What Do We Mean by a Nature-Based Intervention?

Questioning the boundaries between nature exposure, therapeutic intention, and the human relationship with the natural world.

In contemporary health and well-being research, a nature-based intervention is generally understood as an intentionally designed activity, programme, or strategy that engages people with natural environments to support, maintain, or improve their physical, psychological, or social well-being. Such interventions may include forest bathing or Shinrin-Yoku, horticultural therapy, outdoor mindfulness, nature-assisted psychotherapy, and structured activities conducted in forests, gardens, parks, and other natural settings. What these approaches have in common is the deliberate incorporation of nature into an experience intended to influence human health or well-being.

This definition provides a useful scientific framework. It allows researchers to identify what is being studied, how an activity is delivered, how long it lasts, which environmental conditions are involved, and what outcomes are measured. It also helps healthcare professionals consider how nature-based approaches might be integrated into preventive care, rehabilitation, or clinical practice. From a methodological perspective, such clarity is necessary. Without identifying the intervention, how can we investigate its effects, compare findings across studies, or understand which elements of an experience might contribute to particular health outcomes?

Yet the more I reflect on this definition, the more I find myself questioning the assumptions hidden within the word intervention itself.

An intervention generally suggests a deliberate action introduced into an existing situation to influence its course or produce a particular change. Within healthcare, an intervention is commonly associated with a condition, difficulty, or risk that requires prevention, management, or treatment. We intervene because we wish to alter a process, reduce an undesirable outcome, or support a more favourable one. There is usually an identifiable intention, an action undertaken in response to that intention, and an expected result.

When we apply this understanding to nature, however, an interesting question arises: What exactly are we intervening in? Is nature intervening in our health, or are we intervening in a way of living that has gradually separated us from the natural world?

Perhaps both. Or perhaps the very need to describe our relationship with nature as an intervention reveals something about how we have come to understand health, illness, and our place within the environment.

To examine this further, we might first ask what makes an encounter with nature an intervention rather than simply an experience. Is it the intention behind the activity? Its structure? The presence of a professional who facilitates it? Or the physiological and psychological changes that may arise from the encounter?

Imagine someone entering a forest without any particular objective. The person may spend two hours walking, sitting beneath a tree, observing the surrounding vegetation, or simply enjoying the experience of being outdoors. There is no therapeutic programme, no professional guidance, and no conscious attempt to influence health. Nevertheless, during this time, the person is exposed to the environmental characteristics of the forest, including its sounds, visual patterns, microclimate, vegetation, and airborne substances. Such exposure may be associated with physiological changes, including reductions in certain stress-related markers, even when the person has not consciously sought these outcomes.

Now imagine another person entering the same forest for the same length of time, but with a deliberate intention to reduce stress or support emotional well-being. The activities might be almost identical. The person may walk, rest, observe the trees, and breathe the forest air. The environment itself has not changed, and the physiological processes influenced by that environment may be similar. Yet because the second person has identified a health-related intention, we may be inclined to describe the experience as a self-directed nature-based intervention rather than ordinary nature exposure.

Does intention alone fundamentally change what is taking place? Does the forest respond differently because one person wishes to improve their health while the other has no such expectation? Or does the distinction exist primarily within our human systems of classification?

The question becomes even more interesting when we consider research examining passive and active exposure to forest environments. Studies have reported changes in physiological indicators associated with stress regulation not only during forest walking but also during relatively passive activities, such as sitting and viewing the forest. These findings suggest that at least some of the physiological responses associated with forest exposure do not necessarily require deliberate therapeutic engagement, structured sensory invitations, or even significant physical activity.

This brings us to a rather curious situation. If simply being in a forest can influence physiological processes associated with stress regulation, regardless of whether the individual intends to receive a therapeutic benefit, what exactly distinguishes an intervention from an exposure?

Here, I think we need to be careful with the meaning of the word intervene. In a broad causal sense, environmental conditions continuously influence human physiology. A change in temperature, light, sound, or air quality may alter bodily processes without any deliberate human intention. But in scientific and healthcare terminology, an intervention usually refers to an intentionally introduced action or set of conditions rather than to every environmental influence that produces an effect.

The distinction is understandable. Yet it creates an interesting tension between what happens biologically and how we describe it scientifically. The body’s responses are not necessarily organised according to our definitions. A forest environment may influence a person’s physiology whether the encounter is labelled a recreational walk, nature exposure, forest bathing, or a therapeutic intervention.

If the physiological processes can occur independently of the intention to produce them, should the definition of a nature-based intervention depend primarily on the intention of the person or programme, rather than on the influence of the natural environment itself?

And if we answer yes, are we defining the activity according to its therapeutic potential, or according to the way human beings have decided to organise and interpret that activity?

These are not merely philosophical questions. They have consequences for how we design research, interpret findings, and communicate the possible health benefits of natural environments. When a study examines a structured Shinrin-Yoku session, for example, its results may reflect several interacting elements: exposure to the forest environment, walking or other physical movement, a slower pace, guided attention, sensory engagement, social interaction, expectations, and opportunities for reflection. How do we distinguish the influence of the natural environment from the influence of the activities deliberately introduced within it?

If an individual experiences reduced stress following a guided forest session, can we attribute that outcome to the specific method of guidance? To the forest exposure? To the interaction between the two? Or to other factors that have not been adequately identified?

This distinction becomes particularly important when we compare guided and non-guided experiences. A guided session may offer meaningful benefits through its structure, pacing, accessibility, and facilitation. Yet the presence of a guide should not lead us to assume that the therapeutic potential originates exclusively from the guided method. Equally, evidence that unguided forest exposure can be beneficial does not mean that guided and unguided experiences are identical or that facilitation offers no additional value.

Perhaps the more appropriate question is not which experience deserves to be called therapeutic, but what each component contributes and under what circumstances.

We might also question the boundaries we establish between structured interventions and self-directed practices. Consider someone who regularly visits a forest after a difficult working day. Initially, the person may have no particular health-related intention. Over time, however, they begin to notice that being among the trees seems to help them feel calmer or more emotionally balanced. Eventually, they deliberately choose to return to the forest whenever they feel overwhelmed.

At what point does this ordinary activity become a self-directed intervention? When the person first experiences a benefit? When they recognize the relationship between the forest and their well-being? When they begin to seek that benefit intentionally? Or only when the activity becomes a regular and deliberate practice?

And what about an individual who never consciously associates forest visits with health, yet continues to experience physiological or psychological benefits? Would we consider the experience less relevant simply because the person has not given it a therapeutic purpose?

Perhaps our difficulty arises because we are attempting to classify experiences that exist along a continuum into separate and relatively fixed categories. Human relationships with nature do not necessarily begin with a clearly defined intention or follow a predictable progression. A recreational walk may become a contemplative experience. A structured therapeutic activity may gradually evolve into a personal relationship with a particular place. An individual may enter the forest seeking relief from stress and eventually discover an interest in its ecology, seasonal changes, or other living organisms, without continuing to think about personal health at all.

Should we continue calling the activity an intervention once its original therapeutic intention has disappeared? Or has something else emerged that our terminology does not fully describe?

Another important distinction concerns the relationship between the intention to produce an effect and the effect itself. A nature-based programme may be carefully designed to improve well-being without producing a measurable improvement in a particular individual or study. Conversely, an unplanned encounter with nature may be followed by meaningful physiological or emotional changes. The presence of an intervention does not guarantee effectiveness, and the absence of an intervention does not imply the absence of potentially beneficial effects.

This raises another question: Are we defining a nature-based intervention by what it is intended to do, by what actually happens, or by a combination of both?

In formal research, the distinction between intention and outcome is essential. An intervention is generally identified through its design and purpose, while its effectiveness must be evaluated separately. Yet outside this methodological framework, people may understand an intervention more broadly as anything that helps alter an undesirable condition. The difference between these understandings may explain some of the confusion surrounding terms such as forest bathing, forest therapy, nature exposure, and nature-based intervention.

We might also ask whether an activity needs to be specifically therapeutic to qualify as a nature-based intervention. If a structured forest walk is designed to improve environmental awareness, social connection, or emotional well-being, it may fit within a broad understanding of nature-based interventions. But what if the same walk is organised solely to observe wildlife, learn about trees, or appreciate the forest? If participants experience reduced stress as a secondary outcome, should we retrospectively classify the activity as a health intervention?

Doing so might obscure an important distinction between the purpose of an activity and its possible consequences. At the same time, excluding such experiences entirely from discussions of human health may overlook the wider ways in which natural environments contribute to well-being.

Perhaps we need to recognize that an activity can have health-related consequences without being designed as a health intervention. Its effects and its classification are not necessarily the same thing.

There is another element of the definition that deserves examination: the role assigned to nature itself. In some nature-based interventions, the natural environment appears primarily as the setting in which an activity takes place. In others, engagement with nature is considered an essential component of the intervention. These are not necessarily equivalent approaches.

If we move a conventional physical exercise programme from an indoor gym to a park, does it automatically become a nature-based intervention? The participants are now exposed to natural environmental conditions, but does that mean nature is central to the programme? Would the intended activity function in essentially the same way indoors? And if the programme produces different health outcomes outdoors, how would we determine whether those differences arise from the environment, the physical activity, expectations, or other contextual factors?

Conversely, if someone sits quietly in a forest without following any particular programme, the natural environment may be the central feature of the experience, even though no formal intervention has been designed.

We therefore encounter another paradox: a structured activity may qualify as an intervention while nature itself plays only a limited role, whereas an unstructured encounter may involve profound engagement with the natural environment without qualifying as a formal intervention.

Does this suggest that our definitions sometimes place greater emphasis on the organisation of human activity than on the actual relationship between the human being and the natural environment?

Perhaps this is unavoidable within certain research designs. Scientific investigation requires categories, operational definitions, and measurable variables. Yet we should remain conscious that these categories are tools created to study reality, not reality itself.

We might then question what we mean by nature within these definitions. Does a nature-based intervention require a forest, or can it occur in a small urban park? Does the presence of a single tree constitute meaningful contact with nature? What about a garden, a riverbank, a coastal landscape, or a view of vegetation through a window? Does the degree of biodiversity matter? Does the duration of exposure matter? Is there a minimum level of engagement below which an activity can no longer reasonably be described as nature-based?

These questions become especially relevant when research findings from very different natural settings are brought together under the broad category of nature-based interventions. A forest walk, therapeutic gardening session, and coastal mindfulness programme may share an intention to support well-being, but they involve different environmental characteristics, activities, and sensory experiences. If we combine them under one term, what precisely are we claiming they have in common?

Perhaps their common feature is not a single therapeutic mechanism, but an intentional relationship between human activity, natural environments, and health-related objectives. Yet even this formulation invites further inquiry into what role the environment must play for an activity to qualify.

At a deeper level, however, I wonder whether the concept of nature-based intervention reflects a particular way of seeing ourselves in relation to the natural world.

Human beings are biological organisms. Our bodies continuously interact with environmental conditions through breathing, sensory perception, movement, thermoregulation, and many other physiological processes. We are not separate from nature in a biological sense, even when our built environments and cultural practices create the impression that we are.

From this perspective, nature is not something that suddenly enters our lives when we visit a forest. Our relationship with the natural world is already present, whether or not we consciously recognize it.

What, then, does it mean to speak about introducing nature into human health? Are we introducing an external therapeutic element into an otherwise independent human system? Or are we deliberately modifying the conditions of an existing relationship that has become less visible in our everyday lives?

Could it be that what we describe as a nature-based intervention is, in some circumstances, an attempt to restore opportunities for environmental experiences that have become less accessible or less frequent within contemporary ways of living?

This possibility does not diminish the value of nature-based programmes. On the contrary, it may help explain why they are increasingly relevant. But it also encourages us to question whether the language of intervention captures the full relationship between human beings and the natural environments upon which they depend.

The scientific definition of a nature-based intervention serves an important purpose. It makes certain experiences identifiable, comparable, and potentially reproducible. It allows researchers to investigate whether deliberately organised contact with nature contributes to health-related outcomes. It enables healthcare systems to evaluate particular approaches and consider their appropriate applications.

Nevertheless, a definition designed to support scientific investigation should not become the boundary of everything we consider meaningful or beneficial about human–nature contact.

For this reason, I find it necessary to distinguish between a formal nature-based intervention, a self-directed nature-based practice, and general nature exposure. In formal scientific use, a nature-based intervention involves an intentionally designed activity, programme, or strategy in which natural environments are deliberately incorporated to pursue health or well-being objectives. A self-directed nature-based practice may involve an individual’s conscious decision to engage with nature for restoration, emotional regulation, or other health-related purposes without formal facilitation. General nature exposure, meanwhile, refers more broadly to contact with natural environments, whether intentional or incidental, and whether or not any therapeutic outcome is sought.

These distinctions are useful, but they should not be mistaken for separate biological realities. The environmental processes to which an individual is exposed may overlap substantially across all three categories. What changes is often the purpose, context, organisation, and interpretation of the experience.

And this, perhaps, is where the most interesting philosophical question emerges.

If the same forest environment can influence human physiology during both structured interventions and ordinary everyday encounters, is nature-based intervention primarily a description of what nature does, or of what human beings deliberately do with their relationship to nature?

The first interpretation directs our attention toward the mechanisms and consequences of environmental exposure. The second directs our attention toward human intention, organisation, and the use of nature within health-related practices. Both may be necessary, but they are not interchangeable.

Perhaps we have become accustomed to studying health through identifiable actions, methods, and outcomes because these are the elements most readily incorporated into scientific and healthcare systems. We define a problem, design an intervention, measure a response, and evaluate whether the intended change has occurred. This is a valuable approach, but what happens when the phenomenon we are studying is not a discrete action introduced into life, but an ongoing relationship that already exists?

Can we fully understand the health relevance of nature through the framework of interventions alone? Or must we also investigate the ordinary, repeated, and sometimes unconscious ways in which environmental conditions influence human physiology and experience?

Perhaps the question is not whether we should retain the concept of nature-based intervention. I believe we should, particularly where methodological clarity is necessary. Rather, we might ask how far that concept can take us before its limitations become apparent.

We can recognize the importance of structured programmes without assuming that beneficial nature experiences require professional facilitation. We can acknowledge the health relevance of self-directed practices without treating every personal encounter with nature as a formal intervention. We can investigate physiological and psychological outcomes without assuming that every beneficial environmental influence must be deliberate or consciously experienced.

Most importantly, we can question our definitions without dismissing their scientific usefulness.

Ultimately, what interests me is not simply whether a walk in the forest qualifies as a nature-based intervention. It is what our difficulty in answering that question reveals about how we conceptualize the relationship between human beings, their environments, and health.

When we describe contact with nature as an intervention, are we identifying a particular, deliberately organised approach to supporting well-being, or are we giving a new scientific name to processes that have always been taking place between the human body and the natural world?

Perhaps the answer lies in recognizing that we are describing two related but distinct phenomena: the intentional organisation of nature-based experiences and the influence of natural environments on human health, regardless of intention.

The former is what we generally define as a nature-based intervention. The latter is the wider phenomenon that makes such interventions worth investigating in the first place.

And perhaps the question we should continue asking is whether, in our effort to define the intervention with ever greater precision, we risk overlooking the very relationship that gives it meaning.