Updated: Jan 2
There are many risk factors for developing a deep vein thrombosis (DVT). A DVT is a blood clot in the deep veins of the lower extremities, although it can occur anywhere in the venous system.
Long distance travel is a risk factor for DVT. This is due to stagnation of blood secondary to prolonged immobility as a result of long-distance travel.
These clots can occur anywhere, but most commonly in the leg veins.
DVTs are very serious. The clot may travel up the vascular system, into the lungs and potentially cause life threatening problems. This potentially fatal blockage of blood flow to the lung is known as a pulmonary embolism (PE).
Common risk factors for DVT include the use of oral contraceptives, sitting in a window seat (prolonged immobility), advanced age, and pregnancy.
Flying economy class, the so called “economy class syndrome” has been thought to be a risk factor for developing a DVT. However, there is no definitive evidence that flying in economy class will increase the risk of developing a DVT.
It is not flying in economy class that is the risk factor, it is the long term immobility that increases the likelihood of developing a DVT.
This myth of “economy class syndrome” can safely be put to rest.
So what is the actual risk factor for developing a DVT due to long distance travel?
Very low. But not zero! Some estimates put that risk at 1 in 6000.
Although most travelers are unlikely to develop a DVT as a result of long distance travel, there are certain risk factors that can increase your risk significantly and are worth knowing about.
- Previous DVT or known clotting disorder
- Recent traumatic injury
- Prolonged immobility prior to travel
- Older age
- Taking birth control pills
Sitting in a window seat is thought to increase your risk because theoretically you are less likely to get up and move around during the flight.
Although it makes sense and has been recommended, dehydration or alcohol consumption during your flight have not been definitively shown to increase your risk of developing a DVT. However, alcohol consumption (along with coffee) can lead to dehydration. Further, drinking alcohol may decrease your mobility on the flight and increase your risk, hence it is recommended to avoid alcohol and stay hydrated.
The risk for travel related DVT increases on flights that are 6 hours or longer. It is important to get up and walk frequently, and when sitting to stretch your calf muscles regularly.
Compression stockings can help alleviate swelling in the legs. Although there is no definitive proof that travelers with no known risk factors for developing a DVT gain any benefit from wearing them, there is really no downside to wearing compression stockings. Hence, there is no reason not to wear them.
Should you take aspirin before your flight?
Aspirin, also known as acetylsalicylic acid, is a nonsteroidal antiinflammatory drug (NSAID) with antipyretic (fever reducing), analgesic (pain relief), and antiplatelet activities (blood clot prevention). These effects are dose-dependent.
Low doses have antithrombotic effects, intermediate doses have antipyretic and analgesic effects and high doses have antiinflammatory effects.
Aspirin has been suggested to prevent DVT during long distance travel due to its antithrombotic effects. The majority of this data come from patients who have orthopedic surgery.
Unfortunately, it is extremely difficult to extrapolate the findings in patients who had a hip fracture and apply that to long-distance travelers.
Patients with hip fractures are usually treated with aspirin for several days. In a traveler, would a single dose of aspirin offer any protection? And if so, what is the optimal dose of aspirin?
Without any definite evidence that there is benefit in taking aspirin for long distance travel, is it really worth the risk of taking a medication that has potential for causing complications such as bleeding?
These are the questions that have yet to be definitively answered.
However, despite the lack of clear evidence some recommend taking a baby aspirin (81 milligrams) for those who have no contraindications, about an hour prior to takeoff.
We DO NOT agree with this. It would be wise to discuss this option with your doctor as part of your pre-travel planning.
Other preventive measures
- Wear comfortable clothing
- Don’t crossing your legs while seated
- Walk! Walk! Walk! At least once an hour when possible
- Stay hydrated, avoid coffee and alcohol
For travelers that are known to be high risk for DVT
In this specific group, if considering long distance travel which includes a flight that is longer than 6 hours it may be worthwhile to discuss anticoagulation therapy for DVT prevention with your doctor as part of your trip planning.
Take away points:
Clearly we have much to learn about DVT prevention for long distance travelers and some of these recommendations may be modified over the years as we learn more. Aspirin has not been shown to be effective, but these other common sense recommendations mentioned above can help reduce your risk.
Please remember that medical information provided by us must be considered an educational service only. This blog should not be relied upon as medical advice and does not replace your physician’s independent judgement. Please seek the advice of your physician regarding any issues related to your health.