Does your biological age determine your risk of dying?

You could be 50 years old, and feel you can go backpacking around the world and run marathons.

On the other hand, you could be 20 years old, but have the aches and pains of an 80 year old and feel like your joints could use some lubricant. 

Either way, did you know your body has two different ages and what does this mean?

^{Image credit: iStock}