by Alice Park – Time –
It’s an automatic behavior when you meet someone new: subconsciously, you take stock of physical cues to gauge how old they are. Facial wrinkles, gray hairs, an unsteady walk: these all signal older age.
Often, these guesses are pretty accurate, and researchers are attempting to replicate that internal age calculator to figure out how old people are—not chronologically, but biologically.
In a new paper published in Nature Medicine, Tony Wyss-Coray, professor of neurology at Stanford University and director of the Phil and Penny Knight Initiative for Brain Resilience, and his colleagues report on a blood test they developed that can determine a person’s “biological age:” a number based on your internal health that may be able to more accurately capture how well you’re aging than your birthday age.
