Why does redistribution of blood flow happen?

Answer 1

While a person is exercising, the body must adjust to send extra blood to working muscles. When this adjustment takes place, blood must be redirected from somewhere else in the body. During rest only 15-20% of the cardiac output of the heart goes to the skeletal muscles, but during exercise, that number reverses with the other areas of the body, feeding the muscles nearly 85% of the total output of the heart. Muscles like the kidney, brain, and liver eat up nearly 65% of the total blood flow at rest!

When exercise is light, blood flow to the skin increases to compensate for a change in body temperature. This percentage decreases when exercise gets heavier to send more blood to the muscles.

The heart generally receives around 4% regardless of the body being in exercise. Blood flow to the brain increases slightly, as the brain cannot have a decrease in blood flow over several seconds without fainting.

Because our body has a parallel circulatory system, blood flow can be redistributed where needed. Because of vasodialation, a decrease in radius, and vasoconstriction, an increase in radius, the vessels leading to a particular organ or tissue area change diameter depending on where blood is needed in the body. Blood flow into a capillary bed depends on the vasodialation or vasoconstriction of the arteriole supply. Inside the capillary bed are muscular rings called precapillary sphincters have increase or decrease the diameter of the vessel and control the flow of blood into the bed.

The body has an amazing way of keeping itself running, literally!