Guide · Longevity

Blue Zones: where they are, what these populations share and what you can bring into your routine

Sardinia, Okinawa, Ikaria, Nicoya: what demography has confirmed, what is still debated and why there is no recipe for reaching 100.

In this article

1. What Blue Zones are
2. How a region becomes a Blue Zone
3. What long-lived people in the Blue Zones have in common
4. The Blue Zones diet: less recipe, more context
5. What about genes?
6. How to test it on yourself (N=1)
7. Frequently asked questions
8. Sources

What Blue Zones are

The term was born in the early 2000s, when Belgian demographer Michel Poulain and Italian physician Gianni Pes were studying a mountainous area of Sardinia with an unusual concentration of male centenarians. On the map, they marked the villages with a blue pen. Later, American journalist Dan Buettner popularised the idea in books and articles, and the concept spread to other regions EV D.

Today, according to Poulain, four Blue Zones have been validated by demography: the Ogliastra and Barbagia area of Sardinia; the island of Okinawa in Japan; the island of Ikaria in Greece; and the Nicoya peninsula in Costa Rica. Martinique, in the Caribbean, was recognised as the fifth, and Galicia, in Spain, was under evaluation EV D. Buettner's books also include Loma Linda, in the United States, an Adventist community studied by another line of research.

In 2023, a documentary series on a streaming platform brought the topic to a huge audience, and Blue Zones became a reference in biohacking and healthy eating.

How a region becomes a Blue Zone

The least-known part of Blue Zones is also the most important: validating ages. In places with poor historical records, people often exaggerate their age or documents contain errors. That is why the methodology described by Poulain in 2025 has three steps EV D:

1. Validate the age of each very old person with birth certificates and baptism, marriage, military service and other cross-checked records.
2. Calculate longevity indicators for the population, not just count centenarians.
3. Compare with the country: the region must have longevity at least 50% above the national average.

This care responds to a real criticism. Outside researchers have questioned the reliability of ages in regions famous for centenarians, and Poulain himself published an analysis of Okinawa in 2024 arguing for deeper validation of the ages of the oldest people EV B. The debate is healthy and shows why the subject calls for a careful reading.

What long-lived people in the Blue Zones have in common

Studies of these populations point to patterns that repeat. A critical review by Poulain, published in 2026, summarises the recurring traits EV D:

The central point of the review is that none of these factors alone explains extreme longevity. It is their interaction, sustained for decades, that seems to increase the chance of reaching very old ages.

It is worth noting what does not appear on the list. Long-lived people in the Blue Zones do not follow supplement protocols, do not measure markers every day and do not try to optimise every hour. Their longevity seems to come from a lifetime of ordinary habits, repeated without conscious effort because they are built into culture, work and family. For anyone into biohacking, this is a lesson in humility and also good news: the strongest levers tend to be the cheapest. The challenge is making them automatic in a big city, where the environment pushes the other way.

The review also separates two questions that are often confused: what helps you age well and what leads someone to pass 100. The first has many known, applicable answers. The second involves luck, genetics and historical context, and no recipe guarantees it.

One of these traits has strong evidence outside the Blue Zones. The meta-analysis by Holt-Lunstad and colleagues, with 148 studies and more than 300,000 people, associated stronger social relationships with about 50% greater likelihood of survival over the period studied EV A. It is an association, but of a size comparable to other well-known lifestyle factors.

The Blue Zones diet: less recipe, more context

Diet is the most copied topic, and also the most simplified. The 2022 review by Pes and colleagues makes two important caveats EV D:

• the fact that a diet is common in a long-lived population does not prove that it causes longevity;
• the diets of these regions are neither uniform nor stable: they have changed a great deal over recent decades.

Okinawa is the clearest example. A demographic analysis by Poulain and colleagues showed that people born before the Second World War have very favourable longevity, while younger generations, who grew up with different food and a different lifestyle, no longer keep the same advantage. In 2002, Okinawa fell from 4th to 26th place among Japanese prefectures in male life expectancy EV B.

The practical lesson is that the pattern matters more than any miracle food: lots of plants, legumes, little ultra-processed food and home cooking.

What about genes?

It is natural to think these populations simply have better genes. Genetics counts, but less than it seems. An analysis by Ruby and colleagues, using family trees of millions of people, estimated that the heritability of life expectancy is probably below 10% once you correct for the fact that people tend to marry similar partners EV B.

This does not mean genes do not matter for extreme longevity, where some genetic factors seem to weigh more. It means that, for most people, habits and environment weigh heavily on the path to old age in good health.

That is also why strength and balance gain weight with age: they decide how much of a long life is lived independently. In the Blue Zones, older people keep walking up hills, tending animals and taking part in community life.

How to test it on yourself (N=1)

You do not need to live on an island to test a Blue Zone trait. Pick one, such as movement built into your routine, and measure:

1. A 2-week baseline. Note how many minutes you walk each day (your phone usually records it) and your resting heart rate on waking, three times a week.
2. One change only. For 4 to 8 weeks, swap short trips for walking or stairs, without changing your diet at the same time.
3. Measure the same way. Keep tracking steps and resting heart rate.
4. Compare averages. Then test the next trait: a weekly dinner with friends or family, for example.

Frequently asked questions

Sources

1. Poulain M, Herm A. Blue Zone, a Demographic Concept and Beyond. American Journal of Lifestyle Medicine, 2025. doi.org/10.1177/15598276251342502 · Evidence D
2. Poulain M et al. How to become a centenarian in four weeks? Myths and limits of longevity recipes: a critical review. Minerva Medica, 2026;117:147-160. doi.org/10.23736/S0026-4806.26.09890-3 · Evidence D
3. Poulain M, Herm A. Exceptional longevity in Okinawa: Demographic trends since 1975. Journal of Internal Medicine, 2024;295(4):387-399. doi.org/10.1111/joim.13764 · Evidence B
4. Pes GM et al. Diet and longevity in the Blue Zones: A set-and-forget issue? Maturitas, 2022;164:31-37. doi.org/10.1016/j.maturitas.2022.06.004 · Evidence D
5. Holt-Lunstad J, Smith TB, Layton JB. Social relationships and mortality risk: a meta-analytic review. PLoS Medicine, 2010;7(7):e1000316. doi.org/10.1371/journal.pmed.1000316 · Evidence A
6. Ruby JG et al. Estimates of the Heritability of Human Longevity Are Substantially Inflated due to Assortative Mating. Genetics, 2018;210(3):1109-1124. doi.org/10.1534/genetics.118.301613 · Evidence B
7. Buettner D, Skemp S. Blue Zones: Lessons From the World's Longest Lived. American Journal of Lifestyle Medicine, 2016;10(5):318-321. doi.org/10.1177/1559827616637066 · Evidence D