Cases have been known for a long time when under severe stress a person can turn gray almost instantly. However, until now, scientists did not know exactly what causes this body reaction to a sudden shock. Now, researchers from Harvard University found answer.
For a long time, it was assumed that stress accelerates the aging process – and from this, like the natural appearance of gray hair due to age, hair loses its color. Versions have also been voiced about a specific stress response of the immune system that attacks itself. But the reason for the appearance of gray hair due to stress was different.
Researchers have found that sometimes severe stress causes a “hit or run” reaction in the brain – it is inherent in both humans and animals. It is this reaction that acts on the sympathetic nervous system, which activates the stem cells responsible for hair color. Violation of the usual rhythm of stem cells leads to failure, in which they cease to work correctly. Moreover, the consequences are irreversible: the hair will always remain gray.
Scientists have identified this using tests on mice. Three stressful situations were created for them: physical restraint, physical pain and psychological discomfort. In all cases, the mice turned gray, after which the researchers found out the cause of the changes.