Healthspan
The period of life spent in good health, with physical strength, cognitive function, mobility, and independence intact. Distinct from lifespan, which is simply the total years lived.
Healthspan refers to the years of life during which a person is free from serious disease, physical disability, and cognitive impairment. It is the quality-of-life dimension of longevity that modern aging science is most focused on extending.
Unlike lifespan, which simply counts total years from birth to death, healthspan is concerned with how those years are experienced. Two people can have the same lifespan but very different healthspans: one remaining physically active and mentally sharp into their late 80s, the other managing progressive disability from their 60s onward.
The gap between when healthy functioning declines and when death occurs is sometimes called the healthspan-lifespan gap or the morbidity period. Research suggests this gap averages 10 to 20 years in developed countries. Longevity science aims to compress this gap and extend the healthy portion of the lifespan.
A 90-year-old who gardens, travels, reads, and lives independently has a long healthspan. A 90-year-old who has spent the last 25 years managing heart disease, diabetes, and cognitive decline has a shorter healthspan, even if their total lifespan is similar.