Long-haul flights and extended car travel are a known risk factor for deep vein thrombosis (DVT) — a blood clot that forms in the deep veins of the legs. Compression socks are one of the most effective and accessible tools for reducing this risk. Here's what you need to know before your next trip.
Why does travel cause swollen legs and DVT risk?
During long periods of sitting, the calf muscles — which normally act as a pump to return blood to the heart — become inactive. Blood pools in the lower legs, causing swelling, heaviness, and discomfort. In some people, particularly those with additional risk factors, this pooling can lead to clot formation in the deep veins.
Risk factors for travel-related DVT include:
- Flights or journeys longer than 4 hours
- Previous DVT or family history of clotting disorders
- Pregnancy
- Oral contraceptive use
- Recent surgery or hospitalisation
- Obesity
- Cancer or active inflammatory disease
- Dehydration
How do compression socks help?
Graduated compression socks apply firm pressure at the ankle that gradually decreases up the leg. This graduated pressure squeezes the veins, increasing blood flow velocity and reducing pooling in the lower limb. Studies consistently show that graduated compression socks significantly reduce the incidence of travel-related DVT and symptomatic leg swelling on long-haul flights.
What compression level do I need for travel?
- 15–20 mmHg (Class 1) — suitable for most healthy travellers for DVT prevention and general leg comfort
- 20–30 mmHg (Class 2) — recommended for people with varicose veins, history of DVT, or significant leg swelling
- 30–40 mmHg (Class 3) — therapeutic grade, requires a prescription and medical supervision
For most travellers, 15–20 mmHg is sufficient and comfortable enough to wear throughout a long-haul flight.
How to wear travel compression socks correctly
Put compression socks on in the morning before you get up, or at least before swelling develops — they're much harder to put on once your legs are already swollen. Wear them throughout your journey and for several hours after arrival. Remove them if you experience numbness, tingling, or skin discolouration.
If you have poor circulation, peripheral arterial disease, or significant peripheral neuropathy, consult your GP or podiatrist before wearing compression garments.
Additional tips for preventing travel-related leg swelling
- Get up and walk the aisle every 1–2 hours on long flights
- Do calf raises and ankle circles while seated
- Stay well hydrated — dehydration thickens the blood
- Avoid alcohol and caffeine in excess, as both contribute to dehydration
- Choose an aisle seat to make it easier to move
Browse our range of compression and circulation products including OS1st travel socks, performance foot sleeves, and compression bracing sleeves. All products are podiatrist-recommended and available with fast delivery across Australia.
Disclaimer: This article is for general information only. If you have a personal or family history of DVT or clotting disorders, consult your GP before travel.