Hair Growth and the World’s First Credit Card
Have you ever wondered why your hair grows to a certain length and then stops? Once they reach a certain length the amount of growth they undergo is noticeably slower. At first I thought this must be because it just gauges how much time has passed since you cut it. Then I realized that there is nothing that should be telling your brain that your hair was cut.
Sure we could argue some kind of average tugging from weight but the hairs are up against one another and this suggests that if you cut an odd pattern in your hair you’d have uneven growth that would accelerate hairs that shouldn’t be still growing. Amusingly all the weird little theories that I devised in my head were convoluted and unsurprisingly incorrect.
It turns out that your hair grows in phases. There is a period of “wakened” growth and a period of “resting”. This simple little mechanic really explains the whole kit and caboodle. This is the reason why my armpit hair grows just long enough to bother me but not long enough to reach my knees. Also why the hair on my head only seems to grow a certain length before it starts slowing down.
During the resting period your hair falls out and is replaced with new strands. What we are seeing are averages of all our uneven growth cycles. A good thing they are uneven or else we’d be bald randomly once a year. This also means that people can only grow hair to a certain length presuming they have a natural cycle of wake and resting.
Like many things it would appear that our hair length is not something we can nurture as much as it is a matter of genetics. Mildly disappointing but I do like how the obvious answer was hiding underneath my nose. Your body has no idea how long your hair is, it just grows until the clock runs out and we respond to that with cutting at appropriate times. We think we it is reacting to us when really we are reacting to it.
Now to figure out why it feels like my fingernails slow down at a certain length. Are they actually ceasing growth or am I just snipping them (nervously biting them) by a certain “prime” length? Seems like I might have already figured out the truth.