September 28 2006, 3:36 pm PT | Posted in: Other
How long can the human hair grow?
I was once told a story about a beautiful princess (Rapunzel with golden hair, of course) who was imprisoned in a high tower for many, many, many years. Maybe someone will remember the fairy tale better than I, but to the best of my memory (I am now 64 years old) I seem to recall that she was saved by a prince who climbed up on her long hair to save her. There were missing pieces in the fairy tale that my age now brings into focus, like how she got food up there, possible toilet facilities, showering or general cleaning for many years (any prince who climbed up her long hair must have lost his ability to smell, for there were no perfumes in the story to hide what must have been a smelly lady). Sorry, I’ll focus on the original question…
The human hair growth cycle is believed to be between 2-7 years. As I have mentioned in the past, there are three phases to hair growth cycles, telogen (falling out), catagen (about to fall out) and anagen (the growth phase). Each individuals hair cycle is impacted by genetics, hormones, stress and any medications the person takes. You can imagine the difficulties of plotting the growth of individuals hair in different parts of the hair cycle and documenting the factors that address growth rates (impossible) so much of the research is either conjectural or taken from animal models that are not really compatible.
Now I remember my great grandmother (age 114) when I was a young man. On occasional Sundays, the granddaughters would take her hair out of a bun and wash it. I remember it went to the floor and beyond. There was great care in managing the hair wash. Now as a hair surgeon and expert in the hair field, I have to reconcile my memory of her hair with what I know about hair cycles. Could her hair be greater than 5 feet long. The answer I believe to this conundrum is that the hairs that fell out, weaved themselves into the remaining hairs (like dreadlocks) and that although the hair appeared to be greater than 5 feet long, had the granddaughters really brushed the hair when they washed it, most of that long hair would have come out simply because it was not attached at the root.
To really answer the Rapunzel story tale with academic precision, one would have to find a woman (men’s hair usually does not grow the length of women’s hair) who actually washed and brushed her hair so that all of the broken and loose hairs were brushed out. This would have to be on a few hundred women to make the data statistically significant. That would tell us how long a female hair can actually grow. The average hair grows at about ½ inch per month and for 7 years which means that the longest hairs should be no more than 42 inches (a bit over 1 meter) long. Can any of my readership tell me a ‘reality based’ Rapunzel type of story where the actual hair length exceeded 42 inches?
Now that was a bit long winded, but I guess I do get carried away with a form of ‘love’ for this growing baldingblog readership. Thanks for feeding this ‘young’ blog with your questions.