Deep vein thrombosis (DVT) is a potentially dangerous type of blood clot that develops in the deep veins of the legs, torso, or arm. These clots can grow, break off, and travel through the bloodstream to the lungs and cause a life-threatening condition known as pulmonary embolism.
DVT has also been called "economy class syndrome," as sitting still for long periods of time, such as on transoceanic flights, can increase the risk of these clots occurring.
Although these results indicate the stockings are effective at reducing the risk of deep vein thrombosis during long flights, researchers say frequent flyers shouldn't view wearing the stockings as a substitute for following other preventive measures.
According to Aviation Health, risk factors specific to air travel include:
- Cramped position
- Dehydration from excessive use of alcohol
- Compression of the leg veins by the edge of the seat
- Seated posture (especially when sleeping)
They suggest simple steps that can be taken to reduce the risk of developing a DVT:
Try to keep your thighs clear of the edge of your seat by keeping your feet up on the leg rests at the highest elevation or resting your feet on your hand luggage.
- Exercise during the flight by moving around the aircraft cabin or by using a leg exerciser.
- Drink plenty of water to avoid dehydration. Avoid too much alcohol.
- Wear elastic flight socks or support stockings (this is particularly important for passengers with varicose veins).
- Walk briskly for at least half an hour before takeoff.
Stockings Cut Clot Risks
In the study, which appears in the current issue of the Journal of Advanced Nursing, researchers analyzed the results of recent studies on knee-length graduated compression stockings and the risk of deep vein thrombosis conducted in Italy and the U.K.
The nine studies included in the analysis involved nearly 2,500 flyers over a two-year period.
The results showed that two of the 1,237 participants who wore the compression stockings developed deep vein thrombosis after a long flight compared with 46 of the 1,245 passengers who didn't wear the stockings. The authors concluded that a passenger not wearing graduated compression stockings was 12.5 times more likely to develop DVT.
Researchers say wearing the compression stockings appeared to be effective in reducing the risk of deep vein thrombosis, but the stockings did little to reduce the risk of clots developing in smaller veins in the body, a condition which rarely causes serious complications.