Going gray is mostly timing and genetics. On average, most people who carry the genes to go gray will do so on 50% of their head by the time they’re 50. Become a parent at 30? By the time you send the kids to college, you’ll be graying. Or maybe sooner. The very act of parenting — the sleep-deprived, stress-inducing, 18-year roller coaster ride that we go through — may indeed be to blame for an early onset of gray hair. A new study finds a link between certain types of stress and going gray. In other words, if you have a brood at home, it might be time to lean into the whole silver fox thing.
The new study, from Harvard University researchers and published in Nature, was the first to track down a scientific link between stress and gray hair. The researchers found that the nerves responsible for the fight-or-flight stress response in animals (mice, in this instance) also depletes the stem cells responsible for hair pigment. Depleting these cells eventually led the mice to develop patches of gray or white hair.
Here’s how it works: Sympathetic nerves reach into each hair follicle in the skin. When the emergency fight-or-flight response is activated, these nerve cells release a neurotransmitter called noradrenaline. This neurotransmitter causes the stem cells that give hair its pigment, called melanocyte stem cells, to go wild and proliferate in large numbers, then abandon their post. This depletes the number of these cells in the follicle. Eventually, if the follicle loses all of these cells, the hair will appear white.
The researchers put the mice in a state of acute stress by restraining them for four hours a day, or through a combination of damp bedding, tilting their cages, and fast changes in lighting. (If you look at these tests through the sleep-deprived lens of new parents, you can see the corollary between this and raising a child.) Within five days, the mice had patches of hair turning gray or white. The researchers tested several possible stress responses for a connection to the hair color change, but none could explain the shift until they evaluated this nervous system response.
More research needs to be done to understand the connection between the sympathetic nervous system and hair color change, especially in humans, but scientists are hopeful this is a useful first step. “The reason we’re hopeful the mechanisms are related is that both of these systems (pigment-producing stem cells and sympathetic nerve) are very similar in mice and humans,” Harvard stem cell researcher and lead author on the study, Ya-Chieh Hsu, Ph.D., told Fatherly in an email.
The fight-or-flight response is a useful physiological state when animals are in a life-threatening situation. Emergency responders and soldiers in combat situations are prime examples of people who experience this kind of acute stress response, wrote Hsu. If you’ve ever caught a toddler falling off playground equipment, you’ve had a taste of the response.
Usually, the body returns to a normal state after the threat has passed with help from the parasympathetic nervous system, explains Hsu. But if it’s overactivated from repeat exposure to stressful situations, this system can contribute to chronic stress, which is an ongoing strain on the nervous system for longer periods of time.
Hsu is hopeful that this research can be the starting point to better understanding the effects of stress on our physical well-being, including that of individuals who experience post-traumatic stress disorder. “This research is critical to helping scientists understand how stress affects tissue repair in the body,” writes Hsu.
Don’t hold your breath for an antidote to graying locks, she warns. Devising treatments is a long way off. Plus, stress isn’t the only factor that could contribute to graying hair. Genetics and diet also play a role, as Subroto Chatterjee, a biologist at Johns Hopkins University, told The New York Times.
For now, it’s good to know that the next time you tell your child they’re giving you gray hairs, you may not be entirely off base.
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