For doctors, looking at a person’s birth date doesn’t tell them much. Sure, a person might be 75 on paper, but genes, lifestyle and environment all play into health. So it’s important to get a good understanding of our how old our bodies really are — a biological age rather than chronological age.

A new study, published Monday in Frontiers in Aging Neuroscience, found that a simple urine test could deliver valuable information about our biological age.
Age is Just a Number
In the study,