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YEOUCH! That
hurts!
Unless you live your entire life
indoors, you'll no doubt have had a sunburn or two (more?) But
why do we burn? Why do we tan? And why does the tan eventually
fade? It's all in the skin!
The body's
largest organ.
It might seem odd to think of the
skin as an organ, but it is a distinct type of tissue with a
dedicated function -- and that makes it an organ.
Skin is the organ that protects
the entire body by sensing and reacting to heat, cold, pain,
itching and pressure. It has multiple layers
to make it tough and to contain all the sensors that we
require to prevent the external world getting inside
us.
The
cells we see and think of as "skin" are actually dead cells
that have been pushed to the outermost layer by new cells that
replace them. These cells are continually
sloughing off (yuck) and being replaced by more dead
cells.
What's a
tan?
To understand tanning, we have to
understand that one layer of the skin's makeup includes cells
that are specifically designed to react to ultraviolet
light. UV triggers a hormone
that causes the production of melanin in the cells of the skin
layer, and this darker pigmentation protects the exposed skin
from the UV rays. However, this is not an
instantaneous reaction; the melanin takes a few days to build
up when triggered by repeated exposure to UV. Areas not
exposed don't turn darker, hence the "tan lines" we pretend to
hate but are tickled to show off because of the contrast
between tan and normal skin.
So why
does the tan fade away after a while? As
indicated earlier, cells are continually being born, living
and dying in the skin layers. As the cells that produced the
melanin pigment die off, they are pushed to the surface by new
(unpigmented or less pigmented) cells to be shed over time.
Thus, the tan is shed a cell at a
time. Moisturizing the skin can keep the dead
cells on there longer -- but who wants that?
Sunburn
danger.
If we
go out in the sun for longer periods before the melanin in our
skin is ready to protect us, we'll burn. A
sunburn is red because the body rushes to raise capillary
blood vessels to the surface to speed healing and carry away
waste. (This is why you can press gently on a sunburn and it
makes a lighter-colored mark, then returns to red as the blood
rushes back.) And, like any other kind of burn, the damage to
skin is very real. Skin that is burned loses elasticity and
can begin to wrinkle prematurely. UV light can also trigger changes in DNA that
lead to skin cancer -- so take it
seriously.
Sunburn
Prevention and Remedies
Stay out of the sun!
That's the best prevention, and then you don't need a remedy
for pain and skin damage. However,
if you must go out, always use sunscreen with a minimum 30 SPF
rating. It should also say that it protects
against UVA and UVB rays -- as the UVB rays
are the ones that cause damage.
Surprisingly enough, wearing sunglasses can get
you a worse burn than not wearing them! This
is because our eyes are sensitive to UV rays and this
perception helps trigger the release of melanin. When you put
on dark glasses you fool your brain into thinking it's darker
than it is. If you wear glasses (sun or prescription clear
glasses) take them off periodically for 30 seconds or so to
re-educate your brain on the type of day it is.
There are remedies galore for
sunburn pain and damage. Check out these links and choose your
favorite:
Summer is a time for outdoor
activities of all kinds -- but remember your largest organ.
It's doing its best to protect
you, so give it a break and put on the
sunscreen. | 
