The body contains more than five million hair follicles, all of which produce hair, which plays many health functions, including protecting skin health from environmental stressors, while responding to external and internal messages that are transmitted to nerve impulses. The cells inside the hair follicles divide and multiply, and as the space inside the follicle fills, they push the old cells out, and after those old cells harden and come out of the follicle, they form the hair shaft, and the shaft mostly consists of dead tissue and a protein called keratin.
Hair has many important benefits for skin and body health, for example; If your body starts to feel cold, the brain will send signals to the hair on your body to stand up to trap air to insulate and warm the body, and the hair can also detect if there is a foreign body on the skin, such as an insect, so that you can pay attention and try to get rid of it.
The benefit of hair on the body
Back in the Neolithic era, hair protected the skin from wounds, and the sun kept the body warm, and even worked well as camouflage. Hair could no longer be tolerated over the entire body, so skin evolved with less hair.
Mammals have an internal mechanism called thermoregulation that allows the brain to regulate the temperature inside their bodies, but there are limits to this range. For humans, this range is more restricted.
If the internal body temperature increases by more than a dozen degrees or so, the individual is likely to die. To keep the body from overheating, sweating occurs, but for the sweat to do its job and cool the body through evaporation, there can’t be a lot of thick hair getting in the way.
Most adults have about 5 million hairs on their bodies, but the hair’s short, fine structure facilitates a cooling response to sweat. This ability to tolerate heat allowed humans to migrate about 1.7 million years ago from wooded areas to the open savannas of Africa and beyond.
And humans kept abundant tufts on their heads for protection, and this makes sense because the head is one of the main parts of the body that is constantly exposed to sunlight, and this means that there is a greater amount of heat and rays that reach it directly.
Men have thicker hair
Men have thicker facial and body hair than women thanks to the hormones in their bodies, called androgens, and this disparity between the sexes has to do with natural selection. As humans evolved, the total amount of human body hair shrank.
Eyelashes are our body’s first defense in keeping insects and other nuisance things from hurting our eyes, and leg and arm hairs were developed to help prevent friction, so we can move without causing friction.
It is said that the hair on the head helps protect the scalp from the sun’s rays, and the hair on the rest of the body is used as a thermoregulator, with this hair also being able to detect an insect falling on the skin, thus reducing the chances of exposure to insect bites.
