Dr. Neil Resnick, chief of geriatric medicine at the University of Pittsburgh and director of the University of Pittsburgh Institute on Aging, said many people are confused about which physical ailments are caused by natural aging or by decades of abuse to our bodies.
"I think the bottom line is that, if we talk about the impact of aging, alone, it is a slight decline over your lifetime," said Resnick.
That decline, according to Resnick, takes two forms. After about age 30, people's organs naturally experience a 1 percent decline in physiological power per one calendar year of life.
But Resnick said that decline isn't such a big deal, considering that, at top shape, our organs are designed to function at a capacity 4 to 6 times more than a body needs in daily living.
"That's why you can give up a whole kidney and still live," Resnick said. "That's why Johnny Kelly, at 83, ran the Boston Marathon, and I mean, ran the marathon, he didn't walk the marathon."
The second decline, according to Resnick, includes "farsightedness, hearing loss, and 50 percent of people get degenerative arthritis -– that's it, that's aging."
Resnick attributes more health problems in old age to the probability that people have suffered from diseases, like diabetes.
"With longevity, 20 percent of it is determined by genes," said Resnick. "The rest of it is determined by you, and what you choose to do."
Yet, doctors say how to choose an exercise at age 80 can be tricky.
"For this lady, if she can do all that stuff, she's in good physical shape, and she can maintain it, great," Suri said. "For a typical patient, you would not encourage someone to do this sort of thing. ... If someone hasn't exercised regularly, we'd encourage them to see their doctor before they start."
Once a person older than 40, or with a medical problem, gets clearance from the doctors, most experts have two words of advice: Start slow.
"You would want to start with a walking program, or start with dance maneuvers that are much simpler," said Sallis, but "You should go for it."
According to Sallis, people who exercise three to four times a week cut their risk of dementia and Alzheimer's, and by working their bones, they cut their risk of bone fracture injuries in the first place.
"You'd be safer if you sit in the house all day, but you'd die of chronic diseases that way," Sallis said. "The benefits so far outweigh the risk of injury."