How come we bruise?

September 4, 2018


This last weekend, ScienceFM helped move one of their producers, Layne into her new apartment. After a rough few hours, we came out dusty, sweaty, but alive. Our arms? Just a bit tender. Our legs? Just a few bruises.


Black, blue, yellow, fading, where do these bruises come from exactly? When I knocked a large desk again Cara’s leg (hey by accident), a bunch of capillaries burst and started leaking blood to the surrounding tissues. These tiny broken blood vessels can cause tenderness and discoloration under the skin. So bang, little hurting bumps.


At first, a bruise will look red or a dark purple/blue. This can last for 1-5 days, depending on the depth and size of the damage. Our hemoglobin, which carries oxygen, initially gives the bruise its red color. As hemoglobin loses oxygen, the color gradually changes to a blue-ish. From there, our hard-working white blood cells (specifically Phagocytes) start to eat up the leaked blood and the hemoglobin begins to break down. The color becomes closer to a green thanks to the bile type waste product from the phagocytes. Towards the end, when the clean-up process is almost complete, the bruise will look yellow or brown. It even might become a red color again, but this fade doesn't totally disappear until the iron gets absorbed back into the body. Not too bad, bruise!



Not everyone bruises easily, but there are reasons some people do. At its most extreme, an easy bruise can mean a blood-clotting problem or a blood disease. More specifically, Leukemia can cause a frequency of bruises due the body's inability to produce enough platelets. But before you go thinking you have a life-threatening disease, there are many other reasons to be susceptible to bruising. Here are just a few: Women! Yes, unfortunately, with a higher body fat percentage, the easier it is to bruise. The elderly! The older you get, the thinner your skin gets. The protective layer thins out and the cushion for your blood vessels vanishes. You might just drink! D.A.R.E taught you that alcohol can thin out your blood and decease Vitamin C levels. And D.A.R.E was right! P.S.A: Careful running around when drinking. You might work out too much! Due to the constant strain of activity, the muscle’s blood vessels tear just a bit. This can cause some bruises. Pale skin! It's going to show more, guys. Can't do much about that. 


Cara’s pretty pale, but the bruise is looking better by the day. It’s a wonderful green/yellow. We’re all so pleased. ScienceFM is glad to know more and we hope you are too. Check out your next bruise! There’s much more going on there than you’d ever think. 

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