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

如果你担心头发灰白——试着让自己放松。科学家们发现压力太大真的会让头发变白。

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.

研究人员发现当身体处于压力荷尔蒙环境下，那些使头发着色的细胞就会消失。不幸的是，如果‘着色’细胞受到影响后就不可能再新陈代谢、恢复到从前的状态，所以头发就会永远变成灰白色的了。

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.

美国科学家在老鼠身上做了实验，结果显示压力对我们的头发的影响效果是惊人的。研究人员首先假设人体处于阳光暴晒的环境下，身体干细胞负责生产黑色素，在阳光紫外线的照射下，黑色素会对我们有保护作用，毛囊中的黑色素沉淀到皮肤上，会起到减少皮肤伤害的作用。在他们对小白鼠做的实验中，当小白鼠处于压力荷尔蒙条件下，同样出现永久褪色的状态。

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.

研究人员说，这可能会解释为什么压力也会导致色素沉着使皮肤显得更黑。我们大部分人大约在25岁会初次看到有了灰色头发，有多种因素导致我们出现白发，基因、吸烟、喝酒、压力等因素都会使头发变白。经历大的变故的人或经历丧亲之痛休克后，一夜之间头发就会变得灰白。

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.’

纽约大学麻由美-伊藤博士领导了这项最新研究，指出有证据表明压力会使毛囊中的黑色素‘沉淀’到皮肤上。我们原本认为压力过大黑色素沉淀过多这个说法是个很有意思的推测而已，’他说。该项研究发表在《自然医学》杂志上，报告总结：‘已知压力荷尔蒙促使皮肤色素沉淀，但却反而认为促使头发变得灰白。’‘我们的研究结果可以为压力荷尔蒙和头发灰白之间的这一关系提供洞察依据。’