The current WHO definition of health, formulated in 1948, describes health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”At that time this formulation was groundbreaking because of its breadth and ambition. It overcame the negative definition of health as absence of disease and included the physical, mental, and social domains. Although the definition has been criticized over the past 60 years, it has never been adapted. Criticism is now intensifying and as population’s age and the pattern of illnesses changes the definition may even be counterproductive.

Most criticism of the WHO definition concerns the absoluteness of the word “complete” in relation to wellbeing. The first problem is that it unintentionally contributes to the medicalisation of society. The requirement for complete health “would leave most of us unhealthy most of the time.

The second problem is that since 1948 the demography of populations and the nature of disease have changed considerably. Disease patterns have changed, with public health measures such as improved nutrition, hygiene, and sanitation and more powerful healthcare interventions.

Nevertheless, the limitations of the current definition are increasingly affecting health policy. For example, in prevention programmes and healthcare the definition of health determines the outcome measures: health gain in survival years may be less relevant than societal participation, and an increase in coping capacity may be more relevant and realistic than complete recovery.

The first step towards using the concept of “health, as the ability to adapt and to self manage” is to identify and characterise it for the three domains of health: physical, mental, and social. The following examples attempt to illustrate this.

Physical health: the maintenance of physiological homoeostasis through changing circumstance

Mental health: contributes to a successful capacity to cope, recover from strong psychological stress, and prevent post-traumatic stress disorders

Social health: the ability to manage their life with some degree of independence despite a medical condition, and the ability to participate in social activities including work

Measuring health: operational definitions are needed for measurement purposes, research, and evaluating interventions.