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Healthspan vs lifespan
Living longer and staying healthy longer are measured differently, and the gap between them is a real finding.
Lifespan measures length of life. Healthspan is the informal term for the length of life spent in good health. Its formal counterpart in global statistics is healthy life expectancy, or HALE, published by WHO. The two questions — how long, and how much of it in good health — are answered by different numbers, and a country can move one without moving the other.
Four terms, in order of precision
- Lifespan: the length of one actual life.
- Life expectancy: expected further years for a group at a given age, from a life table.
- Healthspan: an informal idea — the years lived in good health — with no single agreed definition.
- Healthy life expectancy (HALE): the formal statistic, expected years of life adjusted for time lived in less than full health.
How HALE is built
HALE starts from an ordinary life table and then discounts years lived with illness or disability by how severe those health states are estimated to be. WHO applies Sullivan's method: the life-table years in each age band are reduced by the equivalent fraction of healthy years lost at that age. The estimates of prevalence and severity come from the Global Burden of Disease framework used in WHO's Global Health Estimates. The result is expressed in the same unit as life expectancy — years — which makes the two directly comparable, but only when they come from the same source, method and age.
Life table
Expected years of life at each age.
Health states
Prevalence and severity estimates from the Global Burden of Disease framework.
Discounting
Years lived with illness or disability weighted down by severity.
HALE
Expected years of life in full health.
Each step is described in the text above. SnapLongevity performs none of them itself; it displays WHO's published result.
Reading the gap
Subtracting HALE from life expectancy gives a figure often described as the healthspan gap. It represents expected years lived in less than full health under this weighting method. It is a methodological construct, not a diagnosis, and it can only be compared between values calculated the same way and at the same age. A larger gap does not automatically mean worse health: it can also reflect longer survival with conditions that are recorded and weighted.
Swipe the table sideways to see all columns.
| Measure | What it answers | What it does not tell you |
|---|---|---|
| Life expectancy | Expected further years of life for a group at a given age. | Nothing about the health of those years. |
| HALE | How many of those expected years are estimated to be in full health. | Nothing about any individual's current or future health. |
| The gap between them | Expected years in less than full health under this weighting method. | It is not a diagnosis, a severity score, or a personal outlook. |
Why healthy life is harder to measure than length of life
Death is a comparatively clear endpoint: it happens once, on a date, and in most countries it is registered. Health loss has no such endpoint. To express it in years, a method has to decide which conditions count, estimate how common each one is at each age, judge how much each reduces full health, and then combine those judgements. Each of those steps is an estimate rather than a count, which is why healthy life expectancy carries wider uncertainty than life expectancy and why revisions to the underlying estimates can move it.
Length of life and healthy life can move at different rates
The two do not have to improve together. WHO reports that global life expectancy at birth rose from 66.8 years in 2000 to 73.1 years in 2019, while healthy life expectancy rose from 58.1 to 63.5 years — an increase of 5.3 years in HALE against 6.4 years in life expectancy. WHO attributes that mainly to falling mortality rather than to a reduction in years lived with disability. At population level, this illustrates that added years are not automatically added years in full health. It says nothing about how any individual will experience later life.
Does a healthy year mean a year free of disease?
No. HALE is not a count of healthy people set against sick people. WHO builds it with Sullivan's method: for each age band, the years lived in the life table are reduced by the estimated fraction of that time spent in less than full health. A population's HALE therefore mixes fractions of years across many people and many conditions. "Years in full health" is an accounting total, not a group of individuals certified as disease-free.
Why similar life expectancy can come with different HALE
Two populations can expect a similar number of years of life while differing in how much of that time is estimated to be lived in less than full health. The mix of conditions behind the same death rates can differ, and so can their estimated severity and duration. The health-loss estimates also depend on the data each country can supply, so part of a difference between two HALE figures can reflect measurement rather than experience.
What HALE cannot do
HALE is a population estimate that rests on modelled prevalence and severity. It does not describe an individual, it cannot be personalised, and it is not a measure of how a specific person will feel at a given age. It is also sensitive to method: WHO notes that revisions to data and methods mean values from different estimate rounds are not directly comparable, so an apparent change between two published series can come from the method rather than from health itself. Compare figures only within one source, one method version and one age.
Country-by-country comparisons of life expectancy and HALE, at the two published ages, are shown on the Healthspan page. Compare healthspan by country.