If you’ve been on an airplane recently, and if your trip lasted for more than seven hours, you may remember that the flight attendants warned you at the beginning of the trip about the risk of getting deep vein thrombosis (DVT) and told you to do exercises with your calf muscles to keep this from happening.
DVT is the formation of a blood clot in a “deep vein,” a vein that is deep inside the body (as opposed to veins that are close to the body’s surface). Usually DVT occurs in a leg vein. If the clot embolizes–that is, if it starts traveling through the blood stream–there is the risk of it blocking arteries within other organs and severely damaging them. Often the lungs are affected, and when this happens the blood clot is called a pulmonary embolism. DVT is sometimes also called deep venous thrombosis.
Often people get DVT by sitting in one place for a long time, such as on plane rides, which is why flight attendants give you that warning. Sitting in one place for a long time can be bad for circulation, while exercise increases it and discourages formation of blood clots.
All of this has been common knowledge among medical professionals for some time. But a new study shows that the risk of DVT on long plane flights is greater than was previously confirmed: on long-haul airplane flights (7 hours or longer), the risk of DVT is roughly tripled. In the study, the mean age of the participants was 40, which makes the researchers suspect that the risk is actually greater in the general population. They do not recommend drugs to pre-empt DVT for most travelers, but say that such measures may be warranted in rare cases of extremely high-risk individuals. Ordinary passengers should take care to follow the crew’s instructions for calf exercises, and also get up and walk around every so often.
For more information:
Dvt.net: Protection and Treatment, with prevention guides, checklists and suggestions for in-flight fitness.