Travelling by air is now a way of life. There has been a lot of recent publicity about deep vein thrombosis of the legs following long-haul travel (economy class syndrome), although it was first described over 50 years ago. Research suggests that the risk of DVT is doubled by flying for more than 4 hours, but statistically a fit individual would have to fly long-haul every day for 15 years to get the condition. The risk of this is increased by being overweight, being very tall or short, taking hormonal medication, having an inherited tendency to blood that clots too quickly, or taking multiple or very long flights. Interestingly there is no evidence that the relative decompression or dehydration associated with jet travel leads to DVT. Far more important is being immobile for long periods which can lead to pooling of blood in the leg veins and then clot formation, regardless of whether travel is by air, rail or car.
Deep vein thrombosis may not cause any symptoms at all, but calf tenderness or swelling within the first week of travel is a common complaint. Occasionally there may be associated chest pain or breathlessness which is suggestive of a pulmonary embolus, when part of the clot moves from the leg to the lungs. Most patients with DVT are treated with warfarin, a blood-thinner, for at least 3 months.
Many airlines now give general advice which may help prevention of flight-induced DVT. Moving and stretching calf muscles at regular intervals, avoiding a cramped position due to hand luggage placed in front of you, and maintaining good hydration with regular non-alcoholic drinks are often mentioned in flight brochures. Walking up and down the aisle may seem like a good idea too, but carries a small risk of injury from unexpected turbulence!