Tennis brought the Atterberrys and the Helgesons together decades ago.

Ever since, the Minnesota couples, now in their 70s, have been meeting on the court — through retirements and knee replacements.

"Tennis can be very social," said Dick Helgeson, who lives in Orono with his wife, Jean.

Researchers say that social aspect may be more important to a long, healthy life than most people realize.

A recent, observational study published in the Mayo Clinic's Proceedings journal found that the social facet of the sport may give it an edge over other sports in promoting longevity.

The international research team took a Danish population study, which tracked thousands of men's and women's sports and exercise habits over 25 years, and compared it with death records. They found that playing tennis created the biggest gain in life expectancy: 9.7 years compared with folks who said they were sedentary.

That gain is even more striking when compared with other active but less social activities, such as swimming (3.4 years) and jogging (3.2 years).

"Surprisingly, we found that tennis players had the longest expected lifetime among the eight different sports," the researchers concluded.

Because the study was observational, the finding doesn't actually prove that the specific sports activities were what caused folks to live longer, it just shows a link. The researchers did take into account other variables that affect longevity before getting these results.

The Helgesons initially thought that golf was going to be their lifetime sport, said Jean Helgeson, but with three boys, they didn't have time to fit golf into their routines. Instead, they decided to learn how to play tennis, so they could practice hitting the ball on city park courts while their kids played nearby.

"That was in 1980. So you'd think I'd be better by this time," joked Jean Helgeson, whose team trophies belie her humble spirit.

Once their kids were older, the pair started taking tennis more seriously — going to lessons, joining local league teams and meeting friends, including Bloomington couple Debbie and Clint Atterberry, on the court.

About 20 years ago, Jean Helgeson and Debbie Atterberry joined a league as doubles partners. They still play as a team, now for Life Time's Oakdale Village Tennis club in Minnetonka.

Recently, the two couples got together to run doubles drills with John Brekken, a tennis instructor for Life Time.

They cheered each other on even as they competed, often exclaiming, "Nice shot!"

"We've become very good friends over the years," Jean Helgeson said. "We've got a lot of the same interests, not just tennis,"

Debbie and Clint Atterberry both started playing in their 20s, but have spent more time on the game now that they're retired. They play several times a week, spending as much as eight hours on the court.

"I love the activity of it. I like to be learning," Debbie Atterberry said. "To me, doubles has been hard to learn, with all of the strategy. It makes a person healthy."

Brekken, the instructor, agrees.

"Your mind is active, your body is active, and it becomes a social network and a lifestyle," he said.

He added that it's physically possible to keep playing tennis as we age, even after knee replacements (like the one Debbie had a few years ago) and other surgeries.

Clint Atterberry explains why.

"You just get addicted to it," he said.