Venous stasis, or venostasis, is a condition of slow blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 flow in the veins, usually of the legs. A patient with venous stasis might be more vulnerable to the formation of blood clot, especially in the deep veins of the legs, called deep vein thrombosis

Deep vein thrombosis

Deep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...

 (DVT).

Causes include long periods of immobility such as when driving for long distances. It has been called the coach-class

Economy class

__FORCETOC__Economy class, also called coach class , steerage, or standard class, is the lowest class of seating in air travel, rail travel, and sometimes ferry or maritime travel....

 syndrome because of prevalence in long distance travel in cramped space. It also occurs in prolonged bed rest

Bed rest

Bed rest is a medical treatment involving a period of consistent recumbence in bed. It is used as a treatment for an illness or medical condition, especially when prescribed or chosen rather than resulting from severe prostration or imminent death...

with an illness or after surgery.