Here's a post for the traveling runner. A couple of years ago I noticed that my ankles and calves started to swell during long flights, so much so that the swelling would sometimes warrant a visit to the clinic and/or massage therapist a day or two after landing. Feeling a little nervous about these recent bouts of travel-induced swelling, I decided to search the internet for tips on how to prevent this from happening on future flights. The following brief article offered some great information and advice:
http://www.wellsphere.com/triathlon-article/runners-could-be-more-prone-to-leg-blood-clots-on-planes/505393.
Runners could be more prone to leg blood clots on planes
Posted Nov 21 2008 10:04am
FYI: I ordered a pair of these stockings from Amazon, and within just a few hours of traveling from Naha to Narita, my legs had ballooned! I had to rush to the bathroom at Narita airport and pull them off. I then spent the next half hour or so walking around the terminal to get my blood re-circulating, and then a further half hour massaging my calves and lying on the floor with my feet up on a chair. Anna suggested that the stockings may have been a size too small, but I had purchased a size larger than usual, to err on the side of caution. Maybe they were still the wrong size, but I won't be trying these again.
http://www.amazon.com/gp/product/B0000AKONA/ref=oh_details_o03_s00_i01

The latest thinking goes like this:
This according to Dr. Lewis G. Maharam one of the world’s premier running physician. He is also medical director of the New York Road Runners, ING New York City Marathon.