Previously thought to affect only air travellers and dubbed 'economy class syndrome' research now suggests that DVT can affect anyone seated in a confined space for longer periods.
Dr Emile Ferrari, a French cardiologist published a report last year that any journey of four hours or more carries the risk of blood clots, regardless of the means of transport. A study of 160 patients admitted for DVT found that 28 had a history of recent travel by car, nine by aircraft and two by train.
Last week a consultant at Addenbrooke's Hospital, Cambridge cited the case of a student who developed DVT after travelling from Leicester to Aberdeen in a friend's Mini.
Edmund King, executive director of the RAC Foundation, said: 'People making long journeys by car should take some sensible precautionary measures, which can also help avoid fatigue.'
RAC Foundation medical consultant Dr Tony Lavelle said: 'Although there is little hard evidence linking DVT to car travel there have been cases of elderly people in coaches suffering from this.
'Drivers should stop more often, using this opportunity to walk around, drink more water and not to drive when feeling tired or sleepy.'
How to minimise DVT risk