DVT: are you at risk?

by Kate Shapland

One of the catalysts to the development of Legology was – curiously enough – our feet. I’m passionate about leg health and beauty, but I was also fascinated by the way feet and ankles (and lower legs) swell when we travel, particularly when we fly. I felt this issue hadn’t been adequately addressed. And it was one of the reasons I was compelled to develop Air-Lite, my first and hero product.

One of the very few studies in understanding fluid retention on long haul flights and the risk of blood clots was done in 2003 by a group of researchers in the US. With more and more people flying for work or recreation, the incidence of a condition called Deep Vein Thrombosis (DVT) had sky-rocketed.

The risk of DVT appears to increase with exposure to more flights within a short time frame and with increasing duration of flights. Incidents appear to be highest in the first two weeks after travel and gradually decrease to baseline after eight weeks.

DVT is said to be particularly high in people under the age of 30, women who use oral contraceptives and individuals who are particularly short, tall or overweight.

In the past few years, interest has focused on a possible causal link between DVT and long-haul flights. Earlier studies (prior to 2000) were mainly done under simulated conditions without the high humidity levels on real flights and without the lower oxygen levels that are present on the aircraft as it travels at thousands of metres above earth.

Even in simulated study conditions the average fluid accumulation is around 130mls in the lower leg and ankles after 12 hours of flying.

As the world begins to open up again and some of us may be travelling more – or even if you sit all day with your legs hanging down or you stand a lot – then this study matters. With the variety of measurements that were conducted in the study on flying and fluid retention, the researchers found considerable retention of fluid in both lower extremities and the head. They measured skin thickness in the forehead, the tibia (front of shin) and just above the ankle. A number of bloods were taken to look for clotting changes and subjects were allowed to drink one glass of alcohol. They ate the meals and drank the water offered with meals.

Not one person showed signs of DVT. But what researchers did find was something even more interesting and especially important for those who exercise a lot as well as those of you who are experiencing swollen ankles during your menopause transition. Researchers found that all the subjects retained water in the superficial tissues, thus increasing the thickness of the tissue on average 1.5mm. This calculated to fluid retention in each lower leg of about 190mls. That’s a lot of fluid! Over 1/3 of the superficial layer just under your skin consists of water that is continually exchanging in deeper tissues and cells, so this superficial layer was affected the most.

What was most important however was this fluid hung around for several days after a flight. This is what increases blood viscosity or thickness. And it’s this that promotes blood clotting or thrombosis for at least a week after a long-haul flight.

The recommendation by the researchers is that all travellers on long-haul flights should wear individually adjusted support stockings before and after the flight. At least invest in a pair of flight socks and apply Air-Lite Daily Lift For Legs before pulling them on (it’s usually best to do this before you leave for the airport). I would also add that, if you are standing all day, and have been experiencing swollen ankles and fluid retention, then invest in some support stockings or socks to wear everyday with your Air-Lite as well. Especially as you begin to exericse again and stimulate your lymphatic system.

And while researchers have found that fluid retention in lower extremities (and the head) stays around for a few days, and risk for clots and blood pooling remains high, it’s super important to start being active again as soon as possible after flying to shift that fluid and improve blood flow back to the heart.