SIT (seated immobility thromboembolism) syndrome: a 21st century lifestyle hazard.

The association between prolonged seated immobility and venous thromboembolism (VTE) is well recognised in relation to travel. In this case series, we report the occurrence of deep vein thrombosis (DVT) or pulmonary embolism (PE) following prolonged sitting in relation to work and/or recreation. The cases were characterised by the considerable length of time the individuals sat, the extensive nature of the VTE events in young individuals without other recognised risk factors, and the lack of recognition by the attending doctors of seated immobility as the likely major risk factor. While recognising that the association may be coincidental rather than causal, we propose the acronym 'SIT' (seated immobility thromboembolism) syndrome to encompass all forms of seated immobility associated with VTE.