And strides in research could boost that figure - and better the odds - for all of us.
"The aging field has just exploded. It's really incredible, what's been achieved in basic labs like this, with worms and flies and yeast cells," Dr. Lithgow said. He showed Petersen "clumps of shiny, green proteins" which had become damaged during normal aging, clumping together. "This is a process we are trying to stop," he said.
"It turns out that we can change the rate of aging quite simply in simple animals, which is really incredible."
By understanding and manipulating genes, Lithgow is learning to design therapies that treat age-related diseases in humans.
"I think we should be thinking about the diseases of aging in the way that we now think about the childhood diseases that we grew up with," Lithgow said.
"Your sense is that someday we may think about Alzheimer's or Parkinson's the way I think of measles or mumps?" Petersen asked.
"I think we will think of them as diseases that still occur that we have to take precautions against," he replied.
But a healthy older body needs a healthy mind . . .and that's where BEES come in.
It turns out they have the same kind of brain cells as humans (though far fewer of them). Arizona State University researcher Gro Amdam plays a mind game that works like this: The bees get a whiff of a distinctive odor, followed by a taste of sugar water.
"Sugar is like a chocolate cake for bees," Amdam said. "And the bee will respond to that by sticking out her tongue."
Amden determines just how quickly the bee figures out that a whiff of the scent means a treat is on its way. The older the bee, the slower the learning curve.
but that can be reversed: Changing the bee's lifestyle can lead to restoring a more youthful brain.
For the proof . . . head to the hive.
The average lifespan of a bee is about 30 days. But in that time, they can give us a fountain of useful knowledge.
Their first task as adults is taking care of the eggs laid by the queen. They all work together. As they age, they become so-called "foragers," leaving the hive to find nourishment for the eggs. Now alone, as single busy bees, their brain CHANGES.
"Because after a while, as a forager the bee brain actually deteriorates, much like you see in people with dementia," Amdam said.
But force the bees back in time by returning them to the hive - and their brains snap back.