For Australians, international travel almost always means long-haul flights. Whether you're heading to Europe, the Americas, or Asia, you'll likely spend many hours confined to an aeroplane seat. This extended immobility creates perfect conditions for leg swelling and increases the risk of deep vein thrombosis. Compression socks have become an essential travel accessory for frequent flyers and first-time long-haul travellers alike.
Why Flying Affects Your Legs
The unique environment inside an aeroplane creates multiple challenges for your circulatory system. Understanding these factors helps explain why compression socks are so valuable for air travel.
Reduced Cabin Pressure
Commercial aircraft cabins are pressurised to the equivalent of approximately 1,800 to 2,400 metres altitude. At this reduced pressure, gases in your body expand and tissue fluid distribution changes. This contributes to the swelling many passengers experience during and after flights.
Immobility
Sitting in a cramped aeroplane seat for hours severely limits your ability to move. When you're not walking or moving your legs, the calf muscle pump that normally assists venous return becomes largely inactive. Blood tends to pool in the lower legs, increasing pressure in the veins and promoting fluid leakage into surrounding tissues.
Dehydration
Cabin air is extremely dry, typically 10-20% humidity compared to the 30-65% we experience on the ground. This dry environment promotes dehydration, which thickens blood and makes it more prone to clotting. Combined with immobility, dehydration significantly increases the risk of venous complications.
The Perfect Storm
The combination of reduced pressure, immobility, and dehydration creates conditions that significantly increase the risk of leg swelling and blood clots. Compression socks address the immobility factor by mechanically supporting blood return even when you can't move around.
Understanding Deep Vein Thrombosis (DVT)
Deep vein thrombosis is a blood clot that forms in a deep vein, typically in the legs. While anyone can develop DVT, the conditions during long flights increase risk for all travellers. DVT is sometimes called "economy class syndrome," though it can occur in any seating class and isn't limited to air travel.
Risk Factors for Travel-Related DVT
- Flights longer than four hours
- Previous history of DVT or blood clots
- Recent surgery, especially hip or leg surgery
- Use of oestrogen-containing medications (birth control pills, HRT)
- Pregnancy or recent childbirth
- Cancer or cancer treatment
- Inherited clotting disorders
- Obesity
- Age over 40 (risk increases with age)
- Varicose veins or chronic venous insufficiency
Know the Symptoms
Symptoms of DVT may include swelling in one leg (usually), pain or tenderness (often described as a cramp), warm skin, and redness, especially at the back of the leg below the knee. If you experience these symptoms during or after a flight, seek medical attention promptly.
How Compression Socks Help
Compression socks work during flights by providing several key benefits that counteract the negative effects of prolonged sitting:
Maintaining Blood Flow Velocity
By gently squeezing your legs, compression socks reduce the diameter of your veins. This narrowing increases the velocity of blood flow, helping prevent the stagnation that can lead to clot formation. Blood that moves quickly is less likely to clot than blood that pools.
Reducing Swelling
The external pressure from compression socks limits the amount of fluid that can accumulate in your leg tissues. Many travellers notice a dramatic difference in their ankle and calf size after long flights when comparing experiences with and without compression socks.
Supporting Venous Valves
The compression helps your venous valves close properly, preventing blood from flowing backward and pooling in lower portions of your legs.
Choosing Compression Socks for Travel
Not all compression socks are ideal for flying. Here's what to look for when selecting travel compression socks:
Compression Level
For most healthy travellers, compression socks rated 15-20 mmHg provide effective protection without being overly restrictive. If you have existing venous issues or additional risk factors, your doctor might recommend 20-30 mmHg. Avoid going higher than 20 mmHg without medical advice, especially if you'll be wearing them for many hours.
Length
Knee-high compression socks are the most popular choice for travel. They're easy to put on and remove in tight spaces and provide protection to the areas most affected by sitting. Thigh-high options exist but offer limited additional benefit for most travellers and can be more cumbersome to manage.
Material
Look for moisture-wicking fabrics that will keep your feet comfortable during long flights. Some travel-specific compression socks include antimicrobial properties to control odour. Avoid compression socks made entirely of cotton, as they can become damp and uncomfortable.
Travel Sock Features to Consider
Look for socks with cushioned soles for added comfort, seamless toe construction to prevent irritation, and colours that complement your travel wardrobe if you prefer a polished look.
How to Use Compression Socks for Flights
Before Your Flight
- Put on your compression socks in the morning before your legs start to swell
- If you have a late flight, elevate your legs for 15-20 minutes before putting on the socks
- Ensure the socks are pulled up smoothly without wrinkles or folds
- Wear comfortable, loose-fitting trousers or skirts that won't create additional pressure points
During Your Flight
- Keep your compression socks on for the entire flight
- Flex your feet and ankles regularly, even while seated
- Walk the aisle when the seatbelt sign is off
- Stay hydrated by drinking water regularly
- Avoid crossing your legs, which can impede blood flow
- Choose an aisle seat if possible for easier movement
After Your Flight
- Continue wearing your compression socks for several hours after landing
- Walk around as much as possible at your destination
- Elevate your legs when resting
- Stay hydrated as your body readjusts
Flight Compression Checklist
- Choose 15-20 mmHg compression for most travellers
- Put socks on before leaving for the airport
- Wear throughout entire flight and several hours after
- Move feet and ankles regularly during flight
- Walk the aisle when possible
- Drink plenty of water
- Avoid alcohol and excessive caffeine
Additional Strategies for Healthy Flying
While compression socks are highly effective, combining them with other strategies maximises your protection:
- Seat exercises: Rotate your ankles, pump your feet up and down, and periodically tense and relax your calf muscles
- Hydration: Drink water throughout the flight; a good rule is one cup per hour of flight time
- Limit alcohol and caffeine: Both contribute to dehydration
- Avoid sleeping pills: They may cause you to remain immobile for extended periods
- Dress comfortably: Avoid tight waistbands, belts, or constrictive clothing
- Request an aisle seat: Makes it easier to get up and move around
Special Considerations for High-Risk Travellers
If you have multiple risk factors for DVT or have experienced blood clots in the past, consult with your doctor before long-haul travel. They may recommend higher compression levels, prescription anticoagulants, or both. Some travellers with very high risk may need to consider alternatives to extended flights.
Pregnant women should discuss travel plans with their healthcare providers, as pregnancy increases DVT risk. Compression stockings are often recommended for pregnant travellers, but the appropriate compression level should be determined with medical guidance.