Flying, especially long-haul flights, has always come with concerns about blood clots. For years, travelers have been advised to consider wearing compression socks to mitigate this risk. But are travel compression stockings truly necessary for every journey?
According to Dr. Joshua Beckman, a leading expert in vascular medicine at UT Southwestern Medical Center, using Travel Stockings Compression is “perfectly fine.” However, he points out that scientific evidence doesn’t definitively quantify how much these stockings genuinely benefit travelers in preventing blood clots.
Travel stockings compression, also known as graduated compression socks, are designed to apply pressure strongest at the ankle and gradually decrease up the leg. This compression is intended to encourage healthy blood flow, assisting blood in the legs to return to the heart more efficiently.
Deep vein thrombosis (DVT), a condition involving blood clot formation in a deep vein, often in the leg, is a serious health concern. In the U.S. alone, approximately 666,000 individuals were hospitalized for DVT in 2020, according to the latest statistics from the American Heart Association. Furthermore, pulmonary embolism (PE), where a clot travels to the lungs, led to 432,000 hospitalizations. Collectively, these conditions, known as venous thromboembolism (VTE), were linked to nearly 81,000 deaths in 2021.
Symptoms of DVT can include leg pain, swelling, and skin warmth, while PE may manifest as shortness of breath, coughing, and chest pain.
Research indicates that long-distance air travel can increase the likelihood of VTE by 1.5 to four times, as highlighted in a Cochrane Database of Systematic Reviews review.
Despite this increased risk, it’s important to remember that the occurrence of dangerous blood clots remains relatively low. A 2007 study published in the Journal of Internal Medicine estimated about 4.8 severe pulmonary embolism cases per million flights exceeding 12 hours. The risk of DVT within four weeks of a flight of at least four hours was calculated to be approximately 1 in 4,600 flights.
Dr. Eri Fukaya, a vascular medicine specialist at Stanford University, explains that flying can create a confluence of factors that may contribute to clot formation. However, she emphasizes that individual risk factors play a more significant role.
Certain individuals are inherently at a higher risk of VTE. These include older adults, smokers, individuals with obesity, or those with a family history of blood clots. People with a prior history of clots, recent cancer treatment, or estrogen use are also at increased risk.
Dr. Fukaya uses an analogy of a bucket to illustrate risk. Individuals with pre-existing risk factors have a bucket already partially filled. Air travel might be the additional factor that causes the bucket to overflow, leading to a blood clot.
Prolonged immobility, characteristic of long flights in cramped seating, is a contributing factor. Dehydration, often resulting from reduced fluid intake to avoid frequent bathroom breaks during flights, can also thicken the blood and elevate risk.
Nevertheless, Dr. Beckman reiterates that the risk of developing severe blood clots solely due to flying remains statistically low, making definitive studies challenging.
He references a 2022 study in the American Journal of Obstetrics and Gynecology: Maternal-Fetal Medicine focusing on pregnant and postpartum women, a high-risk group for VTE. While the study showed a slightly elevated risk in women who flew compared to non-flyers (0.07% vs. 0.05%), Dr. Beckman describes this difference as “very tiny.”
These minute risk differences underscore the difficulty in definitively proving the effectiveness of travel stockings compression for flyers. “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,” Dr. Beckman states.
The Cochrane review, analyzing data from 2,918 participants across 12 clinical trials, found “high‐certainty evidence” that travel compression stockings do reduce the risk of asymptomatic DVT during flights longer than four hours. However, the review couldn’t draw conclusions about their impact on death risk, pulmonary embolism, or symptomatic DVT due to the absence of these events in the trial participants.
The American Society of Hematology guidelines suggest against routine use of travel stockings compression for low-risk travelers on short flights. They recommend considering them for longer flights only for individuals identified as high-risk for blood clots.
Dr. Beckman acknowledges that hospital studies demonstrate the effectiveness of compression socks in preventing blood clots in post-surgical patients. However, their benefit for non-surgical, bedridden patients is less conclusive. He argues, “if it’s hard to establish in sick people at bed rest in a hospital, then it is very, very hard to establish a benefit for ambulatory people who are well and going on vacation in a plane or even a car.”
Despite the limited definitive evidence for the general flying population, Dr. Beckman emphasizes that if a doctor recommends travel stockings compression for an individual, they should “absolutely” follow that advice.
For travelers concerned about blood clots, his primary recommendation is straightforward: “get up and walk every couple of hours. Drink lots of water.”
Dr. Fukaya concurs and adds simple exercises that can be performed while seated: “flex your calf muscles and roll your ankles around in big circles, both directions. Then take off your shoes, and wiggle your toes. All of that motion gets the blood moving.”
For those who already use and appreciate travel stockings compression, there’s no compelling reason to stop.
Dr. Fukaya, while acknowledging the lack of robust scientific consensus for all travelers, is personally a proponent of compression stockings and wears them regularly.
She notes that compression therapy has historical roots and that travel stockings compression can stimulate calf muscles during movement and aid in preventing leg swelling.
“I wear them almost every day,” Dr. Fukaya shares, explaining that her personal experience led her to discover that “my legs feel a lot better wearing them.”
However, she cautions that individuals with poor circulation due to peripheral artery disease should use travel stockings compression with care. For others, experimenting to find what works best is advisable.
The market offers a wide variety of travel stockings compression, from those marketed to athletes to medical-grade options. Medical-grade stockings are categorized by pressure levels (mmHg), but Dr. Fukaya finds these ratings less critical, citing variability in actual pressure and lack of standardized regulation.
She suggests a practical approach: “It’s kind of like going to a restaurant and saying, ‘Do you want mild, medium or spicy?'” Starting with a medium compression level and adjusting based on comfort and perceived benefit is reasonable.
Dr. Fukaya even suggests a simple self-experiment: “You could 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 stockings over thigh-high versions and advises against rolling down knee-high stockings if they are slightly too long, as this can create a tourniquet effect.
Dr. Beckman concludes that while travel stockings compression are acceptable for those who find them comfortable, focusing on other health aspects during travel is more critical. Sunscreen, for instance, is a more universally recommended travel essential.
“There are so many things that people have to think about” for health protection, he states. “It’s also important to get them to not have to think about things they don’t need to think about.”
