Connection Discovered between Gray Hair, Stress

US Senator John McCain. Photo: Reuters
US Senator John McCain. Photo: Reuters
TT

Connection Discovered between Gray Hair, Stress

US Senator John McCain. Photo: Reuters
US Senator John McCain. Photo: Reuters

When Marie Antoinette was captured during the French Revolution, her hair reportedly turned white overnight. In more recent history, John McCain experienced severe injuries as a prisoner during the Vietnam War and lost his hair color.

These incidents urged scientists to connect stressful experiences with the phenomenon of hair graying. However, the reasons remained a mystery until recently.

Harvard University scientists have discovered how the process plays out, and published their findings in the Nature Journal.

A team of researchers led by Dr. Ya-Chieh Hsu, an associate professor of Stem Cell and Regenerative Biology at Harvard, found that stress activates nerves that are part of the fight-or-flight response, which in turn causes permanent damage to pigment-regenerating stem cells in hair follicles.

Researchers first had to narrow down which body system was responsible for connecting stress to hair color, including the possibility of a link between the gray hair and Cortisol, as stress always elevates the levels of the hormone.

They believed that cortisol might play a role, however, as they removed the adrenal gland from the mice so that they couldn't produce cortisol-like hormones, their hair still turned gray under stress.

After systematically eliminating different possibilities, researchers honed in on the sympathetic nerve system, which is responsible for the body's fight-or-flight response.

Sympathetic nerves branch out into each hair follicle on the skin. The researchers found that stress causes these nerves to release the chemical norepinephrine, which gets taken up by nearby pigment-regenerating stem cells.

In a report released by Harvard's website, Hsu said: "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. 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".



Flooding Hits China’s South, Temperatures Sizzle Elsewhere

 Visitors to a mall cool off near a mist machine during the summer heat in Beijing, Saturday, June 15, 2024. (AP)
Visitors to a mall cool off near a mist machine during the summer heat in Beijing, Saturday, June 15, 2024. (AP)
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Flooding Hits China’s South, Temperatures Sizzle Elsewhere

 Visitors to a mall cool off near a mist machine during the summer heat in Beijing, Saturday, June 15, 2024. (AP)
Visitors to a mall cool off near a mist machine during the summer heat in Beijing, Saturday, June 15, 2024. (AP)

China's National Meteorological Center on Sunday issued an alert for high temperatures as multiple regions across the country experience sweltering heat, while many southern provinces issued severe flood warnings due to heavy rains.

The intensity of high temperatures is expected to decrease in north China and regions between the Yellow River and the Huaihe River, the center said.

The center forecast maximum temperatures of 37-39 degrees Celsius (99-102 degrees Fahrenheit) in parts of Xinjiang, Inner Mongolia and Henan on Sunday.

Heavy rains have lashed southeastern Fujian province for seven days and are expected to continue, with water levels in some rivers exceeding warning levels.

Authorities have released water from several reservoirs, China's state television CCTV reported.

Authorities in Guangxi region said water levels of some local rivers had "skyrocketed" and that a student was killed in the floods in the southern city of Guilin, CCTV reported.