Venous pooling occurs due to lack of sympathetic activity and loss of active muscle function in the lower extremities and trunk musculature in persons with a spinal cord injury. This produces a smaller venous blood return to the heart, thus reducing stroke volume and cardiac output. To decrease this effect during exercise, an abdominal binder can be worn. This produces increased intra-abdominal pressure to help prevent redistribution of blood to the abdomen and lower extremities. This, in turn, helps prevent orthostatic hypotension (a sudden drop in systolic blood pressure greater than 20 mm Hg or a drop in diastolic blood pressure greater than 10 mm Hg resulting in nausea, dizziness, or fainting when in an upright position). The binder also helps with breathing.