Growing older often brings unexpected grooming challenges. This is particularly apparent when some areas that, when young, we could otherwise ignore start to develop hair.
This includes our nose and ears, where hair grows thicker and longer as we age. But why do hairs in these areas act like this? The answer predominantly lies in our sex hormones.
Two types of hair
There are two types of hair that grow across our bodies.
Vellus hair is fine and colourless. This hair (also called “peach fuzz”) grows across most of our bodies, including our arms and neck.
Terminal hair is stiff, thick and darker. It stands up from our skin and is usually very obvious. Adult males have terminal hair on about 90 per cent of their bodies, with females growing it on about 30 per cent of their bodies.
Terminal hair stands up when we’re cold (giving goosebumps) and helps trap heat to keep us warm. It also protects us from the sun (such as hair on our scalp), and keeps dust and dirt out of our eyes through eyebrows and eyelashes.
As vellus hair is smaller, thinner and colourless, it is not usually an aesthetic problem (although it can be altered in some diseases). Instead, it is the terminal hair that is often noticed, and the primary target of our razor.
The normal process of hair development involves a growth phase (anagen), follicle-shrinking phase (catagen), and then a short resting phase (telogen) before the hair falls out and is replaced as the cycle begins again. Some 90 per cent of the hair on our body is in the growth phase at any given time.
Nose, ear, eyelash and eyebrow hairs don’t usually grow too long. This is because the growth phase of the follicles only lasts about 100-150 days, meaning there is a limit to how long they can grow.
Alternatively, the hair on your head has a growth phase that lasts several years, so it can grow to more than one meter in length if you don’t get it cut.
What is the effect of ageing?
Androgens are a group of sex hormones that play a key role in puberty, development, and sexual health. The most common androgen is testosterone.
These androgens influence hair growth and are the key to understanding why we have longer and thicker hair in our nose and ears.
Hairs in different parts of the body respond to androgens differently. Unlike some hairs that are stimulated at puberty (such as pubic hairs and facial hair in males), some hairs, such as the eyelashes, don’t respond at all to androgens. (The Conversation)
