Passengers stuck in their seats for more than four hours are twice as likely to develop a potentially life threatening blood clot, according to research published Friday by the World Health Organization, WHO.
The risk of venous thromboembolism, VTE, also rises for air travellers undertaking frequent flights over a short period, but the study stated the danger still remains relatively low at about one in 6,000 people.
The research was carried out following the death of a young English woman who died after flying back from Australia in 2000. She suffered a pulmonary embolism when a blood clot lodged in her lung.
Hours of immobility increased the risk of blood clotting, said the report, with the effect lasting up to four weeks after a journey. Obesity and height might also play a part during travel.
"The study does confirm that there is an increased risk of venous thromboembolism during travel where the passenger is seated and immobile over four hours, whether in a plane, train, bus or car.
"However, it is important to remember that the risk of developing VTE when travelling remains relatively low," said Dr Catherine Le Gales-Camus, WHO Assistant Director-General for Noncommunicable Disease and Mental Health.
