Travelling far distances by car, bus, plane, or train is not always fun. Did you know it can even have a harmful impact on your health, too? Long-distance travel, especially by car, taxi, or bus, can increase the risk of blood clot formation, a condition known as deep vein thrombosis (DVT).

In many instances, people sit still in cramped and confined conditions for hours when they’re travelling a far way. But warns Dr Helen Okoye, a medical expert and spokesperson for the World Thrombosis Day (WTD) campaign, prolonged periods of inactivity can be dangerous.

“When our bodies are in a static position for a lengthy period, our blood circulation slows down, leading to poor circulation and blood pooling in the lower extremities of your body. This can lead to a DVT, where a blood clot forms in your calves,” says Dr Okoye. If this clot breaks loose, it can travel to the lungs, causing a potentially life-threatening condition called a pulmonary embolism (PE).

If the vehicle you’re travelling in is packed with passengers, there may be no room to stretch your legs out. The driver may also be on a tight schedule, meaning limited bathroom stops and opportunities to stretch your legs during the trip.

Dr Okoye cautions that constricted seating that leads to passengers sitting in one position for a long time reduces blood flow and increases the risk of clot formation. “When your legs remain still for hours, your calf muscles don’t contract, which normally helps the blood circulate,” she says.

Who is at risk?

Although prolonged immobility is bad for everyone, specific factors could raise the risk even more. Individuals with a history of blood clotting disorders, who are elderly or obese, who have recently had surgery, or who have a leg cast with limited mobility are at a higher risk. Pregnancy, or three months after giving birth, places women at a higher chance of getting a thrombosis, too.

“Going back home after giving birth or having had surgery so that loved ones can take care of you is understandable, but be aware of the thrombosis risk that comes with long-distance travelling,” says Dr Okoye