How old are you really? Tests reveal your 'biological' age

ATLANTA - You know when you were born. But how old are you really?

There are now commercial tests that can help determine your biological age.

Emory Healthcare internist Dr. Sharon Bergquist says you may be 50 years old, but biologically you are 45 or 55, based on changes in your DNA that reveal the rate at which you are aging at a cellular level.

"That's important because we've known since the 1990s that about 25% of aging is genetic and about 75% relates to our lifestyle in our environment," Dr. Bergquist says.

How can you slow down aging?

If you're ahead of your time, she says, there are ways to slow down your biological clock.

"We know that dietary habits can affect your rate of aging," Bergquist says. "More plant-based diets with more phytochemicals, plant chemicals, can slow the rate of aging."

Regular exercise may be the most powerful way to slow down the clock, she says.

Getting enough sleep, a recommended 7 hours a night, is also important.

So, is managing your stress.

That said, she says, one research study at Emory found having some stress appeared more beneficial in slowing down the clock than having no or very little stress.

"We anticipated the lower stress, the better people would age," Bergquist says. "But there seems to be a sweet spot where some stress helps us age better."

Habits like smoking, eating an unhealthy diet or living a sedentary lifestyle can accelerate our biological clocks.

Still, Dr. Bergquist says when it comes to how we are aging, we actually have a lot of control.

She recommends getting a baseline test to gauge your biological age, making lifestyle changes, and then getting retested to see if you were able to turn back your biological clock.

"I think that if we're really motivated to live longer, that we can not only do that through lifestyle change, but we can now measure and make sure people are on the right track," Dr. Bergquist says.