An international team of longevity scientists recently reached agreement on a formal scientific definition for a “blue zones” region, establishing a measurable standard for places where people live the longest. The new criteria are intended to replace loose popular usage with a definition grounded in validated demographic evidence and transparent review.

Blue zones were validated last year in a Gerontologist article, which helped settle long-running doubts about whether these exceptional longevity populations were real. That validation shifted the discussion from whether blue zones existed to how they should be defined, measured, and studied going forward.

Now, a group of scientists with expertise in demography, aging and age validation has proposed rigorous criteria for identifying blue zones. The researchers say the term “blue zones region” refers to “places where the data show unusually strong longevity after age 70 and unusually high odds of reaching 100, conditional on surviving to 70.”

Those two benchmarks — a longevity metric and a survival metric — form the core of the proposed definition. Researchers say both are necessary because each captures a different aspect of exceptional survival. Over time, they expect future work to expand beyond longevity to include healthspan, or the number of years people live in good health.

Records behind the claims are also important. A place cannot be recognized as a blue zone region without administrative data strong enough to support age validation, and without a willingness to allow qualified outside researchers to examine the evidence.

Under the framework, a location would qualify if either men or women exceed a composite benchmark based on those two demographic measures relative to three of the longest-lived countries. Counts of centenarians will still matter as useful context, when available, but the researchers say centenarian totals alone should not determine whether a place qualifies.

“For years, the term ‘blue zones’ has been used as shorthand for a place where people live remarkably long lives,” said Dan Buettner, National Geographic Fellow who along with Gianni Pes and Michel Poulain created the blue zones concept. “But it has remained on the fringes of science. This gives the term a scientific standard and will attract more researchers seeking to study these extraordinary outlier populations.”

To download the full article, published in the Journals of Gerontology Series B, click here