The average life expectancy in the U.S. is just over 78 years — but in certain countries and regions, more people make it past 100, seemingly without even trying.

What are the secrets of these pockets of the world — known as “blue zones” — where residents have not only more longevity, but more healthy years?

Dan Buettner, a Florida-based author, explorer and longevity researcher who first coined the term “blue zone,” embarked on a mission to find out.

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“Only about 20% of how long you live is dictated by your genes,” he told Fox News Digital during an on-camera interview. 

“The other 80%, we reason we might find among the longest-living populations.” (See the video at the top of this article.) 

For the recent Netflix documentary “Live to 100: Secrets of the Blue Zones,” Buettner visited five destinations — Okinawa, Japan; Sardinia, Italy; Ikaria, Greece; Nicoya, Costa Rica; and Loma Linda, California — to discover why these areas have the highest rates of living centenarians.

“We verified ages and found that in these areas, people were living about 10 years longer at middle age,” he said.

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“It’s because they’re not suffering from the diseases that are plaguing us, like type 2 diabetes. They’re not dying of cardiovascular disease prematurely, or dementia, and they have 40% lower rates of cancer.” 

Buettner and his team of demographers and researchers investigated the lifestyle and environmental characteristics in these five areas to determine what people may be doing differently.

‘Healthy choice is easy’

“The big insight we learned from blue zones is that in places where people are actually living longer, it’s not because they try,” Buettner said. 

“In America, we tend to pursue health. We try to identify the right diet or exercise program or supplement regimen — but our brains are hardwired for novelty.”

“We’re constantly bombarded and bamboozled by new health news and people — and in blue zones, they never tried to live a long time.”

The reason for this longevity, according to Buettner, is that they live in environments where the healthy choice is easy. 

Nutrition and exercise

One of the characteristics most blue zones share is their walkability, as people walk to work, school, friends’ homes or gardens.

“They’re getting 8,000 to 10,000 steps a day without thinking about it,” Buettner said. 

Also, the cheapest and most convenient foods in blue zones are unprocessed.

“The big insight we learned from blue zones is that in places where people are actually living longer, it’s not because they try.”

“People in blue zones also eat healthier, as they consume primarily whole, unprocessed, plant-based foods,” Buettner noted.

The average American eats about 220 pounds of meat a year, which he believes is “too much.”

“I’m not advocating a no-meat diet, but I will tell you, people in blue zones eat about 20 pounds of meat a year, so about once a week as a celebratory food — and they are getting all the nutrients they need.”

People also eat far more fiber in these areas, Buettner found.

“In blue zones, the cheapest and most accessible foods were full fiber,” he said. “They pull them out of their garden … whole grains or beans are the cornerstone of every longevity diet in the world.” 

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Fiber is often neglected in the American diet, Buettner said, with only about 5% to 10% of Americans getting enough.

“If you don’t get enough fiber, it often goes to work at the mucous membrane and creates a certain permeability or leaky gut, and that causes all kinds of problems,” he warned.

Passion and purpose

Studies have shown that people who wake up and have a sense of purpose, whether it’s a duty, a passion or an outlet, have greater health outcomes. 

“The blue zone purpose almost always includes an altruistic dimension,” Buettner shared. 

“There’s almost always doing it for the next generation, or for the community or their church. There’s always some philanthropic dimension to their purpose.”

Power of community

“In blue zones, we see very clearly that people are connecting face to face, probably five to six hours a day,” Buettner said.

People in these areas often live in extended families. 

“Grandma never gets lonely, because she lives upstairs and helps with the garden,” Buettner shared as an example. “She helps cook food and she helps with childcare. And the kids do better because they’re getting better attention. And it’s this virtuous circle.”

In blue zones, people typically live in communities where they care about each other, he added. 

“They’re not spending nearly as many stress hormones arguing about things — and there’s more time for laughter when you’re not angry.”

Faith factor

Data shows that people who regularly go to church live anywhere from four to 14 years longer than people who don’t, Buettner noted.

“You can’t measure faith, but you can measure religiosity,” he said. “Scientists simply ask people how often they show up at church, temple or mosque, and then they compare the longevity of the people who show up to those who don’t show up at all.”

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Part of this likely stems from the fact that churchgoers have a built-in community, he said, as loneliness has proven to be “toxic.”

“Religious people are also less likely to get involved in risky behaviors, and they often have a sense of purpose, which is their faith in God,” Buettner added. 

Those who worship on Sunday may also benefit from having one day a week where they “stop everything.”

“Being human is inherently stressful, and church gives us an hour or maybe a couple of hours where we fully take the focus off of our everyday life and troubles, and we get to sort of elevate to a higher plane and focus on a greater good,” Buettner said. 

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The act of prayer itself could also “stack the deck” in favor of longevity and health, he added.

“By the way, people who sing in the choir actually even live longer,” Beuttner said. “So if you want a little extra bump, join the church and sing in the choir.”

Sleep’s role in health

In his visits to blue zones, Buettner found that the residents are usually early to bed, early to rise.

“They have kind of two sleeps, where they’ll go to bed shortly after sunset, and then get up at 3 or 4 a.m. and do some chores, and then go back to sleep until sunrise,” he told Fox News Digital. 

Napping is also very common throughout all blue zones.

“And some good research shows that people who take a 20-minute nap five days a week have significantly lower rates of cardiovascular disease and about 30% lower rates of cardiovascular mortality,” Buettner said. “So napping is definitely part of the blue zone approach to longevity.”

“Blue zones give us a very clear set of choices and environmental factors that would help us mindlessly get the years we deserve.” 

Overall, he concluded, anyone can benefit from the lessons learned from the blue zones — primarily the importance of keeping people healthy in the first place. 

“It’s about shaping their environment so that healthier choices are easier or unavoidable and setting them up for success, so they’re subconsciously making better decisions on a day-to-day basis for years or decades,” Buettner said. 

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“Blue zones give us a very clear set of choices and environmental factors that would help us mindlessly get the years we deserve.” 

“That’s what works in all the blue zones, and it will indisputably work for you — whether you live in Akron, Ohio, or New York City or Los Angeles.”