Oddly, runners may be susceptible to deep vein blood clots because of efficient vascular systems

Dear Running Doc:

I just participated in the Las Vegas Rock 'n' Roll Marathon last weekend. I, like many, had lots of nausea and vomiting after the race. Then I flew home to NYC and had leg pains and saw my doctor and he found deep vein blood clots in my legs. I have run 6 matathons a year for 20 years and I am just 40 years old and healthy. Was it the dehydration or are runners more susceptible to these clots? Stephen G., NYC, NY.

Dear Stephen: I've been wondering the same thing. In the past year, I have had 10 runners with no risk factors experience the same thing. There is nothing written linking running, dehyration and deep vein thromboses (DVTs), but given what I've observed, I do have some ideas.

DVTs are blood clots that develop in the deep vein of the leg. This can be very serious because the clot can break off, travel to the lung, and cause severe breathing difficulty and even death. Treatment includes initial hospitalization, anti-clotting meds by IV, then a regimen of anti-clotting meds for months out of the hospital until the clot is totally dissolved.

Usually DVTs form after prolonged inactivity. Runners just may be the most active people we know, so initially it does not make sense that there would be an increased frequency amongst traveling runners. Physicians recognize such risk factors for DVTs as long flights of inactivity, bed rest after surgery, birth control pills, clotting disorders, cancer, smoking, heart disease, obesity, family history of DVT, and pregnancy. Symptoms of DVT are pain and swelling. If you flex your foot upward and have calf pain, that is called a positive Homan's sign and indicative of a DVT. If in doubt, you should be checked by a physician immediately and get venous studies to look for this serious problem.

The runners I mentioned earlier had none of the risk factors except the long flights, which one would think they could handle from their running. Could runners' bodies be more susceptible?

I truly think it is possible. Runners' bodies adapt to running by making their leg vascular system more efficient: larger veins and arteries. So if you sit for a long time and are scrunched in an airplane seat, the blood can pool in your larger leg veins, and clot. That-- coupled with the edge of the seat pushing on the back of your knee, preventing or slowing venous return--could be all you need to set up a clot.

What can you do to prevent a clot from forming? On flights of three hours or more:

* Do not sit in one position for more than an hour. Get up and walk every so often.

* Do calf stretches once an hour, standing and leaning against a bathroom wall.

* Stay well-hydrated. As I always say, check your urine color: you want lemonade color; not clear, and not brown like iced tea.

* Avoid crossing your legs at the knees and ankles.

* Wear graduated-compression stockings (the so-called TED stocking you can buy at your local pharmacy).

* If your doctor permits, take one baby aspirin four to six hours before your flight. It mildly prevents clotting as it does for heart patients.

If you do the above, you may prevent a clot in your well-adapted legs en route to your next race.

As to your nausea and vomiting after an evening race, that had nothing to do with your clot. In fact this is a very common complaint at all evening events, incuding Disney's Wine and Dine. The reason is that most do not practice eating and running a long run in the evening and are used to morning runs and morning eating habits. So waiting all day and having regular meals result in "something new" for your body during a long run. Next time you do an evening race, practice eating and training with evening runs, and I bet you won't feel nauseas again.


Lewis G. Maharam, better known as the Running Doc™, is the author of Running Doc's Guide to Healthy Running. He is the past medical director of the NYC Marathon and Rock 'n' Roll Marathon series and is Medical Director of the Leukemia & Lymphoma Society's Team in Training program. He is also past president of the New York Chapter of the American College of Sports Medicine. Learn more at runningdoc.com.

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