His trainer says Pickens is as fit as most 40-year-olds. And neuroscientists who have studied his brain say it appears to function like someone half his age.
So how does he stay sharp?
When my photographer, Charles Johnson, and I get to Pickens office at 6 a.m. (we are early for the shoot), Pickens is already in the building, dressed and ready to work out. His trainer, who has been with him for 17 years, said Pickens never slows down.
"I don't have any trouble keeping up with the people I'm around," Pickens said as he hopped on the treadmill.
I will soon learn, it's quite the opposite. I got on the treadmill next to Pickens and began the interview there.
Pickens is 5-feet-9-inches tall and 181 pounds and said he would be 10 pounds lighter if it weren't for his sweet tooth.
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It's 20 minutes on the treadmill with a five-minute sprint to finish.
Next up: arms. Pickens does dips and curls with 25-pound weights. He squats with a 45-pound vest on.
"No, I don't do yoga," Pickens said.
To finish, Pickens lunges the halls of his hedge fund, BP Capital. The younger analysts smile as he passes a glassed-in conference room.
Like every other day, Pickens will manage his hedge fund and promote his clean-energy plan for America in some other city.
"What I'm after, is that I don't get old and feel bad, and I had started to see that in people as they get older," Pickens said.
Later, he headed to Dallas' Love Field and boarded his Gulfstream 550, headed to his alma mater with wife, Madeleine, and more than a dozen Oklahoma State University fans for a townhall meeting in Stillwater, Okla.
Even his wife, Madeleine, seems impressed.
"He's amazing," she said. "He's really like in his 50s. I never get the impression that he's some other age."
There was a dinner and then another speech when Pickens returned to Dallas that night.
Keeping up with Pickens isn't just a physical feat, but a mental one. Just ask his right hand man, Jay Rosser, Pickens' vice president of public affairs.
"He has an uncanny ability to remember names, people and stories. He is an inspiration," Rosser said.
That brings us to the topic of Pickens' brain.
Dr. Denise Park, a neuroscientist at the University of Texas at Dallas Center for Vital Longevity, has picked Pickens' brain. He was part of a 350-person study of all ages of people who underwent a series of tests while inside an MRI machine.
"We were impressed at what we saw," Park said.
On many of the tests, Pickens' brain seemed to activate like those in the 20- to 29-year-old group.
"He's brilliant," Park said. "He clearly has good genetics, and he has the drive and he puts in the effort to maintain his vitality at the highest level possible."
What is the Pickens Plan for brain vitality?
Park said there are three keys. First, Pickens has good genes. Second, he makes cardiovascular workouts a daily priority. Third -- and perhaps most importantly -- Pickens challenges his brain by stepping outside of his comfort zone, meeting new people and learning new things constantly, Park said.
Pickens is not someone who sits and works crossword puzzles, Park said. His secret is discipline; mind and body. Park said Pickens is proof that age really is just a number.
"I think at 81, everything can go haywire real quick. So I don't want to jinx myself," Pickens said.