A population-based measure of the proportion of expected life span estimated to be healthful and fulfilling, or free of illness, disease, and disability according to social norms and perceptions and professional standards.

While life expectancy has increased over the last 10 years, health expectancy has not, i.e., people spend more years in ill health.
The aim is to make health expectancy as close as possible to life expectancy or, in other words, to make the gained years of life as healthy as possible.

World Health Organization. European Observatory on Health Systems and Policies. Glossary. 2009.