Causes of varicose veins

There are a variety of causes of varicose veins which include your gender, age and family history. But more research is needed into why these occur to develop a greater understanding.

There are risk factors for varicose veins which include:

  • Weak valves or damaged veins
  • Age
  • Gender
  • Job/career
  • Family history
  • Overweight/obese
  • Pregnancy
  • Injury to the leg/legs
  • Constipation
  • Medical conditions, e.g. chronic venous insufficiency
  • Sedentary lifestyle
  • Restrictive clothing, e.g. tights, high heel shoes
  • Heavy lifting, e.g. weights

Weak valves/damaged veins

These can be inherited or become weakened due to an accident, illness or injury. But there are cases where they develop for no reason.

Poorly functioning valves are unable to open and close as normal which allows blood to flow back towards the lower part of the body.

This also occurs if the veins have lost their elasticity. They become overstretched and weaken the valves which then prevent them from functioning properly.


Many parts of the body function less well as we age and your veins are no exception. They start to lose their elasticity and are increasingly prone to vascular conditions such as this.

The valves are also affected by the ageing process: they are less effective at helping to pump blood up through the veins and towards the heart.


This is where it is an advantage to be a man. Women are at a greater risk of developing varicose veins especially during pregnancy. The female hormone oestrogen has the effect of relaxing the veins which causes the valves to leak.

This is not to say men are not affected. Men do develop varicose veins just as some women are fortunate enough to escape this condition. But women are more likely to have varicose veins.

Menstruation and the menopause are also known triggers for varicose veins due to fluctuating hormone levels.


There are jobs which involve standing on your feet for long periods of time. Examples of these include nursing, teaching, hairdressing and retail.

The problem with this is that it causes blood to pool in the lower part of your body, e.g. the legs which put extra pressure on the valves. This forces them to work harder at pumping blood up towards the heart which weakens them over time.

Basically, your blood does not flow as efficiently if you are stood still for long periods of time. If possible, try and have breaks where you can walk around or flex your calves and ankle joints at intervals.

Family history

You are at an increased risk of developing varicose veins if someone in your family has developed this condition. This is a condition which runs in families so it is a good idea to check your family history.

Genetics does play a part but it does not mean that you will automatically develop varicose veins. What it does mean is that you have a greater than normal chance of doing so.

But if you have been unlucky enough to be born with defective valves/veins then this does increase your risk of varicose veins. It is not possible to change your genes but there are ways of reducing this risk by making a few lifestyle changes.

Find out more in our preventing varicose veins section. 


Being overweight or obese puts a strain on various parts of the body which includes the veins. This excess body fat affects the circulation which puts pressure on the veins, causing long term damage.

This is why it is important to take steps to reduce your weight by means of a healthy diet and lifestyle programme. Your GP can advise you further about this.


Pregnancy puts a variety of stresses and strains on the body. Hormonal changes during this time tend to relax the walls of the veins which then affect their ability to pump blood up to the heart. This also causes the valves to relax which means that blood is able to flow back towards the legs rather than towards the upper half of the body.

As the baby develops, the womb expands to accommodate this increase in size which then puts a strain on the veins which surround it. These pelvic veins become weakened as a result which often leads to varicose veins. These veins develop around the buttocks and vagina.

Plus this is a time when extra blood is required to support the developing child. This puts additional pressure on your circulation which works harder than usual to meet these demands.

This extra pressure weakens the veins which then increases the risk of varicose veins.

Injury to the leg/legs

If you sustain an injury to your leg (or legs) then this can put you at an increased risk of varicose veins. This includes leg surgery, fracture to the tibia or fibula or problems with the circulation in your lower legs.

There is also the fact that the majority of cases of varicose veins occur in the legs. So if you have experienced some form of leg trauma then take this risk into account.


Strange as it may seem, constipation or straining whilst on the toilet does increase the risk of varicose veins. This straining puts pressure on the veins by causing them to become over-stretched and eventually damaged. This damage shows itself as varicose veins.

If you find that you are struggling to pass urine or faeces then this requires further investigation to prevent the risk of varicose veins and other medical conditions.

Medical conditions

There are conditions such as chronic venous insufficiency (CVI) which occur when valves within the veins are damaged or missing. This causes a painful swelling in the legs and the risk of skin infections or ulcers.

This is often caused by deep vein thrombosis (DVT).

Chronic venous insufficiency may cause varicose veins although this tends to be rare.

Sedentary lifestyle

A sedentary lifestyle is responsible for a wide range of health problems which also includes varicose veins. A good example of this is spending long periods of time sat at a desk and/or behind a computer.

Doing this without taking or break or sitting with your feet crossed at the ankles means that blood is able to collect in your legs. This blood is unable to fight against gravity and flow towards the heart due to inactivity so it pools in the legs instead. This causes the veins to stretch over time which then increases the risk of developing varicose veins.

Crossing your legs does not mean that you will get varicose veins unless you have a genetic tendency towards them. But it may increase the risk.  

It is probably a good idea to move your feet and/or have regular breaks from your desk.

Restrictive clothing

There are certain types of clothing and/or shoes, for example high heel shoes which constrict the circulation thereby increasing the risk of varicose veins.

A tight fitting shoe prevents blood from flowing as normal which forces it to flow into the superficial veins and back to the lower extremities. This can lead to long term problems with the veins.

Minimise the wearing of tight fitting shoes and clothing and replace them with support garments instead. If you have varicose veins then compression stockings may help.

Heavy lifting

Weight lifting is a popular form of exercise but care must be taken when lifting heavy weights. Remember to exhale when you lift a heavy weight to prevent excess pressure being put on the abdomen. This pressure forces the veins to expand which puts a strain on them, weakening the valves and leading to varicose veins.

If you suffer from varicose veins then exercise will help to relieve the symptoms but avoid weightlifting.

These are all causes of varicose veins but like most conditions there are steps you can take to minimise or eliminate these risks. Find out how to do this in our preventing varicose veins section.

Guide to Varicose Veins

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