Another gray hair? It could be from too much stress.
In a recent study published in Nature, a team of researchers found that stress does, in fact, lead to gray hair. Testing was done on mice and scientists say feeling overwhelmed damages steam cells responsible for hair pigment. “Stress makes the stem cells differentiate faster, exhausting their number and resulting in strands that are more likely to be transparent,” they wrote. The study, also found “the sympathetic nervous system, which prepares the body to respond to threats, plays an important role in the graying process.”
Ya-Chieh Hsu, a stem cell biologist at Harvard University who was the study’s lead author, wrote, “Normally, the sympathetic nervous system is an emergency system for fight or flight, and it is supposed to be very beneficial or, at the very least, its effects are supposed to be transient and reversible”.
They wrote further, “The sympathetic nervous system helps mobilize many biological responses, including increasing the flow of blood to muscles and sharpening mental focus.” However, “in some cases the same system of nerves permanently depleted the stem cell population in hair follicles.”
Although it has long been a popular wives’ tale, Dr. Hsu reports, “The findings provide the first scientific link between stress and hair graying.”
Understanding that stress can affect the entire body, scientists wanted to know whether there was any fact behind the gray hair theory. At first, the team hypothesized that “stress might cause an immune attack on melanocyte stem cells.” So, they “exposed mice to acute stress by injecting the animals with an analogue of capsaicin, the chemical in chili peppers that causes irritation. But even mice that lacked immune cells ended up with gray hair.”
So, next, they tested the hypothesis that cortisol was the main contributor to the impact of stress on the body. However, mice that had their adrenal glands removed so they couldn’t produce cortisol still had hair that turned gray under stress.
“The system responsible for the appearance of silvery strands turns out to be the sympathetic nerves that branch out into each hair follicle in the skin,” researchers wrote.
During testing, “acute stress depleted the entire melanocyte stem cell population in mice in just five days.” The researchers also found that,” in petri dishes, noradrenaline prompted human melanocyte stem cells to proliferate, suggesting that the same acceleration of hair graying occurs in people, too.”
“I was amazed by how dramatic this change is,” said Mayumi Ito, a biologist at the New York University School of Medicine.
There is a light at the end of the tunnel for those constantly under acute stress who do not wish to lose hair pigmentation. Dr. Hsu’s team also found that the graying process in mice could be stopped in its place with “CDK inhibitors, which stop the proliferation of stem cells, or by blocking the release of noradrenaline.”
“Stress is a normal part of life, but there are situations where stress is helpful and situations where it is detrimental,” said Subroto Chatterjee, a biologist at Johns Hopkins University who studies the effects of stress on the cells in blood vessels.
“If we can know more about how our tissues and stem cells change under stress, we can eventually create treatments that can halt or reverse its detrimental impact,” Dr. Hsu said.
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