Healthy leg veins continuously pump blood back towards the heart.
While arteries carry oxygenated blood from our heart to the rest of the body, the veins are responsible for pumping the deoxygenated blood back towards our heart.
Since the natural force of gravity is continuously pooling our blood downwards, especially the leg veins have to perform a good job to pump this blood back up towards our heart.
To manage this job, our leg veins mainly depend on the help of our calf muscles. Once we move our legs, the muscles contract and thereby put pressure on our veins. This way the blood is being pushed upwards. To prevent the blood from flowing back down in times we do not move our muscles, venous valves inside our veins close and thus function as a non-return valve.