When did you start going grey?
If it was after being retrenched, the sudden loss of a loved one or the onset of a chronic condition, you may not be alone in spotting a few more grey hairs.
A new study from researchers at Columbia University Vagelos College of Physicians and Surgeons in New York City is the first to offer quantitative evidence linking psychological stress to greying hair in people.
That might be obvious to some readers but the discovery that surprised the researchers is that hair colour can be restored when stress is eliminated.
“Understanding the mechanisms that allow ‘old’ gray hairs to return to their ‘young’ pigmented states could yield new clues about the malleability of human ageing in general and how it is influenced by stress,” said associate professor of behavioural medicine (in psychiatry and neurology) Martin Picard, senior author of the study, which was published in eLife.
“Our data add to a growing body of evidence demonstrating that human ageing is not a linear, fixed biological process but may, at least in part, be halted or even temporarily reversed.”
Studying hair as an avenue to investigate ageing
“Just as the rings in a tree trunk hold information about past decades in the life of a tree, our hair contains information about our biological history,” Mr Picard went on.
“When hairs are still under the skin as follicles, they are subject to the influence of stress hormones and other things happening in our mind and body. Once hairs grow out of the scalp, they harden and permanently crystallise these exposures into a stable form.”
The study investigated individual hairs from 14 volunteers and compared with each volunteer’s stress diary, in which individuals were asked to review their calendars and rate each week’s level of stress.
The investigators immediately noticed that some grey hairs naturally regain their original colour, which had never been quantitatively documented, Mr Picard said.
“There was one individual who went on vacation, and five hairs on that person’s head reverted back to dark during the vacation, synchronised in time,” he added.
Sorry, this will disappoint you
Sadly, while reducing stress in your life is a good goal, it won’t necessarily turn your hair back to your original colour, the researchers say.
“Based on our mathematical modeling, we think hair needs to reach a threshold before it turns grey,” Mr Picard said.
“In middle age, when the hair is near that threshold because of biological age and other factors, stress will push it over the threshold and it transitions to grey.
“But we don’t think that reducing stress in a 70-year-old who’s been grey for years will darken their hair or increasing stress in a 10-year-old will be enough to tip their hair over the grey threshold.”
The message: don’t throw out the hair dye just yet.
