Causes of Varicose veins

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Varicose veins are produced due to venous insufficiency, that is to say, due to the inability of the veins in the legs to exercise their return function of the blood towards the heart. This causes an accumulation of blood within the leg, which means that the veins swell and can make them visible and/or palpable.

Válvula venosa correcta

To be more precise, it can be said that that the majority of varicose veins arise due to a dysfunction in the venous valves, structures located inside the veins that help the flow of blood to always be in the ascending direction (from the legs into the heart).

Válvula venosa defectuosa

If these valves fail, it appears what is called reflux, this means that the blood, instead of going upwards to the heart, accumulates within the veins of the legs, given that they cannot fight against gravity.

Less frequently, varicose veins may also arise without there being any venous valve failure, only as a compensation of an obstruction of the deep venous system. Thus, on the main drainage route of the leg being obstructed, as a compensation mechanism, the blood comes from the superficial venous system which increases their volume and, thus, can be palpated.

Risk factors for Varicose veins

The main risk factors for varicose veins are:

Old man

Advanced age. The prevalence of varicose veins gradually increases with age. Thus, they are very uncommon in childhood, start to appear during adolescence, and are very prevalent in adulthood, and affecting around 70-80 % of elderly people.

family, hereditary factors

Inherited genetically. It is usual for people who have varicose veins to have a family history. There are studies that show that the likelihood of having varicose veins, if both parents have them, is almost 90%.


Pregnancy. The compressing of the uterus and the foetus on the abdominal veins during pregnancy impedes the venous return of the legs and significantly increases the risk of having varicose veins.

sedentary lifestyle

Sedentarism. Walking helps the return of the blood from the legs, given that with each step the muscle contraction pumps return blood towards the heart. Thus, the sedentary lifestyle and the professions that involve many hours standing up (or sitting in a fixed position) increases the risk of having varicose veins.


Overweight. Increases the risk of having varicose veins, both due to a compressing effect on the venous return of the legs (similar to pregnancy) as well as due to its association with sedentarism.

Substantiated information by:

Esther Armans Moreno
Xavier Yugueros Castellnou

Published: 19 June 2018
Updated: 19 June 2018


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