The concept grew out of demographic work done by Gianni Pes and Michel Poulain outlined in the "Journal of Experimental Gerontology", who identified Sardinia's Nuoro province as the region with the highest concentration of male centenarians. As the two men zeroed in on the cluster of villages with the highest longevity, they drew concentric blue circles on the map and began referring to the area inside the circle as the "Blue Zone". Together with demographers Pes and Poulain, Buettner broadened the term, applying it to validated longevity areas of Okinawa, Japan and among the Seventh-day Adventists in Loma Linda, California. Buettner and Poulain, under the aegis of National Geographic, then identified and validated longevity hotspots in Nicoya, Costa Rica and Icaria, Greece. Buettner mentions in his book that people are doing the right things for long enough, and avoiding the wrong things," there are four main things that people in those zones do in order to live healthier and longer lives, and they consist of moving regularly, which does not consist of exercise alone, but doing daily energy burst habits throughout the day. The second aspect is living with purpose, having a reason to get up every day, and living with perspective. The third aspect of blue zone populations is the social support they receive from friends and family allowing them to move through life outcomes more smoothly. Fourth but not least is the concept that most still do not understand, which is making the "healthy choice the easy choice", and not just an option. Living by these four concepts brings longevity and mental and physical benefits to one's life and society.