The term ‘Economy Class Syndrome’ refers to the occurrence of thrombotic events during long-haul flights that mainly occur in passengers in the economy class of the aircraft. This syndrome results from several factors related to the aircraft cabin (immobilization, hypobaric hypoxia and low humidity) and the passenger (body mass index, thrombophilia, oral contraceptives or hormone replacement therapy, cancer), acting together to predispose to excessive blood coagulation, which can result in venous thromboembolism.
The actual incidence of venous thrombo-embolism in air travel is unknown. It is difficult to arrive at an estimation given that this condition may be asymptomatic or may develop days or even weeks after the flight. In a cohort of healthy subjects, the absolute risk of VTE on flights lasting more than 4 hours was 1 in 6000. A meta-analysis involving 14 studies reported 4055 cases of VTE in trips lasting up to 8 h. These studies included both air and overland trips with the follow-up time after the journey ranging from two to eight weeks. The relative risk of VTE was 2.8 and at each increment of 2 h in travel time, there was an approximate 18% increase in the risk of VTE. Considering only air travel, this risk increased to 26%, suggesting a cumulative effect of flight time in the genesis of VTE.
MacCallum et al. demonstrated that on flights lasting less than 4 h, the risk of VTE is approximately two times higher compared to non-traveler subjects and remained high in the four subsequent weeks. In long-haul flights (greater than 12 h as one or more flights), the risk of VTE is around three times higher.
(Data gathererd from article in Brazilian Journal of Hematology and Hemotherapy
: Economy class syndrome: what is it and who are the individuals at risk? Luci et al)
Things you can do to reduce your DVT risk while planning long haul travel.
Short, 2-3 hour flights should not be a problem, but a long flight , may be a 12-hour flight can be, especially if you are sitting motionless the whole time. Here are some tips to help reduce your risks:
1. Walk around as much as possible.
To reduce your DVT risk, you can take “mini-breaks” by standing up and walking in the airplane every couple of hours. Use bathroom to wash your face may be once in a while.
2. Keep good hydration.
High-altitude flying, long waiting and journey tends to dehydrate you, make sure to bring along a bottle of water and sip from it often.
3. Avoid alcohol and sleeping pills.
However tempting it may be to have a few drinks or take a pill to help you sleep, both hinder your circulation and in turn increase your DVT risk.
4. Wear compression stockings.
Your vein doctor or local pharmacist can recommend medical-grade compression stockings to wear during your flight. These stockings put gentle pressure on the leg muscles and improve circulation. This is especially helpful if you suffer from varicose veins
5. If you have varicose veins, have them assessed.
Even if you don’t have visible varicose veins but know that you are at increased risk, because they run in the family, see your vein doctor and get an examination.