Want to live past 100?

Sharon Jayson reports for Kaiser Health News that although those 100 and older make up a tiny segment of America’s population, U.S. Census reports show that centenarian ranks are growing.

Between 1980 and 2010, the numbers rose from 32,194 to 53,364, an increase of almost 66 percent. The latest population estimate, released in July 2015, reflects 76,974 centenarians.

In her story, Jayson writes about John Henderson and his wife of 77 years, Charlotte. He’s 104. She’s 101. And they regularly hear from people wanting to know how to live a long life.

“Living in moderation,” is the secret, he said. “We never overdo anything. Eat well. Sleep well. Don’t overdrink. Don’t overeat. And exercise regularly.”

Mac Miller, who is 102, has a standard reply.

“People ask me ‘What is the secret?’ The answer is simple. Choose the right grandparents. They were in their 80s. My mother was 89 and my father was 93,” he said.

Genetics and behaviors do play roles in determining why some people live to be 100 or older while others don’t, but they aren’t guarantees. And now, as increasing numbers are reaching triple digits, figuring out the mysteries of longevity has taken on new importance among researchers.

Behaviors are a big influence on survival until the late 80s, but from 90 onward, genetics play a more significant role, says Dr. Thomas Perls.

“The number of centenarians in the U.S. and other countries has been doubling roughly every eight years,” said James Vaupel, founding director of the Max Planck Institute for Demographic Research in Rostock, Germany.

“When the baby boomers hit, there’s going to be acceleration, and it might be doubling every five or six years,” he said.

Henderson and his wife of 77 years live in Austin in the independent living section of Longhorn Village, a community of more than 360, many of whom have ties to the University of Texas (UT) at Austin. Henderson is UT’s oldest-living former football player, arriving in 1932 as a freshman. The couple are the only centenarians in the complex and are a rare breed: married centenarians.

Charlotte Henderson said she believes being married may have helped them reach these 100-plus years.

“We had such a good time when John retired. We traveled a lot,” she said. “We just stay busy all the time, and I’m sure that helps.”

Bernard Hirsh, 100, of Dallas agrees. His wife, Bee, is 102. They married in 1978 when both were in their early 60s and each had been widowed, she for the second time.

“I think it’s been such a wonderful marriage, and we’ve contributed to each other’s benefit,” he said.