Blue Zone, a Demographic Concept and Beyond.

The concept of Blue Zone (BZ) refers to regions with exceptionally high concentrations of centenarians, often in good health. Four BZs have been validated, Okinawa (Japan), Sardinia (Italy), Nicoya (Costa Rica), and Ikaria (Greece), with Martinique recently emerging as the fifth. Despite their popularity, BZs face criticism regarding data reliability, particularly the accuracy of centenarians' ages. This article reviews the process used to identify a BZ through a three-step methodology. First, it outlines the strict age validation procedures used to confirm longevity claims. Second, it reviews key demographic indicators to assess population longevity. Third, it defines BZ criteria, using the Sardinian BZ as a reference and requiring the eligible area to show a longevity level at least 50% higher than the national average. Martinique meets these criteria, while Galicia's validation is still ongoing. The study also highlights core longevity factors-diet, physical activity, social support, and environment-and underscores the importance of adopting the 7 BZ principles to foster longer, healthier lives worldwide. The BZ thus remains a valuable model for understanding the impact of lifestyle on aging and for applying these insights in public health and lifestyle medicine strategies.