Tuesday, November 29, 2011

Mechanical Hair Damage

Hair has a lot of enemies. That's why it keeps growing. Sunlight, chemical treatments, packing tape that your brother sticks in your hair because he thinks it's a great joke - all hard on your hair.
Certain grazing animals have teeth which grow throughout their lives because the grasses they eat contain a lot of silica, which grinds down teeth and the initial parts would soon be worn out.
©Science-y Hair Blog 2013
People have hair which keeps growing to keep our heads covered, even if our hair should be broken or pulled out. You only need see a bald person who was outside with no hat or sunscreen to understand the severity of the sunburn you can get on your scalp. Sunburn leads to water loss from skin, unhealthy skin, potential for infection. Not to mention an overheated scalp can make an overheated person and hair may help us modulate the temperature of our heads. Where we keep our brains. Our constantly-growing hair is always growing and replacing itself because nature expects it to wear out.
©Science-y Hair Blog 2013
The damage nature anticipated the most is mechanical damage. Spend some time in tall grasses, brambles and briars, dense woods down by rivers and you'll catch your hair (and skin) on many things. Branches and shrubs and grasses will catch and tangle your hair. Seeds and twigs and thorns will be caught in your hair and clothing which will anchor firmly without speedy removal.
If that's not your lifestyle, then think of washing your hair - there's some rubbing of hair fibers against each other, your scalp and fingers. Strong shampoos can dissolve oils and free hair's proteins. Combing and brushing create far more friction, and wet combing creates more friction than dry combing. Sleeping applies a massive amount of friction to hair. Sliding a hair under the weight of another hair alone can cause erosion of cuticles. Wearing hair up in a ponytail daily, even with fabric-coverd ponytail holders can result in the same sort of damage because of the friction of the hairs rubbing as you move. Rubbing on collars of shirts and hats is another source of hair damage.©Science-y Hair Blog 2013

We can weaken our hair with too-frequent shampooing and chemical treatments or make it more porous, but it is our handling of it and the forces applied to our hair (knots, twisting, pulling, rubbing, pressure) that can break it, dull it and of course these things also lead to dehydrated, porous, less-healthy hair.©Science-y Hair Blog 2013

You cannot avoid all mechanical damage, but you can try to prevent it - which is important if you want healthy hair without having to add a lot of products to it, if you want your hair to grow long, or if it has already been damaged and you want to prevent further damage.©Science-y Hair Blog 2013

I'll be posting soon with how to line a hat with satin to reduce the friction on your hair and scalp. I didn't believe the difference this could make until I started lining hatbands with satin ribbon. I just snagged some fabric from my local fabric store! If you are accomplished at sewing, please overlook that upcoming post. I only sew when I need to.

Source: Chemical and Physical Behavior of Human Hair 
Robbins, 1994. 3rd Ed. Springer-Verlag, New York


  1. As my hair becomes older, I've had to learn more about why my hair is becoming more damaged. Of course I thought it was the dye, but why was the rest of my hair just barely damaged, when just one section on the side of my head was very damaged.

    Well it's the side I usually sleep on, obvious looking back, but it did take me a while to figure it out.

    I'm ordering a satin pillow case, but will that be enough? I look forward to your next post about mechanical damage ^_^

  2. Hi Shreela. Slippery pillowcases do help a great deal to keep your hair from "scouring" itself while you sleep. Satin can cause static if it is very dry in winter where you live, but silk seems to be less static producing.
    If you are getting tangles, you might consider making a loose ponytail on the very top of your head with a scrunchie.