Why Is Blood Red? Why Red is the Most Recognized Color?

Children have about three liters in their bodies, and adults contain five to six liters of blood. The red liquid in our veins is the most associated color, not only with pain but with love. That should tell a lot about human psychology. But why is blood red in color? Let’s find out.

Why is Blood Red?

We can’t live without blood because it fulfills many vital tasks. It transports nutrients, heat, and oxygen to the internal organs, like to your heart, using many small red blood cells. The building material for the blood cells that are formed in the bone is the blood pigment hemoglobin.

This dye consists of many small iron particles that make our blood look red. You can even taste the iron. But not every blood is red. In fact, the lighter the color of the blood, the more oxygen it contains. 

Our blood consists of two main components: the blood fluid (blood plasma) and the solid cellular components. The blood cells are made up of the red cells(erythrocytes), white cells (leukocytes), and the platelets (thrombocytes).

The white blood cells, the leukocytes, and the platelets are only visible under the microscope, and blood plasma is a clear yellowish liquid that consists of 90% water. There is only one remaining blood component that gives the blood its typical red color.

As the name suggests, the red blood cells, the erythrocytes, are responsible for the red color of our blood because they contain the red dye hemoglobin. The reason why blood is red is that humans have an incredible number of red blood cells that is about 25 trillion.

The Role of the Red Blood Cells

Hemoglobin binds the oxygen and carbon dioxide that are vital for us. Oxygen and carbon dioxide are difficult to dissolve in water, and the gases need a carrier to be transported across the body. Hemoglobin does this job 24 hours a day till we are alive.

When the blood flows through the small blood vessels of the lungs, the inhaled oxygen binds with the Hemoglobin, transported to the cells, and released there. While the carbon dioxide is partially absorbed by the Hemoglobin and transported back to the lungs, where we ultimately exhale it. Our body is only optimally supplied with oxygen if there is enough iron in the blood.

The Hemoglobin in the blood is not only responsible for why blood is red, but it is the main component of red blood cells (erythrocytes). Oxygen and carbon dioxide are transported with the help of Hemoglobin because Hemoglobin contains iron that binds oxygen.

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Red blood cells have a lifespan of 100 to 140 days. Older erythrocytes are continuously broken down, and new ones are added. A total of around 1.2 liters of blood are regenerated each month. The iron contained in the red blood pigment is almost completely used again to build new Hemoglobin.

Every healthy person has a natural iron reserve with which losses can usually be quickly compensated. If necessary, the formation of new red blood cells increases up to 15 times the standard value.

If you donate blood or if you lose more blood, essential iron is lost for the reconstruction of Hemoglobin. If a person does not have enough red blood pigment, which means if the hemoglobin value is too low, losing blood may be fatal, and donating blood is simply impossible.

The History of the Colour Red and its Association With Civilization

Red is the color of fire and blood. In Hebrew, the words blood and red have the same origin. Red is called ADOM, and blood is called DAM. Blood and fire have both a positive and a negative cast. Hatred, war, aggression, and bloodshed as opposed to strength, love, warmth, and passion.

The glowing blood-red was the color of the Greek gods of war Phoebus and Ares. Biblical Adam was created from the red earth. In the early cultures, the dark red of the blood was assigned to the female. These are a few mythological facts about the color red, but they do not explain why blood is red.

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Red was probably the first color that humans could perceive. In the case of brain injuries that cause temporary blindness, the patient first sees the red color again during recovery before the other colors appear. In early history, it was the most important color for the hunters.

These might give you an insight into the association of the color red with human history. Our ancestors might have also wondered why blood is red and must have associated it with food that is bound to give you happiness.