When we need it, it’s either too short or barely there. When we don’t want it, it’s all over the place. During many stages in our life, many of us have experienced a love-hate relationship with our own hair. But what is the function of hair?
Throughout history, hair seems to be the only exterior body part that has been subjected to such a wide range of use and abuse. We’ve pulled, cut, dyed, curled, straightened, tweezed, waxed, shaved, ironed, stretched, tied, and chewed it – among countless other things we’ve done on a regular basis.
If we spend so much of our time, energy, and dollars to grow and maintain our hair, couldn’t we just leave it to grow ‘au naturel’ until it sheds off our bodies, or undergo a total deforestation so we can take a load off of our backs – or in this case, skin?
Not so fast – take a look at the function of hair, four reasons why we all need it, and why it’s important to go to great lengths to care for it:
1. Hair regulates body temperature. Being indoors in a cold room or outdoors in cold weather makes our muscles contract, causing them to pull the hair into an upright position. These erect strands trap air and serve as insulation to protect the body from the cold. This explains why a person who has more hair feels warmer than someone who has little or none at all. Hot temperatures have an opposite effect. As our sweat glands secrete sweat that evaporates to cool us down, the muscles relax, making the hair lie flat to release heat
2. Hair extends our sense of touch. It’s amazing how even before an object touches our skin, our hair makes it possible for us to feel something. A study published by the Johns Hopkins University School of Medicine in 2012 reported how the brain processes and collects information through hair on the skin. David Ginty, Ph.D., professor of neuroscience at Johns Hopkins, says more than 20 classes of mechanosensory nerve cells in the skin detect everything from temperature to pain.
The study tested how the nervous system develops by using genetically engineered mice with a fluorescent protein in one type of nerve cell, called C-type low-threshold mechanosensory receptor or C-LTMR. These C-LTMR cells, which branch from the spinal cord to the skin, were found to send projections to as many as 30 different hair follicles. When two other types of nerve cells were marked, the results showed each hair type (mice have three) having even spacing and pattern on the skin and bearing a different and specific set of nerve endings. “This makes every hair a unique mechanosensory organ,” Ginty noted. The amount of hair may be different in mice and humans but many of the structures are similar and leads us to a new understanding of how hair plays an important role in our sense of touch.
3. Hair protects our bodies from harmful objects. Hair covers almost all of our body except for the palms of our hands, soles of the feet, and lips. Aside from providing cover from the heat of the sun, body hair such as eyebrows, eyelashes, and those found in nostrils help keep dust and foreign matter out.
4. Hair identifies you. Your hair may be a dead giveaway for forensic analysis and paternity testing, but for many, hair is simply the ultimate form of expression. The Jackson 5 and their afros, Dolly Parton and her big hair, Mr. T and his mohawk, Sinead O’Connor and her closely shaven pate, Alicia Keys and her braids, Jennifer Aniston and her “Rachel” locks – these celebrities made their hair a brand of its own by using it to enhance their features and create a style uniquely their own.
Lady Gaga, with her head-turning coifs, sums it up in her 2011 song “Hair”:
I just want to be free, I just want to be me
And I want lots of friends that invite me to their parties
Don’t wanna change, and I don’t wanna be ashamed
I’m the spirit of my hair, it’s all the glory that I bare.