This study employed a narrative review design to synthesize interdisciplinary evidence related to the implementation of GRx programs. The initial phase of the review sought to synthesize evidence of GRx across specific outcome domains, including cardiovascular health, obesity, and related chronic conditions. Early scoping of the literature revealed a growing body of research documenting associations between nature exposure and a range of physical and mental health outcomes. However, this preliminary evidence mapping also highlighted a notable gap. While the benefits of nature exposure were increasingly described, less attention had been paid to how GRx programs are implemented within and beyond healthcare systems.

As an emerging interdisciplinary field, the available evidence base was sporadic and diverse, spanning observational studies, qualitative research, program evaluations, policy documents, and conceptual frameworks. Absence of standardized interventions and outcome measures made a narrative review approach appropriate over a meta- analysis or a quantitative synthesis.

Accordingly, the scope of this review was refined to focus on implementation-oriented evidence related to GRx, with particular attention to structural, clinical, environmental, and patient-level factors shaping access, participation, and equity. These dimensions were considered collectively, as patient access, healthcare system integration, and follow-through are interdependent components of real-world GRx implementation rather than discrete processes.

A structured literature identification process was conducted to capture relevant evidence published over the past three decades. Peer-reviewed literature was identified through searches of PubMed, Scopus, and Google Scholar, selected to capture clinical, public health, and interdisciplinary research relevant to GRx implementation. To reflect the applied and practice-oriented nature of GRx programs, gray literature including government and institutional websites, policy documents, and implementation or evaluation summaries was also reviewed. This review did not involve the collection of primary data, human subjects, interviews, or original qualitative or quantitative analyses.

Search terms were developed iteratively and organized around three primary concept domains:

These terms were searched independently and in Boolean combinations to identify literature spanning clinical medicine, public health, environmental health, urban planning, and design. Key publications were also manually screened to identify relevant sources not captured through database searches. To enable consistency within the search, explicit inclusion and exclusion criteria were defined as a priori and applied throughout the screening and synthesis process (Table 1). Iterative discussions were used to resolve uncertainties in eligibility.

Eligible sources included empirical studies, qualitative research, observational analyses, program evaluations, policy reports, and conceptual or framework-based papers that addressed nature prescriptions or closely related interventions. Studies were excluded if they focused solely on theoretical discussions without application to health or healthcare contexts, or nature exposure without relevance to prescribed, structured, or programmatic interventions. Editorials, opinion pieces without substantive evidence, and studies lacking sufficient methodological or contextual detail were also excluded. These criteria were used to guide title and abstract screening, followed by full-text review where necessary, to ensure alignment with the objectives of this narrative synthesis.

For each included source, we extracted information on the study or program setting, geographic context, population characteristics, type of nature-based intervention or prescription, delivery or referral mechanisms, reported facilitators and barriers, and outcomes relevant to access, engagement, or implementation. Due to the nature of the review, and the scarcity of established programs, evidence was synthesized narratively rather than systematically, using a deductive, theme-informed approach to allow patterns and gaps to be more easily identified. In total, 22 papers were synthesized to identify key barriers to the implementation of GRx interventions within the broader healthcare system.

Across existing literature, GRx aims to connect clinical care with preventive public health strategies by recognizing greenspaces as a health-supporting resource. At their core, GRx consists of structured, evidence-informed recommendations from clinicians encouraging patients to engage in nature-based activities. These prescriptions range from generalized weekly goals to more specific tasks tailored to an individual’s abilities, preferences, and lifestyle. Some programs allow patients to select from curated activity options to support personalization and follow-through, while others incorporate structured follow-up elements such as check-ins or journaling to assess engagement and perceived impact (34).

GRx are consistently characterized as multifaceted, with program modules being applied to a range of issues including depression, anxiety, cardiometabolic disease, physical activity, along with others. Mental health practitioners increasingly incorporate nature-based activities to support stress reduction, mood regulation and management of neurodegenerative diseases (4, 5, 20, 35, 36). These approaches span passive integration such as conducting therapy sessions in shaded courtyards or garden settings to more active formats including walk-and-talk therapy (37). In parallel, GRx is frequently framed as a low-cost strategy to address rising levels of physical inactivity, a major contributor to hypertension, obesity, and cardiovascular disease. These examples are presented to illustrate longstanding cultural relationships between nature and health rather than as formal GRx models, highlighting the diversity of contexts in which nature-based care has been conceptualized outside clinical systems.

The literature also describes the use of GRxs in rehabilitation contexts. Green physical activity (GPA) prescriptions are reported to support physical recovery, including improvements in mobility and rehabilitation outcomes for musculoskeletal and neurological conditions (4, 38). Many GRx models are designed to extend beyond therapeutic settings and into patients’ daily lives, aligning with salutogenic care approaches that emphasize health promotion through routine environments rather than episodic clinical encounters.

Globally, GRx has taken many forms. While some countries have formalized programs, others promote nature engagement through cultural or wellness practices. Formalized programs are most common in Oceania, Europe, and North America, where they are often supported by non-profit organizations, healthcare networks, or government-funded initiatives that link patients to outdoor activities either directly or through clinical referral pathways (Figure 2). In the United States, Park Rx America functions as an educational and implementation hub, offering clinician training resources and registries to support integration of nature prescriptions into care plans (39). In Canada, PaRx partners with organizations such as the BC Parks Foundation and the Canadian Medical Association to increase nature accessibility, with over 13,000 participating physicians offering patients free or discounted access to nature-based destinations (40, 41). New Zealand’s national GRx program, administered by the Ministry of Health, combines clinical referrals with peer coaching and community activity networks to support participation among adults and families (42).

In parts of the world without formal GRx systems, communities continue to engage with nature through traditional practices. In India, Ayurveda is a naturopathic practice that is founded on the harmony between human health and nature, contrasting western medicine (43). In communities across Africa, shamans use herbal remedies and rituals, embedded within the natural world in sacred forest groves (44). In Central America, Costa Rica embodies the way of “Pura Vida,” a lifestyle emphasizing frequent immersion in nature for rejuvenation and health (45).

Despite their success, these programs still serve a niche role within healthcare systems. While the diversity of GRxs highlights its adaptability across contexts, long-term effectiveness depends on whether patients can realistically engage with prescribed activities within their everyday environments. Even when endorsed by clinicians, many models rely heavily on individual capacity to navigate access, logistics, and sustained participation, setting the stage for the implementation challenges that hinder GRx from becoming a consistently equitable and effective healthcare tool.

Literature points to a series of inter-related barriers to the implementation of GRx, spanning environmental conditions, structural access constraints, and clinical practice limitations. At the environmental and structural level, outdoor settings inherently differ from regulated clinical environments, which presents accessibility challenges for certain populations. Unlike clinical spaces, outdoor environments lack controlled conditions, limiting feasibility for individuals with autoimmune disorders, physical disabilities, or heightened vulnerability to environmental exposures. Climate-related factors have been shown to further compound these challenges. Extreme weather events including heatwaves, cold spells, and poor air quality can render outdoor spaces unsafe or impractical for extended periods of the year, particularly in regions already experiencing climate stressors (46). In addition, degradation of urban greenspaces including poor air quality, excessive noise, heat exposure, or competing uses such as tourism and events may reduce their therapeutic suitability and undermine the intended health benefits of nature-based prescriptions. Furthermore, communities facing economic disadvantage often lack proximity to safe, well-maintained, and usable greenspaces, limiting opportunities to act on prescribed activities (19). Transportation barriers, especially for individuals with mobility limitations, limited access to private vehicles, or inadequate public transit represent an additional constraint. For vulnerable populations, including children, older adults, immunocompromised individuals, LGBTQ+ and BIPOC communities, concerns related to physical safety, environmental hazards, supervision, harassment, and social exclusion may further restrict engagement in outdoor activities, even when greenspaces are physically accessible (31, 47). Even with safe access, patients may deprioritize GRx due to time and financial constraints. Incentive structures such as transportation support or insurance-based rewards may help offset participation barriers.

Barriers also emerge within clinical practice. Even in settings with viable green infrastructure, inconsistent physician engagement can limit GRx uptake. The literature describes limited clinician training, absence of standardized prescribing frameworks, and lack of integration into routine workflows as key constraints. In some cases, clinicians express support for nature-based care but hesitate to issue formal prescriptions due to uncertainty around liability or lack of institutional guidance, instead offering informal recommendations (19, 48). Acceptability related barriers are also reported including patient preferences for traditional pharmacological treatment or skepticism toward nature-based care, which may reduce engagement (49). Without system-level support, clinical normalization, or clear implementation pathways, GRx remains peripheral to mainstream care despite increasing awareness and interest.

Beyond identifying barriers, the literature reveals recurring implementation-relevant considerations that help explain why some GRx models demonstrate greater feasibility than others. These patterns highlight where existing approaches succeed, strain, or fail when translated into routine practice. A consistent theme concerns how responsibility for implementation is distributed. GRx models that rely primarily on individual patient initiative are frequently described as difficult to operate. These models unevenly distribute responsibilities by requiring patients to independently identify locations, manage logistics, and sustain engagement over time. In contrast, programs that extend responsibility through referral pathways, navigators, or community partnerships reduce logistical and cognitive burden on patients and are more often reported as feasible.

Integration within healthcare systems also shapes implementation. GRx models operating outside routine clinical infrastructure without documentation, referral mechanisms, or follow-up are commonly described as informal and episodic. Where GRx are embedded within clinical workflows, even in limited ways, the literature suggests greater alignment with provider practices and continuity of care (40, 46, 47). Community context further influences implementation. Programs that leverage local parks, nonprofit organizations, or culturally embedded practices are better positioned to address access, safety, and relevance simultaneously. However, these approaches are often localized, resource-dependent, and unevenly scaled, limiting broader generalizability. Finally, many GRx models also lack mechanisms for monitoring participation or adapting prescriptions over time. Without feedback or accountability structures, prescriptions risk becoming symbolic rather than actionable, contributing to inconsistent engagement and limiting evaluation of impact.

Collectively, these barriers indicate that GRx implementation challenges arise less from lack of perceived benefit than from misalignment between clinical intent and real-world feasibility. How support, infrastructure, and accountability are distributed across patients, clinicians, and systems therefore shapes whether GRx function as actionable care or remain aspirational. These patterns inform the practice-informed framework that follows.

Access emerged as the most immediate and tangible constraint shaping whether nature-based prescriptions can be acted upon in practice. Prescriptions must connect patients to specific, nearby resources that align with their physical capacity, schedules, and neighborhood conditions. Several programs described in the literature emphasize the importance of moving beyond general encouragement toward place-based guidance that patients can realistically use. At a basic level, clinics and hospitals can start small by creating resource packets that map nearby parks, trails, arboretums, and community nature programs. These recommendations are scalable, offering general green space recommendations or personalized locations based on ZIP codes, such as local church trails or neighborhood gardens. These packets can include hours of operation, safety tips, walking difficulty, and transit options to ensure patient safety and adequate engagement. Digital resource programs like Park Rx America, local parks department directories, and third-party apps can be embedded into patient portals as supplementary resources.

Several models described in the literature could be propelled further through partnerships with wellness professionals or community navigators who can help patients identify nature-based options appropriate to their mobility, preferences, and daily routines. These partnerships allow prescriptions to be translated into individualized action plans without substantially altering clinical workload. In some settings, on-site or shared-use programs originally designed to reduce staff burnout have also been adapted for patient use, demonstrating how existing institutional resources can be leveraged with minimal overhead.

The development of standardized GRx protocols that healthcare professionals can reference as clinical guidelines is essential to support consistency and clinical confidence. Currently, nature prescriptions rely on informal counseling or verbal encouragement, which risk being forgotten, ignored, or deprioritized within competing care demands. Embedding accountability mechanisms on both the clinical and patient sides of GRx delivery may improve adherence over time. Clinicians can begin by incorporating nature-based documentation into electronic health records (EHR), alongside referrals or medications. Adding intake questions like, “How much time do you spend outdoors each week?” or “Do you have access to a nearby greenspace? /Do you know where your nearest park is?” helps establish a baseline of patient interest and feasibility, while integrating nature-based language into routine workflows. When systematically captured, these data can inform GRx delivery, support clinical decision-making, and contribute to population-level planning. On the patient side, self-accountability plays a critical role. Self-monitoring tools such as checklists, journaling apps, or wearable devices can help patients track and log their GRx goals. Clinics may also deploy brief follow-up surveys through patient portals, using platforms such as REDCap or Qualtrics, to assess time spent outdoors, perceived benefits, and barriers. Some EHR systems allow patients to log nature-based activities directly within patient portals (50). To enhance engagement, health systems and insurers may consider modest incentive structures tied to participation, such as wellness credits, insurance premium reductions, or charitable donation matching linked to verified activity. Behavioral incentive models already used in step-count and workplace wellness programs may increase adherence while maintaining the preventive ethos of GRx (51). Together, these low-cost strategies support follow-through while minimizing additional administrative burden.

To gain traction within mainstream clinical care, GRx must be framed not only as beneficial but also as cost-conscious, scalable, and patient-centered. Healthcare systems prioritize interventions with clear value propositions, those that reduce risk, lower costs, or improve quality metrics. Accordingly, the potential value of GRx as a complementary intervention, particularly within prevention-oriented and value-based care models, must be clearly articulated and supported by available evidence. Hospitals and clinics can support this shift by offering continuing education opportunities, recognizing participation through internal micro-credentials or departmental awards, and highlighting alignment with existing value-based care incentives. Platforms such as Park Rx America, Nature Sacred, and WELL v2 offer free, evidence-informed training modules that do not impose substantial time or budgetary burdens. Academic institutions can further support this transition by integrating nature-based health concepts into medical education and residency training. Over 90 universities, including institutions such as Cornell University, Texas A&M University, and UC Davis, participate in Campus NatureRx (CNRx) initiatives that prescribe nature through on-campus clinics (34, 52). These models illustrate how GRx concepts can be introduced with minimal curricular restructuring.

A limited but growing body of studies suggests that increased use of green spaces may be associated with reductions in healthcare expenditures in specific populations and contexts (17, 53, 54). For example, one study reported that the construction of an urban park was associated with over CAD 130,000 in reduced healthcare spending, attributed to increased physical activity, improved mental well-being, and reduced exposure to air pollution (55). In Australia, observational studies of office workers reported productivity gains of over ~11% following regular visits to national parks, with associated economic benefits at the population level, with an increase of ~1.8% of GDP, of which healthcare spending was reduced by 0.6% (56). These findings are context-specific and should be interpreted cautiously. Collectively, the evidence suggests that investments in accessible green infrastructure may yield broader public health and economic co-benefits.

Despite available evidence, there remains a need for more causal and longitudinal research to strengthen the scientific foundation linking nature exposure to specific health outcomes. Establishing stronger pathways may enhance clinical confidence, support policy adoption, and promote broader integration of GRx into routine care. For example, the ongoing Green Heart Project in Louisville, Kentucky is investigating how neighborhood greening interventions influence cardiovascular health outcomes, contributing to emerging causal evidence on environment–health relationships (57).