Normal Veins

Veins return blood back to the heart. In the legs, this blood is returning back to heart against gravity. The blood is pumped back by muscular contraction. So, when you walk or move, the venous blood moves. This movement is in one direction; from the feet to the heart: against gravity. How does this occur. The answer is that nature cleverly developed valves within the veins that open allowing blood to return back to the heart and close shut when we are standing to prevent blood pooling in the feet.

The weight of all the blood in your legs is very heavy - so heavy, in fact, you would think it would drain down to your feet when you stand still. The valves in the leg veins prevent this from happening. There are hundreds of small valves within the leg veins. These valves shut when you stand still. They prevent the blood from returning back down to your feet. When you start to walk again, the valves open up and the blood is pumped toward the heart. Nature can be very clever.