The five places in the world where people live the longest are also places where elders spend a good deal of their time tending vegetable gardens.

A recent BBC headline caught my attention: “Gardening could be the hobby that helps you live to 100.” The article discussed how the five places in the world where people live the longest are also places where elders spend a good deal of their time tending vegetable patches.

Centenarians in these five regions—Okinawa, Japan; Nicoya, Costa Rica; Ikaria, Greece; Sardinia, Italy; and Loma Linda, California—have been studied extensively by author Dan Buettner and by many teams of scientists. I’ve read about this research over the years, but somehow, the gardening bit escaped me.

On the subtropical islands of Okinawa, where centenarians are probably more prevalent than in any other region on earth, elders cultivate small crops of bitter melons, purple sweet potatoes, ginger, turmeric, and other plants. The practice likely benefits them in a variety of ways, according to researchers. First, it helps them eat better. Second, it keeps them active.

Many Okinawans in their 80s and 90s tend gardens. Goya, or bitter melon, is a common crop. Photo copyright Okinawa Convention & Visitors Bureau.

In addition, it promotes their psychosocial health. “In Okinawa, they say that anybody who grows old healthfully needs an ikigai, or reason for living,” gerontologist Bradley Willcox of the University of Hawaii, who’s been studying Okinawans for decades, told the BBC. “Gardening gives you that something to get up for every day.”

And since Okinawan elders often exchange their homegrown produce with one another at local markets, Willcox says, gardening keeps them in touch with friends.

Finally, gardening exposes them to a moderate daily dose of sunshine, which a growing number of scholars believe is tied to longer life.

I’m not a gardener, but the article got me wondering: what are some other social, purposeful, active outdoor pastimes that might likewise promote longevity? Birdwatching comes to mind, as do mountain-climbing and jogging.

But many of us live in much colder climates than the Okinawans do, which complicates matters. I love to walk, run, and watch birds in Central Park, but only when it’s nice out.

Here are a few other attributes of the Okinawan lifestyle that Willcox, Buettner, and other researchers believe contribute to their health and longevity:

• They eat small portions, often halting their meals when they’re 80 percent full.

• Plants comprise 90 percent of the traditional Okinawan diet. Meat, fish, and dairy account for less than 1 percent each.

• They generally don’t smoke.

• They place a premium on lifelong friendship.

Of course, Okinawans may also be genetically lucky. Preliminary research suggests that the population’s DNA is different enough from that of the Japanese population as a whole to potentially account for at least part of their longevity edge.