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Varicose veins: what causes them?

1. Historical reasons: the evolution of man
 
Leg vein problems are one of the most frequent ailments that have always afflicted man. Finds from ancient China and Greek statues from the 5th century BC testify to the existence of these pathologies since the dawn of civilization.
 
When the ancestors of man decided to assume a standing position they had to face some disadvantages of their physical structure: the veins of the human legs and their internal valves, in fact, were not suitable to withstand the blood pressure for a long time that, in an upright position , weighs on them.
 
Proof of this is the fact that varicose veins:
  • in animals - with rare exceptions due to excessive selections - do not occur,
  • they hardly affect the upper limbs and upper portions of the trunk,
  • and which generally affect more frequently those individuals who are forced to stand for a long time
2. Cattive abitudini e predisposizione 

To problems of natural origin (and hereditary predisposition) are added bad habits or conditions typical of our civilized society, such as:
  • sedentary lifestyle (resulting in inactivity of the leg muscles);
  • overweight and obesity;
  • clothes that are too tight (which constitute an obstacle to blood circulation in the superficial veins);
  • shoes that are too low or with too high heels;
  • exposure to heat;
  • pregnancy.
3. Physiological reasons
 
From a functional point of view, the veins of our circulatory system have the task of bringing blood back from the tissues to the heart and constitute the place of greatest blood deposit. Since the pressure in the venous system is very low, the walls of these vessels are thin but equipped with a muscular layer that allows them to contract or dilate according to the needs of the body.
 
The blood pressure inside the veins gradually decreases from the feet to the heart. In a man in an upright position, the difference in blood pressure between the lower and upper parts of the body can cause significant disturbances, particularly if they are not in more than optimal conditions:
  • heart,
  • vein valves,
  • leg muscles,
  • elasticity of the walls of the veins.
The tonicity of the vein walls (their "elasticity") is of great importance in the development of these problems, which, together with the valves contained in them, prevents the decrease in the amount of blood in the legs.
 
During the activation of the leg muscles (when running or walking) the muscles compress the tissues and veins and push the blood towards the heart.
 
Problems with these organs have as a natural consequence an increase in venous pressure in the legs, which can lead to chronic venous insufficiency, or poor efficiency of the circulatory system.
 
In the adult in an upright position, completely stationary, the venous pressure at the height of the feet is about +90 mm / Hg, simply due to the weight of the blood present in the veins between the heart and the feet.
 
The venous pressure at the level of the feet of a person in an upright position would always remain at +90 mm / Hg if there were no valves in the veins.
 
Following every normal movement, even minimal, of the legs, the muscles exert a compression on the veins of the lower limbs. The blood contained in it tends to be "squeezed" out of the compressed areas.
Varicose veins: what causes them?
The valves in the veins are made so that blood can only flow in the direction of the heart. Consequently, every time a person moves his leg or in any case activates the muscles, a certain amount of blood is pushed towards the heart and the pressure of the corresponding veins is relieved, preventing the outflow and therefore the return to the lower parts of the body. , avoiding edema and swelling.
 
This pump system, which is called the "venous pump", or "muscle pump", is so efficient that it normally keeps the pressure of the foot veins of an adult walking under 25 mm / Hg.
 
If an individual stands absolutely still, the venous pump does not operate and the venous pressure in the lower parts of the legs can rise rapidly, up to the actual value of 90 mm / Hg, in about 30 seconds.
 
In such circumstances, the pressure inside the capillaries also increases strongly and a certain part of the liquid escapes from the circulatory bed into the interstitial spaces. The result is swelling of the legs and a decrease in blood volume. The pressure in the veins and capillaries increases greatly due to the inefficiency of the venous pump, resulting in a constant edematous state of the legs every time the affected person stands for more than a few minutes. In fact, by remaining absolutely still and upright, the blood volume can decrease by 15 - 20% within the first 15 minutes.
Varicose veins: what causes them?
Unfortunately the veins "wear out" and the valves lose their tightness. In pathological conditions the valves of the venous system can in fact disappear. This in particular occurs when the veins have been subjected to an excessive and prolonged increase in venous pressure, as can happen during pregnancy or when standing for a long time.
 
When such a condition occurs, the venous pressure in the legs increases, further dilating the veins and ultimately completely eliminating the valve function. In this way, varicose veins are formed which are characterized by large bulbous protrusions of the subcutaneous veins of the whole leg and in particular in the most sloping portion.
 
The resulting edema in turn hinders an appropriate diffusion of nutritional materials from the capillaries to the muscles and skin, so that the muscles become weak and painful, while the skin often becomes necrotic and eventually ulcerates.
 
The best immediate treatment in these cases is to keep the limbs raised to the height of the heart, but the application of elastic stockings can be very advantageous in preventing edema and what follows.

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