It is widely perceived that spending time out-doors, particularly in green spaces, has a positive effect in people’s well-being and overall health. This association has persisted across history, but only in the late 20th Century did this notion gather scientific attention, prompting a need for definitions and research frameworks. For convenience, this essay refers to green spaces as any spaces with greenery such as urban gardens, parks and arboreta, as well as traditional farms, rural landscapes and forests. This ad-hoc description should bring to mind images of nature, which refers to everything that lives or self-organizes outside human decisions (De Groot & Van Den Born 2003). Green spaces are ecosystems or parts of ecosystems that are considered here under the umbrella of natural spaces even if some human intervention has occurred. This is done because it is very difficult to identify any space that has not experienced such intervention directly or indirectly. Broadly speaking, all these ideas hint at the relationships between humanity and nature, the globalized impact of human intervention in nature and the preoccupation with human survival and needs.
Green spaces as any spaces with greenery such as urban gardens, parks and arboreta, as well as traditional farms, rural landscapes and forests (Image: Pixy.org).
There is currently an increasing sense of priority placed on multidisciplinary and transdisciplinary research efforts exploring the human health connections to nature and ecosystems. Some of these efforts focus on the physiological and psychological effects that result from experiencing green spaces (Russell et al. 2013). This emphasis results from three main motivators: first, is the intermingling of green spaces with expanding urban settlements; second, is the preoccupation with increasing populations suffering from chronic disease and the quest for comprehensive cause-effect connections, as medicine alone is not solving these problems (Lee et al. 2009); and third, are the effects that ongoing ecosystem destruction may pose to human health and other systems. It is expected that these studies will contribute evidence to building holistic explanations via systems theory and other tools, on the relationships between health and well-being with ecology, biodiversity, and economics (Heylighen 2000; Diaz et al. 2006; Liu et al. 2007; Jokela 2009). Furthermore, establishing these connections can influence values attributed to nature that can guide efforts in ecosystem conservation (Cardinale et al. 2012; McCune, Pellatt & Vellend 2013). Clearly, as these investigations reveal the intricate relationships between human health and the environment at large, they can incite intense dialogue and debate.
This new integrated approach faces several challenges. It requires a more inductive logic than the more traditional reductionist, linear and deductive approach commonly taken by individual sciences, as it must emphasize the understanding of interrelated systems instead of focusing on simple and independent systems (Kennedy & Guigley 1998). This is difficult because it requires a shift to a new paradigm on how research questions are formulated and how evidence is interpreted that includes physiological, ecological and socio-cultural considerations. The following text briefly exposes some of the challenges and great opportunities on this novel research enterprise.
Perception of health benefits and values attributed to green spaces across time
Ethnographical and archaeological evidence reveal both a sense of fear and awe, as well as deep affinity towards green spaces across cultural, geographical and temporal settings (Hughes & Thirgood 1982; De Groot & Van Den Born 2007; Chaitieng & Srisatit 2013). These notions relate to implicit and explicit values that reflect the benefits and threats drawn from these areas. In terms of health and well-being, there are material benefits such as the provision of essential nutrients and medicinals; and nonmaterial benefits that result from experiencing these areas, which are most often associated with socio-cultural development (Russell et al. 2013). Threats refer to pests and diseases that can cause harm, impact survival and incite fear. However, the perception of benefits, threats and values, particularly the nonmaterial ones shifts over time as a reflection of changing needs and current knowledge. For instance, the first hospitals in Medieval Europe were associated with monastic gardens because of the belief that prayer and the growth of plants in proximity to the sick would help repair ill cells (Gerlach-Spriggs, Kaufman & Warner 2004; Cooper Marcus & Sachs 2014). This three-way association between healing, nature and spirituality started to decline during the 14th and 15th Centuries due to periodic plagues, technological and scientific advances, and socio-economic conditions.
The first hospitals in Medieval Europe were associated with monastic gardens because of the belief that prayer and the growth of plants in proximity to the sick would help repair ill cells (Image: Pixy.org).
Generally speaking, in Western cultures, the modern perception that green spaces offer restorative benefits such as reducing mental fatigue began forming in the 18th and 19th Centuries. This coincides with the rise of Romanticism and the changes precipitated by the Industrial Revolution including the rapid migration into cities (Gerlach-Spriggs, Kaufman & Warner 2004). During this time, there was a progressively positive attitude towards mental illness, so psychiatric institutions were designed as places of rest and kindness that often included elaborated green spaces, with the belief that they brought calm to the patients. Interestingly, visits to these green areas as well as cemeteries rose in popularity among urbanites that appreciated escaping the city’s noise and pollution (Yanni 2007). A similar landscape architecture was adopted by other hospitals during the same period.
In the 18th and 19th century visits to cemeteries rose in popularity among urbanites that appreciated escaping the city’s noise and pollution (Image: Pxhere.com).
In contrast, from the 1950’s to the 1990’s, with the exception of some psychiatric facilities, the perceived therapeutic relevance of spending time in green spaces was largely dismissed in patient care due in part to the establishment of high-rise hospitals and large parking lots (Ulrich 1984; Cooper Marcus 2007; Cooper Marcus & Sachs 2014). Most importantly, the advent of evidence-based medicine had a pivotal effect on health care and insurance coverage (Eddy 1992); and the health – green space connection was considered intuitive and too subjective to be studied under the scientific method. Therefore, there was no evidence or interest to support the integration of green spaces into health care (Jorgensen & Gobster 2010). This latter attitude began to reverse in the 1980’s and 1990’s with the growth of the Patient-Centered Care movement and the emergence of environmental and evolutionary psychology (Institute of Medicine 2001; Cooper Marcus & Sachs 2014). Seminal work from this period and subsequent evidence suggests that experiencing ecosystems such as green spaces can play a role in physical and psychological therapy, preventive medicine and longevity (Takano, Nakamura & Watanabe 2002; Grinde & Patil 2009; Lee et al. 2012). Although this evidence-based approach is at an early stage, there is increased acknowledgement of its importance. In turn, this new research attitude towards green spaces, plus the awareness of global environmental decline have influenced discussions on how the conservation of these areas should be approached (Kaplan, Kaplan & Wendt 1972; Liu et al. 2007).
Biophilia, the instinctive bond between humans and other life forms, as it relates to human health
An interesting element in connecting health, well-being and green spaces, relates to the perceived place that humans have vis-á-vis their natural environment. Philosophers, environmentalists and psychologists have taken theoretical and practical approaches to this topic resulting in highly complex dissertations that can be hard to understand (Lamb 1996; De Groot & Van Den Born 2003; Vining, Merrick & Price 2008; Tam, Lee & Chao 2013). The stance taken here is that humans and nature are constantly interacting (Russell et al. 2013). From a human perspective, as discussed in the previous section, these interactions can be positive (i.e. nature provides benefits) or negative (i.e. nature poses threats), so some interactions are pursued while others are avoided.
The main supporting argument for biophilia is that modern humans have lived in natural, non-urbanized environments for most of their evolutionary history; therefore, their bodies and brains are adapted to such environments (Kellert & Wilson 1993) (Image: Pxhere.com).
Some researchers suggest that decoupling or detaching from interacting with nature, especially in urban areas, can have negative effects on quality of life, even when threats are considered (Gómez-Baggethun & Barton 2013). These negative effects may trigger psychological discord or a lack of harmony that can be potentially harmful to mental health and well-being because of an inherent human desire to affiliate with other living species. The biologist Edward Osborne Wilson (1984) proposed the biophilia hypothesis to posit that this inherent desire has a genetic basis. The main supporting argument for biophilia is that modern humans have lived in natural, non-urbanized environments for most of their evolutionary history; therefore, their bodies and brains are adapted to such environments (Kellert & Wilson 1993). It is suspected that if the affiliation between humans and their natural environments breaks, health can be harmed. The brain in particular, seems to be quite vulnerable to discord. Indeed, in Western societies where over 60% of people live in cities (UNICEF 2008); mental illness is of significant concern. Estimates are that 31 to 50% of people in industrialized areas suffer from a mental disorder at some point in their lives (Grinde, 2009). Although it is not clear if there is a cause-and-effect association between living in cities, discord and mental illness, these ideas are strong motivators for research. For instance, some workers are studying the changes on the brain of people who have access to parks or to windows that look out to green areas, or who have potted plants indoors (Grinde & Patil 2009).
Another interesting aspect that the biophilia hypothesis proposes is that human behaviour responds to nature through a wide spectrum of attitudes that in turn shapes the value given to life forms and nature in general (Kellert & Wilson 1995). There are, for example, several and often conflicting mental constructs or ways of thinking about green spaces, that determine how people value them (Kellert & Wilson 1995; Vining, Merrick & Price 2008; Blicharska & Grandin 2015). For some people, nature is there to be enjoyed, respected or protected, while for others, nature is simply a source of raw materials and potential economic gain. Furthermore, some see nature exclusively as a source of disease and danger that needs to be avoided; this extreme attitude includes biophobias (i.e. fear of nature or life forms), which is a topic gathering momentum among psychologists and sociologists (White & Heerwagen 1998). Recall from the previous section that values attributed to green spaces can result from past experiences, so one can begin to see an interesting and fluid association between culture, biology and nature in general across human history. Moreover, it becomes more evident that there are links between human attitudes and the degree of care given to green areas.
Looking at green spaces through different lenses
Researchers have noticed that there are multiple ways of thinking about nature. The two main ones that are relevant in this essay are the anthropocentric and the biocentric (Lamb 1996). Current evidence suggests that people can be anthropocentric or biocentric depending on life’s circumstances, needs and desires (Vining, Merrick & Price. 2008). These views are probably not static in an individual and may change over time, although studies in this area are lacking. However, they are important to discuss because they can help explain how people assign roles to themselves as they interact with nature. On the one hand, the anthropocentric view values nature and ecosystems as resources for humans to use, an idea carried forward from the 18th Century’s Age of the Enlightenment and supported by Descartes’s Dualism (Vining, Merrick & Price 2008). From this perspective, people see themselves as being above nature and as the rightful exploiters of resources; they believe that the ultimate goal of managing and conserving natural areas is to optimize human health and well-being. Hence, human interests are at the core (Sandifer and Sutton-Grier 2014: Sandifer, Sutton-Grier, & Ward 2015). So, benefits are considered “ecosystem services”, some of which are admittedly fundamental to human survival (Costanza et al. 2004; Millennium Assessment 2005). This approach is straightforward and pragmatic: ecosystems are there for humans to use and their protection ensures continuous access to their services. Additionally, benefits are normally assigned a monetary value, implying that they are measurable (McCauley 2006). Proponents of this view argue that assigning a monetary value to natural areas allows the general public to better appreciate those (Costanza et al. 2014). While this seems a fitting argument for some material benefits such as the provision of water or lumber, it is not necessarily appropriate for non-material benefits that are barely evidenced. Critics of this approach caution that purely anthropocentric decisions about ecosystems are based on the known benefits to human health, without considering albeit maybe unintentionally, non-evaluated or yet-to-be-discovered benefits. In such a context, decisions reflecting current values may be detrimental to future human health and ecosystem integrity, hence they may be non sustainable. Therefore careful and tactful discussion must precede decisions where economics, socio-cultural beliefs, health and nature intersect (Costanza et al. 2014).
The biocentric or life-centred perspective is illustrated by a new cultural trend among industrialized countries that acknowledges the intrinsic value of nature. This means that nature and the life forms in it have the right to exist regardless of the services they provide to humankind. This attitude is known as the “new biophilia” where humans are participants in nature. By doing so biocentrism is in contrast to the Cartesian or anthropocentric view that defines humans as the masters of nature (Grendstad and Wollebaek 1998; De Groot & Van Den Born 2003). Biocentrism acknowledges that the value of natural areas is unquantifiable and infinite (McCauley 2006). Since humans are not at the core, they can relate to nature in many different ways (Van Den Born et al. 2001), which is a relevant consideration in studies on well-being and quality of life.
Biocentrism acknowledges that the value of natural areas is unquantifiable and infinite. (Image: Ellen Murphy / Roy Smith (RoySmith at English Wikipedia), CC BY-SA 3.0, via Wikimedia Commons)
Evidence connecting human health and green spaces is still very partial, but some researchers have found that empathy relates to a desire to protect nature (Tam 2013). This attitude may allow for some leeway and avoid ecosystem degradation until more knowledge on health becomes available. On the other hand, an extreme interpretation of biocentrism calls for a stop of human economic development for the sake of nature, a stand that has caused friction among stakeholders (Costanza et al. 2014). A latter section in this essay revisits the connections between health and economic development. Overall, it is likely that most people fit somewhere in between a purely anthropocentric or a purely biocentric view. It would be interesting to discern if the various shades of attitudes relate to specific health outcomes. For example, is there a direct association between nurturing biocentrism in individuals and reduction of their risk of chronic disease?
These are relevant considerations because it is undeniable that population and urbanization are on the rise, particularly in developing countries and the economic pressure on natural areas will intensify regardless of intention (Jimenez-Arias 2008). Also, as history shows, humankind has always attached monetary or cultural valuation to ecosystems (Costanza et al. 2014). Reconciling divergent views of nature with economic expectations appears to be one of the clear challenges of current times. Also, there are some practical challenges in the research of green spaces and health. For instance, the perception that study subjects have of nature can influence their experience of green spaces and could result in a biased assessment of benefits or threats. If the researcher is not aware of these views, studies can carry a large burden due to confounders. It is worth to find out if biocentric subjects are more prone to report positive experiences or to participate more eagerly in experiments. Or to determine if anthropocentric or biocentric views affect the attrition rate in a study.
Most often the way people intimately think about nature, is not overtly identified among scientists or professionals (Wiley 1998). However, it could be useful to identify the dominant perspective among interested groups (i.e. experts on health, environment, as well as the general public) to determine how their views influence their priorities. When priorities diverge, the lack of consensus can create conflict and hinder innovation. Conflict affects funding, research efforts and transfer of newly acquired knowledge. There is an urgent need to build evidence on the health-to-green space connection in the midst of ecosystem degradation. Therefore, it is foremost to develop a new research attitude mindful of divergent or opposing views of nature (Kennedy & Quigley 1998; Noss et al. 2012; Blicharska and Grandin 2015). Consequently, this can have positive effects in communicating findings about health benefits to the general public.
Definitions of health and well-being
Apart from how nature and green spaces are viewed and valued, a caveat in research is how health and well-being are defined within the context of a world that is rapidly changing. Health and well-being are complex concepts that have spurred both theoretical and practical definitions throughout history. Documented discussions on how to define health date back from Ancient Greece via Hippocrates, to contemporary scholars such as Englehardt Jr. and Withbeck among many others (Nordenfelt 1995). Each definition has raised criticism among academics, government agencies and the general public simply because one can’t think of health without thinking of political, social and economic boundaries (Huber et al. 2011). Apart from the view that being healthy equates to being disease-free (Boorse 1977, 1997); the World Health Organization (WHO) defined health as the state of “complete” physical, mental and social well-being (Grad 2002). These core ideas gave rise to current proposals that define health and well-being in terms of physical, mental and social variables that take into consideration supportive physical environments, personal security, freedom of choice, access to education and cultural identity (Millennium Assessment 2005). Furthermore, it has been suggested that health and well-being encompass states in which a person “fully” displays the abilities he or she was born with (Lee et al. 2012). From these later perspectives, a state of good health would differ from one individual to another, even in the presence of a physical disability or chronic disease (Huber et al. 2011). Consequently, good health and well-being can be relative qualifiers, and can be interpreted as the means to lead a constructive life instead of being a goal in them (Lee et al. 2012). Therefore, health and well-being are value-dependant, i.e. they are conditions that are “desirable”; and include both objective and subjective measurements (Huber et al. 2011). This suggests that the standards of optimal health and well-being are ultimately tuned at the individual and population levels, and are context dependent.
The comprehensive view that health and well-being are determined by the interactions of humans with complex environments, including the natural, biomedical, social, and cultural is attractive and far-reaching. However, it is difficult to adapt these ideas to a research environment. For research purposes, a working definition of health needs to be proposed, and there is a requirement for measurement protocols that can be validated at the individual and population levels accounting for various socio-cultural settings (Huber et al. 2011). Since no widely accepted working definition is currently available, multidisciplinary studies encounter limits to develop research questions. Also, when parameters are not clearly established, evidence is difficult to compare through systematic reviews. Health studies normally report the measuring of physiological or psychological parameters independently of each other. Even if these measurements are rigorous and are validated statistically, they may originate divergent interpretations over time once a multidisciplinary lens is applied. Another difficulty is that complex environments change over time and can be conflicting. According to WHO (2009), one of the major health determinants is socio-economic status, which provides better access to food; and exploitation of natural resources tends to have positive socio-economic effects, but it also leads to biodiversity loss and ecosystem degradation (Hough 2014). There is clear evidence that biodiversity loss reduces the number of genes, species and functional groups of organisms in ecosystems, therefore reducing ecosystem productivity (Cardinale et al. 2012). On the other hand, there is limited evidence on how biodiversity loss directly affects human health and well-being outcomes (Russell et al. 2013; Hough 2014; Sandifer, Sutton-Grier & Ward 2015). It is, nonetheless, reasonable to think that since green spaces are ecosystems, and growing evidence fits them into the collage of health determinants, their productivity and stability need to be seriously considered. This exposes an enormous research challenge in multidisciplinary studies because research questions are placed at the interface where conflict is most evident.
Evidence connecting health and well-being with green spaces
Most of the early research done connecting health and well-being with green spaces was exclusively on mental health. This focus produced a large body of literature covering mostly positive effects such as improved cognitive functioning, reduced mental fatigue, and emotional stress relief (Irvine et al. 2013). These studies were based on qualitative assessments and investigations did not connect mental health to physical conditions such as chronic disease. Nevertheless, these studies remained relevant, especially after McEwen and Stellar (1993) identified the allostatic load concept. Allostasis refers to the capability of an organism to maintain physiological homeostasis (i.e. keeping physiology constant through changing circumstances to maintain life). When a healthy organism experiences stress (i.e. anything that threatens homeostasis), it can produce a protective response to restore physiological and/or cognitive equilibrium. If the coping strategy is not successful, the allostatic load builds up and can eventually lead to physical and/or mental illness (Huber et al. 2011). Physical or mental allostatic load can result from chronic emotional stress due to uncomfortable living conditions or other factors (McEwen 1998). This ground-breaking concept facilitated a new research attitude towards the connections between the mental and physical components of health and well-being (Schneiderman, Ironson & Siegel 2005). Some workers are attempting to associate the concept of human-nature discord and the allostatic load concept, and have drawn a variety of research questions linking experiences with physiological events (Russell et al. 2013). Recent studies are shifting away from exclusively qualitative assessments, towards an integrative approach that records physiological changes in subjects exposed to green spaces (Tsunetsugu et al. 2010; 2007).
Experiencing green spaces has been linked to physical and mental stress reduction (Takano, Nakamura & Watanabe 2002; Schneiderman et al. 2005). Stress plays a role in the etiology and progression of some chronic conditions such as cardiovascular disease, anxiety and depression (Grinde & Patil 2009). The global burden from chronic disease is very significant, with cardiovascular disease being one of the leading causes of death. Despite mounting epidemiological and economic evidence, applying measures to prevent and manage cardiovascular disease has been very slow (WHO 2011). Exceptions are seen in countries like Japan, which have growing elderly populations showing chronic disease. In these nations, chronic disease has put enormous economic pressure in the healthcare system, forcing governments to look at research and development on multidisciplinary domains to design cost-effective and widely accessible interventions. This diagram below (Fig 1.) illustrates some of the possible interactions between humankind and natural environments by proposing a scheme of the interplay between the main concepts discussed in this essay.
Fig 1. Interactions Between Humankind and the Natural Environment. Humans experience benefits and threats from nature, and those experiences shape how nature is viewed, valued, cared for and used. Economic and socio-cultural practices are some of strategies used across history to interact with nature. The effects of those practices reflect back to humans and can influence health and well-being. One of the current challenges is to find sustainable practices that benefit humans and nature alike.
A Japanese research model: the therapeutic effects of forests
One multidisciplinary research trend receiving increased attention relates to the effects of shinrin-yoku or forest therapy on mental and physiological health. The main goal is to determine direct associations between health and well-being with experiencing green spaces through walkabouts. The original research project was designed in Japan but the trend has now extended to other Asian countries, Europe and North America. Interesting traits of this research include well-being quality assessments, as well as biomarker assessments related to relaxation responses. While the studies are designed as randomized controlled trials to assess physiological effects related to stress, there is some consideration of the socio-cultural context, health and well-being perceptions, and ecosystem conservation values of the study subjects. Because of these contextual considerations, the shinrin-yoku’s research model can be placed at the interface of three domains: human health and well-being (via environmental determinants), the biophilia hypothesis and ecosystem conservation.
Shinrin-yoku is a Japanese concept introduced in 1982, which resembles loosely the Kneipp or Naturopathic Therapy from 19th Century Germany (Tsunetsugu et al. 2010). The basis of these alternative or complementary therapies is that there are healing effects resulting from contact with natural settings, such as green spaces. To understand the incorporation of shinrin-yoku into multidisciplinary research is useful to consider the context that gave it origin. In the 1980’s, the Japanese Forest Agency devised a marketing tool to promote visiting forest trails and other conservation areas under the argument that “taking in the forest” would promote well-being in urban dwellers. The promotion of this practice included qualities such as affordability and accessibility to all socio-economic, age, and fitness level groups. This was a successful strategy because the Japanese have a time-honoured tradition of regarding nature as a source of wisdom and spiritual development, so visiting forests was an attractive idea. During the 1980’s the therapeutic value of shinrin-yoku was not scientifically validated and was simply based on intuition. However, by the end of the decade, Miyazaki and colleagues turned this into a research opportunity by designing field studies to observe the neural activity and stress response in human subjects (Lee et al. 2012).
Shinrin-yoku is a Japanese concept introduced in 1982 whereby time spent in the forest is viewed as therapeutic to one’s health. (Image: Freddie Marriage fredmarriage, CC0, via Wikimedia Commons)
The main purpose of the shinrin-yoku studies is to obtain reliable and reproducible physiological and psychological indications that exposure to green spaces is beneficial to human health and well-being. These studies typically include control settings (laboratory spaces), field settings (forested areas), and male and female subjects of several age groups. The physiological observations are measured in real-time using novel technology that is minimally intrusive and include salivary cortisol (e.g. reliable indicator of endocrine stress responses), pulse rate and blood pressure (e.g. indices of autonomic nervous system activity), and lymphocyte counts (e.g. indicators of immune function) among others. The psychological observations are based on qualitative tests measuring comfort and calm, which are later compared to physiological changes (Park et al. 2007). Current evidence shows that shinrin-yoku has a positive effect on reducing high blood pressure (Lee et al. 2012), which is a major risk factor for cardiovascular disease (WHO 2011). This association makes research models like the one applied to study the shinrin-yoku very relevant to global health.
Most recently some studies have looked at the relationship of physiological effects and human behavioural types A and B to explain individual differences in stress responses. Type A behaviour patterns include excessive competitiveness, striving for achievement, time urgency, restlessness and insensitivity to the environment, and have been associated with a higher likelihood of developing heart disease. Type B individuals do not display the characteristics of type A and so far shinrin-yoku evidence shows that this group’s biomarkers reflecting relaxation responses are significantly higher (Song et al. 2013). These findings point towards individual differences in responses that translate to various levels of health benefits (Lee et al. 2012). More sophisticated studies include the isolation of forest elements to observe their specific effects, for instance, the study of olfactory stimulation of phytoncides (substances produced by plants that influence other organisms such as essential oils), the tactile sensation effects, i.e. touching wood, auditory stimulation, i.e. listening to forest sounds, and thermal and light intensity. However, various confounders are still present in these studies such as unaccounting for previous negative experiences of subjects in forests or urban areas, and the direct effects of socio-cultural values. For example, if there is an effect on the physiological response based on study subjects being biocentric or anthropocentric. Hence, there is a need to accumulate more data on the health benefits of shinrin-yoku and the frequency at which experiences are recommended to obtain positive effects. Outside Japan, most studies still focus on psychological outcomes, but there are some novel European and American studies suggesting the benefits of forest experiences on fibromyalgia and ADHD management (Taylor & Kuo 2008; López-Pousa et al. 2015). The expectation is that this research trend will continue and that multidisciplinary evidence will clarify the effects of shinrin-yoku on health and well-being outcomes.
Today, there is a lot of interest among the Japanese on the health outcomes of shinrin-yoku because over 54% of the population above 12 years of age rate their stress level as high or very high, and 42% rate their health status as mediocre. Self-reported stress and health status are quality assessments that are difficult to use but reflect an overall attitude among the population at large and have value as proxies of health and well-being (de Vries et al. 2003; Takano, Nakamura & Watanabe 2002). Japan is a highly urbanized nation, with one of the highest population densities among industrialized countries (337 inhabitants/km2), and has widespread use of computerized technology, which reduces physical activity. Interestingly, it has one of the longest life expectancies in the world. In general terms, the Japanese value overall health, as well as the integration of the natural and cultural characteristics of local sites, particularly near urban areas (Asakawa, Yoshida & Yabe 2004). These characteristics point towards a good fit between the practice of shinrin-yoku and support for its research, particularly as it relates to longevity and chronic disease. By doing so, there is increased public interest towards conservation of forested areas.
Concluding Remarks
Integrated studies of coupled human and natural systems are very complex and still quite rare, as this is a relatively new research theme. So far, most attempts by multidisciplinary groups have revealed big variations and types of human-nature interactions across time and space (Liu et al. 2007). The essay presented here highlighted some of the challenges and opportunities on researching integrated multi-level social and biological domains such as human health, well-being and green spaces.
Researching health benefits attained from green spaces is challenging because of the long-standing and complex associations that humans have with these areas. Therefore, it is difficult to isolate elements and to follow the classic reductionist approach that is typical of scientific inquiry. Another challenge arises from the rapid changes than the human and natural worlds are currently experiencing, such as increased urbanization and ecosystem degradation. Green spaces have been valued across time as sources of mental, physical and spiritual healing, but it is just recently that there is interest in formally connecting evidence from science, medicine and the humanities to best determine the wide range of associations between humankind and nature. Another interesting challenge involves the attitudes and ways of thinking about nature in general; particularly as they affect the way people interact with and protect their natural surroundings, which in turn can affect health and well-being. It is expected that new findings will guide decisions and positive actions that are sensitive to both human health and the environment.
The shinrin-yoku research model was presented as an example of multidisciplinary research that uses the scientific method while considering some aspects of the socio-cultural context of a population. The potential of shinrin-yoku as an affordable and accessible practice to improve health and well-being should be pursued with more research. Cumulative evidence can demonstrate the wide range and intricacy of benefits and threats that experiencing forests and other green spaces offer to increasingly urbanized communities. The potential of shinrin-yoku to ameliorate physical and psychological stress can have important repercussions on our understanding of longevity and chronic disease.
ABOUT THE AUTHOR
Verena Kulak is a member of a human health and nutrition research team dedicated to the scholarship of teaching and learning, and knowledge transfer and translation. Other research interests include the environmental effects of the functional foods and nutraceuticals industry, as well as the connections between human health and the environment across time, with a special emphasis on Early Holocene environments as they relate to paleodiets and migration.
