Deep vein thrombosis is a disease where the blood clots within your veins when it is not necessary and these clots cause the blood vessels to be blocked. Recently someone asked me, what causes a DVT?

The predominant causes of a DVT are:

  • Genetic factors
  • Physical condition and
  • Lack of exercise
  • Medical Procedures
  • Travel, particularly plane flight.

Genetic Factors causing DVTs

There are a range of genetic factors that cause DVT's, including factor V leiden, factor k, and several others that are reasonably common. People can be genetically susceptible to having DVT's. The good thing to realise is that just having a Genetic cause of the disease doesn't mean you will necessarily develop blood clots.

Depending on the seriousness of the genetic blood clotting factor's deficiency, there are three main treatments:

  • Time on a blood thinner, such as Warfarin or Low Molecular Weight Heparin
  • Surgical treatments including stents, to prevent any blood clots reaching the lung and
  • Monitoring.

Most often, people do not receive treatment until they have had at least one DVT, and unless there are substantial risks most people are monitored rather than treated.

Physical Condition

Obesity or bad health when it restricts mobility can both be significant causes of DVT. In fact, they are the largest factors behind getting DVT's that you have some control over. You don't have to be super fit but being able to do normal activities reasonably well is perhaps the best prevention available for DVT's.


Lack of exercise, or mobility, is a large factor. You need to be regularly active. This exercise does not need to be rigorous, and doing things like walking to the shops, going up stairs rather than the lift, or taking the dog walking are all great.

One of the main causes of DVT is simply not being active enough.

This is something people with disabilities need to consider.

Medical Procedures

Any open surgery can increase your risk of DVT. If you have had previous DVT's or, are genetically susceptible, you must inform your doctor of these facts. Normally people who are likely to get DVT's are given an anti-clotting drug to reduce the risks,

Plane Flight

While this is controversial, DVT's have been linked to long haul plane flight, so I would advise you to keep active, walk around as much as possible, and take plenty of water.

What to do if you are at risk of DVT?

If you have had a previous DVT or have a family history of DVT, by far the best things you can do on your own are the common sense things:

  • Try to lose weight if you are fat
  • Eat a good healthy balanced diet
  • Keep in contact with your doctor.

As a rule, if you have had a DVT, the doctors will give you anti-clotting drugs. They will monitor you for a period, and probably take you off them. Once you are off them, the ideal thing is to stay as fit and healthy as you can.

People are sometimes worried about exercise after DVT, but by far the best thing to do is build up slowly but get physically active.

Mostly, don't worry too much about it, the chances of a second DVT are low, especially if you get physically fit.