Thanks to modern technological advancements, the average American lifespan has reached 79—41% higher than it was 100 years ago. But modern life has also resulted in an increase of chronic diseases, which now affect nearly half of all Americans. In other words, a long life doesn't always translate to a higher quality of life. [1-2] In fact, your chronological (AKA calendar) age might not accurately represent your body's internal or biological age at all.  What is biological age? Biological age ...