During the French Revolution, after being captured, Marie Antoinette’s hair turned grey overnight.
United States Senator John McCain lost all colour in his hair after experiencing injuries during his capture in the Vietnam War.
Throughout time, many people have linked stressful experiences with the sudden greying of hair.
For the first time Harvard University scientists have unravelled exactly how this occurs.
They found that stress activates nerves that are part of the fight-or-flight response, and this in turn permanently damages pigment-rejuvenating stem cells in our hair follicles.
This means that nerve cells can control stem cells and their function under certain stimuli, either favourably or unfavourably.
(Zhang B, et. al. Hyperactivation of sympathetic nerves drives depletion of melanocyte stem cells. Nature, 2020; DOI: 10.1038/s41586-020-1935-3).