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If you’re worried about going grey – try to relax. Scientists have found too much stress really does turn our hair white.

如果你擔心頭發灰白——試著讓自己放松。科學家們發現壓力太大真的會讓頭發變白。

Researchers discovered the cells that give hair its colour disappear when the body is exposed to stress hormones. And unfortunately for those affected, these ‘colourful’ cells are unlikely to return, leaving the hair grey for good.

研究人員發現當身體處于壓力荷爾蒙環境下，那些使頭發著色的細胞就會消失。不幸的是，如果‘著色’細胞受到影響后就不可能再新陳代謝、恢復到從前的狀態，所以頭發就會永遠變成灰白色的了。

US scientists carried out experiments on mice which showed the startling effect that stress has on our hair. They began with the premise that when the human body is injured, stem cells responsible for producing melanin – the dark pigment that protects us from sunlight – move from hair follicles to the skin, to help limit the damage. In their tests on mice, the same permanent draining of colour occurred when the animals were exposed to stress hormones.

美國科學家在老鼠身上做了實驗，結果顯示壓力對我們的頭發的影響效果是驚人的。研究人員首先假設人體處于陽光暴曬的環境下，身體干細胞負責生產黑色素，在陽光紫外線的照射下，黑色素會對我們有保護作用，毛囊中的黑色素沉淀到皮膚上，會起到減少皮膚傷害的作用。在他們對小白鼠做的實驗中，當小白鼠處于壓力荷爾蒙條件下，同樣出現永久褪色的狀態。

The researchers said this could explain why stress can also cause pigmentation which makes the skin appear darker. Most of us spot our first grey hairs around the age of 25, and everything from genes to alcohol and smoking have been blamed for kicking off the process. There are tales of people going grey overnight after bereavement or shock.

研究人員說，這可能會解釋為什么壓力也會導致色素沉著使皮膚顯得更黑。我們大部分人大約在25歲會初次看到有了灰色頭發，有多種因素導致我們出現白發，基因、吸煙、喝酒、壓力等因素都會使頭發變白。經歷大的變故的人或經歷喪親之痛休克后，一夜之間頭發就會變得灰白。

Dr Mayumi Ito from New York University, who led the latest study, said there was evidence that stress could make melanin ‘migrate’ away from the hair follicle to the skin.‘We thought it would be interesting to speculate that excessive stress might promote this migration too much,’ he said. The study, which was published in the journal Nature Medicine, concludes: ‘Stress hormones are known to promote skin pigmentation, yet paradoxically and anecdotally, they are believed to promote hair greying.‘Our results may provide insight into the relationship between stress hormones and hair greying.’

紐約大學麻由美-伊藤博士領導了這項最新研究，指出有證據表明壓力會使毛囊中的黑色素‘沉淀’到皮膚上。我們原本認為壓力過大黑色素沉淀過多這個說法是個很有意思的推測而已，’他說。該項研究發表在《自然醫學》雜志上，報告總結：‘已知壓力荷爾蒙促使皮膚色素沉淀，但卻反而認為促使頭發變得灰白。’‘我們的研究結果可以為壓力荷爾蒙和頭發灰白之間的這一關系提供洞察依據。’