There are a number of factors in any form of long distance travel which may increase the risk of a thrombosis these include:
Immobility
Passengers, particularly those not seated in aisle seats, may remain immobile for long periods of time. The return of blood from the legs to the heart is greatly slowed down as a result. The reduced blood flow increases the chances of a clot.
Dehydration
Passengers who experience dehydration will have a reduced blood volume, the blood is thickened and more likely to clot. Dehydration can result from the very dry air in most aircraft, the consumption of alcohol and to a lesser extent coffee and tea. Also from the inadequate intake of water and non-alcoholic drinks.
Hypoxia
The reduced cabin pressure and oxygen levels in aircraft makes airline travel a much greater risk than travel at ground level.
To avoid a DVT
Wear compression socks and exercise the legs to encourage blood flow through the veins and keep well hydrated. (please see your GP for advice regarding taking medication such as asprin).
