Deep Vein Thrombosis: the “Economy Class Syndrome”

At this point it’s very likely that you have already heard or read more than once about the so-called “economy class syndrome”, which probably sounds like something quite serious that could potentially happen when travelling by plane, especially under the conditions of cheapest fares.

The truth is that naming it this way is quite confusing, mainly because this was an unfortunate designation that was invented and popularised by the tabloids. This brought a whole set of wrong beliefs and misunderstandings around it, which I will try to clarify today.

This syndrome is related to the development of a deep vein thrombosis (DVT) in the lower limbs during – or immediately after – travelling a long flight. Deep vein thrombosis (DVT) happens when a clot develops inside one of the main veins of the deep vein system in the lower limbs. Usually, the thrombus starts immediately behind one of the venous valves, and then it grows until occluding the vein (totally or partially). Then, it can continue growing and extending like a chain reaction along the whole vein. This situation, as it hinders the returning venous blood flow, causes edema (swelling) of the limb, but its real threat comes from the possibility of it causing a pulmonary embolism.

Commercial flights nowadays usually give little room for every passenger in the cabin (and that way, more passengers fit in on each flight, great business!), so there is hardly enough place to move the legs. This space is usually less in economy class than in first or business class.

The relative immobility of the legs during long flights means slow venous blood flow. This often leads to swollen ankles or leg heaviness after a long travel. However, occasionally, a passenger presents a real deep vein thrombosis (DVT) as a result of this situation.

The confusion associated with this unfortunate name, and the advertisement that mass media made of this idea at that time, has led many people to wonder if indeed this happens only when traveling in economy class, and if they would be free from this risk if traveling in first class. About this, I would like to point out the following:

• It is not yet completely clear whether the pressure changes that occur inside the aircraft cabin at flying heights may also have an influence on the possibility of developing a deep vein thrombosis (DVT). If ultimately proven to be so, then both passengers traveling in economy and in business or first classes would be under the same risk factor.
• The real risk factor is the lack of movement of the lower limbs. Because of this reason, both passengers traveling in economy and business classes are advised to practice certain leg exercises – to avoid them to be immobile during all flight – and take a little walk around the plane at least once every two hours. The best exercise for this purpose, very simple to do, is the movement of pressing and releasing the pedals of the car: through this, we are contracting the calf muscles (the gastrocnemius and the soleus), which are the ones having the best ability to “milk” our deep veins, and thus to help moving the venous blood flow in an upwards direction.
• The truth is that the development of a deep vein thrombosis (DVT) while traveling is not even privilege of flights: people traveling long distances by car or bus without getting up to move the leg muscles from time to time, may also present with a deep vein thrombosis (DVT) for exactly the same reasons.
• It is generally true that in economy class a passenger has less room to move his legs than in first class, but the key for prevention in both cases is exercises and mobilization.
• High-risk individuals (patients who already suffered a deep vein thrombosis before, or presenting other risk factors for DVT) are also often advised to use compression stockings during the flight. And even under some circumstances we advise the use of certain medications (usually subcutaneous heparin injections) prior to flight, although this is becoming increasingly rare. In any case, as usual, when in doubt you should consult it to your doctor.