People who spend long hours sitting in front of a computer screen risk developing life-threatening blood clots as was recently reported by researchers. Deep vein thrombosis is a condition in which a blood clot forms in the deep veins of the legs. It can be fatal when part of the clot breaks off and blocks a blood vessel in the lungs. In view of the widespread use of computers in relation to work, recreation and personal communication, the potential burden of thrombosis may be considerable. This may be similar to the situation of blood clot risk with air travel where the real extent of the problem was not recognised until publicised. A team of researchers from the New Zealand Medical Research Institute, diagnosed a life-threatening case of this type of clot in a 32-year-old man who regularly spent up to 12 hours a day using his computer, often going hours without standing up. The man had no other risk factors for the condition, known as venous thromboembolism, in which blood clots that form in immobile limbs travel to the lungs. The patient originally developed painful swelling in his calf, which cleared up after 10 days, according to the report. For the next four weeks he had increasing trouble breathing, which culminated in him losing consciousness and being admitted to the hospital. He recovered after treatment with the blood-thinning drugs heparin and warfarin. With the current state of knowledge it would seem prudent to advise all individuals who commonly sit for prolonged periods at a computer to undertake frequent leg and foot exercises and take regular breaks for mobilisation away from the computer. It is very common for people sitting still for a few hours to get tiny clots, and when they walk these disappear. But continued sitting for long periods might allow the clot to grow and the leg might swell. A bit of the clot might break off and go to the lung. For most fit young people, sitting at a desk would probably not be enough to trigger a dangerous blood clot but when added to other risk factors like a leg fracture in the past or some co-existing illness, there may be a risk of developing a serious blood clot.

European Respiratory Journal January 2003 Vol. 21:374-376