Veins carry blood back to the heart. Valve flaps in the veins prevent the blood from flowing back in the wrong direction. In addition, the “muscle pump” supports the return transport of blood: like a water hose that you squeeze, the muscles squeeze the leg veins with every movement and thus the blood further.
Facts and figures about veins
But about one in two Germans stands on legs that are no longer completely healthy. Man has the upright gait ahead of other mammals, but it also brings him disadvantages. For example, maximum performance is demanded of the circulatory system, because the blood must return from the toes to the heart: through the veins and against the force of gravity flow 9,000 liters daily. That’s the equivalent of lifting over 500 cases of mineral water onto the table.
The flow of blood through the veins
Blood does not flow back from the body to the heart solely because the heart is pumping. The blood in the veins is also transported to the heart because the vein walls, along with their muscles, contract.
To prevent the blood from going astray in the process, the veins have valve-like locks, also called venous valves. These check valves open only when pressure is applied from below and immediately close again when backflow occurs from above. The venous muscle pumps on the sole of the foot, ankle and calf are also involved in transporting blood back to the heart. When you run, the muscles keep pressing on the veins and help drive the blood toward the heart.
Origin of vein problems
Knowing how blood flow works, it’s easy to imagine that some stresses are poison to the veins, such as standing all the time in many occupations. Gravity causes the blood to press downward and thus constantly against the valves and walls in the deep veins of the legs. After some time, the vein walls can no longer withstand the strain and give way. As a result of the dilation, the venous valves no longer close properly and only part of the blood is transported back. Another part is pressed into superficial veins, which also expand as a result.
Varicose veins (varices) develop. There, the blood flow is slowed down, the blood backs up and water is pressed out of the bloodstream into surrounding tissue (edema). Especially in the evening, the legs are heavy and swollen, aching, tingling or itching. Over time, the vein walls also suffer damage. They lose tone and become susceptible to inflammation and blood clot formation (thrombosis).
Causes of weak veins
The development of venous disease is particularly favored by the following risk factors:
- Lack of exercise
- Overweight
- Predominantly standing or predominantly sitting (legs motionless in the vertical position)
- Pregnancy
- Taking birth control pills, especially in smokers and women over 30 years of age.
- Blood stasis due to surgery
- Increased tendency to clotting
- Hereditary weakness of veins and connective tissue
