Redefining human health: physical wellbeing, mental wellbeing, social wellbeing, and environmental wellbeing

In 1948, the World Health Organization (WHO) identified three dimensions of human health—physical wellbeing, mental wellbeing, and social wellbeing.^[1] Physical wellbeing is distinguished by the absence of disease as well as the active pursuit of fitness, while mental wellbeing is distinguished by a lack of depressive symptoms and the presence of calm and happy mental states. The notion of social wellbeing arose following World War II and emerged from a belief that good health not only entailed wellness of the body and mind but also required a society in which sexism, chauvinism, and extremism ceased to exist. This concept recognized individual responsibility for living in peace and contributing to the welfare of others. The definition of health as a composite of these three facets—physical wellbeing, mental wellbeing, and social wellbeing—has been adopted since then.

However, at the time when that tripartite definition of health was first conceived, human activity had only made a limited impact on the environment. Because humans were less productive than we are now, their actions—even those that degraded the environment such as clearcutting forests or burning vegetation—did not result in serious, long-term consequences for the planet. As globalization has progressed and our collective productivity has increased, human activities have made increasingly greater impacts on the environment, and the rate at which we have exploited natural resources has grown.^[2] At present, the global community is more than capable of causing tremendous harm to the planet, which in turn poses a great risk to our collective wellbeing. Given the dire current situation—characterized by biodiversity loss, unhealthy ecosystems, unsustainable land use, unfettered wildlife trade, intensive livestock production, climate change, pollution, and other environmental detriments, humankind can no longer sit back and let this planetary catastrophe continue to play out.^[3]

This state of affairs makes clear that the three dimensions of health identified by the WHO more than 70 years ago are insufficient to convey what health really means in the present day. We believe the definition of health should be expanded to include a fourth dimension—environmental wellbeing. Environmental wellbeing is distinguished by appropriate interaction between humans and the environment. Just as the role humans play in bringing about environmental degradation has intensified, the impact of that environmental degradation on human health has also become increasingly significant. For example, global warming has and will continue to lead to more frequent extreme weather events, which in turn will disrupt food and water supply systems, severely impacting nutrition and food security.^[4] In addition, the emergence and global spread of coronavirus disease 2019 (COVID-19) was not necessarily an unpredictable or random event and was most likely the product of ecological conditions that we have created.^[5] Climate change, biodiversity loss, and alterations in the relationships between humans and other species have caused us to be more vulnerable to emerging infectious disease,^[6] with zoonotic diseases becoming increasingly common. In fact, out of all the emerging infectious diseases that have plagued humanity in the 21^st century, 75% have been zoonotic in origin,^[7] and out of these zoonotic diseases, 70% originated from wildlife, including, COVID-19, severe acute respiratory syndrome (SARS), human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), and Ebola.^[8] Moreover, the environment is becoming increasingly suitable for the transmission of long-known pathogens such as dengue, chikungunya, West Nile virus, water-borne Vibrio bacteria, and other disease-causing agents.^[9] Humans need to realize that environmental health is a critical component of human health, respect the boundaries of the planet that we all live on, and understand how to be kind to nature.

The proposed inclusion of environmental wellbeing in the definition of health is related to the concept of "One Health," which has been defined as "an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems,"^[10] including plants, microorganisms (both pathogenic and nonpathogenic), and other biotic and abiotic components. However, the concept of environmental wellbeing is distinct from One Health in that environmental wellbeing seeks to position planetary wellbeing as a necessary component of human health rather than placing human and environmental health in parallel. Just as social wellbeing was recognized as a facet of human health following World War II, environmental wellbeing ought to be recognized as a necessary precursor for human health in the wake of the COVID-19 pandemic and under the shadow of catastrophic climate change. Recognition of environmental wellbeing as an element of human health could lead healthcare workers to see the environment as an important medium between their practices and the positive health outcomes they seek to produce for those under their care. For example, in being cognizant of environmental wellbeing, a clinician may take better care to avoid overprescribing antibiotics or producing large amounts of carbon emissions and medical pollutants in their practices to maximize the long-term health outcomes of not only their individual patients but also human beings collectively.^[11]

We must recognize that a normal and healthy human existence should not involve only taking selfishly without giving back to nature. Humans' unrestrained exploitation of nature resembles the relationship between cancer cells and the human body, in which cancer cells extract all available energy from the host for their own purposes. It may seem as though the cancer cells are benefitting themselves, when, in fact, they are sealing their own doom by ensuring that the host will eventually be destroyed. We must avoid permitting such a destructive relationship between humans and nature to continue. Instead, we should find a way to live in harmony with the Earth.

Looking to the future, when we are evaluating an individual's health, we must not only examine whether they are in a good physical, mental, and social state, we must also see if they are in a good environmental state—i.e., living free from significant, controllable environmental risks such as those associated with climate change, pollution, and zoonotic spillovers, as well as taking responsibility for living in harmony with the environment and contributing to its preservation. To achieve such a condition, we must start by redefining human health to include four dimensions—physical wellbeing, mental wellbeing, social wellbeing, and environmental wellbeing.

Conflicts of interest

None.