Blood clot risk persists days after flying
The risk of venous thromboembolism (VTE) doubles after a flight of more than four hours, research shows.
The risk remains high for a week after landing, making multiple flights in a short period a potential hidden hazard for passengers.
In a report on the danger of clots from long-haul travel, the World Health Organization (WHO) said the absolute risk for healthy people after a four-hour flight was low, at one in 6000.
The risk was higher for people with prothrombotic blood abnormalities, oral contraceptive users, the obese, and people who were short (<1.6 m) or tall (>1.9 m). Venous thromboembolism risk remained high for a week after a long flight, WHO found.
