We've built entire health systems around one metric: lifespan. How long did the patient live? It's on the charts, in the research, driving the policy. But living to 85 with 15 years of chronic disease isn't a success story. It's a failure we've agreed to call progress.
The Wrong Scoreboard
Lifespan is the metric we measure because it's the metric we can measure. It's binary. Alive or not. Easy to track, easy to compare across populations, easy to put on a graph.
Healthspan - the number of years lived in good health, free from chronic disease and disability - is harder to define and harder to measure. So we don't. And because we don't measure it, we don't optimise for it.
63.3 years
average global healthy life expectancy (HALE), compared to 73.3 years total life expectancy - a gap of 10 years lived with illness or disability
Source: World Health Organization, Global Health Estimates, 2019
Think about that gap. On average, people spend the last decade of their lives unwell. And our health systems are designed to manage that decade, not prevent it.
Prevention Is the Point
The entire model of modern healthcare is built around intervention after illness. Screening catches cancer early - but after it starts. Medication manages diabetes - but after the pancreas is damaged. Surgery fixes joints - but after the cartilage is gone.
Every one of these interventions is necessary. None of them is optimal. The optimal intervention is the one that prevents the condition in the first place.
We have the data to do this. Genetic risk profiles can flag predispositions decades before symptoms. Biomarker tracking can catch metabolic drift years before a diagnosis. Lifestyle data, when properly contextualised, can identify risk patterns that simple clinical observation misses.
If we measured healthspan with the same rigour we measure lifespan, we'd fund prevention properly and stop treating it as an optional extra.
Jay Harrison
Health Technology Advisory
What Changes If We Shift
If healthspan becomes the primary metric, everything changes. Funding shifts from treatment to prevention. Research priorities shift from managing disease to maintaining health. Workplace wellness stops being a perk and starts being a strategy. Insurance models start rewarding health maintenance instead of just covering illness.
This isn't utopian thinking. It's economic logic. Treating chronic disease is extraordinarily expensive. Preventing it is comparatively cheap. But the return on prevention takes years to materialise, and our funding models think in budget cycles, not decades.
The organisations that understand this - the ones measuring healthspan alongside lifespan - will be the ones that reshape health outcomes for their people.
Lifespan tells you how long someone lasted. Healthspan tells you how well they lived. It's time we cared about the right number.