Medical Myth: Is Blood Red or Blue?

Have you ever wondered “If blood is red, why are veins blue?” Have you heard that our blood cells are first blue and become red after obtaining oxygen? Is it true? Today we’re getting to the bottom of this medical myth once and for all.

Where does blood get its redness?

The level of oxygen in our blood determines how bright the redness is. Blood pumped directly from the heart is rich in oxygen and appears bright red. Arteries carry blood away from the heart to other parts of the body. As blood gets farther and farther away from the heart, arteries transfer blood to tiny blood vessels called capillaries. Capillaries transfer oxygen and nutrients in the blood to cells that need it. As oxygen is removed, the redness becomes darker.

How dark can blood get?

From the skin’s surface, it appears that veins are blue or even a deep purple color. But that’s not actually an indication of the color inside our veins. All blood is red, but the shade of red can vary depending on how much oxygen is in the blood.

Why do the veins in my hands and arms appear blue?

The color our eyes perceive has a lot to do with the science of light. The colors we see are the result of which wavelengths are reflected back into our eyes. Scientists also believe that blue light tends to scatter and reflect more easily when it passes through tissue. This also contributes to the blue color we see. Guess you can say our eyes deceive us!

TL;DR: The blue color we see in our veins has more to do with how our eyes absorb color than the actual color of blood. All blood is red but can range from very bright red (high in oxygen) to a rich, dark color that contains less oxygen.