How much sun could a good beard block?
NOTE: Sci's got
some major stuff going on professionally which requires her full attention. I
would hate for you all to go without your weekly dose of Friday awesome,
however, and so have arranged these reposts. Thanks for your patience!
...ok I guess that probably
won't work for some of us. Fake beards, maybe?
I know a guy with a rather
luxuriant amount of facial hair. I once asked him if he ever put sunblock on
it. Get in the cracks, you know? He said of course not, hair blocks sun. He's
never gotten a burn there, after all.
This is definitely true
enough, I've never gotten a sunburn where my hair is, either. But how much sun
does a good beard block if a good beard could block sun?
Answer? It blocks the sun
that a good beard could block if a good beard could block sun.* At least,
depending on the angle, and the thickness of the beard. But how to find out
PRECISELY?!
Well for that you need
SCIENCE. Science and fake heads with beards on them. On a weathervane. Really.
Parisi et al.
"DOSIMETRIC INVESTIGATION OF THE SOLAR ERYTHEMAL
UV RADIATION PROTECTION PROVIDED BY BEARDS AND MOUSTACHES" Radiation Protection Dosimetry, 2012.
UV RADIATION PROTECTION PROVIDED BY BEARDS AND MOUSTACHES" Radiation Protection Dosimetry, 2012.
By now I think we all know
the risks of UV radiation from the sun. Wear layers, slather on some SPF 30
until your skin can take no more, wear a hat, etc. But what about facial hair?
To investigate this point,
the scientists in this study needed to look at the UV damage caused by the sun,
at various angles, and with different lengths of facial hair. And since humans
guys probably can't hold very still for the many hours it would take to measure
this...well, this is what they built.
(I would have LOVED to see this thing hangin' out behind someone's lab on campus. Science in action, my friends!!)
They authors then looked at
protection from UV radiation (using dosiometry ,
which measures dose exposure to UV radiation) at several angles of sunlight,
and on several angles of chin, cheek, upper jaw, etc. They had a no beard
condition, a "short" beard condition (10 mm on the upper lip, 40 mm
on the chin), and a "long" beard condition (up to 20 mm on the upper
lip and 90 mm on the chin). The beards were fake, as manikin heads have a
terrible record of growing their own facial hair.
What you can see here is
the exposure ratio, after 1 hour in the sun with the face angled up to receive
the light (described as horizontal, they did 1 hour at most angles, except for
the 25ish degree angle, which had 2 hours of exposure). You can see that beard
presence significantly decreased the amount of UV exposure. When teased apart,
the longer beards provided more protection.
So clearly, in addition to
all our layers and sunblock, we need to be growing us some beards! Or,
possibly, get fakes. There are of course caveats. Wither the stubble, my
friends?! Wither the short goatee?! The "short" length here was 40mm
long on the chin (almost 2 inches), which is pretty hefty, and the
"long" was full on lumberjack. But most guys don't have facial hair
that long, what protection, if any, are they getting? Does a couple of mm do
any good? Or do we need to start a trend for some long and luxuriant facial
locks?
Me, I think fake beards are
going to be all the rage next summer.