Long-Haul Flight Risk: How a Blood Clot Can Turn Deadly Within an Hour

A 28-year-old woman collapsed 40 minutes after a 14-hour flight, as a blood clot that formed in her leg during the journey traveled to her lungs. This condition, known as pulmonary embolism, occurs when a clot blocks an artery in the lung, preventing normal blood flow and putting strain on the heart.

Doctors caution that while the risk of pulmonary embolism after a long flight is low for healthy individuals, it should not be ignored, especially for those with risk factors. Dr Virender K. Sheorain, associate director of Peripheral Vascular and Endovascular Sciences at Medanta, Gurugram, explains that prolonged immobility during flights lasting more than four hours can slow blood flow in the deep veins of the legs, increasing the chance of deep vein thrombosis (DVT).

DVT itself may not cause immediate harm, but the real danger arises if a part of the clot breaks off and travels to the lungs. Contrary to a common misconception, standing or walking after landing does not trigger a clot to move; in fact, movement improves circulation and reduces clot formation.

Symptoms of DVT include swelling, pain, tenderness, warmth, or redness in one leg. If a clot reaches the lungs, symptoms such as sudden shortness of breath, chest pain, coughing up blood, rapid heartbeat, or fainting may occur. Anyone experiencing these after prolonged travel should seek emergency medical attention.

Treatment depends on severity and may include blood-thinning medications, clot-dissolving drugs, catheter-based or surgical removal, and oxygen therapy. Preventive measures include standing and walking every one to two hours, performing ankle and calf exercises while seated, staying hydrated, and avoiding prolonged immobility. Those with risk factors should consult a doctor before long journeys, as they may need compression stockings or preventive medication.