DVT and long haul flights

We have received a number of enquiries from policyholders regarding the dangers of death or serious illness from blood clots forming while travelling on aircraft and particularly long haul flights.

We have taken medical advice from MediQuote, one of the UK's leading travel related medical assessment companies, and their recommendations and advice appear below. This advice is based on the recent report by the scientific committee of the House of Lords (November 2000).

We would like to assure you that, for most people, the risk of developing thrombosis is quite low. However, there are some very basic precautions that everyone should take when flying. The following list of points may therefore be useful to you.

What is DVT?
Deep vein thrombosis (DVT) involves the formation of a blood clot in the leg. Sufferers are not always aware that a clot has formed and, on occasion, people have collapsed shortly after leaving the aircraft. This is because the clot can move from the leg to the lung, a condition known as pulmonary embolism. Pulmonary embolism can be instantly fatal, whilst untreated DVT is extremely dangerous and may require a stay in hospital.

What causes it?
Primarily, lack of movement over a prolonged period is thought to be the main cause, leading to impaired blood circulation. On an aeroplane, this can be more likely on long flights. Dehydration, which is often made worse by the dry air circulated on aeroplanes, increases the risk - and alcohol, which is served on most flights, increases the risk of dehydration.

DVT can happen anywhere. Lack of movement on a long train trip or car journey could also bring it on. However, the length of some flights and the relatively cramped seat conditions can make flying a more likely cause for some people.

Warning signs
Signs can be slight and mistaken for numbness or cramp, but you may feel a hot, painful or swollen leg. If cramp does not resolve after movement, seek medical advice without delay. Try to avoid flight related DVT. Everyone should follow these points when flying:

  • Move around occasionally in the cabin and seat - don't let your legs get too cramped or immobile.
  • Whilst sitting, exercise calf muscles by flexing and rotating ankles every half hour.
  • Avoid excess alcohol and caffeinated drinks (coffee, tea, some soft drinks) before and during flight.
  • Drink water (for example, a glass each hour), or non-caffeinated drinks and juices.

Additional precautions for higher risk groups
The above precautions should be taken by all air passengers. However, the following three levels of higher risk groups need to take additional precautions, in addition to those listed above:

Minor: Age 40+; very tall/short/obese; previous/current leg swelling for any reason; recent minor leg injury or body surgery; extensive varicose veins. In addition to the normal precautions outlined above, people with any of these conditions should keep sleep breaks short (no pills), and possibly consider wearing support stockings.

Moderate: Pregnancy; on contraceptive pill; recent major leg injury or surgery; recent heart disease; hormone medication/HRT; family DVT history. These people should seek professional medical advice. They should discuss with a doctor the taking of low dose aspirin and wearing compression stockings.

Substantial: Previous or current DVT; known clotting tendency; recent major surgery or stroke; current malignant disease or chemotherapy; paralysed lower limbs. These people should consider avoiding or postponing their flight and should seek medical advice. If they do travel, they should undertake all of the above precautions and should see a doctor about taking low molecular weight heparin instead of aspirin.

quote for travel insurance

CLUB DIRECT (UK) LIMITED. Reg. No. 4573579. Registered in England and Wales. Reg. Add: Cutlers Exchange, 123 Houndsditch, London, EC3A 7BU.

Club Direct (UK) Limited trading as Club Direct is a specialist travel insurance intermediary which is authorised and regulated by the Financial Conduct Authority under registration number 311886.

The products offered on this site are only available to United Kingdom residents.