How to Use the Flight DVT Prevention Timer
Sitting in a cramped seat for hours slows blood flow in your legs, raising the risk of deep vein thrombosis (DVT), sometimes called economy class syndrome. This calculator uses your flight duration and risk level to recommend how often you should get up, walk, and move to reduce that risk.
As a general guideline, walk the aisle or stand up at least every 2 hours on flights of 4 hours or longer. Travelers at higher risk — pregnant, obese, with varicose veins, or recovering from recent surgery — should move about every hour instead. While seated, flexing your ankles up and down every 30 minutes also helps keep blood circulating.
Staying hydrated and limiting alcohol or caffeine can further reduce clot risk, and compression stockings are often recommended for higher-risk travelers. This tool provides general guidance only — talk to your doctor about a prevention plan that fits your personal health history before a long flight.
Frequently Asked Questions
It refers to deep vein thrombosis (DVT), where blood clots form in the leg veins after sitting for a long time in a cramped seat. In severe cases the clot can travel to the lungs and cause a pulmonary embolism, so prevention matters on long flights.
Risk generally starts increasing after about 4 hours of flying, and on flights over 8 hours, regular movement and stretching are strongly recommended.
Pregnant travelers, people with obesity, varicose veins, a history of blood clots, recent surgery, or those taking oral contraceptives are considered higher risk and should move more often and consider compression stockings.