Preventing Blood Clots (Deep Vein Thrombosis) during Air Travel

Stay healthy on your next trip with tips from Rebalance Sports Medicine, your destination for physiotherapy and compression socks in downtown Toronto.

Understanding Deep Vein Thrombosis (DVT)

Planning your winter vacation? Before you board that long flight, it’s important to be aware of a common travel-related health risk: Deep Vein Thrombosis (DVT). A DVT occurs when a blood clot forms in a deep vein, most often in the legs. These clots can block blood flow, causing pain, redness, and swelling. In some cases, the clot can travel to the lungs, leading to a pulmonary embolism (PE), a serious medical emergency.

Your leg veins return blood to the heart against gravity. They rely on tiny valves and the pumping action of your calf muscles that push blood upward, much like squeezing a tube of toothpaste. In fact, your calf muscles account for nearly 90% of the blood flow returning from your lower legs. When you’re inactive for long periods, that pumping system slows down and blood can start to pool, increasing the risk of clots.

Why Air Travel Increases the Risk of Blood Clots

Sitting for more than four hours, especially on a plane (where you’re crammed into a small space), reduces leg movement and muscle activity. Add the lower cabin pressure during flights, and your legs and feet can swell even more. You might have even noticed passengers struggling to put their shoes back on after landing, that’s mild edema (swelling) from fluid buildup due to reduced venous return. When blood becomes sluggish, clots can form. If these clots travel to the lungs, they can cause a pulmonary embolism, which may result in shortness of breath or loss of consciousness.

Anyone can develop a DVT, but the risk increases for those who are:

Smokers
Taking oral contraceptives
Pregnant
Over 60 years old
Overweight or diabetic
With a personal or family history of blood clots

Simple Steps to Prevent DVTs While Traveling

The best way to prevent DVTs is to keep your legs moving and support circulation during travel.

Move frequently. Stand up, stretch, or walk around the cabin every hour if possible. If you can’t get up, perform ankle pumps (move your feet back and forth) and heel raises while seated.
Wear compression socks. Properly fitted compression socks improve blood flow and help prevent swelling and clots. They apply gentle, graduated pressure (strongest at the ankle and gradually decreasing up the leg) to keep blood moving effectively.

Get Custom Compression Socks at Rebalance

At Rebalance Sports Medicine in downtown Toronto, our physiotherapists provide professional fittings for custom compression socks and hosiery. In a 15-minute visit, we’ll measure your legs and help you choose from a variety of styles, from sheer options to fine wool ski socks and pregnancy pantyhose.

We offer different compression levels:

10–15 mmHg and 15–20 mmHg: Non-prescription options for travel and daily use
20–30 mmHg or higher: Medical-grade compression often covered by extended health benefits

Compression socks aren’t just for flying, they’re also beneficial for anyone who stands or sits for long periods, including office workers, nurses and doctors, and flight attendants.

Book a Physiotherapy Appointment

If you want to learn more about preventing DVTs or are interested in finding the best sitting compression socks for you, contact us to book an appointment with one of our experienced physiotherapists. We’ll help you select the right compression level and fit for your needs, and teach you how to maintain healthy circulation for travel and daily life.

Pro Tip: Remember to wear your compression socks on the plane, not pack them in your luggage! Many travelers have arrived at their destination with swollen ankles because their socks were in cargo instead of on their feet!

References

Meissner, MH. Lower extremity venous anatomy. Semin Intervent Radiol 2005; 22: 147-56.
Alimi YS, Barthelemy P, Juhan C. Venous pump of the calf: a study of venous and muscular pressures. J Vasc Surg 1994;20:728-35.