A recent Harvard research has found that acute stress can result in graying of hair due to the release of the hormone, norepinephrine by the sympathetic system. The hormone works by depleting the stem cell reservoir in hair follicles which usually differentiate into pigment-producing cells.
Graying of hair is a slow physiologic process associated with aging. But according to some myths and cultural anecdotes, hair can lose color earlier on in life due to high stress. This myth, often mentioned in the quote,‘I don’t have gray hair, I have stress highlights’ is no longer a myth. Researchers have recently proven that acute stress can in fact permanently depigment the hair.
A Harvard Research
In a recent study published in the Nature Journal by Zhang, Hsu, and their team from the Department of Stem Cell and Regenerative Biology, Harvard University and Harvard Stem Cell Institute, Cambridge, USA, researchers studied animal models and found conclusive evidence to prove that stress can actually cause graying of hair.
Method of Study
Zhang and his team of researchers performed the study with the objective of validating that stress can actually result in depigmentation of the hair. However, it was not an easy task. Since stress affects the entire body, it was difficult for the research team to narrow it down to a single focus point.
Initially, they assumed that stress causes graying of hair due to an immune attack. However, that hypothesis was rejected when mice animal models lacking immune cells still lost color in their hair due to stress.
After that, the team of researchers hypothesized that the graying of hair because of stress was due to the negative effect of stress hormone cortisol on the hair follicles. When they tested this hypothesis on the mice animal models by performing adrenalectomy and then, exposing them to stress, they found that the mice experienced graying of hair regardless. This led to the rejection of the hormone-associated hair graying hypothesis as well.
Eventually, the team of researchers hit the jackpot and found the main culprit, the sympathetic nervous system.
What is the sympathetic nervous system?
The sympathetic nervous system is one of the main divisions of the body’s autonomic nervous system and is responsible for the body’s fight or flight response, which usually kicks in when exposed to high-stress levels. During high-stress situations, the sympathetic nervous system which has fibers extending to each hair follicle releases a flash flood of hormones to heighten the body’s alertness.
How does the sympathetic system causes graying of hair?
Each hair follicle has a reservoir of stem cells, that usually differentiate into pigment-producing cells to color the regenerating hair. The depletion of these stem cell supply due to any cause can result in the graying of hair.
Norepinephrine, one of the main hormones released by the sympathetic system in response to high-stress situations, negatively affects the stem cell accumulation in the hair follicles. The hormone prematurely converts all stem cells into pigment-producing cells, hence depleting the reservoir and resulting in permanent graying of hair.
The research team, after proving this hypothesis on animal models, hopes that this new finding will help pave the pathway for further research into stress and its impact on other organ systems.