Defining “Nature” In Outdoor-Based Health Research: A Thematic Analysis of Conceptual Inconsistency

Background and Purpose: Growing evidence demonstrates a positive link between human health and time spent in natural environments, positioning human-nature research as an important contributor to public health policy and outdoor-based health programming. For environmental policy decisions and outdoor programming initiatives to be equitable and evidence-based, a consistent understanding of what constitutes “nature” is essential. However, “nature” is often implicitly or inconsistently defined in existing research, encompassing a wide range of contexts. This variability limits methodological rigor, reduces interpretability, and weakens the field’s influence on policy and social work practice. Thus, this qualitative study examined how “nature” is defined in human-nature health research and developed a clearer typology of these definitions to support conceptual clarity in research and practice.

Methods: To address this aim, an inductive thematic analysis of 51 articles included in a highly-cited systematic review and meta-analysis (Coventry, P. A., Brown, J. V. E., Pervin, J., Brabyn, S., Pateman, R., Breedvelt, J., Gilbody, S., Stancliffe, R., McEachan, R., & White, P. C. L. (2021). Nature-based outdoor activities for mental and physical health: Systematic review and meta-analysis. SSM – Population Health, 16, 100934). Full texts were imported into Nvivo 15, a qualitative data analysis software, and analyzed iteratively. Descriptions of “nature” were coded and grouped into themes (e.g., comparisons, spaces, environmental characteristics, and synonyms). A supplementary content analysis using keyword searches was conducted to assess the frequency of specific terms across studies.

Findings: Out of 51 articles, only one provided an explicit definition of “nature.” While some studies defined related terms (e.g., green exercise, green environments, green space, nature therapy, ecotherapy), most relied on indirect or implicit descriptions. These included comparisons to less “natural” settings (e.g., urban settings; industrial, noisy, or densely populated areas), examples of specific environments (e.g., parks, gardens, reserves, outdoor trails, wilderness), descriptions of study contexts, or the use of broad synonyms (e.g., “natural,” “nature-based,” or “green”). Conceptualizations of nature varied widely, ranging from small, discrete objects (e.g., a potted plant) to expansive settings (e.g., national parks). Parks (n = 44), particularly urban parks (n = 12), and forests (n = 31) were the most frequently referenced environments. Descriptions often emphasized vegetation, especially trees, while rarely incorporating other elements arguably aspects of nature such as animals or humans. Across studies, “nature exposure” encompassed diverse contexts, including urban and rural settings, indoor and outdoor environments, physical and virtual experiences, and both direct immersion and passive exposure (e.g., views from a window).

Conclusions and Implications: These findings highlight substantial conceptual inconsistency in how “nature” is defined and operationalized across the field. This lack of clarity leads to the conflation of diverse environments, limiting interpretability and weakening translation into policy and practice. For nature-centered social work research and practice, establishing consistent definitions of “nature” is critical. Conceptual clarity can improve measurement, strengthen evidence synthesis, and support the development of more targeted, equitable nature-based interventions. This is particularly important for advancing environmental justice and outdoor-based health programming.