The study, carried out on lab mice, suggest that constant worrying affects melanocyte stem cells, which produce the melanin pigment that is responsible for the colour of hair and skin, the Daily Express reported.

The examination explains that when the skin is damaged, these cells travel from their usual position, in a bulge at the base of the hair follicle, to carry out whatever repairs have to be done.

The researcher also revealed that stress causes the same migration and prevents cells from returning, thus turning hair white.

The author of the study, Dr Mayumi Ito, said that stress hormones promote melanocyte migration from hair follicles to damaged skin.

It asserted that excessive stress might mean fewer cells would be preserved within the follicle.

Rick Sturm, Associate Professor from Australia’s University of Queensland, explained that normally stem cells only stay in the bulge region and if you lose the stem cells from there, the hair follicles in that area would become white.

The research was published in the Nature Medicine journal.