What is hypovolemia? Hypovolemia is a decrease in the volume of blood in your body, which can be due to blood loss or loss of body fluids. Blood loss can result from external injuries, internal bleeding, or certain obstetric emergencies. Diarrhea and vomiting are common causes of body fluid loss. Fluid can also be lost as a result of large burns, excessive perspiration, or diuretics. Inadequate fluid intake can also cause hypovolemia. At the onset of hypovolemia, the mouth, nose, and other mucous membranes dry out, the skin loses its elasticity, and urine output decreases. Initially, the body compensates for the volume loss by increasing the heart rate, increasing the strength of heart contractions, and constricting blood vessels in the periphery while preserving blood flow to the brain, heart and kidneys. With continuing volume loss, the body loses its ability to compensate and blood pressure drops. At this point, the heart is unable to pump enough blood to vital organs to meet their needs and tissue damage is likely to occur. Hypovolemic shock occurs when a fifth of the blood volume is lost. Symptoms may include cold, clammy skin, paleness, rapid breathing and heart rate, weakness, decreased or absent urine output, sweating, anxiety, confusion, and unconsciousness. Hypovolemic shock is a medical emergency requiring immediate intervention. Treatment of hypovolemia depends upon its severity. When severe, intravenous fluids and possibly blood transfusions may be necessary to rapidly raise blood volume. Medications may be used to increase blood pressure and stabilize heart rate and strength of heart contractions. Any underlying cause of hypovolemia, such as injury, must also be treated to prevent ongoing fluid losses. In some circumstances, body fluid loss, such as that caused by vomiting and diarrhea, can be reversed with increased fluid consumption and hypovolemia averted. In other cases, however, blood or fluid losses may be severe enough to warrant medical intervention. Hypovolemic shock is a medical emergency. Seek immediate medical care (call 911) for serious symptoms, such as dry mucous membranes, loss of skin elasticity, cold and clammy skin, pale skin or pallor, rapid breathing and heart rate, weakness, decreased or absent urine output, sweating, confusion, or unconsciousness.