Blue Zones

What are Blue Zones?

Blue Zones are regions in which an unusually large share of the population reaches a very great age. What counts is not a single famous centenarian but the frequency: how many of those born in a given period lived to 100, compared with the region around them. The term comes from Sardinia. There the physician Gianni Pes and the demographer Michel Poulain marked an area of extreme longevity on a map in blue, and the name stuck. The first scientific article to use it appeared in 2004.

Since then the idea has travelled far beyond science. The journalist Dan Buettner carried it to other regions, wrote books about it and had the term registered as a trademark. In public, Blue Zones now mostly stand for advice on how to live. In research they remain what they were at the start: a demographic finding that has to be checked village by village and record by record.

How the Sardinian Blue Zone was found

In the 1990s, researchers in Sardinia began a study of the island's centenarians. Pes and Poulain then asked where on the island they came from. For every municipality they calculated an extreme longevity index: the share of those born between 1880 and 1900 who reached the age of 100. A smoothing method made the pattern visible on the map. Longevity was concentrated in the mountainous interior of central eastern Sardinia, and there especially among men. In 2004 the result appeared in Experimental Gerontology as the AKEA study.

The striking feature was the balance between the sexes. Almost everywhere in the world, women reach very old age far more often than men. In Villagrande Strisaili, one of the core villages, the researchers found 30 centenarians among those born between 1876 and 1912; 16 of them were men.

In November 2005 Dan Buettner wrote about Sardinia, Okinawa and the Adventist community of Loma Linda in California in National Geographic. In his book The Blue Zones in 2008 he presented further regions, among them the Nicoya peninsula in Costa Rica and the Greek island of Ikaria.

Which villages belong to it

According to the research, the Sardinian Blue Zone comprises fourteen villages in Ogliastra and Barbagia, the mountain districts around the Gennargentu massif. In six of them the ages of the oldest inhabitants have been fully validated; the others have been studied but not yet checked in the same depth. A study from 2020 names Arzana, Baunei, Seulo, Talana, Villagrande Strisaili and Urzulei as the group of six municipalities.

The boundaries are not fixed. A recalculation for those born between 1907 and 1920 covers a larger area of 44 municipalities. Blue Zones describe particular generations in particular places, and they can grow, shrink or disappear.

What may explain the long lives

No single cause has been proven. The research discusses several factors that probably work together.

Movement in steep terrain. An ecological study compared all 377 Sardinian municipalities. Most dietary variables hardly differed between more and less long-lived areas. What did differ was pastoralism, the slope of the terrain and the distance people walked to work each day. The authors conclude that physical effort in daily life helps explain why men in particular grew so old.

A simple diet. Until the 1960s, food in the mountain villages was based on cereals, dairy from sheep and goats, pulses and vegetables. Animals were a source of income and were rarely slaughtered; meat was eaten seldom and mostly preserved with salt. The change to a richer diet came later in the mountains than in the lowlands. Researchers suggest that the old cohorts may have benefited from both: from a frugal but nutritious diet for most of their lives and from more variety in old age. They call this a hypothesis. The traditional diet is described in more detail under Mediterranean diet.

Family and community. The study on Villagrande Strisaili points to strong family support and to long marriages in which couples live together into old age.

Genetics and isolation. Until the Second World War, people in the mountain villages mostly married within their own community. This raised the genetic uniformity of the population, and researchers discuss whether certain inherited features favour long life. So far, several studies have not found an excess of longevity genes. Isolation itself is a common theme of the classic Blue Zones. In Sardinia the pastoral economy of the mountains resisted change for longer than the lowlands did.

Doubts and age validation

Exceptional age claims have often turned out to be wrong. Birth dates were misremembered or records were missing. The demographer Saul Justin Newman argues in a preprint, first published in 2019 and revised in 2024, that extreme age records follow patterns that point to clerical errors and fraud rather than to long life. He names the Blue Zones of Sardinia, Okinawa and Ikaria among others.

For Sardinia the researchers reply with their method. The age of every nonagenarian and centenarian was checked twice: against civil records going back to 1866 and against handwritten church registers that are available from the 17th century onwards. In addition, the families of the villages were reconstructed generation by generation. In their reply to the critics in 2025, Steven Austad and Gianni Pes hold that the Sardinian ages stand up to this test.

Elsewhere the picture is less clear. For Okinawa it is disputed whether the region still meets the criteria of a Blue Zone today. In Nicoya the advantage of younger generations is fading. For Loma Linda, longevity cannot be measured with the same method as in the validated zones. The Sardinian Blue Zone is therefore the best documented of all, and at the same time a reminder that every Blue Zone stands or falls with its records.

Blue Zones and permaculture

Nothing in the research proves that a garden, a diet or a single habit lengthens life. What the studies describe for the Sardinian villages is a whole way of life: daily movement over uneven ground, food that grew close by, frugal meals, and old age spent within a family and a community.

Permaculture designs for exactly these conditions, though for other reasons. Its second ethic is care for people, and it reads a place in terms of distance and daily movement: what is needed every day belongs close to the house. A food forest or a kitchen garden brings food back to the door. Shared work, seed saving and passing on knowledge tie people to a place and to each other. A design that serves people therefore resembles the old villages in many ways without promising their life expectancy.

How Terra Humana understands Blue Zones

For Terra Humana the Blue Zones are a picture, not a recipe. They show that a long, good life in old age can grow out of ordinary things: work on the land, simple food from the place, and a community that keeps its old people at its centre. That is close to what we call rehumanization and to the ethics of permaculture. We do not sell longevity and we do not claim that our land makes anyone live longer. We take the honest version of the story seriously, including its doubts, and we let the well-documented villages of the Sardinian mountains remind us what really matters.