Are Travel Pressure Socks a must-have for your next flight? For years, travelers have been cautioned about the potential risks of blood clots during air travel, and compression socks have often been suggested as a preventative measure. But how effective are they really?
While “it’s perfectly fine to use them,” according to Dr. Joshua Beckman, a leading expert in vascular medicine at UT Southwestern Medical Center in Dallas, the scientific evidence supporting their widespread use for all travelers is not definitive. He clarifies that the exact extent of their benefit for air travelers remains somewhat uncertain.
Compression socks, also known as graduated compression stockings, are designed to apply pressure at the ankle and gradually decrease it up the leg. This compression is intended to promote healthy blood flow, aiding the return of blood from the legs back to the heart. This mechanism is particularly relevant when considering the risks associated with prolonged periods of immobility, such as during long flights.
Deep vein thrombosis (DVT), a condition where blood clots form in large veins, typically in the legs, is a serious concern. According to the latest statistics from the American Heart Association, approximately 666,000 people in the U.S. were hospitalized with DVT in 2020. Furthermore, pulmonary embolism (PE), which occurs when a clot travels to the lungs, led to 432,000 hospitalizations. Venous thromboembolism (VTE), encompassing both DVT and PE, was cited as a contributing factor in nearly 81,000 deaths in 2021.
Symptoms of DVT can include leg pain, swelling, and skin that is warm to the touch. Pulmonary embolism may manifest as shortness of breath, coughing, and chest pain. Extended air travel has been identified as a risk factor for VTE, increasing the likelihood by 1.5 to four times, as highlighted in a comprehensive review of research from the Cochrane Database of Systematic Reviews.
However, it’s crucial to contextualize these risks. While the increased risk is statistically significant, the absolute occurrence of dangerous blood clots remains relatively low. A 2007 research review published in the Journal of Internal Medicine estimated approximately 4.8 cases of severe pulmonary embolism per million flights exceeding 12 hours. The risk of DVT within four weeks of a flight of at least four hours was estimated at 1 in 4,600 flights.
Dr. Eri Fukaya, a vascular medicine specialist at Stanford University, points out that flying can indeed create conditions that are conducive to clot formation, describing it as potentially “a perfect storm for a clot.” However, she emphasizes that individual risk factors play a more significant role.
Certain pre-existing conditions and lifestyle factors significantly elevate the risk of VTE. These include older age, smoking, obesity, and a family history of blood clots. Individuals with a prior history of blood clots, recent cancer treatment, or those using estrogen-containing medications are also at increased risk.
Dr. Fukaya uses the analogy of a bucket to explain these risk factors. Individuals with multiple risk factors have a “bucket” that is already partially filled. In such cases, air travel, with its associated immobility and potential dehydration, might be the “overflow” trigger that leads to a blood clot.
Immobility during long flights is a key concern. Sitting in cramped conditions for extended periods reduces blood circulation in the legs. Furthermore, some travelers may consciously limit fluid intake to avoid frequent bathroom breaks, which can lead to dehydration and potentially thicker blood, further contributing to the risk.
Despite these theoretical risks, quantifying the specific contribution of air travel to severe blood clots remains challenging due to the low baseline risk, according to Dr. Beckman.
He references a 2022 study in the American Journal of Obstetrics and Gynecology: Maternal-Fetal Medicine, which examined VTE risk in a high-risk group – pregnant and postpartum women. While the study found a slightly elevated risk of VTE in women who flew compared to those who did not (0.07% versus 0.05%), Dr. Beckman emphasizes that the difference was “very tiny.”
These low numbers underscore the difficulty in definitively proving the effectiveness of travel pressure socks in preventing blood clots in air travelers. “If the risk is really low, and you go from really low to really, really low, you can’t have enough people in a study to actually figure it out,” Beckman explains.
The Cochrane review, which analyzed data from 2,918 participants across 12 randomized clinical trials, provided “high‐certainty evidence” that compression stockings reduce the risk of asymptomatic DVT during flights longer than four hours. However, the review could not draw conclusions about the impact on death, pulmonary embolism, or symptomatic DVT due to the absence of these events in the study participants.
Current guidelines from the American Society of Hematology do not universally recommend compression socks for air travel. They advise against them for low-risk travelers on short flights and suggest considering them for longer flights only for individuals at high risk of blood clots.
While studies in hospital settings have demonstrated the effectiveness of compression socks in preventing blood clots in post-surgical patients, Dr. Beckman notes that the benefits are less clear for non-surgical patients on bed rest. He argues that if establishing a clear benefit is challenging even for hospitalized, bedridden patients, it is even more difficult to demonstrate a significant benefit for healthy, mobile individuals traveling by plane or car.
Nevertheless, Dr. Beckman stresses that if a physician recommends compression socks for an individual, they should “absolutely” follow that advice.
For most travelers concerned about blood clots, Dr. Beckman’s primary recommendation is simple and practical: “get up and walk every couple of hours. Drink lots of water.”
Dr. Fukaya concurs and adds specific exercises that can be performed while seated. She recommends flexing calf muscles and rotating ankles in “big circles, both directions.” Additionally, she suggests removing shoes and wiggling toes to further stimulate blood circulation.
For those who already use and find comfort in travel pressure socks, both experts agree there’s no harm in continuing to use them.
In fact, Dr. Fukaya personally uses them regularly, stating, “I wear them almost every day.” Her personal experience led her to discover that “my legs feel a lot better wearing them,” particularly in reducing swelling and fatigue.
She notes that compression therapy has a long history and that compression socks can aid in stimulating calf muscles and preventing swelling. However, she cautions that individuals with peripheral artery disease and poor circulation should use compression socks with care.
Dr. Fukaya encourages individuals to experiment with different types of travel pressure socks to find what works best for them. She explains the market offers a wide range of options, from those marketed towards athletes to medical-grade socks. Medical-grade socks are categorized by pressure levels (millimeters of mercury), but she finds these ratings less critical in practical use. She likens choosing compression levels to choosing spice levels at a restaurant: “mild, medium or spicy?” She suggests starting with a medium compression level and adjusting based on comfort and perceived benefit.
A practical way to test effectiveness, according to Dr. Fukaya, is to “wear it on one leg and not the other and see if one leg feels better than the other at the end of travel.” She recommends knee-high socks as opposed to thigh-high versions and advises against rolling down knee-high socks if they are too long, as this can create a tourniquet effect.
In conclusion, while travel pressure socks may offer a degree of benefit, especially for high-risk individuals and in reducing asymptomatic DVT, maintaining adequate hydration and regular movement during flights are arguably more impactful and universally recommended strategies for preventing blood clots. For low-risk travelers, focusing on these fundamental measures and enjoying the journey may be more beneficial than stressing about packing compression socks. As Dr. Beckman humorously points out regarding essential travel health priorities, “There are so many things that people have to think about… It’s also important to get them to not have to think about things they don’t need to think about,” perhaps suggesting that for many, the peace of mind from packing sunscreen is more critical than debating the necessity of travel pressure socks.
