John Thompson CEO Virtual Instruments Bloomberg When John Thompson retired from the CEO role at Symantec after 10 enormously successful 10 years, he had planned a quiet life as an angel investor and board member.

That didn't happen. Today, at age 65, he's the CEO of Virtual Instruments, one of the startups he invested in, a job he has been doing for five years come April.

And his decade at Symantec was after a long 28-year career with IBM, rising to general manager of IBM Americas. That's ironic, because IBM is one of the few tech companies that still holds onto an ancient tradition where a CEO must retire at age 60. (We'll see if they change it for Ginni Rometty, 57. But word is her predecessor, Sam Palmisano didn't want to retire in 2012 and, well, he retired.)

Today, a growing number of CEOs are sticking around in the job through at least their mid-60s, such as Cisco CEO John Chambers (65), EMC CEO Joe Tucci (67), Qualys CEO Philippe Courtot (70), even Oracle cofounder Larry Ellison, who stuck in the CEO role until he turned 70, and then took on the executive chairman and CTO role. He's far from retired and still holds the power at Oracle.

In an interview with Business Insider, Thompson told us what it's like to be an older CEO in the Valley's youth-oriented tech culture.

"Well, you cannot ignore the fact that youth has a certain level of energy to it that perhaps a 65-year-old guy doesn’t have," he laughs. "But by the same token, all of us are gonna live one hell of a lot longer than we did when IBM and many other companies set up the policies that said, 'When you turn 60 you’re an old fart and you have to leave.'"

He says that retirement in your 60's doesn't make a lot of sense these days.

"The average lifespan for an adult in this country probably is closer to 80 or 83, which says if you retired at 60 you’ve got 23 years to sit around and do nothing. That’s about the most boring idea I’ve ever heard," he says.

"As long as I’m able-bodied and able-minded it would seem appropriate to me to want to be engaged, as opposed to playing golf every day, which my golf game sucks, so why would I want to do that everyday? Plus, my wife married me for life, not for breakfast, lunch, and dinner. Staying home all day is not something she wanted either."

As to spending his time trying to keep up with all the latest tech trends and culture that younger CEOs would be into, like, for instance, Snapchat, he says, "No I don’t."

But if he's short on energy it's hard to tell from his travel schedule, which would bring a person half his age to his knees.

In a two week period he will travel from the Bay Area to Detroit to Toronto back to the Bay Area and then to New York, London and to Columbus, Ohio with his wife, "to see our granddaughter in her first play." Then back to the Bay Are for one night, and then off to Singapore, Australia, and Hong Kong for ten days. And in between, he'll dash to Seattle for a Microsoft board meeting, he tells us.

He does own his own plane, which helps, but he flies commercial for many flights, particularly international ones, he says.

"Welcome to the world of leading a startup," he says. "I have had to travel like this for 25 or 30 years. It’s what I do. And so, if you’re not prepared to do that, you shouldn’t even consider the role that I have."