Why Do Bruises Change Color?

Bruises can turn a rainbow of colors before they heal -- but why? Learn the science behind color-changing contusions in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from how Stuff Works. Hey, brain Stuff,
I'm Lauren Bogle Bomb And if you're anything like me
and absent blindedly attempt to walk through solid objects instead
of around them, you're familiar with bruises. They can be
embarrassing reminders of less than graceful moments, or, perhaps for
an athlete with hard one marks from a vigorous workout,

(00:23):
a mark of profound pride. But however you choose to
view bruises, they're pretty fascinating. The variety of colorful patterns
they create on the skin is reason enough to want
to learn more about these weird and sometimes painful spots
that everyone is coped with at one point or another.
Otherwise known as a contusion, a bruise is a mark
that appears when blood is trapped underneath the surface of

(00:45):
the skin. Bruises occur when some type of trauma or
injury crushes tiny blood vessels known as capillaries, but doesn't
break the skin. As a result of the injury, the
broken capillaries leak out red blood cells, which get trapped
under the skin, collecting in a pool that forms the blue, purple, red,
black blemish. Bruises can feel tender when they first form

(01:05):
and can be accompanied by some swelling. They usually take
about two weeks to heal, but some bruises can last months.
During the healing period, the body breaks down and reabsorbs
the pooled blood that produced the mark. As this happens,
the color of the bruises can fade from dark to
light and take on all kinds of interesting hues along
the way. When a bruise first forms, it's usually some

(01:27):
shade of red thanks to the fresh blood just below
the skin surface. After about a day or two, the
hemoglobin in the blood cells starts losing its oxygen, which
is what gives blood its red color in the first place.
Hemoglobin is the protein that transports oxygen to cells, so
as it's broken down by the body, it loses that
oxygen it was carrying, and its red tone darkens and

(01:47):
shifts to blue, purple, and blackish tones. After a few
more days, the mark usually fades to green or yellow,
before being hit with a hint of brown and then
fading away completely. This color change occurs as the body
uses the iron in the hemoglobin to form new red
blood cells. The unused decomposed hemoglobin transforms into a green

(02:07):
pigment called billa verden, which then converts into a yellow
or light brown tinged compound called bilirubin. As all these
products are either reabsorbed or purged from the body, the
mark fades and disappears. Just About everyone gets bruises, but
some people are more prone to them than others. Elderly people,
for example, may be more likely to bruise to too

(02:28):
thinner skin and softer tissue. Other factors like certain diseases,
medical conditions, and medications can also increase a person's risk
for bruising. So what do you do when you get
a hickey, a shiner, or any other form of contusion.
The usually time really does heal all wounds. Eventually, a
serious bruise can develop clots that take months to resolve,

(02:48):
but will usually go away on their own. And while
there are plenty of urban myths and tails about how
to magically banish bruises in a snap, the only legit
healing method is to chill, literally and figuratively. Doctors recommend
applying ice right after the injury occurs, and then resting
the injured area as much as you can for the
next few days. After that, you can try applying mild

(03:10):
heat to increase blood flow, which might speed the healing
process up a little bit. By the way, if you
find yourself constantly battling bruises, you might want to talk
to a doctor to investigate whether you have a nutrient deficiency.
Because your blood requires vitamin K o'clock properly. If you
don't have enough, you might bruise more easily. Vitamin C
is also important to protect your blood vessels. Today's episode

(03:36):
was written by Michelle Konstantinovski and produced by Tyler. Playing
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