Since the jet age took flight, the specter of blood clots on airplanes has cast a shadow over travel excitement. For years, health advice has often included a recommendation to pack compression socks for your journey. But is this travel essential truly necessary, or just another piece of travel hype?
“Using them is absolutely okay,” states Dr. Joshua Beckman, a leading expert in vascular medicine at UT Southwestern Medical Center in Dallas. However, he points out that scientific evidence doesn’t definitively quantify the benefits for travelers. So, while Travel Circulation Socks might be on many packing lists, let’s explore the real story behind their effectiveness.
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Understanding Travel Circulation Socks
Travel circulation socks, also known as graduated compression socks or stockings, are designed to apply pressure, strongest at the ankle and gradually decreasing up the leg. This graduated compression is intended to encourage healthy blood flow, assisting blood in the legs to return more efficiently to the heart. The idea is to combat the risks associated with prolonged periods of sitting, especially during long flights.
The Real Risks: Deep Vein Thrombosis (DVT) and Flying
Deep vein thrombosis (DVT) is a serious condition where blood clots form in large veins, typically in the legs. According to the American Heart Association’s most recent data from 2020, an estimated 666,000 people in the U.S. were hospitalized with DVT. Furthermore, 432,000 were hospitalized for pulmonary embolism (PE), a condition where a clot travels to the lungs. Collectively, these conditions are known as venous thromboembolism (VTE), and in 2021, they were linked to nearly 81,000 deaths.
Symptoms of DVT can include leg pain, swelling, and skin that feels unusually warm. Pulmonary embolism symptoms are more severe, featuring shortness of breath, coughing, and chest pain.
Research indicates that long-haul flights can increase the likelihood of VTE by 1.5 to four times, as highlighted in a 2021 Cochrane Database of Systematic Reviews update. However, it’s crucial to remember that while the risk increases, the overall occurrence of these dangerous clots remains relatively low for air travelers.
A 2007 research review in the Journal of Internal Medicine estimated only 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 calculated to be around 1 in 4,600 flights.
Who is at a Higher Risk of Blood Clots During Travel?
Dr. Eri Fukaya, a vascular medicine specialist at Stanford University, emphasizes that while flying can create a “perfect storm” for clot formation, individual risk factors play a more significant role.
Certain individuals are predisposed to a higher risk of VTE. These include older adults, smokers, people with obesity, and those with a family history of blood clots. Individuals with a prior history of clots, recent cancer treatment, or those taking estrogen are also at elevated risk.
Dr. Fukaya uses an analogy of a bucket to explain risk levels. People with pre-existing risk factors have buckets that are already partially filled. For them, air travel might be the factor that causes the bucket to overflow, leading to a blood clot.
Immobility during long flights, exacerbated by cramped seating, is a contributing factor. Dehydration, often caused by reduced water intake to avoid bathroom trips, can also thicken the blood, further increasing risk.
The Scientific Challenge: Studying Travel Circulation Socks
Despite the theoretical benefits, proving the effectiveness of travel circulation socks through scientific studies is challenging due to the low baseline risk of blood clots in air travelers.
Dr. Beckman points to a 2022 study in the American Journal of Obstetrics and Gynecology: Maternal-Fetal Medicine focusing on pregnant and postpartum women, a high-risk group. While the study showed a slightly increased VTE risk for women who flew compared to those who didn’t (0.07% vs. 0.05%), Dr. Beckman emphasizes the difference was “very tiny.”
These small numbers illustrate why it’s statistically difficult to demonstrate a significant impact of compression socks on blood clot prevention in 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,” Beckman explains.
The Cochrane review, analyzing data from 2,918 participants across 12 trials, found “high‐certainty evidence” that compression stockings reduce the risk of asymptomatic DVT during flights longer than four hours. However, the review couldn’t draw conclusions about death, pulmonary embolism, or symptomatic DVT because these events were absent in the study participants.
Expert Guidelines and Recommendations
The American Society of Hematology guidelines do not recommend travel circulation socks for low-risk travelers on short flights. They suggest considering them for longer flights only for individuals identified as high-risk for blood clots.
Dr. Beckman notes that hospital studies confirm the effectiveness of compression socks in preventing blood clots for post-surgical patients. However, for non-surgical patients on bed rest, the benefits are less clear. He argues that if establishing benefit is difficult for sick, bedridden hospital patients, it’s even more challenging to prove effectiveness for healthy, mobile travelers.
However, if a doctor recommends compression socks for specific health reasons, Dr. Beckman stresses that it’s “absolutely” important to follow that medical advice.
Practical Advice for Healthy Travel
For most travelers concerned about blood clots, Dr. Beckman’s primary advice is simple and effective: “Get up and walk every couple of hours. Drink lots of water.”
Dr. Fukaya adds to this, suggesting seated exercises: “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.”
Personal Experiences and Choosing Your Socks
Even with the limited definitive scientific proof for travelers, Dr. Fukaya is personally a proponent of travel circulation socks. She wears them regularly, stating, “I wear them almost every day,” after starting to understand her patients’ experiences. She found, “my legs feel a lot better wearing them.”
She points out that compression has been used for its potential benefits since ancient times. The socks can stimulate calf muscles during movement and help reduce swelling.
For those interested in trying travel circulation socks, Dr. Fukaya suggests experimenting to find what works best. Various types are available, from those marketed for athletes to medical-grade options. Medical-grade socks are rated by pressure (millimeters of mercury), but Dr. Fukaya finds these ratings less critical, comparing it to restaurant spice levels: “mild, medium or spicy?”. She recommends starting with a “medium” compression and adjusting based on comfort. Trying a sock on one leg only can also help gauge personal benefit. She suggests knee-high socks and cautions against rolling down any excess length, which can create a tourniquet effect.
Focus on Overall Travel Health
Dr. Beckman concludes that while travel circulation socks are acceptable for those who find them comfortable, travelers should prioritize broader health concerns. Sunscreen, for instance, is a definite essential.
“There are so many things that people have to think about” for health protection while traveling, he says. It’s important to focus on proven strategies and avoid overemphasizing interventions with unclear benefits for low-risk individuals.
In conclusion, while the scientific jury is still out on the definitive benefits of travel circulation socks for preventing blood clots in air travelers, they are generally harmless and may offer some benefit, especially for high-risk individuals or those seeking to reduce leg swelling. Staying hydrated, moving regularly during flights, and performing simple leg exercises are evidence-based strategies that all travelers can adopt to promote healthy circulation.
