Does Stress Cause Gray Hair?

It is just another day. You get out of bed to wash your face. A splash later, just as you are reaching for the towel, your nose makes its way closer to the mirror. What is that? It is a bunch of gray hair just above your right temple. 

Is it genetic? Is it stress? Are you getting older faster? 

Harvard University researchers blame sympathetic activation. According to Dr. Bing Zhang from the Department of Stem Cell and Regenerative Biology and colleagues, the sympathetic nervous system activation triggers a fight or flight response in the body which causes permanent damage to the pigment-regenerating stem cells in hair follicles. 

Is it cortisol?

During an acute stress reaction, the body produces cortisol. Cortisol, also called the “stress hormone” is a steroid hormone that is made in the adrenal glands. 

The research team ran a couple of experiments to figure out how the stress response is involved in hair graying. First, the researchers hypothesized that hair graying might be caused by an immune attack on pigment producing cells. They tested this hypothesis on mice but failed to find any supporting evidence. They found that even without immune cells, mice still showed hair graying. Next, they removed the adrenal gland from mice to see if a lack of cortisol production would stop hair graying. However, the mice still grew gray hair when they were put under stress. 

Following a series of puzzling results, the researchers studied the effects of sympathetic activation more closely. When we perceive something as dangerous, the amygdala which is involved in emotional processing sends a threat signal to the hypothalamus. The hypothalamus then communicates with the rest of the body via the autonomic nervous system. The autonomic nervous system (ANS) controls involuntary functions like blood pressure, breathing, constriction and dilation of blood vessels. 

In the face of a threatening situation, the sympathetic nervous system which is a branch of the ANS triggers the “fight or flight” response that most of us are familiar with. Consequently, the adrenal glands start to pump adrenaline or epinephrine into the bloodstream. Adrenaline in the blood leads to physiological changes like increased heart rate and blood pressure. 

As this study shows, the sympathetic nerves also branch out into hair follicles. When we feel stressed, these nerves release another hormone called norepinephrine. According to the researchers, the release of norepinephrine into hair follicles activates stem cells and causes them to proliferate. Once stem cells leave their niche – the specific area that they reside in the follicle – they convert into pigment producing cells or move into the skin. The migration of stem cells into different areas depletes the niche and stops the production of pigment producing cells. 

Dr. Ya-Chieh Hsu explains that “After just a few days, all of the pigment-regenerating stem cells were lost. Once they’re gone, you can’t regenerate pigments anymore. The damage is permanent.”

In essence, the researchers propose that it is the release of norepinephrine into hair follicles that leads to hair graying. 

Ways to reduce stress

Since hair graying seems to occur due to the sympathetic nervous system (SNS) activation, we can practice stress reduction techniques to counterbalance SNS activation with activities that help us relax. 

Time and time again, physical activity has been shown to reduce stress. According to Harvard Health Publishing, walking relieves muscle tension and deepens the breath. 

Do you feel supported by your friends and family? Social support is also one of the best ways to alleviate stress. As the buffering theory suggests, friends, spouses and loved ones act as a shield against the debilitating effects of chronic stress.

As Dr. Zhang and colleagues’ study shows stress affects a variety of systems in the body. By investing in activities that support our wellbeing, we can reduce stress and face everyday challenges in more skilled ways, gray hair or not.