But that's not to say that you don't have a say in how your body ages.
"Aging is inevitable, but you can age gracefully," said Jean, who at 57 years old and works out six days a week proves that you can fight your fate. "I definitely notice that my muscle tone is better than I would have thought."
The latest research shows that exercise fights aging ? from your heart all the way down to your DNA.
One study found that six months of endurance training reverses the typical age-related cardiovascular decline for men in their fifties.
Harvard exercise physiologist Dr. Tom Storer says exercise may even help the body create new cells.
"These satellite cells bond with existing muscle fibers to increase their size and strength," he said. "It's like an older muscle performing as if it were younger."
With that in mind, the looming question remains: how can you keep your body young?
"The more strength training we can do as we age, the more elasticity is going back into our bodies and the actual younger our bodies are going to feel and look," said Liz Miersch, a trainer at an Equinox gym and editor of the digital magazine for Equinox gyms "Q."
She recommends functional training, or in other words, working multiple muscle groups at the same time.
"When you work your body that way the brain releases a hormone that helps enhance the building of that muscle tissue," she said.
Regardless of how fit one may be, there are still those four troubles spots that seem to drop and drag for everyone over time.
But whether it's the arms, abs, chest or the behind, you can defy gravity.
"The key is really training the muscles underneath, which will help lift and tighten no matter what the area it is," said Miersch.
However, Jean did admit that exercise doesn't come as easy as it once had.
"I will tell you that after the age of 50, you do have to work a little bit harder," said Jean. "The fat comes on easier than it did before."
But it's never too late to start!