DVT is a serious condition where blood clots develop in the deep veins of the legs. It should be distinguished from blood clots in superficial varicose veins in the legs, called phlebitis, which is much less serious.

One in every hundred people who develop DVT dies. The cause of death is usually a blood clot, travelling from the legs to the lungs. This is called pulmonary embolus or PE. When PE is severe it causes the lungs to collapse and heart failure.

What causes DVD?

Flying causes fluid in the blood to move into the surrounding blood vessels and the clotting mechanism gets switched on. Eating foods rich in saturated fat can encourage this process. As does any alcohol and caffeine, which are all dehydrating. Think of what is on your meal-tray during the flight - cheese, pats of butter, creamy sauces, sausage, bacon, croissants, all rich in saturated fats. Some airlines are taking steps to offer lighter options - but it is up to you to make your own choices, complain to airlines, eat before you fly etc. What are DVD-friendly flight options?

If you can, take your own food with you on board. Oily fish (salmon, sardines, tuna); soups, fruits and vegetables; butter free, salad sandwiches are ideal (use a olive oil based dressing instead; also water, (a glass every hour); fruit salad and anything water-rich.

Treatment

Aspirin in low doses, can act as a blood thinning drug and is used to prevent clotting conditions in the arteries like coronary thrombosis. Its benefit in preventing DVT is debatable however and if you are unsure ask a qualified medical doctor. DVT combined with PE or other blood clots is often referred to as Venous Thrombo-Embolism or VTE.

According to government sources, DVT has been associated with any form of long distance travel, whether by air, car, coach or train. In particular long-haul air travel (flights lasting longer than five hours) where passengers remain immobile in the seated position for long periods of time, may be associated with an increased risk.

Who is most at risk?

People with heart conditions.
Pregnant women.
Women taking HRT or anything containing Oestrogen compounds (ie contraceptive pill).
Anyone with a family history of DVT.

The risk of DVT and PE is greater in those...

over 40
if you have had blood clots already
with a family history of blood clots
suffering from or who have had treatment for cancer
with certain blood diseases
being treated for heart failure and circulation problems
who have had recent surgery especially on the hips or knees
who have an inherited clotting tendency.

Consult your doctor before travelling if you have:

ever had a DVT or PE
a family history of clotting conditions
an inherited tendency to clot (thrombophilia)
cancer or had treatment for cancer in the past
had major surgery in the last three months
had hip or knee replacement within the last three months or
ever suffered a stroke.

Some airlines are introducing simple instructions during your flight to encourage movement during your journey. These are usually movements of the feet that stretch the calves, many people ignore this advice.

Yoga Exercise

If you can, stand up and do some yoga stretches, even if you have to queue for the toilets and do them in there.

Preferably standing in bare feet, lift the heels off the floor and come up on the toes. At the same time rise the arms in the air, overhead. Do this 20 times in all, using the in-breath to rise and the out-breath to lower. Next, pointing the toes away from the body lift the leg a few inches off the floor and rotate the ankle, 10 times in a clockwise direction and 10 in an anti-clockwise direction, change feet and repeat on the other side.

If possible, do these every hour, as well as practicing periodically in your seat, avoiding the arm raises!

Turn your head to the extreme right, 3 times and 3 times to the extreme left, with your shoulders pressed against the back of the seat. Hold the arms straight out in front, one at a time. Make twisting movements from the shoulders, 10 times each side.

Flight socks:

These are next to useless unless they have been measured specifically for you. Some people buy the socks at an airport, and make the mistake of thinking they can eat what they like and not make any movements for several hours.

This reply was written with the help of the British government website on this important subject.

http://www.doh.gov.uk/blood/dvt/index.htm