Last week about 30 of us spent 36 hours in The Hague discussing whether we could produce a new definition of health—and eventually deciding that we couldn’t. But we had an interesting time, and I concluded that I would think of health not as a state or a destination but rather as a journey.

The best known definition of health is the WHO one from 1947: “Health is a state of complete physical, mental and social wellbeing and not merely the absence of disease.” This was important in that it made clear that health is not simply the absence of disease, which is probably the working definition of most doctors, but the word “complete” creates great difficulties. The irreverent epidemiologist Petr Skrabanek famously said that the WHO definition of health is achieved only at the moment of mutual orgasm. Most of us would be defined as unhealthy most of the time.

Those at the meeting mostly thought the definition unhelpful, although it is durable and well known. Various attempts to replace it have got nowhere. The definition is short and memorable, and perhaps people like its aspirational nature.

Why exactly, I wondered, might we need a new definition? What is the problem we are trying to solve?

One problem, which is worrying WHO itself, is that the definition is not operational and so doesn’t allow measurement of health. We can measure death rates and disease rates, but as WHO is dedicated to health not disease it would be good to be able to measure and compare the health of individuals and countries. People at WHO have been thinking about this problem and contemplated a composite measure that might include death and disease rates, measures of function (perhaps mobility, cognition, vision, sleep, etc), and a subjective measure of overall quality of life and well being.

We were warned, however, about the dangers of combining different types of scores, particularly when people might have very different weightings for each of the scores. (Have you ever seen the widely used picture of the entry sign to a village that says “Population 1030, altitude 640 m, number of churches 6, result 1676”?)

Interestingly when people across Europe are asked to rate their quality of life on a score of 1 (low) to 10 (high) their average is consistently 8 from age 10 to 80. Yet over that time function declines considerably. I can’t run as fast or remember things as well as I would when I was 20, and I’m fatter and balder—and no doubt my arteries are atherosclerotic, but I feel just as healthy. My 80 year old mother, who has no short term memory, is always telling me how lucky she is. And the year after an adverse life event, such as a partner dying, people still rate their quality of life as high. We have a powerful capacity to adapt, and that capacity is surely an important part of health. People can adapt to having cancer and other chronic and life threatening diseases and to being disabled—and so in some sense stay healthy.

One organiser of the meeting was the Health Council of the Netherlands, and it was interested in the possibility of a new definition because it has to advise the Dutch government on health—which implies being clear about what health is.

Another organiser was the Netherlands Organisation for Health Research and Development. It wants to fund research that will produce health gain, meaning that it would like a definition of health that unlike the present one would allow measurement.

But perhaps the biggest use of a new definition of health might be to stop health absorbing absurd amounts of resources. Developments in imaging and genetic screening combined with the steadily falling thresholds for hypertension, diabetes, and dyslipidaemia mean that an ever increasing proportion of the population is potentially defined as unhealthy—paradoxically at a time when life expectancy for adults is increasing dramatically. Perhaps a more robust and less expansive definition of health could help hold back this trend to define ever more people as unhealthy and so see an ever increasing proportion of countries’ resources devoted to “health.”

Similarly perhaps a new definition could shift the “health” debate from one of hospitals, doctors, disease, and drugs to one  more about population health and its determinants—water, sanitation, housing, income, employment, and social justice.

I probably have unrealistic expectations of what a new definition might achieve, but I heard some definitions at the meeting that I liked better than the WHO one. Ivan Illich defined health in 1976 as “the ability to adapt to a changing environment, to growing up and ageing, to healing when damaged, to suffering and to the peaceful expectation of death.” His emphasis is on adaption, and he reminds us that ageing, death, healing, and suffering are all part of life—and not simply the property of hospitals and doctors.

The International Epidemiological Association in 1982 defined health as “a state characterised by anatomical, physical, and psychological integrity, ability to perform personally valued family, work and community roles; ability to deal with physical, biological, and social stress; a feeling of well being; and freedom from the risk of disease and untimely death.” The definition recognises the many dimensions of health, and I like the emphasis on being able to do what you want to do, the recognition that individuals have meaning only within families and social roles, and the importance placed on being able to deal with the stresses that will inevitably come along.

But neither of these definitions nor any other one has succeeded in replacing the 1947 WHO definition, and most of us by the end of meeting thought that it wouldn’t be possible or even helpful to spend time trying to replace it. I certainly concluded, however, that everybody working in health (all of us in a way) should at some time spend not 36 hours but at least one hour discussing what we mean by health.