Recent study revealed that person sitting on the window seat faces double risk of developing a deep vein thrombosis (DVT) as compared to those sitting on the aisle or in a middle seat. A DVT clot can cause death if it passes through a passenger's bloodstream to the lungs, causing pulmonary embolism.

Research team from Leiden University Medical Centre found that obese people have six times higher risk of developing a blood clot when seated by the window. Hence obese passengers should prefer to sit either in the middle or aisle seats.

Research team said that an hour sleep can reduce the risk of developing a DVT during a long journey by air. Findings also indicated that flying business class reduces the risk of a DVT by 30 per cent. The risk of blood clot is also reduced by single alcoholic drink.