Secrets of the Blue Zones

Dr. Wareham has been taking patients into the operating room since before Dr. Oz was born. To learn more of his secrets of longevity, Dr. Oz scrubs in with Dr. Wareham, who's glad to have him. "I think that if you're old, you should keep away from old people. And keep with young people, you see," Dr. Wareham says. "If I can keep around fellas like you, I'll be invigorated for days from having met you."

Having performed more than 12,000 operations in his life, Dr. Wareham credits his passion for work with keeping him healthy. "I doubt if my health would be as good as it is now," he says. "And I am fearful to change anything I'm doing because I'm not only alive, but I feel good. I'm not taking any medications."

But it may not be the work that's keeping Dr. Wareham healthy. It's more about a sense of purpose, Dr. Oz says. Dan says people in most blue zones don't even have a word for retirement. "Before you retire, knowing what your values are, knowing what your gifts are and where to share those gifts. That's a great investment," Dan says.

Not even Barbara, Dr. Wareham's wife of 58 years, wants him to retire. "People ask me that a lot and I just say, 'Leave him alone. He's happy,'" she says. "I don't think he'd be nearly so happy just sitting at home."

As seen in Nicoya and Sardinia, strong relationships are also key to a long life. So what's the secret of the Warehams' marriage? "Don't try to change them," Dr. Wareham says. "We all have different backgrounds, and we have different genes. Let the person be who they are."