Physical activity, immobilization and the risk of venous thrombosis

Deep venous thrombosis is a common disease. Already in 1856 it was suggested that immobilization could cause venous thrombosis. However, so far little research has shown whether exercise or ambulation could decrease the risk of venous thrombosis. We performed a historical review regarding the role of venous thrombosis risk in the change of the practices regarding ambulation after delivery. We could not find well-performed studies showing that early ambulation reduced venous thrombosis risk. Furthermore we performed two studies on the relation between participating in physical activity and venous thrombosis risk. In one case-control study in the Netherlands we showed that exercise decreases the risk of venous thrombosis. However, in a cohort study in elderly people from the USA, we showed that exercise seemed to increase this risk. A possible explanation for this difference might be due to an increased risk of injuries among elderly people as we showed that injuries increase the risk of venous thrombosis 5 fold. Furthermore we showed that for the very rare thrombosis of the arm, sports activities which highly involve the arm result in an increased risk. In summary, although immobilization seems to increase venous thrombosis risk, it is unclear whether mobilization or exercise decrease this risk.