When Ya-Chieh Hsu, professor of stem cell and regenerative biology at Harvard University and the Harvard Stem Cell Institute, wanted to figure out exactly what makes hair turn grey, she started with an obvious, albeit anecdotal, culprit: stress.
There are well-known historical examples of the connection between stress and hair greying—Marie Antoinette’s coif reportedly blanched after she was captured during the French Revolution—and studies have even linked stress in animals to greying hair. But for the first time, Hsu and her colleagues figured out the biological reason why stress saps the pigment out of hair.
In a study published in Nature, Hsu and her team report that the process starts with the sympathetic nervous system, which orchestrates all of the critical body processes that we never have to think about—our heart rate, our breathing, as well as things like digesting food and fighting off germs.
It is also responsible for the fight-or-flight response—the auto-pilot behavior system that helps us to recognize and respond to threats before we really have time to think about and process them. The sympathetic nervous system is intimately linked to our stress response, so in that respect, it’s not entirely surprising it might have something to do with greying hair.
