Explorer and author Dan Buettner, who has studied the world's centenarian hot spots—which he calls blue zones—has observed that centenarians tend to have sunny dispositions.
Buettner has not studied the children of centenarians, though that methodology is "absolutely" valid, he said.
(Buettner has also received funding from the National Geographic Society, which owns National Geographic News.)
In the blue zone of Okinawa, Japan, Buettner asked expert Nobuyoshi Hirose what he thought explains Okinawans' longevity.
"He thought for a moment, and said, They're likable people," Buettner said.
That likeability translates to a robust social circle, one of the common threads among the long-lived, Buettner added.
Though many aspects of our personalities are already set by our genes, Buettner said, we can all make lifestyle improvements to help us live longer.
For one, becoming more extroverted—and by extension widening our social networks—can be cultivated and trained, Buettner said.
Also high on his list is eating a plant-based diet—"the more meat you eat, the quicker you die," he said.
And having a clear sense of purpose in your life, he added, is worth seven years of life expectancy.
Study leader Perls added that numerous strategies exist to deal with stress, such as exercising, meditation, or just taking a "nice deep breath."
"It's a matter of setting aside the time and effort to effectively manage your stress well," he said. "One of the keys is to realize how important it is to do that."
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