According to a study that tracked more than 2.6 million people from Sweden and which was published Sept. 5 in Circulation: Cardiovascular Genetics, tall men are significantly more likely to develop potentially dangerous blood clots in their leg veins than their more down-to-earth (more accurately, closer-to-the-earth) brothers.
Why is that a problem?
Because if a part of a blood clot in a deep vein of the leg breaks off, like all blood parts, it then travels north up towards the heart, and if it makes it out of the heart on that circular route that blood travels throughout the body, it can then lodge in the lungs, and that is a potentially huge (read: life-threatening) problem.
In the lungs, that clot becomes what’s called a pulmonary embolus, and pulmonary emboli can kill you.
Those are the always media-hyped cases of young people dying suddenly from what is commonly called economy class syndrome, after they’ve developed a clot from prolonged sitting in a cramped space (this has little to do with economy class, of course, cuz it also happens in business class, and horrors! even first class).
So yes, you want to avoid a deep vein clot in the legs (aka a deep vein thrombosis or DVT).
Since you can’t really do anything about your height, the best advice is to consider this as just one more risk factor to account for when in a situation (flying,
long car trip, etc) that raises the risk of clotting (other risk factors are being on certain medication such as most notoriously birth control pills, having had a clot previously, being significantly overweight, smoking, and others).
But even if you are not a tall person, you should still always make sure in a confined space for a long time to move around a lot or at the very least do some flexing exercises.