Let's face it: Nobody wants to look in the mirror and see gray hair. Graying signals the undesired start of aging.

But relax. No really. Relax.

Turns out, recent studies show that stress is a major contributor to those pesky gray strands. So instead of going to a hair salon, and trying to hide gray hairs with dyes, try watching a movie with friends or getting a massage.

The graying culprits turn out to be stress hormones, which are released when you think about that upcoming math test or looming deadline. The hormones damage melanin, the key to our hair color.

But more on that later. First, let’s go over the basics on how hair grows.

Hair, Hair, Hair

Most people take for granted that their hair grows each day, even if that process seems to take forever after a bad haircut. On average, though, hair grows half a millimeter each day. But that doesn’t just happen like magic. Thousands of proteins and fibers are working together in order for hair to grow.

Here’s how it works: There are about 100,000 tiny sunken pits in each person’s head. These are called follicles, and at the bottom of each follicle is where hair begins to grow.

Hair is made up of keratinocyte cells, which layer on top of one another to lengthen hair strands. After keratinocytes die, they become keratin proteins which give both texture and strength to hair. However, since keratin is colorless, nature relies on another substance, melanocytes, to give hair the varying colors that we see on people's heads each day.

Through a process called melanogenesis, melanocytes make melanin which is a pigment found in eyes, skin and hair. This melanin is delivered to the keratinocytes in melanosome packages to give hair color. There are different kinds of hair melanin. Eumelanin gives hair a dark brown or black color. Pheomelanin gives hair a blond or red color. These two mixed together in varying amounts give hair a wide variety of colors. At any given time, eighty to ninety percent of hair is actively growing. After the growing phase, the follicle shrivels up and the hair eventually falls out

In order for new hair to grow, new keratinocytes and melanocytes are needed. This is where the stem cells under each follicle come into play. These unspecialized cells live longer and can reproduce. To grow a new strand of hair, the stem cells are differentiated into new keratinocytes and melanocytes and the process starts over again. Each hair can take two to seven years to grow before falling out.

Stress and Premature Graying

Our grandparents always told us that the reason they have so many gray hairs is because they are stressing about us all the time. Even though it may sound like they are just guilt-tripping us or reciting old myths, there is now scientific research to back up their claims. An experiment published in the June issue of the “Cell” magazine, has shown that stress can and does cause premature graying.



These researchers from Japan subjected mice to ultraviolet radiation and rubbed stress-causing chemicals on their bodies to test the relationship between stress and graying. The researchers determined that mice under stress had more gray hairs at the end of the experiment. After further analysis, the researchers found that the graying happened because the anxiety that the mice experienced caused stress hormones to be released, some of which were close enough to the follicles to cause inflammation. The inflammationin caused the release of free radicals, atoms or molecules with a single unpaired valence electron, which are highly likely to react with cells and damage them. The damaged cells have the potential to grow into tumors. In order to prevent this, the mice's bodies cause these damaged stem cells to differentiate into mature melanocytes immediately.
However, since stem cells have a longer life span than melanocytes and can reproduce unlike melanocytes, the more rapid depletion of stem cells causes premature graying. Also, because this differentiation happened before the stem cells were moved to the right part of the follicle, where they would be useful, the new melanocytes aren't in a position to influence hair color.

But it's not all bad. Compared to the potential tumors that might grow from the damaged cells, grey hairs seem like a piece of cake.

Prevention

Now for the good news: If stress is the reason behind the gray hairs on your head, forget that hair salon. Go find those friends, and watch that movie. Find ways to relax every day. It will do your hair good.

Selected Sources:

http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-stress-causes-gray-hair

http://www.cbc.ca/technology/story/2009/06/11/tech-stress-grey-hair-dna.html

http://www.cbc.ca/technology/story/2009/06/11/tech-stress-grey-hair-dna.html