Deep Vein Thrombosis

What is deep vein thrombosis?

Deep vein thrombosis (DVT) is the formation of blood clots in major deep veins, commonly in the thigh or calf.
Deep vein thrombosis has been linked to long distance travel and is also colloquially known as economy class syndrome.

It is important to realise that it is not just long distance air travel that puts people at risk. Sitting in one position for too long is a major factor, which means the popular label “economy class syndrome” can also arise in business class, or during long car, bus or train journeys – prolonged inactivity is the real problem.

What causes deep vein thrombisis (DVT)?

Blood clots are formed when blood stops moving and coagulates.

When blood clots outside a blood vessel, this is a normal process which protects the body against losing blood following minor accidents and cuts. If the blood clots inside a blood vessel however (as with DVT), this can be dangerous.

The risk while flying is increased because of the reduced cabin pressure at high altitudes, which causes fluid to pass from the blood vessels into the surrounding tissue, causing thickening of the blood. Normal movement of the calf muscle when walking helps to pump blood from the legs to the heart, but with the loss of fluid while sitting for long periods, the blood can thicken, coagulate and form a clot in the deep veins of the leg.

Symptoms of DVT

In most cases of DVT, the clots are small and do not cause any symptoms. The body is able to gradually break down the clot and there are no long-term effects.3

Larger clots may partially or totally block the blood flow in the vein and cause symptoms:

 

• Swelling of the calf – this is usually different from the mild ankle swelling that many people get during long haul flights for example1,3
• Pain in the calf3
• Calf pain that is noticeable, or worse when standing or walking3

What are the risk factors for DVT?

The risk factors include:

 

• Blood clotting disorders
• Varicose veins
• Cancer
• Heart failure
• Pregnancy
• Use of estrogen-containing medications
• Recent surgery or trauma
• Smoking
• Being overweight (body mass index > 27)
• Age over 40 years
• Prolonged immobility

Deep vein thrombosis prevention tips

Steps to help prevent DVT on long airline fights and during long car, train or bus travel include:

 

• Do ankle and knee exercises every half hour while seated
• Walk down the aisles regularly, or if travelling by car, stop frequently, get out and take a walk
• Wriggle toes frequently
• Dink plenty of water (one litre every five hours)
• Go easy on alcohol and caffeine
• Take aspirin (if advised by your doctor)
• Wear knee-high compression stockings (if advised by your doctor)

Compression stockings are favoured by many long distance travellers to reduce the risk of blood clots. Wearing a compression stocking counteracts the loss of fluid into the tissue of the leg, and so reduces the risk of clotting. Some doctors are now routinely recommending these stockings to people over the age of 40 who will be travelling for more than five hours.

Travelooce is NOT a medical advice website – please consult your doctor for specific advice.