman, B. Cochran, S. de Vries, Jon Flanders, C. Folke, H. Frumkin, J. Gross, T. Hartig, P. Kahn, Ming Kuo, J. Lawler, P. Levin, T. Lindahl, A. Meyer-Lindenberg, R. Mitchell, Z. Ouyang, Jenny Roe, L. Scarlett, Jeffrey R. Smith, Matilda van den Bosch, B. Wheeler, M. White, Hua Zheng, G. Daily

Journal: Science Advances

Journal ranking: Q1

Key takeaways: Nature experience positively impacts mental health, and integrating it into urban design can enhance cognitive functioning, emotional well-being, and overall well-being.

Abstract: We provide consensus on the benefits of nature experience for mental health, and a model for integrating them into urban design. A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so.

Association between Contact with Nature and Anxiety, Stress and Depression Symptoms: A Primary Survey in Brazil

Type of study:

Number of citations: 28

Year: 2022

Authors: Adriano Bressane, R. Negri, Irineu de Brito Junior, Líliam César de Castro Medeiros, I. Araújo, Mirela Beatriz Silva, A. Galvão, Graziele Coraline Scofano da Rosa

Journal: Sustainability

Journal ranking: Q1

Key takeaways: Frequent contact with nature lowers the occurrence of stress, anxiety, and depression symptoms, with significant benefits observed when the contact is moderate (once or twice a week) or higher.

Abstract: Mental health benefits have been linked to human interaction with nature. However, most studies have been carried out in developed countries, limiting the generalizability of empirical findings to other parts of the world. To address this gap, this study was conducted in Brazil. The objective of the study was to assess whether the frequency of contact with nature affects the occurrence of anxiety, stress, and depression. Data were collected between June and July 2022 through an online survey (n = 1186, 1 − α = 0.95, p = 0.05, 1 − β = 0.85, rho = 0.1). Thus, the public online survey made it possible to carry out voluntary response sampling suitable for an exploratory study, with the purpose of an initial understanding of an under-researched population. First, a logistic regression was performed for quantifying the association between contact with nature and mental symptoms. In addition, three groups of people having different frequencies (low, medium, and high) of contact with nature and a reference group, comprised of those who reported no contact, were compared using Kruskal–Wallis and Dwass–Steel–Chritchlow–Fligner tests. This study employs a cross-sectional design and relies on retrospective recall. As a result, the research hypothesis was confirmed. People who very rarely have contact with nature had a 97.95% probability of moderate occurrence of stress, which decreases to 20.98% for people who have contact with nature frequently. Furthermore, in the same comparison, the probability of occurrence was 3.6 times lower for anxiety and 4.8 times lower for depression. In conclusion, the evidence indicates that the greater the frequency of contact with nature, the lower the occurrence of stress, anxiety, and depression symptoms. Nevertheless, the benefits of this contact were significant only when its frequency was moderate (about once or twice a week) or higher.

Natural outdoor environments and mental health: Stress as a possible mechanism

Type of study: non-rct observational study

Number of citations: 165

Year: 2017

Authors: M. Triguero‐Mas, David Donaire-Gonzalez, E. Seto, Antònia Valentín, D. Martinez, Graham R. Smith, Gemma Hurst, G. Carrasco-Turigas, Daniel Masterson, Magdalena van den Berg, Albert Ambros, Tania Martínez-Íñiguez, A. Dėdelė, N. Ellis, Tomas Gražulevičius, Martin Voorsmit, M. Cirach, Judith Cirac-Claveras, W. Swart, E. Clasquin, A. Ruijsbroek, Jolanda Maas, M. Jerret, R. Gražulevičienė, H. Kruize, C. Gidlow, M. Nieuwenhuijsen

Journal: Environmental Research

Journal ranking: Q1

Key takeaways: Contact with natural outdoor environments, particularly surrounding greenness, benefits mental health, with stress reduction being a potential mediator.

What is the impact of nature on human health? A scoping review of the literature

Type of study: systematic review

Number of citations: 30

Year: 2022

Authors: R. Nejade, D. Grace, L. Bowman

Journal: Journal of Global Health

Journal ranking: Q1

Key takeaways: Nature-based interventions effectively improve mental, physical, and cognitive health outcomes, with factors like wilderness, accessibility, opportunities for physical activity, and absence of noise/air pollution increasing engagement.

Abstract: Background The burden of non-communicable diseases (including poor mental health) is increasing, and some practitioners are turning to nature to provide the solution. Nature-based interventions (NBIs) could offer cost-effective solutions by reconnecting individuals with nature, but the success of these interventions depends partially on the way in which people engage with blue and green spaces. Methods We conducted a scoping review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and Cochrane guidelines to establish the evidence base for treating poor mental and physical health with NBIs. We searched five databases and the grey literature. Exposure was the active engagement with natural environments. The primary outcome was mental health and the secondary outcome was physical health defined using established metrics. All data were extracted to a charting table and reported as a narrative synthesis. Results 952 studies were identified, of which 39 met the inclusion criteria. 92% demonstrated consistent improvements across any health outcome where individuals engaged with natural outdoor environments. Mental health outcomes improved across 98% of studies while physical and cognitive health outcomes showed improvement across 83% and 75% of studies respectively. Additionally, we identified 153 factors affecting engagement with nature, 78% of which facilitated engagement compared with 22% that reduced engagement. Aspects such as the sense of wilderness, accessibility, opportunities for physical activity and the absence of noise/ air pollution all increased engagement. Conclusions Further research (accompanied by a global improvement in study design) is needed to establish the magnitude and relative effect of nature-based interventions, and to quantify the compounding effect of factors that improve engagement with green and blue spaces. Nevertheless, this review has documented the increasing body of evidence in support of NBIs as effective tools to improve mental, physical, and cognitive health outcomes, and highlighted key factors that improve engagement with the natural world. Registration Open Science Framework: https://doi.org/10.17605/OSF.IO/8J5Q3.

Testing the Biophilia theory: Automatic approach tendencies towards nature

Type of study:

Number of citations: 32

Year: 2021

Authors: Tanja Schiebel, J. Gallinat, Simone Kühn

Journal: Journal of Environmental Psychology

Journal ranking: Q1

Key takeaways: Biophilia theory suggests that people have an automatic need for contact with nature, and living in cities may contribute to mental health problems due to a lack of this contact.

Healthy nature healthy people: 'contact with nature' as an upstream health promotion intervention for populations.

Type of study: literature review

Number of citations: 1221

Year: 2006

Authors: C. Maller, M. Townsend, A. Pryor, Peter Brown, L. S. St Leger

Journal: Health promotion international

Journal ranking: Q1

Key takeaways: Contact with nature can significantly improve human health and well-being, potentially preventing mental ill health and promoting environmental sustainability.

Abstract: Whilst urban-dwelling individuals who seek out parks and gardens appear to intuitively understand the personal health and well-being benefits arising from 'contact with nature', public health strategies are yet to maximize the untapped resource nature provides, including the benefits of nature contact as an upstream health promotion intervention for populations. This paper presents a summary of empirical, theoretical and anecdotal evidence drawn from a literature review of the human health benefits of contact with nature. Initial findings indicate that nature plays a vital role in human health and well-being, and that parks and nature reserves play a significant role by providing access to nature for individuals. Implications suggest contact with nature may provide an effective population-wide strategy in prevention of mental ill health, with potential application for sub-populations, communities and individuals at higher risk of ill health. Recommendations include further investigation of 'contact with nature' in population health, and examination of the benefits of nature-based interventions. To maximize use of 'contact with nature' in the health promotion of populations, collaborative strategies between researchers and primary health, social services, urban planning and environmental management sectors are required. This approach offers not only an augmentation of existing health promotion and prevention activities, but provides the basis for a socio-ecological approach to public health that incorporates environmental sustainability.

Which dimensions of nature contact in Urban Green Spaces most significantly contribute to mental wellbeing? A multidimensional analysis in Brazilian metropolitan cities.

Type of study: non-rct observational study

Number of citations: 3

Year: 2024

Authors: Adriano Bressane, Joao Pedro da Cunha Pinto, Ana Paula Garcia Goulart, Líliam César de Castro Medeiros

Journal: Health & place

Journal ranking: Q1

Key takeaways: Multidimensional aspects of nature contact in Urban Green Spaces, such as naturalness, intensity, duration, frequency, and infrastructure, positively influence mental wellbeing in urban dwellers.

Environment and mental health: empirical study on the relationship between contact with nature and symptoms of anxiety and depression (Ambiente y salud mental: estudio empírico sobre la relación entre contacto con la naturaleza, síntomas de ansiedad y de depresión)

Type of study: non-rct observational study

Number of citations: 7

Year: 2020

Authors: Samantha Tomasi, S. Di Nuovo, M. Hidalgo

Journal: PsyEcology

Journal ranking: Q3

Key takeaways: Contact with nature positively affects well-being and life satisfaction, while having a negative correlation with symptoms of anxiety and depression.

Abstract: This paper sets out to investigate the relationship between environment and mental health, and specifically between contact with nature and the presence of well-being, satisfaction with life, personality traits and symptoms of anxiety and depression. The sample comprised 59 people aged 18 to 70, and included 29 subjects from Spain and 30 from Italy. The following tests were utilized: a questionnaire about the frequency of activities carried out in natural surroundings, the Five Factor Inventory, the State-Trait Anxiety Inventory, the Beck Depression Inventory II, the Satisfaction With Life Scale and the Warwick-Edinburgh Mental Well-being Scale. All variables were analysed using Pearson’s correlation coefficient with the exception of level of education, which was analysed using Spearman’s coefficient. The results suggest that contact with nature positively affects well-being and satisfaction with life, and that there is a negative correlation between contact with nature and symptoms of anxiety and depression.

Nature contact, nature connectedness and associations with health, wellbeing and pro-environmental behaviours

Type of study: non-rct observational study

Number of citations: 544

Year: 2020

Authors: Leanne Martin, M. White, A. Hunt, M. Richardson, S. Pahl, Jim Burt

Journal: Journal of Environmental Psychology

Journal ranking: Q1

Key takeaways: Regular nature visits and nature documentaries boost health and eco-friendly actions, while nature connection enhances well-being and environmental behaviors.

Nature tourism and mental health: parks, happiness, and causation

Type of study: non-rct observational study

Number of citations: 124

Year: 2020

Authors: R. Buckley

Journal: Journal of Sustainable Tourism

Journal ranking: Q1

Key takeaways: Nature tourism, especially in national parks, can improve mental health and create a large potential new market for commercial nature therapies.

Abstract: Abstract Poor mental health costs about a tenth of global GNP. For many people, nature exposure improves mental health. This generates a newly recognised health service value for national parks worldwide, estimated at trillions of dollars annually. It creates a correspondingly large potential new market for commercial nature tourism, as a provider of nature therapies, especially in national parks. Before this opportunity can be realised, however, we must establish whether voluntary park visits generate mental health gains for everyone. Currently, psychology researchers and protected area managers hold opposing views. I therefore interviewed 238 outdoor nature and adventure tourists of all ages and backgrounds, at subtropical national parks in Queensland, Australia, to determine whether they visit parks because they are happy, or they are happy because they visit parks. A large majority, 82%, picked the latter. Of those asked, 87.5% reported short-term emotional benefits; 60%, medium-term recovery from stress; and 20%, long-term changes in worldview. Each timescale corresponds to a different opportunity for commercial nature tourism. Future research priorities include: economic scale; experiential components and commercial design for different market segments; comparisons of individual benefits for people with different personalities; and tests of mental health benefits for other types of tourism.

Is physical activity in natural environments better for mental health than physical activity in other environments?

Type of study: non-rct experimental

Number of citations: 414

Year: 2013

Authors: R. Mitchell

Journal: Social science & medicine

Journal ranking: Q1

Key takeaways: Physical activity in natural environments is associated with a lower risk of poor mental health compared to physical activity in non-natural environments.

Progress on Relationship between Natural Environment and Mental Health in China

Type of study: systematic review

Number of citations: 18

Year: 2021

Authors: Dongfang Zhu, L. Zhong, Hu Yu

Journal: Sustainability

Journal ranking: Q1

Key takeaways: In China, research on the relationship between natural environment and mental health has progressed through three stages, with a need for systematic study on foreign research and a better evaluation system for the psychological effects of natural environments.

Abstract: Natural environment has a positive effect on individual mental health, which can be proved by many studies, both domestic and overseas. At present, some sunrise industries such as forest healthcare and natural tourism are booming in China. However, academically speaking, there’s still a lack of systematic summary of researches on the relationship between natural environment and mental health in China, as well as a lack of comparison with foreign research achievements, which hinders the further development of the field to some extent in China. Therefore, this paper reviews the literature systematically by using the database, China National Knowledge Infrastructure (CNKI), in order to understand the research status in China and find out its gap with foreign studies. The results show that the study in this area in China can be divided into three stages, namely the embryonic stage (prior to 2000), the start-up stage (2001–2008) and the stage of initial development (since 2009); disciplines involved in the study mainly cover forestry, agriculture, psychology, medicine, sports science, tourism, ecology, education and geography. In general, the research in China concentrates on four topics: ecological psychology, the impact of natural ecological environment on mental health, the impact of artificial ecological environment on mental health, as well as the impact of natural tourism on mental health. Based on the findings, a future study framework and some main study lines are suggested: firstly, a systematic study on the relationship between natural environment and mental health in other countries should be conducted; secondly, factors affecting mental health in natural environment should be identified; thirdly, an evaluation system of psychological effect of natural environment should be established; finally, the utilization modes and influencing mechanism of natural environment should be explored.

The impacts of nature experience on human cognitive function and mental health

Type of study: literature review

Number of citations: 1008

Year: 2012

Authors: Gregory N. Bratman, J. Hamilton, G. Daily

Journal: Annals of the New York Academy of Sciences

Journal ranking: Q1

Key takeaways: Contact with nature positively impacts human cognitive function and mental health, with varying effects depending on the type, duration, and frequency of exposure.

Abstract: Scholars spanning a variety of disciplines have studied the ways in which contact with natural environments may impact human well‐being. We review the effects of such nature experience on human cognitive function and mental health, synthesizing work from environmental psychology, urban planning, the medical literature, and landscape aesthetics. We provide an overview of the prevailing explanatory theories of these effects, the ways in which exposure to nature has been considered, and the role that individuals’ preferences for nature may play in the impact of the environment on psychological functioning. Drawing from the highly productive but disparate programs of research in this area, we conclude by proposing a system of categorization for different types of nature experience. We also outline key questions for future work, including further inquiry into which elements of the natural environment may have impacts on cognitive function and mental health; what the most effective type, duration, and frequency of contact may be; and what the possible neural mechanisms are that could be responsible for the documented effects.

Effect of Nature Space on Enhancing Humans’ Health and Well-Being: An Integrative Narrative Review

Type of study: systematic review

Number of citations: 6

Year: 2024

Authors: Zhiyong Zhang, Bing Ye, Wenjuan Yang, Yue Gao

Journal: Forests

Journal ranking: Q1

Key takeaways: Exposure to nature promotes health and well-being, with benefits ranging from physical (reduces CVDs, increases immunity, improves sleep quality) to psychological (restores attention, improves mood, reduces stress, and enhances cognitive development).

Abstract: With the progress of science and technology, humans’ ability to transform and create has been greatly enhanced, but so have the physical and mental ailments associated with environmental degradation and urbanization. Human survival and health are strongly linked to nature, and there is growing evidence that exposure to nature promotes health and well-being. However, there is currently a lack of synthesis among empirical studies on these aspects for the findings to be sufficient for informing public health strategies and social policy. Here, following basic guidelines for systematic review and meta-analysis, we searched PubMed, Web of Science, ScienceDirect, and Scopus databases in January 2023. The results of our search and analysis show that nature can improve people’s health and well-being from two aspects: physical (reduces CVDs, increases immunity, improves autonomic nervous system function, and improves sleep quality) and psychological (restores attention, improves mood, reduces stress, and improves cognitive development). The ways in which people derive health from nature are varied, and tailored, personalized, symptom-specific exposure can further increase the health benefits. More importantly, it seems that people can gain the health benefits of nature by only being exposed to it for a short time. We incorporate the existing scientific evidence in our review and develop a new heuristic point of view on the necessity of exposure to natural environments for the health of individuals.

Into the Woods or a Stroll in the Park: How Virtual Contact with Nature Impacts Positive and Negative Affect

Type of study: rct

Number of citations: 60

Year: 2017

Authors: E. McAllister, Navjot Bhullar, N. Schutte

Journal: International Journal of Environmental Research and Public Health

Journal ranking: Q2

Key takeaways: Virtual contact with nature, particularly wild nature, increases positive affect and reduces negative affect, with perceived restorativeness acting as a significant mediator.

Abstract: This study examined the effects of virtual contact with nature on positive and negative affect, and investigated the psychological process of perceived restorativeness as a mediator of this relationship. A sample of 220 Australians aged between 18 and 75 years (M = 49.07, SD = 14.34, female = 72%) participated in the study. Participants were randomly allocated to one of the three experimental conditions experienced through video presentations: (1) ‘wild’ nature, (2) ‘urban’ nature, and (3) non-nature control. They then completed measures of perceived restorativeness as well as positive and negative affect. Compared to the non-nature control condition, the experience of wild nature resulted in significantly higher levels of positive affect and lower levels of negative affect. The experience of urban nature resulted in significantly lower levels of negative affect only compared to the non-nature control video. Experience of wild and urban nature resulted in greater perceptions of restorativeness as compared to the non-nature control video. Restorativeness was a significant underlying psychological mediating path through which nature experience exerted its influence on affect. These results have the potential to inform nature-based green care interventions for mental health as well as for urban planning to maximize beneficial effects of natural environments.

Benefits for emotional regulation of contact with nature: a systematic review

Type of study: systematic review

Number of citations: 7

Year: 2024

Authors: M. L. Ríos-Rodríguez, C. Rosales, Bernardo Hernández, Maryurena Lorenzo

Journal: Frontiers in Psychology

Journal ranking: Q2

Key takeaways: Contact with nature may improve emotional regulation and contribute to decreased stress, anxiety, and depression.

Abstract: Introduction Exposure to natural environments, such as parks, forests, and green areas, is often linked to a decrease in stress, anxiety and depression, while contributing to improved emotional wellbeing. These observations are supported by well-established theories, such as the Stress Reduction Theory and Attention Restoration Theory, which highlight the psychological benefits of interacting with nature. However, the relationship between exposure to nature and emotions, and in particular, with emotional regulation, is an evolving aspect of research with no clear conclusions. Emotional regulation can be deliberate in nature, where individuals voluntarily participate in modifying various aspects of their emotions, such as their type, intensity, quality or duration. Alternatively, it may be automatic, originating from sensory perception and acting without full awareness, but significantly influencing emotional experiences. In this context, the environmental self-regulation hypothesis, suggests that people consciously or unconsciously use their physical environment to regulate their emotions. Method To analyze the evidence of the relationship between contact with nature and emotional regulation, we conducted this review. Using the PRISMA statement as a reference, we conducted keyword searches in five databases in the period between 2013 and 2023. The databases selected were Scopus, Web of Science (WoS), PubMed, PsycINFO and ScienceDirect. Results In addition, a manual search was carried out of journals in the research field. Initially, from which gray literature, reviews and duplicates were removed in a first step. The resulting articles were then filtered using their titles and abstracts. Subsequently, the abstracts of the 25 selected articles were reviewed and discussed by researchers to reach a final decision based on consensus about the adequacy of each paper. Finally, nine articles were included in the systematic review. Discussion In general terms, this review suggests that research on the relationship between contact with nature and emotional regulation provides valuable insights into how natural environments can contribute to the emotional wellbeing and physical and mental health of the population.

Nature at work: The effects of day-to-day nature contact on workers’ stress and psychological well-being

Type of study:

Number of citations: 15

Year: 2021

Authors: S. Perrins, U. Varanasi, E. Seto, Gregory N. Bratman

Journal: Urban Forestry & Urban Greening

Journal ranking: brak

Key takeaways: Exposure to natural outdoor environments is significantly associated with reduced state anxiety in office workers.

The effect of contact with natural environments on positive and negative affect: A meta-analysis

Type of study: meta-analysis

Number of citations: 628

Year: 2015

Authors: Ethan A. McMahan, D. Estes

Journal: The Journal of Positive Psychology

Journal ranking: brak

Key takeaways: Exposure to natural environments moderately increases positive affect and decreases negative affect, with factors like emotion assessment, exposure type, location, and age of the sample influencing this effect.

Abstract: A growing body of empirical research suggests that brief contact with natural environments improves emotional well-being. The current study synthesizes this body of research using meta-analytic techniques and assesses the mean effect size of exposure to natural environments on both positive and negative affect. Thirty-two studies with a total of 2356 participants were included. Across these studies, exposure to natural environments was associated with a moderate increase in positive affect and a smaller, yet consistent, decrease in negative affect relative to comparison conditions. Significant heterogeneity was found for the effect of nature on positive affect, and type of emotion assessment, type of exposure to nature, location of study, and mean age of sample were found to moderate this effect. The implications of these findings for existing theory and research are discussed, with particular emphasis placed on potential avenues for fruitful future research examining the effects of nature on well-being.

Nature Therapy: Part One: Evidence for the Healing Power of Contact with Nature

Type of study: systematic review

Number of citations: 1

Year: 2021

Authors: K. Beil

Journal: Journal of Restorative Medicine

Journal ranking: brak

Key takeaways: Contact with nature, including visual nature, forest therapy, gardening, residential greenspace, and blue space, has been shown to positively impact physical and mental health.

Abstract: Human enjoyment of natural environmental settings is common to all cultures. It is a complex, evolutionary, psychophysiological response with notable potential to positively impact both physical and mental health of individuals and populations. Four decades of research have produced a large body of empirical and experimental studies demonstrating the benefits of contact with Nature. A sufficient evidence base now allows for meaningful systematic reviews and meta-analyses to begin to guide health recommendations. This is the first of three articles to review the state of the science on the potential health benefits of contact with Nature, covering Visual Nature, Forest Therapy, Gardening, Residential Greenspace, and Blue Space.

Regulation of Affective States: benefits of contact with the Nature

Type of study:

Number of citations: 2

Year: 2020

Authors: T. Almeida

Journal: International Journal of Advanced Engineering Research and Science

Journal ranking: brak

Key takeaways: Contact with nature has beneficial effects on human health, but increasing distance from nature can be harmful to our body and mind, with implications for society as a whole.

Abstract: It has long been known of the beneficial effects of nature on human health. However, more and more, the human being is disconnected from nature. Unfortunately, our routine takes us further and further away from nature and this can be harmful to our body and mind. What implications does the lack of such contact with nature have for society as a whole? This manuscript, which is a bibliographic review, based on the psychobiological perspective, covers this subject and proposes some solutions to this issue.

Understanding Nature and Its Cognitive Benefits

Type of study:

Number of citations: 113

Year: 2019

Authors: Kathryn E. Schertz, M. Berman

Journal: Current Directions in Psychological Science

Journal ranking: Q1

Key takeaways: Exposure to natural stimuli improves working memory performance, potentially through the perception of low-level features like edge density.

Abstract: Many people have the intuition that interacting with natural environments benefits their psychological health. But what has research actually demonstrated about the benefits of nature experience and the potential mechanisms underlying those benefits? This article describes empirical research on the cognitive benefits of interacting with natural environments and several theories that have been proposed to explain these effects. We also propose future directions that may be useful in exploring the extent of nature’s effects on cognitive performance and some potential mediating factors. Specifically, exposure to a variety of natural stimuli (vs. urban stimuli) consistently improves working memory performance. One potential mechanism for this is the perception of low-level features of natural environments, such as edge density in the visual domain. Although low-level features have been shown to carry semantic information and influence behavior, additional studies are needed to indicate whether perceiving these features in isolation is necessary or sufficient for obtaining the cognitive benefits of interacting with nature.

Enhanced functional connectivity properties of human brains during in-situ nature experience

Type of study: rct

Number of citations: 58

Year: 2016

Authors: Zheng Chen, Yujia He, Yuguo Yu

Journal: PeerJ

Journal ranking: Q1

Key takeaways: In-situ nature experiences promote more efficient and stronger brain connectivity, potentially benefiting cognitive processes and mental well-being compared to stressful urban experiences.

Abstract: In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with “coherent” experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being.

Associations between Nature Exposure and Health: A Review of the Evidence

Type of study: literature review

Number of citations: 352

Year: 2021

Authors: Marcia P. Jimenez, N. DeVille, E. Elliott, Jessica E Schiff, G. Wilt, J. Hart, Peter James

Journal: International Journal of Environmental Research and Public Health

Journal ranking: Q2

Key takeaways: Exposure to nature is associated with improved cognitive function, brain activity, blood pressure, mental health, physical activity, and sleep, with potential long-term benefits on depression, anxiety, cognitive function, and chronic disease.

Abstract: There is extensive empirical literature on the association between exposure to nature and health. In this narrative review, we discuss the strength of evidence from recent (i.e., the last decade) experimental and observational studies on nature exposure and health, highlighting research on children and youth where possible. We found evidence for associations between nature exposure and improved cognitive function, brain activity, blood pressure, mental health, physical activity, and sleep. Results from experimental studies provide evidence of protective effects of exposure to natural environments on mental health outcomes and cognitive function. Cross-sectional observational studies provide evidence of positive associations between nature exposure and increased levels of physical activity and decreased risk of cardiovascular disease, and longitudinal observational studies are beginning to assess long-term effects of nature exposure on depression, anxiety, cognitive function, and chronic disease. Limitations of current knowledge include inconsistent measures of exposure to nature, the impacts of the type and quality of green space, and health effects of duration and frequency of exposure. Future directions include incorporation of more rigorous study designs, investigation of the underlying mechanisms of the association between green space and health, advancement of exposure assessment, and evaluation of sensitive periods in the early life-course.

Nature can get it out of your mind: The rumination reducing effects of contact with nature and the mediating role of awe and mood

Type of study: non-rct experimental

Number of citations: 63

Year: 2020

Authors: S. Lopes, Mariely Lima, Karine Silva

Journal: Journal of Environmental Psychology

Journal ranking: Q1

Key takeaways: Contact with nature, even a 30-minute walk in an urban park, can reduce rumination in healthy individuals by increasing awe and mood, without directly affecting rumination.

Can a nature walk change your brain? Investigating hippocampal brain plasticity after one hour in a forest.

Type of study: non-rct experimental

Number of citations: 6

Year: 2024

Authors: Sonja Sudimac, Simone Kühn

Journal: Environmental research

Journal ranking: Q1

Key takeaways: A one-hour walk in a forest increases subiculum volume in the brain, potentially benefiting mental health and reducing rumination.

Kontak dengan Alam Sebagai Media Peminimalisir Mengatasi Stres Ringan

Type of study:

Number of citations: 0

Year: 2025

Authors: Nia Azizunnisa

Journal: Jurnal Manajemen dan Pendidikan Agama Islam

Journal ranking: brak

Key takeaways: Contact with nature, such as mountain climbing, camping, or walking in the forest, can minimize mild stress and improve mental well-being.

Abstract: This article discusses contact with nature as a medium to minimize mild stress. At a mild level, stress can actually increase the enthusiasm for life in fighting challenges, but if stress increases to a more severe level, it can cause nervous tension, and have an impact on suffering not only physically, but also our soul (mind). The aim of this research is to increase awareness of the importance of contact with nature for mental health. This research uses qualitative research methods, including in the library research category, so in the process of collecting data, the author collects data in the form of information through literature. The results of this research are that contact with nature can minimize mild stress for some people. Activities in nature, such as mountain climbing, camping, or simply walking in the forest, are believed to have therapeutic effects that can improve mental well-being. Nature can have a positive impact on health and well-being. One application can be implemented is through natural schools, nature-based schools which aim to restore essential human values ​​that are one with nature. In nature schools, students are free to interact with the outdoors. Students look cheerful and enjoy learning without any pressure and school does not become a boring prison. This is the most important thing, so that children do not get stressed and bored easily.

Affective Benefits of Nature Contact: The Role of Rumination

Type of study: non-rct observational study

Number of citations: 35

Year: 2021

Authors: Gregory N. Bratman, G. Young, Ashish Mehta, Ihno Lee Babineaux, G. Daily, J. Gross

Journal: Frontiers in Psychology

Journal ranking: Q2

Key takeaways: Nature contact is associated with higher levels of positive affect and lower levels of negative affect, with rumination partially mediating this association for positive affect.

Abstract: 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.

Green Perspectives for Public Health: A Narrative Review on the Physiological Effects of Experiencing Outdoor Nature

Type of study: systematic review

Number of citations: 186

Year: 2014

Authors: D. Haluza, Regina Schönbauer, R. Cervinka

Journal: International Journal of Environmental Research and Public Health

Journal ranking: Q2

Key takeaways: Outdoor nature experiences have significant positive effects on physiological stress reactions across all body systems, but more interdisciplinary research is needed to optimize their health promotion and disease prevention potential.

Abstract: Natural environments offer a high potential for human well-being, restoration and stress recovery in terms of allostatic load. A growing body of literature is investigating psychological and physiological health benefits of contact with Nature. So far, a synthesis of physiological health outcomes of direct outdoor nature experiences and its potential for improving Public Health is missing. We were interested in summarizing the outcomes of studies that investigated physiological outcomes of experiencing Nature measuring at least one physiological parameter during the last two decades. Studies on effects of indoor or simulated Nature exposure via videos or photos, animal contact, and wood as building material were excluded from further analysis. As an online literature research delivered heterogeneous data inappropriate for quantitative synthesis approaches, we descriptively summarized and narratively synthesized studies. The procedure started with 1,187 titles. Research articles in English language published in international peer-reviewed journals that investigated the effects of natural outdoor environments on humans by were included. We identified 17 relevant articles reporting on effects of Nature by measuring 20 different physiological parameters. We assigned these parameters to one of the four body systems brain activity, cardiovascular system, endocrine system, and immune function. These studies reported mainly direct and positive effects, however, our analyses revealed heterogeneous outcomes regarding significance of results. Most of the studies were conducted in Japan, based on quite small samples, predominantly with male students as participants in a cross-sectional design. In general, our narrative review provided an ambiguous illustration of the effects outdoor nature exerted on physiological parameters. However, the majority of studies reported significant positive effects. A harmonizing effect of Nature, especially on physiological stress reactions, was found across all body systems. From a Public Health perspective, interdisciplinary work on utilizing benefits of Nature regarding health promotion, disease prevention, and nature-based therapy should be optimized in order to eventually diminish given methodological limitations from mono-disciplinary studies.

PSYCHOLOGICAL WELL BEING AND HEALTH BENEFITS DERIVED FROM CONTACT WITH NATURE

Type of study: literature review

Number of citations: 3

Year: 2019

Authors: H. Özgüner

Journal:

Journal ranking: brak

Key takeaways: Contact with nature is beneficial for human health and psychological well-being, with a growing body of research supporting this claim.

Abstract: There has been a common belief through history that contact with nature is beneficial for human health and psychological well being. The explosive growth of urban areas and decline of nature in the 20th Century led an increasing alienation between people and natural world. This has prompted an increasing interest in natural areas, and research on the possible benefits of contact with nature steadily increased in the last three decades. This article reviews the studies on the effects of nature on human well being and health, and provides a critical discussion of their results.Keywords: Nature, Natural landscape, Human health

Nature Contact Increases Perceived Humanness in Others

Type of study:

Number of citations: 1

Year: 2024

Authors: Lei Cheng, Xijing Wang, Jiaxin Shi, Fei Teng

Journal: Journal of Environmental Psychology

Journal ranking: Q1

Key takeaways: Nature contact, such as spending time in nature or imagining interacting with nature, increases perceived humanness in others, promoting prosociality.

A butterfly flaps its wings

Type of study: literature review

Number of citations: 16

Year: 2020

Authors: S. Prescott

Journal: Annals of Allergy, Asthma & Immunology

Journal ranking: Q2

Key takeaways: Increased contact with biodiversity benefits physical and mental health, immune function, and promotes environmental responsibility.

Interplay between natural environment, human microbiota and immune system: A scoping review of interventions and future perspectives towards allergy prevention.

Type of study: systematic review

Number of citations: 26

Year: 2022

Authors: C. Tischer, P. Kirjavainen, U. Matterne, J. Tempes, K. Willeke, T. Keil, C. Apfelbacher, M. Täubel

Journal: The Science of the total environment

Journal ranking: Q1

Key takeaways: Biodiversity interventions, such as nature-related educational programs, can potentially increase human microbiota diversity and potentially help prevent allergic diseases.

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

Type of study: systematic review

Number of citations: 74

Year: 2021

Authors: Liisa Andersen, S. Corazon, U. Stigsdotter

Journal: International Journal of Environmental Research and Public Health

Journal ranking: Q2

Key takeaways: Nature exposure may have positive effects on immune health parameters, such as anti-inflammatory effects and increased NK cell activity, but more research is needed to confirm these findings.

Abstract: 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.

Short‐term direct contact with soil and plant materials leads to an immediate increase in diversity of skin microbiota

Type of study: non-rct experimental

Number of citations: 81

Year: 2018

Authors: M. Grönroos, A. Parajuli, O. Laitinen, M. Roslund, Heli K. Vari, H. Hyöty, R. Puhakka, A. Sinkkonen

Journal: MicrobiologyOpen

Journal ranking: Q2

Key takeaways: Short-term contact with soil and plant materials increases skin microbiota diversity, potentially reducing immune system disorders.

Abstract: Immune‐mediated diseases have increased during the last decades in urban environments. The hygiene hypothesis suggests that increased hygiene level and reduced contacts with natural biodiversity are related to the increase in immune‐mediated diseases. We tested whether short‐time contact with microbiologically diverse nature‐based materials immediately change bacterial diversity on human skin. We tested direct skin contact, as two volunteers rubbed their hands with sixteen soil and plant based materials, and an exposure via fabric packets filled with moss material. Skin swabs were taken before and after both exposures. Next‐generation sequencing showed that exposures increased, at least temporarily, the total diversity of skin microbiota and the diversity of Acidobacteria, Actinobacteria, Bacteroidetes, Proteobacteria and Alpha‐, Beta‐ and Gammaproteobacteria suggesting that contact with nature‐based materials modify skin microbiome and increase skin microbial diversity. Until now, approaches to cure or prevent immune system disorders using microbe‐based treatments have been limited to use of a few microbial species. We propose that nature‐based materials with high natural diversity, such as the materials tested here, might be more effective in modifying human skin microbiome, and eventually, in reducing immune system disorders. Future studies should investigate how long‐term changes in skin microbiota are achieved and if the exposure induces beneficial changes in the immune system markers.

Association of the Salivary Microbiome With Animal Contact During Early Life and Stress-Induced Immune Activation in Healthy Participants

Type of study: non-rct experimental

Number of citations: 5

Year: 2020

Authors: D. Langgartner, Cristian A. Zambrano, Jared D. Heinze, C. Stamper, Till S. Böbel, Sascha B. Hackl, M. Jarczok, N. Rohleder, G. Rook, H. Gündel, C. Waller, C. Lowry, S. Reber

Journal: Frontiers in Psychiatry

Journal ranking: Q1

Key takeaways: Urban upbringing without daily contact with pets leads to long-lasting effects on the salivary microbiome composition and increased stress-induced immune activation.

Abstract: The prevalence of stress-associated somatic and psychiatric disorders is increased in environments offering a narrow relative to a wide range of microbial exposure. Moreover, different animal and human studies suggest that an overreactive immune system not only accompanies stress-associated disorders, but might even be causally involved in their pathogenesis. In support of this hypothesis, we recently showed that urban upbringing in the absence of daily contact with pets, compared to rural upbringing in the presence of daily contact with farm animals, is associated with a more pronounced immune activation following acute psychosocial stressor exposure induced by the Trier Social Stress Test (TSST). Here we employed 16S rRNA gene sequencing to test whether this difference in TSST-induced immune activation between urban upbringing in the absence of daily contact with pets (n = 20) compared with rural upbringing in the presence of daily contact with farm animals (n = 20) is associated with differences in the composition of the salivary microbiome. Although we did not detect any differences in alpha or beta diversity measures of the salivary microbiome between the two experimental groups, statistical analysis revealed that the salivary microbial beta diversity was significantly higher in participants with absolutely no animal contact (n = 5, urban participants) until the age of 15 compared to all other participants (n = 35) reporting either daily contact with farm animals (n = 20, rural participants) or occasional pet contact (n = 15, urban participants). Interestingly, when comparing these urban participants with absolutely no pet contact to the remaining urban participants with occasional pet contact, the former also displayed a significantly higher immune, but not hypothalamic-pituitary-adrenal (HPA) axis or sympathetic nervous system (SNS) activation, following TSST exposure. In summary, we conclude that only urban upbringing with absolutely no animal contact had long-lasting effects on the composition of the salivary microbiome and potentiates the negative consequences of urban upbringing on stress-induced immune activation.

Environmental pollution and the immune system

Type of study:

Number of citations: 0

Year: 2022

Authors: M. Abdelnasser

Journal: Al-Azhar Medical Journal

Journal ranking: brak

Key takeaways: Environmental pollution negatively impacts the immune system, leading to disease and highlighting the need for effective prevention and management of environmental pollutants.

Abstract: : Environmental pollution, particularly air pollution, is now a worldwide problem. Pollution represents a challenge not only to human health, but also to animals and plants. In turn, human health will also be affected. The immune system is also sensitive to any environmental changes. The immune system itself consists of multiple types of immune cells that act together to generate (or fail to generate) immune responses. Understanding the effects of ambient pollutants on the immune system is vital to understanding how pollution causes disease, and how that pathology could be abrogated. It is also aimed to know how to lessen or prevent their effects on human health.

Environmental Pollutants: Effects on the Immune System and Resistance to Infectious Disease

Type of study: literature review

Number of citations: 26

Year: 1981

Authors: L. D. Caren

Journal: BioScience

Journal ranking: Q1

Key takeaways: Environmental pollutants, such as metals, organic pesticides, and gaseous pollutants, can perturb the immune response and increase susceptibility to infectious diseases.

Abstract: The immune system is a complex of interrelated reactions, which protects animals from invasion by foreign substances. Many environmental substances, such as metals, organic pesticides, and gaseous pollutants, perturb the immune response and increase susceptibility to infectious disease. There is a need for a large number of systematic studies. They should include long-term, low dose experiments on large numbers of animals, studies of impaired resistance to infection using a greater variety of infectious agents, studies of the effects of fetal and neonatal pollution exposure, and studies of the mechanism of impaired resistance once an effect is observed. 26 references reviewed.

Environmental Chemicals and the Immune System

Type of study:

Number of citations: 0

Year: 2021

Authors: Alfred Poulos

Journal: The Secret Life of Chemicals

Journal ranking: brak

Key takeaways: Environmental chemicals may compromise the immune system's function, potentially contributing to the development of diseases.

Abstract: The immune system plays a key role in the maintenance of our health and wellbeing. However, its function may be compromised by exposure to the some of the thousands of environmental chemicals to which we are exposed in our every day life. Given that environmental chemicals have been shown to affect the function of different types of immune cells, it would seem likely that they may contribute to the development of some of the diseases that affect us.

Environmental Toxicant and Immune cells: A Review

Type of study:

Number of citations: 0

Year: 2021

Authors: A. Ray, C. Dey

Journal:

Journal ranking: brak

Key takeaways: Environmental toxicants negatively impact immune cells, potentially compromising the immune system's ability to defend against pathogens and cancer.

Abstract: Immune system is the adaptive defense mechanism which is evolved in vertebrates to keep them from invading pathogenic microorganisms and cancer. In immune system consists of some specialized cells like: lymphocytes, neutrophils, NK cells, basophils, macrophages, eiosinophils, mast cells, etc.Ecotoxicology is a subdisicipline of environmental toxicology concerd with studing the damaging effects of toxicants at the population and nature. Environmental toxicants are simply toxic substances in the nature. Environmental toxicant which is effect on ecosystem very badly.In this paper we discuss that how environmental toxicant effect on immune system or immune cells.

How might contact with nature promote human health? Promising mechanisms and a possible central pathway

Type of study:

Number of citations: 583

Year: 2015

Authors: Ming Kuo

Journal: Frontiers in Psychology

Journal ranking: Q2

Key takeaways: Contact with nature may promote human health through enhanced immune functioning, among other pathways identified in this paper.

Abstract: How might contact with nature promote human health? Myriad studies have linked the two; at this time the task of identifying the mechanisms underlying this link is paramount. This article offers: (1) a compilation of plausible pathways between nature and health; (2) criteria for identifying a possible central pathway; and (3) one promising candidate for a central pathway. The 21 pathways identified here include environmental factors, physiological and psychological states, and behaviors or conditions, each of which has been empirically tied to nature and has implications for specific physical and mental health outcomes. While each is likely to contribute to nature’s impacts on health to some degree and under some circumstances, this paper explores the possibility of a central pathway by proposing criteria for identifying such a pathway and illustrating their use. A particular pathway is more likely to be central if it can account for the size of nature’s impacts on health, account for nature’s specific health outcomes, and subsume other pathways. By these criteria, enhanced immune functioning emerges as one promising candidate for a central pathway between nature and health. There may be others.

Nature Contact and Human Health: A Research Agenda

Type of study:

Number of citations: 797

Year: 2017

Authors: H. Frumkin, Gregory N. Bratman, S. Breslow, B. Cochran, Peter H. Kahn, Jr., J. Lawler, P. Levin, P. Tandon, U. Varanasi, Kathleen L Wolf, S. Wood

Journal: Environmental Health Perspectives

Journal ranking: Q1

Key takeaways: Nature contact may offer various health benefits, but a robust research effort focused on key unanswered questions can yield high-impact, consequential public health insights.

Abstract: Background: At a time of increasing disconnectedness from nature, scientific interest in the potential health benefits of nature contact has grown. Research in recent decades has yielded substantial evidence, but large gaps remain in our understanding. Objectives: We propose a research agenda on nature contact and health, identifying principal domains of research and key questions that, if answered, would provide the basis for evidence-based public health interventions. Discussion: We identify research questions in seven domains: a) mechanistic biomedical studies; b) exposure science; c) epidemiology of health benefits; d) diversity and equity considerations; e) technological nature; f) economic and policy studies; and g) implementation science. Conclusions: Nature contact may offer a range of human health benefits. Although much evidence is already available, much remains unknown. A robust research effort, guided by a focus on key unanswered questions, has the potential to yield high-impact, consequential public health insights. https://doi.org/10.1289/EHP1663

An overview of the immune system

Type of study:

Number of citations: 1316

Year: 2001

Authors: J. Parkin, B. Cohen

Journal: The Lancet

Journal ranking: Q1

Key takeaways: The immune system plays a crucial role in recognizing, repelling, and eradicating pathogens and foreign molecules, protecting against diseases like immunodeficiency and autoimmune diseases.

Immunity by equilibrium

Type of study:

Number of citations: 162

Year: 2016

Authors: G. Eberl

Journal: Nature Reviews Immunology

Journal ranking: Q1

Key takeaways: The healthy immune system is always active and in a dynamic equilibrium between antagonistic types of response, regulated by internal milieu and microbial environment, affecting tolerance, protective immunity, and inflammatory pathology.

Diet and Immune Function

Type of study:

Number of citations: 246

Year: 2019

Authors: C. Childs, P. Calder, E. Miles

Journal: Nutrients

Journal ranking: Q1

Key takeaways: Dietary modulation of immune function can reduce or delay the onset of immune-mediated chronic diseases, benefiting both clinical settings and healthy populations.

Abstract: A well-functioning immune system is critical for survival. The immune system must be constantly alert, monitoring for signs of invasion or danger. Cells of the immune system must be able to distinguish self from non-self and furthermore discriminate between non-self molecules which are harmful (e.g., those from pathogens) and innocuous non-self molecules (e.g., from food). This Special Issue of Nutrients explores the relationship between diet and nutrients and immune function. In this preface, we outline the key functions of the immune system, and how it interacts with nutrients across the life course, highlighting the work included within this Special Issue. This includes the role of macronutrients, micronutrients, and the gut microbiome in mediating immunological effects. Nutritional modulation of the immune system has applications within the clinical setting, but can also have a role in healthy populations, acting to reduce or delay the onset of immune-mediated chronic diseases. Ongoing research in this field will ultimately lead to a better understanding of the role of diet and nutrients in immune function and will facilitate the use of bespoke nutrition to improve human health.

Contact system revisited: an interface between inflammation, coagulation, and innate immunity

Type of study:

Number of citations: 287

Year: 2016

Authors: Andy T. Long, E. Kenne, R. Jung, Tobias A. Fuchs, T. Renné

Journal: Journal of Thrombosis and Haemostasis

Journal ranking: Q1

Key takeaways: The contact system plays a crucial role in host defense by coordinating inflammation, coagulation, and innate immunity, offering potential therapeutic targets for thromboprotection.

Abstract: The contact system is a plasma protease cascade initiated by factor XII (FXII) that activates the proinflammatory kallikrein‐kinin system and the procoagulant intrinsic coagulation pathway. Anionic surfaces induce FXII zymogen activation to form proteolytically active FXIIa. Bacterial surfaces also have the ability to activate contact system proteins, indicating an important role for host defense using the cooperation of the inflammatory and coagulation pathways. Recent research has shown that inorganic polyphosphate found in platelets activates FXII in vivo and can induce coagulation in pathological thrombus formation. Experimental studies have shown that interference with FXII provides thromboprotection without a therapy‐associated increase in bleeding, renewing interest in the FXIIa‐driven intrinsic pathway of coagulation as a therapeutic target. This review summarizes how the contact system acts as the cross‐road of inflammation, coagulation, and innate immunity.

Nature contact and mood benefits: contact duration and mood type

Type of study: non-rct experimental

Number of citations: 74

Year: 2018

Authors: C. Neill, Janelle Gerard, K. Arbuthnott

Journal: The Journal of Positive Psychology

Journal ranking: Q1

Key takeaways: Brief nature contact improves both hedonic and self-transcendent emotions, with no impact on the duration of contact in the range tested.

Abstract: ABSTRACT There is robust evidence that contact with the natural world improves human health, including emotional well-being. However, the specific conditions of emotional benefits of nature contact are sparsely understood. Two studies were conducted with university students to examine whether the duration of nature contact influences the magnitude of benefits for both hedonic (positive and negative affect) and self-transcendent emotions. Study 1 investigated whether 5 minutes of sedentary nature contact influenced both emotion types, and Study 2 examined whether mood improvements are sensitive to the duration of nature contact (5 vs. 15 minutes). Results indicate that brief nature contact reliably improved both hedonic and self-transcendent emotions, and that the duration of contact in the range tested had no impact on this improvement.

Interaction of the Human Contact System with Pathogens—An Update

Type of study:

Number of citations: 53

Year: 2018

Authors: Sonja Oehmcke-Hecht, J. Köhler

Journal: Frontiers in Immunology

Journal ranking: Q1

Key takeaways: The human contact system serves as an inflammatory response mechanism against foreign organisms and artificial materials, with pathogens like bacteria, fungi, and viruses developing their own mechanisms to activate the system.

Abstract: The name human contact system is related to its mode of action, as “contact” with artificial negatively charged surfaces triggers its activation. Today, it is generally believed that the contact system is an inflammatory response mechanism not only against artificial material but also against misfolded proteins and foreign organisms. Upon activation, the contact system is involved in at least two distinct (patho)physiologic processes:i. the trigger of the intrinsic coagulation via factor XI and ii. the cleavage of high molecular weight kininogen with release of bradykinin and antimicrobial peptides (AMPs). Bradykinin is involved in the regulation of inflammatory processes, vascular permeability, and blood pressure. Due to the release of AMPs, the contact system is regarded as a branch of the innate immune defense against microorganisms. There is an increasing list of pathogens that interact with contact factors, in addition to bacteria also fungi and viruses bind and activate the system. In spite of that, pathogens have developed their own mechanisms to activate the contact system, resulting in manipulation of this host immune response. In this up-to-date review, we summarize present research on the interaction of pathogens with the human contact system, focusing particularly on bacterial and viral mechanisms that trigger inflammation via contact system activation.

Transforming the understanding of brain immunity

Type of study:

Number of citations: 164

Year: 2023

Authors: G. Castellani, T. Croese, Javier M. Peralta Ramos, M. Schwartz

Journal: Science

Journal ranking: Q1

Key takeaways: The brain is in close communication with the immune system, supporting its maintenance, function, and repair, and involving multiple peripheral immunological players.

Abstract: Contemporary studies have completely changed the view of brain immunity from envisioning the brain as isolated and inaccessible to peripheral immune cells to an organ in close physical and functional communication with the immune system for its maintenance, function, and repair. Circulating immune cells reside in special niches in the brain’s borders, the choroid plexus, meninges, and perivascular spaces, from which they patrol and sense the brain in a remote manner. These niches, together with the meningeal lymphatic system and skull microchannels, provide multiple routes of interaction between the brain and the immune system, in addition to the blood vasculature. In this Review, we describe current ideas about brain immunity and their implications for brain aging, diseases, and immune-based therapeutic approaches. Description Changing ideas about brain immunity Our understanding of how the brain and immune system interact has changed substantially over the past years and decades. Initially, the brain was thought to be immune privileged and isolated from the rest of the body. In a Review, Castellani et al. discuss recent discoveries, including attribution of central nervous system immune surveillance to tissue-resident microglia and acknowledging the existence of a complex brain-immune network that involves multiple peripheral immunological players. This complex brain-immune relationship is important during development, adulthood, and aging, as well as during various pathologies. Rethinking brain immunity could reveal new therapeutic targets for various neurological disorders. —GKA A review discusses the current perception of brain immunity and its implications for brain aging, diseases, and immune-based therapies. BACKGROUND Beginning in the early 19th century, the brain was considered a self-contained organ behind barriers and thus as “immune privileged.” This assumption was supported by experiments showing that a dye injected into the circulation did not stain the brain and by evidence of prolonged survival of tissue grafts in the brain compared with transplants into peripheral tissues. These conclusions led to the axiomatic view that the brain cannot tolerate any immune activity. The identification of brain-resident immune cells, the microglia, was often used as an additional argument to support the immunological self-sufficiency of the brain. In addition, despite the early description of brain lymphatic drainage, which dates back to 1787, the supposed absence of lymphatic vessels within the brain was, until recently, among the most common rationales used to support the view of a complete separation between the brain and the immune system. ADVANCES Our perception of the relationship between the brain and the immune system has completely changed over the past decades. It is now established that immune cells operate as guardians of the central nervous system (CNS), support brain function and repair, and reside in specialized immunological niches at its borders, including the meninges, the choroid plexus, and the perivascular spaces. The meninges remotely affect the brain through immune cell–derived cytokine release. The choroid plexus hosts and orchestrates the selective homing of immune cells to the CNS parenchyma. The perivascular spaces are populated by immune cells regulating cerebrospinal fluid flow. The demonstration of the CNS lymphatic system and brain drainage led to the identification of the brain-draining cervical lymph nodes as crucial supplementary sites of the interaction between the CNS and the immune system. Additional observations revealed that microscopic channels in the bone of the skull allow exposure of the bone marrow (BM) to the cerebrospinal fluid, thereby influencing cellular maturation in the BM and migration into the brain. Such an intricate communication network guarantees efficient CNS-monitoring activities by neighboring immune cells, the phenotype of which is shaped by the CNS microenvironment to which they are constantly exposed. The bidirectional nature of the CNS–immune system interplay is supported by emerging studies demonstrating the ability of neuronal cells to modulate the immune response through lymphoid organ innervation in the context of CNS diseases. OUTLOOK The negative side of the immune system participating in brain physiology is that imbalanced brain-immune interactions might be critical in aging and in autoimmune, neurodegenerative, and neurodevelopmental disorders. Under such conditions, the perturbed brain microenvironment might lead to a harmful immune response, which may exacerbate disease manifestations. Further advances in our understanding of brain immunity and the reciprocal ability of the CNS and the immune system to sense and influence each other will offer intervention tools for the design of new therapeutic strategies for treating brain pathologies. Understanding what goes awry in each of the brain’s immune niches, including the skull BM, the meninges, and the choroid plexus, as well as in lymphatic drainage, might reveal new potential targets for therapeutic approaches in the near future. New perception of brain immunity. Shown is a representation of the communication network allowing fine-tuned brain immunosurveillance. The immune cells are strategically positioned in immunological niches, where they are constantly exposed to CNS cues transported by the intracranial interstitial, cerebrospinal, and lymphatic fluid. Upon sensing brain signals, the immune cells can migrate toward the CNS to exert their effector functions.