Health is the level of functional and metabolic efficiency of a living organism. The old English word for health comes from a Germanic origin relating to the idea of “whole”. In this respect, we can think of health as the whole or complete physical functionality of an organism. If we think of the organism as a system we can define health as the degree to which all of the components parts are working together as a functioning whole system. The health of a human is then a function of the anatomic, physiologic, and psychological integrity of the person which gives the whole system the capacity to perform work. Inversely illness can be understood as the lack of integration when parts are interacting through negative synergies that render the whole dysfunctional.
In this respect, the health of a person is akin to the concept of ecosystems ascendancy, which describes the “organized power” of the ecosystem. This index represents the magnitude of the power that is flowing within the system towards particular ends, as distinct from power that is dissipated willy-nilly. It is intended to capture in a single index the ability of an ecosystem to prevail against disturbance by virtue of its combined organization and size.1
Ascendancy relates to the idea the Constructal law which is a term recently coined by Adrian Bejan to describe the natural tendency of flow systems, such as rivers, trees, lungs, tectonic plates, to generate and evolve structures that increase flow access. It holds that shape and structure arise to facilitate flow. The designs that happen spontaneously in nature reflect this tendency: they allow entities to flow more easily – to measurably move more resources further and faster per unit of useful energy. In this respect, health can be thought of in terms of the integrity of the organism which enables the flow of metabolic processes required for the whole system to function as an autonomous entity.
Health is often understood in terms of personal ability to maintain homeostasis and recover from external alterations. The ability to deal with physical, biological, social and psychological stress. Mental, intellectual, emotional and social health refers to a person’s ability to handle stress, to acquire skills, to maintain relationships, all of which form resources for resiliency and independent living.2
The definition of health has evolved over time. In keeping with the biomedical perspective, early definitions of health focused on the body’s ability to maintain homeostasis; health was seen as a state of normal functionality that could be disrupted from time to time by disease. A closed conception of health of this kind sees a dichotomy, between health and illness; there are a normal accepted set of states that are considered healthy and when one goes outside of those one is sick. The aim then is to maintain homeostasis; as soon as one is outside the “normal” parameters to try and return back to the equilibrium state.
Inversely an open systems approach would look at health in terms of a dynamic process, that health is not a given “normal” state but instead something that is created through the self-organization of parts. The aim is not to maintain homeostasis at all times, but resilience, which is created out of some dynamic interaction between order and disorder within the organism. Just as we understand now that ecosystems require external perturbations – such as forest fires – to maintain resilience and trying to maintain them constantly within their normal operating parameters leads ultimately to disastrous effects, so to the health of an individual is something that is created out of periods of disorder and disequilibrium, within a dynamic process. The development of the human immune system through being exposed to different antigens is a good illustration of this.
Put simply a static closed system’s view of health sees it as something innately given and illness as something to always be avoided. A more open systems process-oriented view of health sees it more as something to be created; that organisms are constantly evolving through a process of self-organization that involves a dynamic interplay between disorder – disintegration, disequilibrium – and order – integration and equilibrium.
Healthcare then refers to all of the activities involved in development and maintenance of health. Health is a state or condition resulting from the multiple interactions internal to the individual and between people and their biological, chemical, physical, social, cultural and economic conditions of their environment. Determinants of health are factors that contribute to a person’s current state of health.3 Scientists generally recognize five determinants of health of a population including, genes and biology: for example, sex and age. The person’s lifestyle choices: the combination of decisions over which the individual has control that can be seen to contribute to, or influence, illness. For example, unprotected sex, alcohol abuse, drug abuse or smoking. Likewise, one’s life outlook can strongly affect one’s perception of one’s own health. There may be two people who have a similar kind of heart attack without any lasting damage, one person who has a positive and robust mentality may get on with there life requiring no further assistance from the health system, while another may not.
A third determinant is health services or medical care: for example, having or not having adequate insurance and access to quality healthcare.4 The physical environment and the whole ecology within which the individual finds themselves: for example, whether a person lives in a city or countryside is a fourth key determinant of health. Social and cultural environment, for example, the person’s income, social discrimination, or other cultural aspects. It is increasingly recognized that health is maintained and developed not only through the advancement of health science and its application but also through the efforts and intelligent lifestyle choices of the individual and society. As can be seen in the adjacent graphic social determinants and behavioral choices are now thought to make up the majority of the health determinants.5
According to the World Health Organization health systems “consist of all organizations, people and actions whose primary intent is to promote, restore or maintain health.” A health system is all of the component parts that are interrelated in delivering the functions required to maintain and develop the health of a population of people. There is a wide variety of formal health systems around the world, with as many long histories and organizational structures as there are nation-states, but a number of key elements can be identified to constitute any comprehensive health system. A complete health system needs: finance, resources, organization & governance, human resources, knowledge, service delivery, technology and information and all these parts need to be working together.
Health care systems perform the function of delivering health services to a given group of people. The effectiveness of that service can be looked at along a number of parameters. Firstly what is the range of services? Does the system provide all of the services required by the population? Secondly the reach, for what percentage of the given population is the system really accessible to, due to financial constraints, geographic constraints, cultural constraints etc? Finally, what is the quality of the service being delivered? All of these three factors are believed to constitute the effectiveness of the service delivered by a formal health system in responding to both chronic and immediate health requirements.
Health systems are networks of different elements interacting. The health of a group of people is not just a product of all of the formal institutions of the health system but also all of the informal factors that determine health. Whereas the formal health system constitutes all of the well-defined components that form what we traditionally consider the health system – hospitals, clinics, practitioners, labs etc – the informal system consists of all the ill-defined components that determine the health of a population – the quality of the local ecosystem, pollution, agriculture, food retail, the form of the built environment etc. Ultimately health is a function of all of these factors – both formal and informal – interacting.
The challenge is to get all of these components and get them working together in a synergistic fashion across the whole system so as to deliver an effective service. How can not only hundreds of hospitals, medical centers, pharmacies, and physicians be united into a successfully functioning healthcare sector but also how can that formal system also be supported by all of the informal factors that are required to get the desired outcome?
Much of the complexity of health systems comes from their multiple scales. The considerations of a health system span all the way from the molecular level to the global population of all of humanity. At different levels, new requirements and considerations emerge. The nature of health at the individual level – where we may be considering the molecular makeup of a medicine or the physiology of the body – is very different from that of what we have to consider when looking at the management of a local hospital or at the level of a population of people as a whole. While on the individual level health may be understood as a science, on the macro-level of whole health systems it is anything but a science, being an open system that has to interact with many other factors – economic, social, cultural, ecological – all of which make macro-scale health systems highly complex.
Health systems are complex because they consist of many autonomous components and actors that are dynamic, interconnected and interdependent in delivering the overall outcome. Firstly the number of autonomous parts. Health systems are typically large distributed systems of many actors in many different spheres – from research and academia to pharmaceutical companies, to government legislators, to public administrators, to clinicians, to independent consultants – all have some degree of autonomy to act and affect the system while at the same time they are interconnected and interdependent in affecting the behaviour and results of the whole system.
Health systems consist of many actors with their own local agendas and metrics for success – private enterprises optimizing for profit, policymakers trying to stay in office, clinicians following standards and best practices, insurance companies trying to reduce costs, patients trying to return to health etc. In order to understand such a system advanced stakeholder analysis is required – asking what are the gains and losses to different agents in the system and what are the motives under which they are acting. For example, the development of healthcare technologies such as new drugs is driven largely by privates sector activity that is rewarded through intellectual properties, that particular structure of incentives is what ultimately creates the forces shaping the system. Health systems involve huge vested interests and it is necessary to analyze these before one can understand how the system might behave given some alteration or why certain patterns of behavior persist long after they have become redundant.
Because health systems involve a wide variety of adaptive agents that are interacting and interdependent they can be understood as complex adaptive systems that evolve over time. While formal health systems are largely designed – we create health systems out of our models – informal health systems involve a wide variety of actors adapting to local conditions, interacting, competing or cooperating as the system evolves over time.