Symptoms of Low Blood Volume

Fact Checked

iLow blood volume can lead to Confusion Because the Brain is not Recieving Enough Blood to Properly Function;

Low blood volume (hypovolemia) is the condition of having dangerously low amounts of circulating blood within the body. Low blood volume can be caused by an injury to the body or a medical condition that results in hemorrhaging or internal bleeding. This condition can be very dangerous for a person and can cause a host of symptoms and medical conditions. It can even lead to hypovolemic shock and death.


The Mayo Clinic reports that a normal heart beats 60 to 100 times per minute. Tachycardia occurs when the heart beats too fast and this beating can be raised significantly above the normal level. This can be very uncomfortable for the sufferer and in some situations tachycardia can be life-threatening. Low blood volume leads to tachycardia because the heart is trying to overcompensate for the lack of blood volume in the body. It causes the heart to overwork, beating quicker and quicker to try to keep enough blood going to extremities (such as feet, legs, arms and hands) and to the brain.


Dizziness is another symptom of low blood volume. It can be caused when the brain is not receiving the blood supply and oxygen that it needs to fully function. Some people having this symptom report having a hazy and light-headed feeling. A person with this symptom may feel the need to lie or sit down. If the condition worsens, fainting could follow. According to the National Library of Medicine, fainting is a common sign that is seen in the elderly who attempt to rise to their feet suddenly.


Confusion can occur in more severe cases of low blood volume. When there is not enough blood flowing to the brain the person is not able to think clearly. As a result she will make poor decisions; others may even notice that she is exhibiting odd behaviors. If the low blood volume worsens then the confusion can become increasingly severe and even result in unconsciousness.


Fatigue is a common symptom of a person that suffers from low blood volume. The fatigue is caused by the lack of blood and oxygen that is being pumped throughout the body. If there is not enough oxygen supplied to the brain, heart or lungs then the body begins to compensate for this loss by causing fatigue. Fatigue forces the person to rest and thus reserve energy for vital functions.

Decreased Urine Output

Decreased urine output is defined as producing less than 500 milliliters of urine in a 24-hour period. Decreased urine output is a result when there is not enough blood to properly run the kidneys and bladder. This can cause a buildup of toxins in the body because the body is not able to flush them out. This is a very serious medical condition and can lead to a need for dialysis if it is not corrected.