According to new research, published in the journal Nature, stress triggers nerves involved in the flight-or-fight response which, in turn, causes permanent damage to the pigment in your hair follicles.
"Everyone has an anecdote to share about how stress affects their body, particularly in their skin and hair – the only tissues we can see from the outside," the study’s senior author Ya-Chieh Hsu said in a statement. "We wanted to understand if this connection is true, and if so, how stress leads to changes in diverse tissues. Hair pigmentation is such an accessible and tractable system to start with – and besides, we were genuinely curious to see if stress indeed leads to hair greying."
Via a series of experiments on mice, the researchers established that stress causes the sympathetic nervous system to produce a hormone called noradrenaline, which gets taken up by nearby pigment-regenerating stem cells and causes them to work overtime. Translation? The colour-giving compounds are prematurely and permanently depleted.
"When we started to study this, I expected that stress was bad for the body – but the detrimental impact of stress that we discovered was beyond what I imagined," Hsu said. "After just a few days, all of the pigment-regenerating stem cells were lost. Once they're gone, you can't regenerate pigment anymore. The damage is permanent."
The researchers hope that the findings can also help them understand the implication of stress on other parts of the body.
"By understanding precisely how stress affects stem cells that regenerate pigment, we've laid the groundwork for understanding how stress affects other tissues and organs in the body," Hsu added. "Understanding how our tissues change under stress is the first critical step towards eventual treatment that can halt or revert the detrimental impact of stress."