Does Hair Keep Growing Even After Death?

Apparently, hair woes may not be exclusive to the living. Humans have long sought answers to a wide array of post-mortem mysteries. What happens after death? How long until your blood goes cold? Is there any consciousness in death? Or, more importantly, what happens to your hair? Does it just simply stop growing and fall off, or does it continue to increase in length for a period of time after you die?

We spend so much time tending to our tresses while we are alive, so the thought of that hard work going to waste post-humously is admittedly a bit disheartening to say the very least. This is likely why within popular culture, there has been a pervasive urban legend about human hair continuing its growth cycles even after death. But researchers already have an answer to this: As one would reasonably expect, hair growth ceases when you cease to exist.

According to a team of medical professionals (via a 2007 study article published in the BMJ), the short answer is that no, human hair does not continue to grow after one's death. 

The growth of one's hair and nails requires a hormonal regulation sequence that does not, and cannot, occur after death. Underneath hair follicles lies a cluster of cells called the hair matrix. These cells receive energy from the burning of glucose, and then use that energy to stimulate the hair follicles and eventually create hair growth. Glucose burning, however, is contingent upon the body's receipt of oxygen, which, of course, cannot occur while deceased (via StatPearls). 

Human fingernails are quite similar, in this context. Cell production underneath the nail beds promotes fingernail growth, and the process of this cell production is contingent upon glucose. Without glucose, which, again, cannot be supplied during death, the fingernails cannot grow.

Have you ever heard the commonly-touted "trivia" that humans only utilize 10% of the human brain? Well, that is not quite true either, according to researchers at the Association for Psychological Science. Technological advances in medicine, such as PET scans, have allowed neuroscientists to gauge human brain activity. From what's been studied, it is evident that the entirety of the human brain is constantly in usage, even during periods of rest. Researchers have also concluded that even individuals with cognitive impairments or diseases such as Alzheimer's, for example, still utilize far more than 10% of their brain. 

Has your mother ever told you that reading in the dark will ruin your eyesight? Well, turns out, mama doesn't always know best. Ophthalmologists at the University of Utah concede that reading in dark or dim light does not catalyze any permanent or substantial damage to the eyes. The general consensus amongst medical professionals is that while reading in low light can cause temporary eye strain, it is not capable of ruining one's eyesight.