Deep Vein Thrombosis (DVT)
Also known as: Economy class syndrome, Travel thrombosis, Blood clot, VTE (Venous thromboembolism)
DVT is a blood clot in a deep vein, usually in the leg, that can develop during long-haul flights or extended immobility.
Last updated: 2 April 2026
Real-world example
After a 14-hour flight from London to Singapore, you notice your left calf is swollen, warm, and painful. At a clinic in Singapore, an ultrasound confirms a DVT. You're started on blood thinners immediately. If the clot had broken loose and reached your lungs (pulmonary embolism), it could have been fatal.
Why travellers need to know
DVT risk increases on any journey over 4 hours where you're immobile: flights, buses, trains, or cars. Risk factors include previous DVT, recent surgery, pregnancy, oral contraceptives, obesity, and age over 40. Simple prevention measures (walking the aisle hourly, ankle exercises, hydration, compression socks) reduce risk significantly. Travellers on blood thinners or with clotting disorders should consult their doctor about flight-specific precautions.
Country-specific notes
Longest common flight routes increase DVT risk
Flights to Australia from Europe (22-24 hours) and the US East Coast (20+ hours) are among the longest in commercial aviation. Australian health authorities actively promote DVT awareness for inbound long-haul passengers.
Tip
Request an aisle seat for flights over 8 hours so you can walk the cabin hourly without disturbing others.
Frequently asked questions
How Nomedic helps
Your Nomedic record includes clotting risk factors, current medications, and contraceptive use, so any doctor can assess your DVT risk accurately.
Your health records, anywhere you go
Your risk factors, visible before the flight.
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